1
|
van Veggel L, Mocking TA, Sijben HJ, Liu R, Gorostiola González M, Dilweg MA, Royakkers J, Li A, Kumar V, Dong YY, Bullock A, Sauer DB, Diliën H, van Westen GJ, Schreiber R, Heitman LH, Vanmierlo T. Still in Search for an EAAT Activator: GT949 Does Not Activate EAAT2, nor EAAT3 in Impedance and Radioligand Uptake Assays. ACS Chem Neurosci 2024; 15:1424-1431. [PMID: 38478848 PMCID: PMC10995951 DOI: 10.1021/acschemneuro.3c00731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 04/04/2024] Open
Abstract
Excitatory amino acid transporters (EAATs) are important regulators of amino acid transport and in particular glutamate. Recently, more interest has arisen in these transporters in the context of neurodegenerative diseases. This calls for ways to modulate these targets to drive glutamate transport, EAAT2 and EAAT3 in particular. Several inhibitors (competitive and noncompetitive) exist to block glutamate transport; however, activators remain scarce. Recently, GT949 was proposed as a selective activator of EAAT2, as tested in a radioligand uptake assay. In the presented research, we aimed to validate the use of GT949 to activate EAAT2-driven glutamate transport by applying an innovative, impedance-based, whole-cell assay (xCELLigence). A broad range of GT949 concentrations in a variety of cellular environments were tested in this assay. As expected, no activation of EAAT3 could be detected. Yet, surprisingly, no biological activation of GT949 on EAAT2 could be observed in this assay either. To validate whether the impedance-based assay was not suited to pick up increased glutamate uptake or if the compound might not induce activation in this setup, we performed radioligand uptake assays. Two setups were utