1
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Digles D, Ingles-Prieto A, Dvorak V, Mocking TAM, Goldmann U, Garofoli A, Homan EJ, Di Silvio A, Azzollini L, Sassone F, Fogazza M, Bärenz F, Pommereau A, Zuschlag Y, Ooms JF, Tranberg-Jensen J, Hansen JS, Stanka J, Sijben HJ, Batoulis H, Bender E, Martini R, IJzerman AP, Sauer DB, Heitman LH, Manolova V, Reinhardt J, Ehrmann A, Leippe P, Ecker GF, Huber KVM, Licher T, Scarabottolo L, Wiedmer T, Superti-Furga G. Advancing drug discovery through assay development: a survey of tool compounds within the human solute carrier superfamily. Front Pharmacol 2024; 15:1401599. [PMID: 39050757 PMCID: PMC11267547 DOI: 10.3389/fphar.2024.1401599] [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: 03/15/2024] [Accepted: 05/31/2024] [Indexed: 07/27/2024] Open
Abstract
With over 450 genes, solute carriers (SLCs) constitute the largest transporter superfamily responsible for the uptake and efflux of nutrients, metabolites, and xenobiotics in human cells. SLCs are associated with a wide variety of human diseases, including cancer, diabetes, and metabolic and neurological disorders. They represent an important therapeutic target class that remains only partly exploited as therapeutics that target SLCs are scarce. Additionally, many small molecules reported in the literature to target SLCs are poorly characterized. Both features may be due to the difficulty of developing SLC transport assays that fulfill the quality criteria for high-throughput screening. Here, we report one of the main limitations hampering assay development within the RESOLUTE consortium: the lack of a resource providing high-quality information on SLC tool compounds. To address this, we provide a systematic annotation of tool compounds targeting SLCs. We first provide an overview on RESOLUTE assays. Next, we present a list of SLC-targeting compounds collected from the literature and public databases; we found that most data sources lacked specificity data. Finally, we report on experimental tests of 19 selected compounds against a panel of 13 SLCs from seven different families. Except for a few inhibitors, which were active on unrelated SLCs, the tested inhibitors demonstrated high selectivity for their reported targets. To make this knowledge easily accessible to the scientific community, we created an interactive dashboard displaying the collected data in the RESOLUTE web portal (https://re-solute.eu). We anticipate that our open-access resources on assays and compounds will support the development of future drug discovery campaigns for SLCs.
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Affiliation(s)
- Daniela Digles
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Alvaro Ingles-Prieto
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Vojtech Dvorak
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Tamara A. M. Mocking
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Ulrich Goldmann
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Andrea Garofoli
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Evert J. Homan
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | | | - Felix Bärenz
- Sanofi, Integrated Drug Discovery, Industriepark Hoechst, Frankfurt am Main, Hessen, Germany
| | - Antje Pommereau
- Sanofi, Integrated Drug Discovery, Industriepark Hoechst, Frankfurt am Main, Hessen, Germany
| | - Yasmin Zuschlag
- Sanofi, Integrated Drug Discovery, Industriepark Hoechst, Frankfurt am Main, Hessen, Germany
| | - Jasper F. Ooms
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Jeppe Tranberg-Jensen
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jesper S. Hansen
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Josefina Stanka
- Lead Identification and Characterization, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Hubert J. Sijben
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Helena Batoulis
- Lead Identification and Characterization, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Eckhard Bender
- Lead Identification and Characterization, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Riccardo Martini
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Adriaan P. IJzerman
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - David B. Sauer
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Laura H. Heitman
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | | | | | - Alexander Ehrmann
- Lead Identification and Characterization, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Philipp Leippe
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Gerhard F. Ecker
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Kilian V. M. Huber
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas Licher
- Sanofi, Integrated Drug Discovery, Industriepark Hoechst, Frankfurt am Main, Hessen, Germany
| | | | - Tabea Wiedmer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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2
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Sijben HJ, Dall’ Acqua L, Liu R, Jarret A, Christodoulaki E, Onstein S, Wolf G, Verburgt SJ, Le Dévédec SE, Wiedmer T, Superti-Furga G, IJzerman AP, Heitman LH. Impedance-Based Phenotypic Readout of Transporter Function: A Case for Glutamate Transporters. Front Pharmacol 2022; 13:872335. [PMID: 35677430 PMCID: PMC9169222 DOI: 10.3389/fphar.2022.872335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/29/2022] [Indexed: 11/18/2022] Open
Abstract
Excitatory amino acid transporters (EAAT/SLC1) mediate Na+-dependent uptake of extracellular glutamate and are potential drug targets for neurological disorders. Conventional methods to assess glutamate transport in vitro are based on radiolabels, fluorescent dyes or electrophysiology, which potentially compromise the cell’s physiology and are generally less suited for primary drug screens. Here, we describe a novel label-free method to assess human EAAT function in living cells, i.e., without the use of chemical modifications to the substrate or cellular environment. In adherent HEK293 cells overexpressing EAAT1, stimulation with glutamate or aspartate induced cell spreading, which was detected in real-time using an impedance-based biosensor. This change in cell morphology was prevented in the presence of the Na+/K+-ATPase inhibitor ouabain and EAAT inhibitors, which suggests the substrate-induced response was ion-dependent and transporter-specific. A mechanistic explanation for the phenotypic response was substantiated by actin cytoskeleton remodeling and changes in the intracellular levels of the osmolyte taurine, which suggests that the response involves cell swelling. In addition, substrate-induced cellular responses were observed for cells expressing other EAAT subtypes, as well as in a breast cancer cell line (MDA-MB-468) with endogenous EAAT1 expression. These findings allowed the development of a label-free high-throughput screening assay, which could be beneficial in early drug discovery for EAATs and holds potential for the study of other transport proteins that modulate cell shape.
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Affiliation(s)
- Hubert J. Sijben
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Laura Dall’ Acqua
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Rongfang Liu
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Abigail Jarret
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Medical University of Vienna, Vienna, Austria
| | - Eirini Christodoulaki
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Medical University of Vienna, Vienna, Austria
| | - Svenja Onstein
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Medical University of Vienna, Vienna, Austria
| | - Gernot Wolf
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Medical University of Vienna, Vienna, Austria
| | - Simone J. Verburgt
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Sylvia E. Le Dévédec
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Tabea Wiedmer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Medical University of Vienna, Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Medical University of Vienna, Vienna, Austria
| | - Adriaan P. IJzerman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Laura H. Heitman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
- Oncode Institute, Leiden, Netherlands
- *Correspondence: Laura H. Heitman,
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3
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Poulie CBM, Larsen Y, Leteneur C, Barthet G, Bjørn-Yoshimoto WE, Malhaire F, Nielsen B, Pin JP, Mulle C, Pickering DS, Bunch L. ( S)-2-Mercaptohistidine: A First Selective Orthosteric GluK3 Antagonist. ACS Chem Neurosci 2022; 13:1580-1587. [PMID: 35475632 DOI: 10.1021/acschemneuro.2c00162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The development of tool compounds for the ionotropic glutamate receptors (iGluRs) remains an important research objective, as these are essential for the study and understanding of the roles of these receptors in health and disease. Herein, we report on the pharmacological characterization of (S)-2-hydroxyhistidine (2a) and (S)-2-mercaptohistidine (2b) as mediators of glutamatergic neurotransmission. While 2a displayed negligible binding affinity or activity at all glutamate receptors and transporters investigated, 2b displayed selectivity for homomeric GluK3 with binding affinities in the low micromolar range (Ki = 6.42 ± 0.74 μM). The iGluR subtype selectivity ratio for 2b was calculated at ∼30-fold for GluK1/GluK3, GluA3/GluK3, and GluA4/GluK3 and >100-fold for GluK2/GluK3, GluA1/GluK3, and GluA2/GluK3. Unexpectedly, functional characterization of 2b revealed that the compound is an antagonist (Kb = 7.6 μM) at homomeric GluK3 receptors while exhibiting only weak agonist activity at GluA2 (EC50 = 3.25 ± 0.55 mM). The functional properties of 2b were explored further in electrophysiological recordings of mouse hippocampal neurons.
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Affiliation(s)
- Christian B. M. Poulie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Younes Larsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Cindie Leteneur
- Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Université de Bordeaux, CNRS, F-33000 Bordeaux, France
| | - Gaël Barthet
- Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Université de Bordeaux, CNRS, F-33000 Bordeaux, France
| | - Walden E. Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Fanny Malhaire
- IGF, INSERM, Université de Montpellier, CNRS, F-34094 Montpellier, France
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jean-Phillippe Pin
- IGF, INSERM, Université de Montpellier, CNRS, F-34094 Montpellier, France
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Université de Bordeaux, CNRS, F-33000 Bordeaux, France
| | - Darryl S. Pickering
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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4
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Madjroh N, Mellou E, Davies PA, Söderhielm PC, Jensen AA. Discovery and functional characterization of N-(thiazol-2-yl)-benzamide analogs as the first class of selective antagonists of the Zinc-Activated Channel (ZAC). Biochem Pharmacol 2021; 193:114782. [PMID: 34560054 PMCID: PMC9979163 DOI: 10.1016/j.bcp.2021.114782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 10/20/2022]
Abstract
The Zinc-Activated Channel (ZAC) is an atypical member of the Cys-loop receptor (CLR) superfamily of pentameric ligand-gated ion channels, with its very different endogenous agonists and signalling properties. In this study, a compound library screening at ZAC resulted in the identification of 2-(5-bromo-2-chlorobenzamido)-4-methylthiazole-5-methyl ester (1) as a novel ZAC antagonist. The structural determinants for ZAC activity in 1 were investigated by functional characterization of 61 analogs at ZAC expressed in Xenopus oocytes by two-electrode voltage clamp electrophysiology, and couple of analogs exerting more potent ZAC inhibition than 1 were identified (IC50 values: 1-3 μM). 1 and N-(4-(tert-butyl)thiazol-2-yl)-3-fluorobenzamide (5a, TTFB) were next applied in studies of the functional properties and the mode of action of this novel class of ZAC antagonists. TTFB was a roughly equipotent antagonist of Zn+- and H+-evoked ZAC signaling and of spontaneous ZAC activity, and the slow on-set of its channel block suggested that its ZAC inhibition is state-dependent. TTFB was found to be a selective ZAC antagonist, exhibiting no significant agonist, antagonist or modulatory activity at 5-HT3A, α3β4 nicotinic acetylcholine, α1β2γ2S GABAA or α1 glycine receptors at 30 μM. 1 displayed largely non-competitive antagonism of Zn2+-induced ZAC signalling, and TTFB was demonstrated to target the transmembrane and/or intracellular domains of the receptor, which collectively suggests that the N-(thiazol-2-yl)-benzamide analog acts a negative allosteric modulator of ZAC. We propose that this first class of selective ZAC antagonists could constitute useful pharmacological tools in future explorations of the presently poorly elucidated physiological functions governed by this CLR.
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Affiliation(s)
- Nawid Madjroh
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Eleni Mellou
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Paul A. Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Pella C. Söderhielm
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark,Corresponding author. (A.A. Jensen)
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5
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Dvorak V, Wiedmer T, Ingles-Prieto A, Altermatt P, Batoulis H, Bärenz F, Bender E, Digles D, Dürrenberger F, Heitman LH, IJzerman AP, Kell DB, Kickinger S, Körzö D, Leippe P, Licher T, Manolova V, Rizzetto R, Sassone F, Scarabottolo L, Schlessinger A, Schneider V, Sijben HJ, Steck AL, Sundström H, Tremolada S, Wilhelm M, Wright Muelas M, Zindel D, Steppan CM, Superti-Furga G. An Overview of Cell-Based Assay Platforms for the Solute Carrier Family of Transporters. Front Pharmacol 2021; 12:722889. [PMID: 34447313 PMCID: PMC8383457 DOI: 10.3389/fphar.2021.722889] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/19/2021] [Indexed: 12/12/2022] Open
Abstract
The solute carrier (SLC) superfamily represents the biggest family of transporters with important roles in health and disease. Despite being attractive and druggable targets, the majority of SLCs remains understudied. One major hurdle in research on SLCs is the lack of tools, such as cell-based assays to investigate their biological role and for drug discovery. Another challenge is the disperse and anecdotal information on assay strategies that are suitable for SLCs. This review provides a comprehensive overview of state-of-the-art cellular assay technologies for SLC research and discusses relevant SLC characteristics enabling the choice of an optimal assay technology. The Innovative Medicines Initiative consortium RESOLUTE intends to accelerate research on SLCs by providing the scientific community with high-quality reagents, assay technologies and data sets, and to ultimately unlock SLCs for drug discovery.
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Affiliation(s)
- Vojtech Dvorak
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Tabea Wiedmer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Alvaro Ingles-Prieto
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | | | - Helena Batoulis
- Drug Discovery Sciences–Lead Discovery, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Felix Bärenz
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Eckhard Bender
- Drug Discovery Sciences–Lead Discovery, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Daniela Digles
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | | | - Laura H. Heitman
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Adriaan P. IJzerman
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Stefanie Kickinger
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Daniel Körzö
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Philipp Leippe
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Thomas Licher
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | | | | | | | | | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Vanessa Schneider
- Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Hubert J. Sijben
- Division of Drug Discovery and Safety, LACDR, Leiden University, Leiden, Netherlands
| | | | | | | | | | - Marina Wright Muelas
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Diana Zindel
- Drug Discovery Sciences–Lead Discovery, Bayer Pharmaceuticals, Wuppertal, Germany
| | - Claire M. Steppan
- Pfizer Worldwide Research, Development and Medical, Groton, MA, United States
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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6
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Todd AC, Hardingham GE. The Regulation of Astrocytic Glutamate Transporters in Health and Neurodegenerative Diseases. Int J Mol Sci 2020; 21:E9607. [PMID: 33348528 PMCID: PMC7766851 DOI: 10.3390/ijms21249607] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022] Open
Abstract
The astrocytic glutamate transporters excitatory amino acid transporters 1 and 2 (EAAT1 and EAAT2) play a key role in nervous system function to maintain extracellular glutamate levels at low levels. In physiology, this is essential for the rapid uptake of synaptically released glutamate, maintaining the temporal fidelity of synaptic transmission. However, EAAT1/2 hypo-expression or hypo-function are implicated in several disorders, including epilepsy and neurodegenerative diseases, as well as being observed naturally with aging. This not only disrupts synaptic information transmission, but in extremis leads to extracellular glutamate accumulation and excitotoxicity. A key facet of EAAT1/2 expression in astrocytes is a requirement for signals from other brain cell types in order to maintain their expression. Recent evidence has shown a prominent role for contact-dependent neuron-to-astrocyte and/or endothelial cell-to-astrocyte Notch signalling for inducing and maintaining the expression of these astrocytic glutamate transporters. The relevance of this non-cell-autonomous dependence to age- and neurodegenerative disease-associated decline in astrocytic EAAT expression is discussed, plus the implications for disease progression and putative therapeutic strategies.
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Affiliation(s)
- Alison C. Todd
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Giles E. Hardingham
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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7
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Liu N, Jensen AA, Bunch L. β-Indolyloxy Functionalized Aspartate Analogs as Inhibitors of the Excitatory Amino Acid Transporters (EAATs). ACS Med Chem Lett 2020; 11:2212-2220. [PMID: 33214831 DOI: 10.1021/acsmedchemlett.0c00342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/26/2020] [Indexed: 11/28/2022] Open
Abstract
The excitatory amino acid transporters (EAATs) mediate uptake of the major excitatory neurotransmitter l-glutamate (Glu). The essential functions governed by these transporters in regulating the central Glu level make them interesting therapeutic targets in a wide range of neurodegenerative and psychiatric disorders. l-Aspartate (Asp), another EAAT substrate, has served as a privileged scaffold for the development of EAAT inhibitors. In this study, we designed and synthesized the first β-indolyloxy Asp analogs 15a-d with the aim to probe a hitherto unexplored adjacent pocket to the substrate binding site. The pharmacological properties of 15a-d were characterized at hEAAT1-3 and rEAAT4 in a conventional [3H]-d-Asp uptake assay. Notably, thiophene analog 15b and the para-trifluoromethyl phenyl analog 15d were found to be hEAAT1,2-preferring inhibitors exhibiting IC50 values in the high nanomolar range (0.21-0.71 μM) at these two transporters versus IC50 values in the low micromolar range at EAAT3,4 (1.6-8.9 μM). In summary, the results presented herein open up for further structure-activity relationship studies of this new scaffold.
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Affiliation(s)
- Na Liu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
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8
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Exploring the molecular determinants for subtype-selectivity of 2-amino-1,4,5,6-tetrahydropyrimidine-5-carboxylic acid analogs as betaine/GABA transporter 1 (BGT1) substrate-inhibitors. Sci Rep 2020; 10:12992. [PMID: 32747622 PMCID: PMC7400577 DOI: 10.1038/s41598-020-69908-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/17/2020] [Indexed: 12/13/2022] Open
Abstract
We have previously identified 2-amino-1,4,5,6-tetrahydropyrimidine-5-carboxylic acid (ATPCA) as the most potent substrate-inhibitor of the betaine/GABA transporter 1 (BGT1) (IC50 2.5 µM) reported to date. Herein, we characterize the binding mode of 20 novel analogs and propose the molecular determinants driving BGT1-selectivity. A series of N1-, exocyclic-N-, and C4-substituted analogs was synthesized and pharmacologically characterized in radioligand-based uptake assays at the four human GABA transporters (hGATs) recombinantly expressed in mammalian cells. Overall, the analogs retained subtype-selectivity for hBGT1, though with lower inhibitory activities (mid to high micromolar IC50 values) compared to ATPCA. Further characterization of five of these BGT1-active analogs in a fluorescence-based FMP assay revealed that the compounds are substrates for hBGT1, suggesting they interact with the orthosteric site of the transporter. In silico-guided mutagenesis experiments showed that the non-conserved residues Q299 and E52 in hBGT1 as well as the conformational flexibility of the compounds potentially contribute to the subtype-selectivity of ATPCA and its analogs. Overall, this study provides new insights into the molecular interactions governing the subtype-selectivity of BGT1 substrate-inhibitors. The findings may guide the rational design of BGT1-selective pharmacological tool compounds for future drug discovery.
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9
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Wu P, Bjørn-Yoshimoto WE, Staudt M, Jensen AA, Bunch L. Identification and Structure-Activity Relationship Study of Imidazo[1,2- a]pyridine-3-amines as First Selective Inhibitors of Excitatory Amino Acid Transporter Subtype 3 (EAAT3). ACS Chem Neurosci 2019; 10:4414-4429. [PMID: 31573179 DOI: 10.1021/acschemneuro.9b00447] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In the present study, screening of a library of 49,087 compounds at the excitatory amino acid transporter subtype 3 (EAAT3) led to the identification of 2-(furan-2-yl)-8-methyl-N-(o-tolyl)imidazo[1,2-a]pyridin-3-amine (3a) which showed a >20-fold preference for inhibition of EAAT3 (IC50 = 13 μM) over EAAT1,2,4 (EAAT1: IC50 ∼ 250 μM; EAAT2,4: IC50 > 250 μM). It was shown that a small lipophilic substituent (methyl or bromine) at the 7- and/or 8-position was essential for activity. Furthermore, the substitution pattern of the o-tolyl group (compound 5b) and the chemical nature of the substituent in the 2-position (compound 7b) were shown to be essential for the selectivity toward EAAT3 over EAAT1,2. The most prominent analogues to come out of this study are 3a and 3e that display ∼35-fold selectivity for EAAT3 (IC50 = 7.2 μM) over EAAT1,2,4 (IC50 ∼ 250 μM).
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Affiliation(s)
- Peng Wu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Walden E. Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Markus Staudt
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
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10
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Poulie CBM, Alcaide A, Krell-Jørgensen M, Larsen Y, Astier E, Bjørn-Yoshimoto WE, Yi F, Syrenne JT, Storgaard M, Nielsen B, Frydenvang KA, Jensen AA, Hansen KB, Pickering DS, Bunch L. Design and Synthesis of 2,3- trans-Proline Analogues as Ligands for Ionotropic Glutamate Receptors and Excitatory Amino Acid Transporters. ACS Chem Neurosci 2019; 10:2989-3007. [PMID: 31124660 DOI: 10.1021/acschemneuro.9b00205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Development of pharmacological tools for the ionotropic glutamate receptors (iGluRs) is imperative for the study and understanding of the role and function of these receptors in the central nervous system. We report the synthesis of 18 analogues of (2 S,3 R)-2-carboxy-3-pyrrolidine acetic acid (3a), which explores the effect of introducing a substituent on the ε-carbon (3c-q). A new synthetic method was developed for the efficient synthesis of racemic 3a and applied to give expedited access to 13 racemic analogues of 3a. Pharmacological characterization was carried out at native iGluRs, cloned homomeric kainate receptors (GluK1-3), NMDA receptors (GluN1/GluN2A-D), and excitatory amino acid transporters (EAAT1-3). From the structure-activity relationship studies, several new ligands emerged, exemplified by triazole 3p-d1, GluK3-preferring (GluK1/GluK3 Ki ratio of 15), and the structurally closely related tetrazole 3q-s3-4 that displayed 4.4-100-fold preference as an antagonist for the GluN1/GluN2A receptor ( Ki = 0.61 μM) over GluN1/GluN2B-D ( Ki = 2.7-62 μM).
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Affiliation(s)
- Christian B. M. Poulie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Anna Alcaide
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Mikkel Krell-Jørgensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Younes Larsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Eloi Astier
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Walden E. Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Feng Yi
- Department of Biomedical and Pharmaceutical Sciences, Center for Structural and Functional Neuroscience, and Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
| | - Jed T. Syrenne
- Department of Biomedical and Pharmaceutical Sciences, Center for Structural and Functional Neuroscience, and Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
| | - Morten Storgaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Karla A. Frydenvang
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Kasper B. Hansen
- Department of Biomedical and Pharmaceutical Sciences, Center for Structural and Functional Neuroscience, and Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
| | - Darryl S. Pickering
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
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11
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Kickinger S, Hellsberg E, Frølund B, Schousboe A, Ecker GF, Wellendorph P. Structural and molecular aspects of betaine-GABA transporter 1 (BGT1) and its relation to brain function. Neuropharmacology 2019; 161:107644. [PMID: 31108110 DOI: 10.1016/j.neuropharm.2019.05.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/14/2019] [Accepted: 05/16/2019] [Indexed: 01/09/2023]
Abstract
ɣ-aminobutyric-acid (GABA) functions as the principal inhibitory neurotransmitter in the central nervous system. Imbalances in GABAergic neurotransmission are involved in the pathophysiology of various neurological diseases such as epilepsy, Alzheimer's disease and stroke. GABA transporters (GATs) facilitate the termination of GABAergic signaling by transporting GABA together with sodium and chloride from the synaptic cleft into presynaptic neurons and surrounding glial cells. Four different GATs have been identified that all belong to the solute carrier 6 (SLC6) transporter family: GAT1-3 (SLC6A1, SLC6A13, SLC6A11) and betaine/GABA transporter 1 (BGT1, SLC6A12). BGT1 has emerged as an interesting target for treating epilepsy due to animal studies that reported anticonvulsant effects for the GAT1/BGT1 selective inhibitor EF1502 and the BGT1 selective inhibitor RPC-425. However, the precise involvement of BGT1 in epilepsy remains elusive because of its controversial expression levels in the brain and the lack of highly selective and potent tool compounds. This review gathers the current structural and functional knowledge on BGT1 with emphasis on brain relevance, discusses all available compounds, and tries to shed light on the molecular determinants driving BGT1 selectivity. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Stefanie Kickinger
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Eva Hellsberg
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Bente Frølund
- University of Copenhagen, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Arne Schousboe
- University of Copenhagen, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Gerhard F Ecker
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Petrine Wellendorph
- University of Copenhagen, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 2 Universitetsparken, 2100, Copenhagen, Denmark.
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12
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Delgado-Acevedo C, Estay SF, Radke AK, Sengupta A, Escobar AP, Henríquez-Belmar F, Reyes CA, Haro-Acuña V, Utreras E, Sotomayor-Zárate R, Cho A, Wendland JR, Kulkarni AB, Holmes A, Murphy DL, Chávez AE, Moya PR. Behavioral and synaptic alterations relevant to obsessive-compulsive disorder in mice with increased EAAT3 expression. Neuropsychopharmacology 2019; 44:1163-1173. [PMID: 30622300 PMCID: PMC6462043 DOI: 10.1038/s41386-018-0302-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 12/01/2018] [Accepted: 12/15/2018] [Indexed: 12/12/2022]
Abstract
Obsessive-compulsive disorder (OCD) is a severe, chronic neuropsychiatric disorder with a strong genetic component. The SLC1A1 gene encoding the neuronal glutamate transporter EAAT3 has been proposed as a candidate gene for this disorder. Gene variants affecting SLC1A1 expression in human brain tissue have been associated with OCD. Several mouse models fully or partially lacking EAAT3 have shown no alterations in baseline anxiety-like or repetitive behaviors. We generated a transgenic mouse model (EAAT3glo) to achieve conditional, Cre-dependent EAAT3 overexpression and evaluated the overall impact of increased EAAT3 expression at behavioral and synaptic levels. Mice with EAAT3 overexpression driven by CaMKIIα-promoter (EAAT3glo/CMKII) displayed increased anxiety-like and repetitive behaviors that were both restored by chronic, but not acute, treatment with fluoxetine or clomipramine. EAAT3glo/CMKII mice also displayed greater spontaneous recovery of conditioned fear. Electrophysiological and biochemical analyses at corticostriatal synapses of EAAT3glo/CMKII mice revealed changes in NMDA receptor subunit composition and altered NMDA-dependent synaptic plasticity. By recapitulating relevant behavioral, neurophysiological, and psychopharmacological aspects, our results provide support for the glutamatergic hypothesis of OCD, particularly for the increased EAAT3 function, and provide a valuable animal model that may open novel therapeutic approaches to treat this devastating disorder.
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Affiliation(s)
- Claudia Delgado-Acevedo
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencias de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Sebastián F Estay
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencias de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Anna K Radke
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
- Department of Psychology and Center for Neuroscience and Behavior, Miami University, Oxford, OH, USA
| | - Ayesha Sengupta
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
| | - Angélica P Escobar
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencias de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Francisca Henríquez-Belmar
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Cristopher A Reyes
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Valentina Haro-Acuña
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Elías Utreras
- Functional Genomics Section and Gene Transfer Core, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Ramón Sotomayor-Zárate
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Neurobiología y Fisiolopatogía Integrativa, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Andrew Cho
- Functional Genomics Section and Gene Transfer Core, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | - Jens R Wendland
- Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, MD, USA
- Takeda Pharmaceutical Company Limited, 35 Landsdowne Street, Cambridge, MA, 02139, USA
| | - Ashok B Kulkarni
- Functional Genomics Section and Gene Transfer Core, National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
| | - Dennis L Murphy
- Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, MD, USA
| | - Andrés E Chávez
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Centro Interdisciplinario de Neurociencias de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
| | - Pablo R Moya
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Núcleo Milenio NUMIND Biology of Neuropsychiatric Disorders, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Centro Interdisciplinario de Neurociencias de Valparaíso CINV, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
- Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, MD, USA.
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13
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Corbetta C, Di Ianni N, Bruzzone MG, Patanè M, Pollo B, Cantini G, Cominelli M, Zucca I, Pisati F, Poliani PL, Finocchiaro G, Pellegatta S. Altered function of the glutamate–aspartate transporter GLAST, a potential therapeutic target in glioblastoma. Int J Cancer 2019; 144:2539-2554. [DOI: 10.1002/ijc.31985] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 10/17/2018] [Accepted: 10/31/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Cristina Corbetta
- Unit of Molecular Neuro‐OncologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Natalia Di Ianni
- Unit of Molecular Neuro‐OncologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Maria Grazia Bruzzone
- Experimental Imaging and Neuro‐RadiologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Monica Patanè
- Unit of PathologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Bianca Pollo
- Unit of PathologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Gabriele Cantini
- Unit of Molecular Neuro‐OncologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | | | - Ileana Zucca
- Experimental Imaging and Neuro‐RadiologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Federica Pisati
- Unit of Molecular Neuro‐OncologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | | | - Gaetano Finocchiaro
- Unit of Molecular Neuro‐OncologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Serena Pellegatta
- Unit of Molecular Neuro‐OncologyFondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
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14
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Fu H, Zhang J, Tepper PG, Bunch L, Jensen AA, Poelarends GJ. Chemoenzymatic Synthesis and Pharmacological Characterization of Functionalized Aspartate Analogues As Novel Excitatory Amino Acid Transporter Inhibitors. J Med Chem 2018; 61:7741-7753. [PMID: 30011368 PMCID: PMC6139576 DOI: 10.1021/acs.jmedchem.8b00700] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Aspartate (Asp) derivatives are privileged
compounds for investigating
the roles governed by excitatory amino acid transporters (EAATs) in
glutamatergic neurotransmission. Here, we report the synthesis of
various Asp derivatives with (cyclo)alkyloxy and (hetero)aryloxy substituents
at C-3. Their pharmacological properties were characterized at the
EAAT1–4 subtypes. The l-threo-3-substituted
Asp derivatives 13a–e and 13g–k were nonsubstrate inhibitors, exhibiting pan
activity at EAAT1–4 with IC50 values ranging from
0.49 to 15 μM. Comparisons between (dl-threo)-19a–c and (dl-erythro)-19a–c Asp analogues
confirmed that the threo configuration is crucial
for the EAAT1–4 inhibitory activities. Analogues (3b–e) of l-TFB-TBOA (3a)
were shown to be potent EAAT1–4 inhibitors, with IC50 values ranging from 5 to 530 nM. Hybridization of the nonselective
EAAT inhibitor l-TBOA with EAAT2-selective inhibitor WAY-213613
or EAAT3-preferring inhibitor NBI-59159 yielded compounds 8 and 9, respectively, which were nonselective EAAT inhibitors
displaying considerably lower IC50 values at EAAT1–4
(11–140 nM) than those displayed by the respective parent molecules.
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Affiliation(s)
- Haigen Fu
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy , University of Groningen , Antonius Deusinglaan 1 , 9713 AV Groningen , The Netherlands
| | - Jielin Zhang
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy , University of Groningen , Antonius Deusinglaan 1 , 9713 AV Groningen , The Netherlands
| | - Pieter G Tepper
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy , University of Groningen , Antonius Deusinglaan 1 , 9713 AV Groningen , The Netherlands
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , DK-2100 Copenhagen OE , Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , DK-2100 Copenhagen OE , Denmark
| | - Gerrit J Poelarends
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy , University of Groningen , Antonius Deusinglaan 1 , 9713 AV Groningen , The Netherlands
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15
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Helms HC, Aldana BI, Groth S, Jensen MM, Waagepetersen HS, Nielsen CU, Brodin B. Characterization of the L-glutamate clearance pathways across the blood-brain barrier and the effect of astrocytes in an in vitro blood-brain barrier model. J Cereb Blood Flow Metab 2017; 37:3744-3758. [PMID: 28145808 PMCID: PMC5718321 DOI: 10.1177/0271678x17690760] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim was to characterize the clearance pathways for L-glutamate from the brain interstitial fluid across the blood-brain barrier using a primary in vitro bovine endothelial/rat astrocyte co-culture. Transporter profiling was performed using uptake studies of radiolabeled L-glutamate with co-application of transporter inhibitors and competing amino acids. Endothelial abluminal L-glutamate uptake was almost abolished by co-application of an EAAT-1 specific inhibitor, whereas luminal uptake was inhibited by L-glutamate and L-aspartate (1 mM). L-glutamate uptake followed Michaelis-Menten-like kinetics with high and low affinity at the abluminal and luminal membrane, respectively. This indicated that L-glutamate is taken up via EAAT-1 at the abluminal membrane and exits at the luminal membrane via a low affinity glutamate/aspartate transporter. Metabolism of L-glutamate and transport of metabolites was examined using [U-13C] L-glutamate. Intact L-glutamate and metabolites derived from oxidative metabolism were transported through the endothelial cells. High amounts of L-glutamate-derived lactate in the luminal medium indicated cataplerosis via malic enzyme. Thus, L-glutamate can be transported intact from brain to blood via the concerted action of abluminal and luminal transport proteins, but the total brain clearance is highly dependent on metabolism in astrocytes and endothelial cells followed by transport of metabolites.
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Affiliation(s)
- Hans Cc Helms
- 1 Department of Pharmacy, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- 2 Department of Drug Design and Pharmacology, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simon Groth
- 1 Department of Pharmacy, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten M Jensen
- 1 Department of Pharmacy, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- 2 Department of Drug Design and Pharmacology, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Carsten U Nielsen
- 1 Department of Pharmacy, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,3 Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark
| | - Birger Brodin
- 1 Department of Pharmacy, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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16
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Krogsgaard-Larsen N, Delgar CG, Koch K, Brown PMGE, Møller C, Han L, Huynh THV, Hansen SW, Nielsen B, Bowie D, Pickering DS, Kastrup JS, Frydenvang K, Bunch L. Design and Synthesis of a Series of l-trans-4-Substituted Prolines as Selective Antagonists for the Ionotropic Glutamate Receptors Including Functional and X-ray Crystallographic Studies of New Subtype Selective Kainic Acid Receptor Subtype 1 (GluK1) Antagonist (2S,4R)-4-(2-Carboxyphenoxy)pyrrolidine-2-carboxylic Acid. J Med Chem 2016; 60:441-457. [PMID: 28005385 DOI: 10.1021/acs.jmedchem.6b01516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ionotropic glutamate receptor antagonists are valuable tool compounds for studies of neurological pathways in the central nervous system. On the basis of rational ligand design, a new class of selective antagonists, represented by (2S,4R)-4-(2-carboxyphenoxy)pyrrolidine-2-carboxylic acid (1b), for cloned homomeric kainic acid receptors subtype 1 (GluK1) was attained (Ki = 4 μM). In a functional assay, 1b displayed full antagonist activity with IC50 = 6 ± 2 μM. A crystal structure was obtained of 1b when bound in the ligand binding domain of GluK1. A domain opening of 13-14° was seen compared to the structure with glutamate, consistent with 1b being an antagonist. A structure-activity relationship study showed that the chemical nature of the tethering atom (C, O, or S) linking the pyrrolidine ring and the phenyl ring plays a key role in the receptor selectivity profile and that substituents on the phenyl ring are well accommodated by the GluK1 receptor.
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Affiliation(s)
| | | | | | - Patricia M G E Brown
- Bowie Lab, Department of Pharmacology & Therapeutics, Faculty of Medicine, McGill University , Montreal, Quebec H3G 0B1, Canada
| | | | | | | | | | | | - Derek Bowie
- Bowie Lab, Department of Pharmacology & Therapeutics, Faculty of Medicine, McGill University , Montreal, Quebec H3G 0B1, Canada
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17
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γ-Glutamyl-dipeptides: Easy tools to rapidly probe the stereoelectronic properties of the ionotropic glutamate receptor binding pocket. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.11.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Rives ML, Shaw M, Zhu B, Hinke SA, Wickenden AD. State-Dependent Allosteric Inhibition of the Human SLC13A5 Citrate Transporter by Hydroxysuccinic Acids, PF-06649298 and PF-06761281. Mol Pharmacol 2016; 90:766-774. [PMID: 27754898 DOI: 10.1124/mol.116.106575] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/13/2016] [Indexed: 01/16/2023] Open
Abstract
In the liver, citrate is a key metabolic intermediate involved in the regulation of glycolysis and lipid synthesis and reduced expression of the hepatic citrate SLC13A5 transporter has been shown to improve metabolic outcomes in various animal models. Although inhibition of hepatic extracellular citrate uptake through SLC13A5 has been suggested as a potential therapeutic approach for Type-2 diabetes and/or fatty liver disease, so far, only a few SLC13A5 inhibitors have been identified. Moreover, their mechanism of action still remains unclear, potentially limiting their utility for in vivo proof-of-concept studies. In this study, we characterized the pharmacology of the recently identified hydroxysuccinic acid SLC13A5 inhibitors, PF-06649298 and PF-06761281, using a combination of 14C-citrate uptake, a membrane potential assay and electrophysiology. In contrast to their previously proposed mechanism of action, our data suggest that both PF-06649298 and PF-06761281 are allosteric, state-dependent SLC13A5 inhibitors, with low-affinity substrate activity in the absence of citrate. As allosteric state-dependent modulators, the inhibitory potency of both compounds is highly dependent on the ambient citrate concentration and our detailed mechanism of action studies therefore, may be of value in interpreting the in vivo effects of these compounds.
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Affiliation(s)
- Marie-Laure Rives
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Morena Shaw
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Bin Zhu
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Simon A Hinke
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Alan D Wickenden
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
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19
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Hansen JC, Bjørn-Yoshimoto WE, Bisballe N, Nielsen B, Jensen AA, Bunch L. β-Sulfonamido Functionalized Aspartate Analogues as Excitatory Amino Acid Transporter Inhibitors: Distinct Subtype Selectivity Profiles Arising from Subtle Structural Differences. J Med Chem 2016; 59:8771-8786. [PMID: 27636002 DOI: 10.1021/acs.jmedchem.6b01066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this study inspired by previous work on 3-substituted Asp analogues, we designed and synthesized a total of 32 β-sulfonamide Asp analogues and characterized their pharmacological properties at the excitatory amino acid transporter subtypes EAAT1, EAAT2, and EAAT3. In addition to several potent EAAT inhibitors displaying IC50 values ∼1 μM at all three subtypes, this elaborate structure-activity relationship also identified analogues exhibiting distinct preferences or selectivities for specific transporter subtypes. Introduction of two fluorine atoms on the phenyl ring yielded analogue 4y that displayed an IC50 of 0.8 μM at EAAT1 with a 14- and 9-fold preference over EAAT2 and EAAT3, respectively. Conversely, the m-CF3-phenyl analogue 4r was a potent selective EAAT2-inhibitor (IC50 = 2.8 μM) exhibiting 30- and 50-fold selectivity over EAAT1 and EAAT3, respectively. In conclusion, even small structural differences in these β-sulfonamide Asp analogues provide analogues with diverse EAAT subtype selectivity profiles.
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Affiliation(s)
- Jacob C Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Niels Bisballe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
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20
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Hansen SW, Erichsen MN, Fu B, Bjørn-Yoshimoto WE, Abrahamsen B, Hansen JC, Jensen AA, Bunch L. Identification of a New Class of Selective Excitatory Amino Acid Transporter Subtype 1 (EAAT1) Inhibitors Followed by a Structure-Activity Relationship Study. J Med Chem 2016; 59:8757-8770. [PMID: 27626828 DOI: 10.1021/acs.jmedchem.6b01058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Screening of a small compound library at the three excitatory amino acid transporter subtypes 1-3 (EAAT1-3) resulted in the identification of compound (Z)-4-chloro-3-(5-((3-(2-ethoxy-2-oxoethyl)-2,4-dioxothiazolidin-5-ylidene)methyl)furan-2-yl)benzoic acid (1a) that exhibited a distinct preference as an inhibitor at EAAT1 (IC50 20 μM) compared to EAAT2 and EAAT3 (IC50 > 300 μM). This prompted us to subject 1a to an elaborate structure-activity relationship study through the purchase and synthesis and subsequent pharmacological characterization of a total of 36 analogues. Although this effort did not result in analogues with substantially improved inhibitory potencies at EAAT1 compared to that displayed by the hit, it provided a detailed insight into structural requirements for EAAT1 activity of this scaffold. The discovery of this new class of EAAT1-selective inhibitors not only supplements the currently available pharmacological tools in the EAAT field but also substantiates the notion that EAAT ligands not derived from α-amino acids hold considerable potential in terms of subtype-selective modulation of the transporters.
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Affiliation(s)
- Stinne W Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Mette N Erichsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Bingru Fu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Bjarke Abrahamsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Jacob C Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, Copenhagen Ø 2100, Denmark
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21
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Danbolt NC, Furness DN, Zhou Y. Neuronal vs glial glutamate uptake: Resolving the conundrum. Neurochem Int 2016; 98:29-45. [PMID: 27235987 DOI: 10.1016/j.neuint.2016.05.009] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/03/2016] [Accepted: 05/17/2016] [Indexed: 12/30/2022]
Abstract
Neither normal brain function nor the pathological processes involved in neurological diseases can be adequately understood without knowledge of the release, uptake and metabolism of glutamate. The reason for this is that glutamate (a) is the most abundant amino acid in the brain, (b) is at the cross-roads between several metabolic pathways, and (c) serves as the major excitatory neurotransmitter. In fact most brain cells express glutamate receptors and are thereby influenced by extracellular glutamate. In agreement, brain cells have powerful uptake systems that constantly remove glutamate from the extracellular fluid and thereby limit receptor activation. It has been clear since the 1970s that both astrocytes and neurons express glutamate transporters. However the relative contribution of neuronal and glial transporters to the total glutamate uptake activity, however, as well as their functional importance, has been hotly debated ever since. The present short review provides (a) an overview of what we know about neuronal glutamate uptake as well as an historical description of how we got there, and (b) a hypothesis reconciling apparently contradicting observations thereby possibly resolving the paradox.
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Affiliation(s)
- N C Danbolt
- The Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
| | - D N Furness
- School of Life Sciences, Keele University, Keele, Staffs. ST5 5BG, UK
| | - Y Zhou
- The Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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22
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Bjørn-Yoshimoto WE, Underhill SM. The importance of the excitatory amino acid transporter 3 (EAAT3). Neurochem Int 2016; 98:4-18. [PMID: 27233497 DOI: 10.1016/j.neuint.2016.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 05/09/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022]
Abstract
The neuronal excitatory amino acid transporter 3 (EAAT3) is fairly ubiquitously expressed in the brain, though it does not necessarily maintain the same function everywhere. It is important in maintaining low local concentrations of glutamate, where its predominant post-synaptic localization can buffer nearby glutamate receptors and modulate excitatory neurotransmission and synaptic plasticity. It is also the main neuronal cysteine uptake system acting as the rate-limiting factor for the synthesis of glutathione, a potent antioxidant, in EAAT3 expressing neurons, while on GABAergic neurons, it is important in supplying glutamate as a precursor for GABA synthesis. Several diseases implicate EAAT3, and modulation of this transporter could prove a useful therapeutic approach. Regulation of EAAT3 could be targeted at several points for functional modulation, including the level of transcription, trafficking and direct pharmacological modulation, and indeed, compounds and experimental treatments have been identified that regulate EAAT3 function at different stages, which together with observations of EAAT3 regulation in patients is giving us insight into the endogenous function of this transporter, as well as the consequences of altered function. This review summarizes work done on elucidating the role and regulation of EAAT3.
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Affiliation(s)
- Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
| | - Suzanne M Underhill
- National Institute of Mental Health, National Institutes of Health, 35 Convent Drive Room 3A: 210 MSC3742, Bethesda, MD 20892-3742, USA.
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23
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Haym I, Huynh THV, Hansen SW, Pedersen MHF, Ruiz JA, Erichsen MN, Gynther M, Bjørn-Yoshimoto WE, Abrahamsen B, Bastlund JF, Bundgaard C, Eriksen AL, Jensen AA, Bunch L. Bioavailability Studies and in vitro Profiling of the Selective Excitatory Amino Acid Transporter Subtype 1 (EAAT1) Inhibitor UCPH-102. ChemMedChem 2016; 11:403-19. [PMID: 26797816 DOI: 10.1002/cmdc.201500527] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/14/2015] [Indexed: 02/03/2023]
Abstract
Although the selective excitatory amino acid transporter subtype 1 (EAAT1) inhibitor UCPH-101 has become a standard pharmacological tool compound for in vitro and ex vivo studies in the EAAT research field, its inability to penetrate the blood-brain barrier makes it unsuitable for in vivo studies. In the present study, per os (p.o.) administration (40 mg kg(-1) ) of the closely related analogue UCPH-102 in rats yielded respective plasma and brain concentrations of 10.5 and 6.67 μm after 1 h. Three analogue series were designed and synthesized to improve the bioavailability profile of UCPH-102, but none displayed substantially improved properties in this respect. In vitro profiling of UCPH-102 (10 μm) at 51 central nervous system targets in radioligand binding assays strongly suggests that the compound is completely selective for EAAT1. Finally, in a rodent locomotor model, p.o. administration of UCPH-102 (20 mg kg(-1) ) did not induce acute effects or any visible changes in behavior.
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Affiliation(s)
- Isabell Haym
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Tri H V Huynh
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Stinne W Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Martin H F Pedersen
- Technical University of Denmark, Center for Nuclear Technologies, DTU Nutech/Hevesy Laboratory, Frederiksborgvej 399, Building 202, 4000, Roskilde, Denmark
| | - Josep A Ruiz
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Mette N Erichsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Mikko Gynther
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Bjarke Abrahamsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | | | | | - Anette L Eriksen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen Ø, Denmark.
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24
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Hansen SW, Erichsen MN, Huynh THV, Ruiz JA, Haym I, Bjørn-Yoshimoto WE, Abrahamsen B, Hansen J, Storgaard M, Eriksen AL, Jensen AA, Bunch L. New Insight into the Structure-Activity Relationships of the Selective Excitatory Amino Acid Transporter Subtype 1 (EAAT1) Inhibitors UCPH-101 and UCPH-102. ChemMedChem 2016; 11:382-402. [DOI: 10.1002/cmdc.201500525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Stinne W. Hansen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Mette N. Erichsen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Tri H. V. Huynh
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Josep A. Ruiz
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Isabell Haym
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Walden E. Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Bjarke Abrahamsen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Jeanette Hansen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Morten Storgaard
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Anette L. Eriksen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Ø Denmark
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25
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Medrano MC, Mendiguren A, Pineda J. Effect of ceftriaxone and topiramate treatments on naltrexone-precipitated morphine withdrawal and glutamate receptor desensitization in the rat locus coeruleus. Psychopharmacology (Berl) 2015; 232:2795-809. [PMID: 25787747 DOI: 10.1007/s00213-015-3913-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 03/08/2015] [Indexed: 12/22/2022]
Abstract
RATIONALE Morphine withdrawal is associated with a hyperactivity of locus coeruleus (LC) neurons by an elevated glutamate neurotransmission in this nucleus. We postulate that reductions in the amount of glutamate in the LC by enhancing its reuptake or inhibiting its release could attenuate the behavioral and cellular consequences of morphine withdrawal. OBJECTIVES We investigated the effect of chronic treatment with ceftriaxone (CFT), an excitatory amino acid transporter (EAAT2) enhancer, and acute administration of topiramate (TPM), a glutamate release inhibitor, on morphine withdrawal syndrome and withdrawal-induced glutamate receptor (GluR) desensitization in LC neurons from morphine-dependent rats. METHODS Morphine withdrawal behavior was measured after naltrexone administration in rats implanted with a morphine (200 mg kg(-1)) emulsion for 3 days. GluR desensitization in the LC was assessed by performing concentration-effect curves for glutamate by extracellular electrophysiological recordings in vitro. RESULTS Treatments with CFT or TPM reduced, in a dose-related manner, the total behavioral score of naltrexone-precipitated morphine withdrawal. CFT and TPM, at doses that were effective in behavioral tests, also reduced the induction of GluR desensitization normally occurring in LC neurons from morphine-dependent rats. Acute treatment with the specific EAAT2 inhibitor dihydrokainic acid (DHK) prevented the effect of CFT on withdrawal syndrome and GluR desensitization. Perfusion with TPM inhibited KCl-evoked but not glutamate-induced activation of LC neurons in vitro. CONCLUSIONS Our results suggest that a reduction of synaptic concentrations of glutamate by enhancing EAAT2-mediated uptake or inhibiting glutamate release alleviates the behavioral response and the cellular changes in the LC during opiate withdrawal.
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Affiliation(s)
- María Carmen Medrano
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940, Leioa, Bizkaia, Spain
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26
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Wilhelm CJ, Hashimoto JG, Roberts ML, Bloom SH, Andrew MR, Wiren KM. Astrocyte Dysfunction Induced by Alcohol in Females but Not Males. Brain Pathol 2015; 26:433-51. [PMID: 26088166 DOI: 10.1111/bpa.12276] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/10/2015] [Indexed: 01/08/2023] Open
Abstract
Chronic alcohol abuse is associated with brain damage in a sex-specific fashion, but the mechanisms involved are poorly described and remain controversial. Previous results have suggested that astrocyte gene expression is influenced by ethanol intoxication and during abstinence in vivo. Here, bioinformatic analysis of astrocyte-enriched ethanol-regulated genes in vivo revealed ubiquitin pathways as an ethanol target, but with sexually dimorphic cytokine signaling and changes associated with brain aging in females and not males. Consistent with this result, astrocyte activation was observed after exposure in female but not male animals, with reduced S100β levels in the anterior cingulate cortex and increased GFAP(+) cells in the hippocampus. In primary culture, the direct effects of chronic ethanol exposure followed by recovery on sex-specific astrocyte function were examined. Male astrocyte responses were consistent with astrocyte deactivation with reduced GFAP expression during ethanol exposure. In contrast, female astrocytes exhibited increased expression of Tnf, reduced expression of the neuroprotective cytokine Tgfb1, disrupted bioenergetics and reduced excitatory amino acid uptake following exposure or recovery. These results indicate widespread astrocyte dysfunction in ethanol-exposed females and suggest a mechanism that may underlie increased vulnerability to ethanol-induced neurotoxicity in females.
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Affiliation(s)
- Clare J Wilhelm
- VA Portland Health Care System, Portland, OR.,Department of Psychiatry, Oregon Health & Science University, Portland, OR
| | - Joel G Hashimoto
- VA Portland Health Care System, Portland, OR.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | | | | | - Melissa R Andrew
- Cincinnati Center for Growth Disorders, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Kristine M Wiren
- VA Portland Health Care System, Portland, OR.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
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27
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Demmer CS, Møller C, Brown PMGE, Han L, Pickering DS, Nielsen B, Bowie D, Frydenvang K, Kastrup JS, Bunch L. Binding mode of an α-amino acid-linked quinoxaline-2,3-dione analogue at glutamate receptor subtype GluK1. ACS Chem Neurosci 2015; 6:845-54. [PMID: 25856736 DOI: 10.1021/acschemneuro.5b00038] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Two α-amino acid-functionalized quinoxalines, 1a (CNG-10301) and 1b (CNG-10300), of a quinoxaline moiety coupled to an amino acid moiety were designed, synthesized, and characterized pharmacologically. While 1a displayed low affinity at native AMPA, KA, and NMDA receptors, and at homomeric GluK1,3 receptors, the affinity for GluK2 was in the midmicromolar range (Ki = 136 μM), 1b displayed low to midmicromolar range binding affinity at all the iGluRs (Ki = 9-126 μM). In functional experiments (outside-out patches excised from transfected HEK293T cells), 100 μM 1a partially blocked GluK1 (33% peak response), while GluK2 was unaffected (96% peak response). Furthermore, 1a was shown not to be an agonist at GluK1 and GluK2 at 100 μM. On the other hand, 100 μM 1b fully antagonized GluK1 (8% peak response) but only partially blocked GluK2 (33% peak response). An X-ray structure at 2.3 Å resolution of 1b in the GluK1-LBD (ligand-binding domain) disclosed an unexpected binding mode compared to the predictions made during the design phase; the quinoxaline moiety remains to act as an amino acid bioisostere, but the amino acid moiety is oriented into a new area within the GluK1 receptor. The structure of the GluK1-LBD with 1b showed a large variation in domain openings of the three molecules from 25° to 49°, demonstrating that the GluK1-LBD is capable of undergoing major domain movements.
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28
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Pedraz-Cuesta E, Christensen S, Jensen AA, Jensen NF, Bunch L, Romer MU, Brünner N, Stenvang J, Pedersen SF. The glutamate transport inhibitor DL-Threo-β-Benzyloxyaspartic acid (DL-TBOA) differentially affects SN38- and oxaliplatin-induced death of drug-resistant colorectal cancer cells. BMC Cancer 2015; 15:411. [PMID: 25981639 PMCID: PMC4445981 DOI: 10.1186/s12885-015-1405-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/29/2015] [Indexed: 11/10/2022] Open
Abstract
Background Colorectal cancer (CRC) is a leading cause of cancer death globally and new biomarkers and treatments are severely needed. Methods Here, we employed HCT116 and LoVo human CRC cells made resistant to either SN38 or oxaliplatin, to investigate whether altered expression of the high affinity glutamate transporters Solute Carrier (SLC)-1A1 and -1A3 (EAAT3, EAAT1) is associated with the resistant phenotypes. Analyses included real-time quantitative PCR, immunoblotting and immunofluorescence analyses, radioactive tracer flux measurements, and biochemical analyses of cell viability and glutathione content. Results were evaluated using one- and two-way ANOVA and Students two-tailed t-test, as relevant. Results In SN38-resistant HCT116 and LoVo cells, SLC1A1 expression was down-regulated ~60 % and up-regulated ~4-fold, respectively, at both mRNA and protein level, whereas SLC1A3 protein was undetectable. The changes in SLC1A1 expression were accompanied by parallel changes in DL-Threo-β-Benzyloxyaspartic acid (TBOA)-sensitive, UCPH101-insensitive [3H]-D-Aspartate uptake, consistent with increased activity of SLC1A1 (or other family members), yet not of SLC1A3. DL-TBOA co-treatment concentration-dependently augmented loss of cell viability induced by SN38, while strongly counteracting that induced by oxaliplatin, in both HCT116 and LoVo cells. This reflected neither altered expression of the oxaliplatin transporter Cu2+-transporter-1 (CTR1), nor changes in cellular reduced glutathione (GSH), although HCT116 cell resistance per se correlated with increased cellular GSH. DL-TBOA did not significantly alter cellular levels of p21, cleaved PARP-1, or phospho-Retinoblastoma protein, yet altered SLC1A1 subcellular localization, and reduced chemotherapy-induced p53 induction. Conclusions SLC1A1 expression and glutamate transporter activity are altered in SN38-resistant CRC cells. Importantly, the non-selective glutamate transporter inhibitor DL-TBOA reduces chemotherapy-induced p53 induction and augments CRC cell death induced by SN38, while attenuating that induced by oxaliplatin. These findings may point to novel treatment options in treatment-resistant CRC. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1405-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elena Pedraz-Cuesta
- Department of Biology, Faculty of Science, University of Copenhagen, 13, Universitetsparken, DK-2100, Copenhagen, Denmark.
| | - Sandra Christensen
- Department of Biology, Faculty of Science, University of Copenhagen, 13, Universitetsparken, DK-2100, Copenhagen, Denmark.
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 13, Universitetsparken, DK-2100, Copenhagen, Denmark.
| | - Niels Frank Jensen
- Faculty of Health and Medical Sciences, Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 13, Universitetsparken, DK-2100, Copenhagen, Denmark.
| | - Maria Unni Romer
- Faculty of Health and Medical Sciences, Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark. .,Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
| | - Nils Brünner
- Faculty of Health and Medical Sciences, Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Jan Stenvang
- Faculty of Health and Medical Sciences, Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Stine Falsig Pedersen
- Department of Biology, Faculty of Science, University of Copenhagen, 13, Universitetsparken, DK-2100, Copenhagen, Denmark.
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29
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Zhou Y, Danbolt NC. Glutamate as a neurotransmitter in the healthy brain. J Neural Transm (Vienna) 2014; 121:799-817. [PMID: 24578174 PMCID: PMC4133642 DOI: 10.1007/s00702-014-1180-8] [Citation(s) in RCA: 529] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 02/11/2014] [Indexed: 12/13/2022]
Abstract
Glutamate is the most abundant free amino acid in the brain and is at the crossroad between multiple metabolic pathways. Considering this, it was a surprise to discover that glutamate has excitatory effects on nerve cells, and that it can excite cells to their death in a process now referred to as "excitotoxicity". This effect is due to glutamate receptors present on the surface of brain cells. Powerful uptake systems (glutamate transporters) prevent excessive activation of these receptors by continuously removing glutamate from the extracellular fluid in the brain. Further, the blood-brain barrier shields the brain from glutamate in the blood. The highest concentrations of glutamate are found in synaptic vesicles in nerve terminals from where it can be released by exocytosis. In fact, glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. It took, however, a long time to realize that. The present review provides a brief historical description, gives a short overview of glutamate as a transmitter in the healthy brain, and comments on the so-called glutamate-glutamine cycle. The glutamate transporters responsible for the glutamate removal are described in some detail.
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Affiliation(s)
- Y. Zhou
- The Neurotransporter Group, Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Blindern, P.O. Box 1105, 0317 Oslo, Norway
| | - N. C. Danbolt
- The Neurotransporter Group, Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Blindern, P.O. Box 1105, 0317 Oslo, Norway
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30
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Pharmacological identification of a guanidine-containing β-alanine analogue with low micromolar potency and selectivity for the betaine/GABA transporter 1 (BGT1). Neurochem Res 2014; 39:1988-96. [PMID: 24852577 DOI: 10.1007/s11064-014-1336-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/08/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
Abstract
The γ-aminobutyric acid (GABA) transporters (GATs) are key membrane transporter proteins involved in the termination of GABAergic signaling at synapses in the mammalian brain and proposed drug targets in neurological disorders such as epilepsy. To date, four different GAT subtypes have been identified: GAT1, GAT2, GAT3 and the betaine/GABA transporter 1 (BGT1). Owing to the lack of potent and subtype selective inhibitors of the non-GAT1 GABA transporters, the physiological role and therapeutic potential of these transporters remain to be fully understood. Based on bioisosteric replacement of the amino group in β-alanine or GABA, a series of compounds was generated, and their pharmacological activity assessed at human GAT subtypes. Using a cell-based [(3)H]GABA uptake assay, several selective inhibitors at human BGT1 were identified. The guanidine-containing compound 9 (2-amino-1,4,5,6-tetrahydropyrimidine-5-carboxylic acid hydrochloride) displayed more than 250 times greater potency than the parent compound β-alanine at BGT1 and is thus the most potent inhibitor reported to date for this subtype (IC50 value of 2.5 µM). In addition, compound 9 displayed about 400, 16 and 40 times lower inhibitory potency at GAT1, GAT2 and GAT3, respectively. Compound 9 was shown to be a substrate for BGT1 and to have an overall similar pharmacological profile at the mouse orthologue. Compound 9 constitutes an interesting pharmacological tool for specifically investigating the cellular pharmacology of BGT1 and is the first small-molecule substrate identified with such a high selectivity for BGT1 over the three other GAT subtypes.
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31
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Pinto A, Tamborini L, Mastronardi F, Ettari R, Safoz Y, Bunch L, Nielsen B, Jensen AA, De Micheli C, Conti P. Synthesis of (3-hydroxy-pyrazolin-5-yl)glycine based ligands interacting with ionotropic glutamate receptors. Eur J Med Chem 2014; 75:151-8. [PMID: 24531228 DOI: 10.1016/j.ejmech.2014.01.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 11/27/2013] [Accepted: 01/20/2014] [Indexed: 11/18/2022]
Abstract
Following the concept that increasing the molecular complexity may enhance the receptor selectivity, we replaced the 3-hydroxy-isoxazoline ring of model compound tricholomic acid with a 3-hydroxy-pyrazoline ring, which could be variously decorated at the N1 position, inserting groups characterized by different electronic and steric properties. Binding assays on rat brain synaptic membranes showed that, depending on the nature of the substituent, some of the new synthesized ligands interacted with either AMPA or KA receptors, with affinities in the mid-micromolar range.
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Affiliation(s)
- Andrea Pinto
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy.
| | - Lucia Tamborini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy
| | - Federica Mastronardi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy
| | - Roberta Ettari
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy
| | - Yeliz Safoz
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen OE, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen OE, Denmark
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen OE, Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen OE, Denmark
| | - Carlo De Micheli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy
| | - Paola Conti
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Via Mangiagalli 25, 20133 Milano, Italy
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Probing for Improved Potency and In Vivo Bioavailability of Excitatory Amino Acid Transporter Subtype 1 Inhibitors UCPH-101 and UCPH-102: Design, Synthesis and Pharmacological Evaluation of Substituted 7-Biphenyl Analogs. Neurochem Res 2014; 39:1964-79. [DOI: 10.1007/s11064-014-1264-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/19/2014] [Accepted: 02/20/2014] [Indexed: 02/02/2023]
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Medrano MC, Gerrikagoitia I, Martínez-Millán L, Mendiguren A, Pineda J. Functional and morphological characterization of glutamate transporters in the rat locus coeruleus. Br J Pharmacol 2014; 169:1781-94. [PMID: 23638698 DOI: 10.1111/bph.12235] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 04/19/2013] [Accepted: 04/29/2013] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Excitatory amino acid transporters (EAATs) in the CNS contribute to the clearance of glutamate released during neurotransmission. The aim of this study was to explore the role of EAATs in the regulation of locus coeruleus (LC) neurons by glutamate. EXPERIMENTAL APPROACH We measured the effect of different EAAT subtype inhibitors/enhancers on glutamate- and KCl-induced activation of LC neurons in rat slices. EAAT2-3 expression in the LC was also characterized by immunohistochemistry. KEY RESULTS The EAAT2-5 inhibitor DL-threo-β-benzyloxaspartic acid (100 μM), but not the EAAT2, 4, 5 inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (100 μM) or the EAAT2 inhibitor dihydrokainic acid (DHK; 100 μM), enhanced the glutamate- and KCl-induced activation of the firing rate of LC neurons. These effects were blocked by ionotropic, but not metabotrobic, glutamate receptor antagonists. DHK (100 μM) was the only EAAT inhibitor that increased the spontaneous firing rate of LC cells, an effect that was due to inhibition of EAAT2 and subsequent AMPA receptor activation. Chronic treatment with ceftriaxone (200 mg·kg(-1) i.p., once daily, 7 days), an EAAT2 expression enhancer, increased the actions of glutamate and DHK, suggesting a functional impact of EAAT2 up-regulation on the glutamatergic system. Immuhistochemical data revealed the presence of EAAT2 and EAAT3 surrounding noradrenergic neurons and EAAT2 on glial cells in the LC. CONCLUSIONS AND IMPLICATIONS These results remark the importance of EAAT2 and EAAT3 in the regulation of rat LC by glutamate. Neuronal EAAT3 would be responsible for terminating the action of synaptically released glutamate, whereas glial EAAT2 would regulate tonic glutamate concentrations in this nucleus.
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Affiliation(s)
- M C Medrano
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country (UPV/ EHU), Bizkaia, Spain
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Huynh THV, Demmer CS, Abrahamsen B, Marcher E, Frykman M, Jensen AA, Bunch L. Structure-activity-relationship study of N-acyl-N-phenylpiperazines as potential inhibitors of the Excitatory Amino Acid Transporters (EAATs): improving the potency of a micromolar screening Hit is not truism. SPRINGERPLUS 2013; 2:112. [PMID: 25530930 PMCID: PMC4225009 DOI: 10.1186/2193-1801-2-112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 02/28/2013] [Indexed: 11/10/2022]
Abstract
Abstract
The excitatory amino acid transporters (EAATs) are transmembrane proteins responsible for the uptake of (S)-glutamate from the synaptic cleft. To date, five subtypes EAAT1-5 have been identified for which selective inhibitors have been discovered for EAAT1 and EAAT2. By screening of a commercially available compound library consisting of 4,000 compounds, N-acyl-N-phenylpiperazine analog (±)-
exo
-1 was identified to be a non-selective inhibitor at EAAT1-3 displaying IC50 values in the mid-micromolar range (10 μ M, 40 μ M and 30 μ M at EAAT1, 2 and 3, respectively). Subsequently, we designed and synthesized a series of analogs to explore the structure-activity-relationship of this scaffold in the search for analogs characterized by increased inhibitory potency and/or EAAT subtype selectivity. Despite extensive efforts, all analogs of (±)-
exo
-1 proved to be either inactive or to have least 3-fold lower inhibitory potency than the lead, and furthermore none of the active analogs displayed selectivity for a particular subtype amongst the EAAT1-3. On the basis of our findings, we speculate that (±)-
exo
-1 binds to a recess (deepening) on the EAAT proteins than a well-defined pocket.
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Discovery of a subtype selective inhibitor of the human betaine/GABA transporter 1 (BGT-1) with a non-competitive pharmacological profile. Biochem Pharmacol 2013; 86:521-8. [DOI: 10.1016/j.bcp.2013.06.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 06/07/2013] [Accepted: 06/11/2013] [Indexed: 12/21/2022]
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36
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Dumont AO, Hermans E, Goursaud S. Differential regulation of the glutamate transporter variants GLT-1a and GLT-1b in the cortex and spinal cord of transgenic rats expressing hSOD1(G93A). Neurochem Int 2013; 63:61-8. [PMID: 23665075 DOI: 10.1016/j.neuint.2013.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/22/2013] [Accepted: 04/29/2013] [Indexed: 12/11/2022]
Abstract
Altered expression and activity of GLT-1 have been characterized in amyotrophic lateral sclerosis (ALS) patients and in animal models of the disease. Data suggest that the expression of two C-terminus splice variants of GLT-1 (namely GLT-1a and GLT-1b) can be differentially regulated in this pathological context. We herein characterized the expression of GLT-1a and GLT-1b mRNA and the glutamate uptake activity in the fronto-temporal cortex and the lumbar spinal cord of transgenic rats expressing hSOD1(G93A) at various stages of the disease. We also investigated the expression and activity of the other key glutamate transporters GLAST and EAAC1. While the progression of the disease was associated with a reduction of the overall GLT-1 activity in both cortex and spinal cord, the regulation of GLT-1a and GLT-1b transcripts showed different profiles. In the cortex, GLT-1a mRNA which appears as the most abundant isoform at a pre-symptomatic stage was strongly decreased during the progression of the disease while GLT-1b mRNA increased to reach a similar level as GLT-1a at end-stage. In the lumbar spinal cord of transgenic rats, both GLT-1a and GLT-1b mRNAs, expressed at the same levels before the symptom onset, were strongly decreased in the ventral horns. While no modification of GLAST was detected, EAAC1 mRNA was highly increased at a pre-symptomatic stage in transgenic animals, explaining a higher activity of glutamate transporters at this age. These results demonstrate that glutamate transporters are differentially expressed in nervous structures of wild-type and transgenic animals although the total GLT-1 activity was constantly decreased during the disease progression.
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Affiliation(s)
- Amélie O Dumont
- Institute of Neuroscience, Group of Neuropharmacology, Université catholique de Louvain, Brussels, Belgium
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37
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Allosteric modulation of an excitatory amino acid transporter: the subtype-selective inhibitor UCPH-101 exerts sustained inhibition of EAAT1 through an intramonomeric site in the trimerization domain. J Neurosci 2013; 33:1068-87. [PMID: 23325245 DOI: 10.1523/jneurosci.3396-12.2013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the present study, the mechanism of action and molecular basis for the activity of the first class of selective inhibitors of the human excitatory amino acid transporter subtype 1 (EAAT1) and its rodent ortholog GLAST are elucidated. The previously reported specificity of UCPH-101 and UCPH-102 for EAAT1 over EAAT2 and EAAT3 is demonstrated to extend to the EAAT4 and EAAT5 subtypes as well. Interestingly, brief exposure to UCPH-101 induces a long-lasting inactive state of EAAT1, whereas the inhibition exerted by closely related analogs is substantially more reversible in nature. In agreement with this, the kinetic properties of UCPH-101 unblocking of the transporter are considerably slower than those of UCPH-102. UCPH-101 exhibits noncompetitive inhibition of EAAT1, and its binding site in GLAST has been delineated in an elaborate mutagenesis study. Substitutions of several residues in TM3, TM4c, and TM7a of GLAST have detrimental effects on the inhibitory potency and/or efficacy of UCPH-101 while not affecting the pharmacological properties of (S)-glutamate or the competitive EAAT inhibitor TBOA significantly. Hence, UCPH-101 is proposed to target a predominantly hydrophobic crevice in the "trimerization domain" of the GLAST monomer, and the inhibitor is demonstrated to inhibit the uptake through the monomer that it binds to exclusively and not to affect substrate translocation through the other monomers in the GLAST trimer. The allosteric mode of UCPH-101 inhibition underlines the functional importance of the trimerization domain of the EAAT and demonstrates the feasibility of modulating transporter function through ligand binding to regions distant from its "transport domain."
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38
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Assaf Z, Larsen AP, Venskutonytė R, Han L, Abrahamsen B, Nielsen B, Gajhede M, Kastrup JS, Jensen AA, Pickering DS, Frydenvang K, Gefflaut T, Bunch L. Chemoenzymatic synthesis of new 2,4-syn-functionalized (S)-glutamate analogues and structure-activity relationship studies at ionotropic glutamate receptors and excitatory amino acid transporters. J Med Chem 2013; 56:1614-28. [PMID: 23414088 DOI: 10.1021/jm301433m] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the mammalian central nervous system, (S)-glutamate (Glu) is released from the presynaptic neuron where it activates a plethora of pre- and postsynaptic Glu receptors. The fast acting ionotropic Glu receptors (iGluRs) are ligand gated ion channels and are believed to be involved in a vast number of neurological functions such as memory and learning, synaptic plasticity, and motor function. The synthesis of 14 enantiopure 2,4-syn-Glu analogues 2b-p is accessed by a short and efficient chemoenzymatic approach starting from readily available cyclohexanone 3. Pharmacological characterization at the iGluRs and EAAT1-3 subtypes revealed analogue 2i as a selective GluK1 ligand with low nanomolar affinity. Two X-ray crystal structures of the key analogue 2i in the ligand-binding domain (LBD) of GluA2 and GluK3 were determined. Partial domain closure was seen in the GluA2-LBD complex with 2i comparable to that induced by kainate. In contrast, full domain closure was observed in the GluK3-LBD complex with 2i, similar to that of GluK3-LBD with glutamate bound.
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MESH Headings
- Animals
- Aspartate Aminotransferases/chemistry
- Brain/metabolism
- Catalysis
- Crystallography, X-Ray
- Glutamate Plasma Membrane Transport Proteins/metabolism
- Glutamates/chemical synthesis
- Glutamates/chemistry
- Glutamates/pharmacology
- Glutamic Acid/analogs & derivatives
- Glutamic Acid/chemical synthesis
- Glutamic Acid/chemistry
- Glutamic Acid/pharmacology
- HEK293 Cells
- Humans
- In Vitro Techniques
- Ketoglutaric Acids/chemical synthesis
- Ketoglutaric Acids/chemistry
- Ligands
- Models, Molecular
- Molecular Structure
- Radioligand Assay
- Rats
- Rats, Sprague-Dawley
- Receptors, AMPA/chemistry
- Receptors, AMPA/metabolism
- Receptors, Ionotropic Glutamate/chemistry
- Receptors, Ionotropic Glutamate/metabolism
- Receptors, Kainic Acid/chemistry
- Receptors, Kainic Acid/metabolism
- Receptors, N-Methyl-D-Aspartate/metabolism
- Stereoisomerism
- Structure-Activity Relationship
- GluK3 Kainate Receptor
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Affiliation(s)
- Zeinab Assaf
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen Ø, Denmark
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Huynh TH, Abrahamsen B, Madsen KK, Gonzalez-Franquesa A, Jensen AA, Bunch L. Design, synthesis and pharmacological characterization of coumarin-based fluorescent analogs of excitatory amino acid transporter subtype 1 selective inhibitors, UCPH-101 and UCPH-102. Bioorg Med Chem 2012; 20:6831-9. [DOI: 10.1016/j.bmc.2012.09.049] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/24/2012] [Accepted: 09/25/2012] [Indexed: 11/30/2022]
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40
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Huynh THV, Shim I, Bohr H, Abrahamsen B, Nielsen B, Jensen AA, Bunch L. Structure-activity relationship study of selective excitatory amino acid transporter subtype 1 (EAAT1) inhibitor 2-amino-4-(4-methoxyphenyl)-7-(naphthalen-1-yl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (UCPH-101) and absolute configurational assignment using infrared and vibrational circular dichroism spectroscopy in combination with ab initio Hartree-Fock calculations. J Med Chem 2012; 55:5403-12. [PMID: 22594609 DOI: 10.1021/jm300345z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excitatory amino acid transporters (EAATs) play essential roles in regulating the synaptic concentration of the neurotransmitter glutamate in the mammalian central nervous system. To date, five subtypes have been identified, named EAAT1-5 in humans, and GLAST, GLT-1, EAAC1, EAAT4, and EAAT5 in rodents, respectively. In this paper, we present the design, synthesis, and pharmacological evaluation of seven 7-N-substituted analogues of UCPH-101/102. Analogue 9 inhibited EAAT1 in the micromolar range (IC(50) value 20 μM), whereas analogues 8 and 10 were inactive (IC(50) values >100 μM). The diastereomeric pairs 11a/11b and 12a/12b were separated by HPLC and the absolute configuration assigned by VCD technique in combination with ab initio Hartree-Fock calculations. Analogues 11a (RS-isomer) and 12b (RR-isomer) inhibited EAAT1 (IC(50) values 5.5 and 3.8 μM, respectively), whereas analogues 11b (SS-isomer) and 12a (SR-isomer) failed to inhibit EAAT1 uptake (IC(50) values >300 μM).
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Affiliation(s)
- Tri H V Huynh
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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41
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Jungblut M, Tiveron MC, Barral S, Abrahamsen B, Knöbel S, Pennartz S, Schmitz J, Perraut M, Pfrieger FW, Stoffel W, Cremer H, Bosio A. Isolation and characterization of living primary astroglial cells using the new GLAST-specific monoclonal antibody ACSA-1. Glia 2012; 60:894-907. [PMID: 22374709 DOI: 10.1002/glia.22322] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 02/14/2012] [Indexed: 12/23/2022]
Abstract
Astrocytes show large morphological and functional heterogeneity and are involved in many aspects of neural function. Progress in defining astrocyte subpopulations has been hampered by the lack of a suitable antibody for their direct detection and isolation. Here, we describe a new monoclonal antibody, ACSA-1, which was generated by immunization of GLAST1 knockout mice. The antibody specifically detects an extracellular epitope of the astrocyte-specific L-glutamate/L-aspartate transporter GLAST (EAAT1, Slc1a3). As shown by immunohistochemistry, immunocytochemistry, and flow cytometry, ACSA-1 was cross-reactive for mouse, human, and rat. It labeled virtually all astrocytes positive for GFAP, GS, BLBP, RC2, and Nestin, including protoplastic, fibrous, and reactive astrocytes as well as Bergmann glia, Müller glia, and radial glia. Oligodendrocytes, microglia, neurons, and neuronal progenitors were negative for ACSA-1. Using an immunomagnetic approach, we established a method for the isolation of GLAST-positive cells with high purity. Binding of the antibody to GLAST and subsequent sorting of GLAST-positive cells neither interfered with cellular glutamate transport nor compromised astrocyte viability in vitro. The ACSA-1 antibody is not only a valuable tool to identify and track astrocytes by immunostaining, but also provides the possibility of separation and further analysis of pure astrocytes.
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Affiliation(s)
- Melanie Jungblut
- Miltenyi Biotec GmbH, Friedrich-Ebert-Straße 68, Bergisch Gladbach, Germany
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42
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Kvist T, Hansen KB, Bräuner-Osborne H. The use of Xenopus oocytes in drug screening. Expert Opin Drug Discov 2011; 6:141-53. [PMID: 22647133 DOI: 10.1517/17460441.2011.546396] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION The physiological roles of ion channels are receiving increased interest in both basic research and drug discovery, and a demand for pharmacological approaches that can characterize or screen ion channels and their ligands with higher throughput has emerged. Traditionally, screening of compound libraries at ion channel targets has been performed using assays such as binding assays, fluorescence-based assays and flux assays that allow high-throughput, but sacrifice high data quality. The use of these assays with ion channel targets can also be problematic, emphasizing the usefulness of automated Xenopus oocyte electrophysiological assays in drug screening. AREAS COVERED This review summarizes the use of Xenopus oocytes in drug screening, presents the advantages and disadvantages of the use of Xenopus oocytes as expression system, and addresses the options available for automated two-electrode voltage-clamp recordings from Xenopus oocytes. EXPERT OPINION Automated and manual Xenopus oocyte two-electrode voltage-clamp recordings are useful and important techniques in drug screening. Although they are not compatible with high-throughput experimentation, these techniques are excellent in combination or as alternatives to fluorescence-based assays for hit validation, screening of focused compound libraries and safety screening on ion channels with their high flexibility for the choice of molecular targets, quality of data and reproducibility.
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Affiliation(s)
- Trine Kvist
- University of Copenhagen, Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Fruebjergvej 3, 2100 Copenhagen, Denmark
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43
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Erichsen MN, Huynh THV, Abrahamsen B, Bastlund JF, Bundgaard C, Monrad O, Bekker-Jensen A, Nielsen CW, Frydenvang K, Jensen AA, Bunch L. Structure-activity relationship study of first selective inhibitor of excitatory amino acid transporter subtype 1: 2-Amino-4-(4-methoxyphenyl)-7-(naphthalen-1-yl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (UCPH-101). J Med Chem 2010; 53:7180-91. [PMID: 20857912 DOI: 10.1021/jm1009154] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excitatory amino acid transporters (EAATs) are expressed throughout the central nervous system, where they are responsible for the reuptake of the excitatory neurotransmitter (S)-glutamate (Glu). (1) Recently, we have reported the discovery of the first subtype selective EAAT1 inhibitor 2-amino-4-(4-methoxyphenyl)-7-(naphthalen-1-yl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (UCPH-101) (1b) and presented an introductory structure-activity relationship (SAR) study. (2) Here, we present a detailed SAR by the design, synthesis, and pharmacological evaluation of analogues 1g-1t. By comparison of potencies of 1b, 1h, and 1i versus 1j, it is evident that potency is largely influenced by the chemical nature of the R(1) substituent. The study also demonstrates that any chemical change of the functional groups or a change to the parental scaffold results in the complete loss of inhibitory activity of the compounds at EAAT1. Finally, a bioavailability study of UCPH-101 determined the half-life to be 30 min in serum (rats) but also that it was not able to penetrate the blood-brain barrier to any significant degree.
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Affiliation(s)
- Mette N Erichsen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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44
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Gebhardt FM, Mitrovic AD, Gilbert DF, Vandenberg RJ, Lynch JW, Dodd PR. Exon-skipping splice variants of excitatory amino acid transporter-2 (EAAT2) form heteromeric complexes with full-length EAAT2. J Biol Chem 2010; 285:31313-24. [PMID: 20688910 PMCID: PMC2951206 DOI: 10.1074/jbc.m110.153494] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 08/02/2010] [Indexed: 12/12/2022] Open
Abstract
The glial transporter excitatory amino acid transporter-2 (EAAT2) is the main mediator of glutamate clearance in brain. The wild-type transporter (EAAT2wt) forms trimeric membrane complexes in which each protomer functions autonomously. Several EAAT2 variants are found in control and Alzheimer-diseased human brains; their expression increases with pathological severity. These variants might alter EAAT2wt-mediated transport by abrogating membrane trafficking, or by changing the configuration or functionality of the assembled transporter complex. HEK293 cells were transfected with EAAT2wt; EAAT2b, a C-terminal variant; or either of two exon-skipping variants: alone or in combination. Surface biotinylation studies showed that only the exon-7 deletion variant was not trafficked to the membrane when transfected alone, and that all variants could reach the membrane when co-transfected with EAAT2wt. Fluorescence resonance energy transfer (FRET) studies showed that co-transfected EAAT2wt and EAAT2 splice variants were expressed in close proximity. Glutamate transporter function was measured using a whole cell patch clamp technique, or by changes in membrane potential indexed by a voltage-sensitive fluorescent dye (FMP assay): the two methods gave comparable results. Cells transfected with EAAT2wt or EAAT2b showed glutamate-dependent membrane potential changes consistent with functional expression. Cells transfected with EAAT2 exon-skipping variants alone gave no response to glutamate. Co-transfection of EAAT2wt (or EAAT2b) and splice variants in various ratios significantly raised glutamate EC(50) and decreased Hill coefficients. We conclude that exon-skipping variants form heteromeric complexes with EAAT2wt or EAAT2b that traffic to the membrane but show reduced glutamate-dependent activity. This could allow glutamate to accumulate extracellularly and promote excitotoxicity.
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Affiliation(s)
| | - Ann D. Mitrovic
- the Discipline of Pharmacology and Bosch Institute, University of Sydney, Sydney 2006, Australia
| | - Daniel F. Gilbert
- the Queensland Brain Institute and School of Biomedical Sciences, University of Queensland, Brisbane 4072 and
| | - Robert J. Vandenberg
- the Discipline of Pharmacology and Bosch Institute, University of Sydney, Sydney 2006, Australia
| | - Joseph W. Lynch
- the Queensland Brain Institute and School of Biomedical Sciences, University of Queensland, Brisbane 4072 and
| | - Peter R. Dodd
- From the School of Chemistry and Molecular Biosciences and
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45
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Bunch L, Pickering DS, Gefflaut T, Vinatier V, Helaine V, Amir A, Nielsen B, Jensen AA. 4,4-Dimethyl- and diastereomeric 4-hydroxy-4-methyl- (2S)-glutamate analogues display distinct pharmacological profiles at ionotropic glutamate receptors and excitatory amino acid transporters. ChemMedChem 2010; 4:1925-9. [PMID: 19731281 DOI: 10.1002/cmdc.200900258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Subtype-selective ligands are of great interest to the scientific community, as they provide a tool for investigating the function of one receptor or transporter subtype when functioning in its native environment. Several 4-substituted (S)-glutamate (Glu) analogues were synthesized, and altogether this approach has provided important insight into the structure-activity relationships (SAR) for ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs), as well as the excitatory amino acid transporters (EAATs). In this work, three 4,4-disubstituted Glu analogues 1-3, which are hybrid structures of important 4-substituted Glu analogues 4-8, were investigated at iGluRs and EAATs. Collectively, their pharmacological profiles add new and valuable information to the SAR for the iGluRs and EAAT1-3.
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Affiliation(s)
- Lennart Bunch
- Department of Medicinal Chemistry, University of Copenhagen, Denmark.
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46
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Jensen AA, Erichsen MN, Nielsen CW, Stensbøl TB, Kehler J, Bunch L. Discovery of the first selective inhibitor of excitatory amino acid transporter subtype 1. J Med Chem 2009; 52:912-5. [PMID: 19161278 DOI: 10.1021/jm8013458] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The discovery of the first class of subtype-selective inhibitors of the human excitatory amino acid transporter subtype 1 (EAAT1) and its rat orthologue GLAST is reported. An opening structure-activity relationship of 25 analogues is presented that addresses the influence of substitutions at the 4- and 7-positions of the parental skeleton 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile. The most potent analogue 1o displays high nanomolar inhibitory activity at EAAT1 and a >400-fold selectivity over EAAT2 and EAAT3, making it a highly valuable pharmacological tool.
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Affiliation(s)
- Anders A Jensen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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47
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Bunch L, Erichsen MN, Jensen AA. Excitatory amino acid transporters as potential drug targets. Expert Opin Ther Targets 2009; 13:719-31. [DOI: 10.1517/14728220902926127] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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48
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Shin JW, Nguyen KTD, Pow DV, Knight T, Buljan V, Bennett MR, Balcar VJ. Distribution of glutamate transporter GLAST in membranes of cultured astrocytes in the presence of glutamate transport substrates and ATP. Neurochem Res 2009; 34:1758-66. [PMID: 19440835 DOI: 10.1007/s11064-009-9982-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 04/20/2009] [Indexed: 11/27/2022]
Abstract
Neurotransmitter L-glutamate released at central synapses is taken up and "recycled" by astrocytes using glutamate transporter molecules such as GLAST and GLT. Glutamate transport is essential for prevention of glutamate neurotoxicity, it is a key regulator of neurotransmitter metabolism and may contribute to mechanisms through which neurons and glia communicate with each other. Using immunocytochemistry and image analysis we have found that extracellular D-aspartate (a typical substrate for glutamate transport) can cause redistribution of GLAST from cytoplasm to the cell membrane. The process appears to involve phosphorylation/dephosphorylation and requires intact cytoskeleton. Glutamate transport ligands L-trans-pyrrolidine-2,4-dicarboxylate and DL-threo-3-benzyloxyaspartate but not anti,endo-3,4-methanopyrrolidine dicarboxylate have produced similar redistribution of GLAST. Several representative ligands for glutamate receptors whether of ionotropic or metabotropic type, were found to have no effect. In addition, extracellular ATP induced formation of GLAST clusters in the cell membranes by a process apparently mediated by P2 receptors. The present data suggest that GLAST can rapidly and specifically respond to changes in the cellular environment thus potentially helping to fine-tune the functions of astrocytes.
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Affiliation(s)
- Jae-Won Shin
- Anatomy and Histology, School of Medical Sciences and Bosch Institute for Biomedical Research, The University of Sydney, Sydney, NSW 2006, Australia
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Bunch L, Krogsgaard-Larsen P. Subtype selective kainic acid receptor agonists: Discovery and approaches to rational design. Med Res Rev 2009; 29:3-28. [DOI: 10.1002/med.20133] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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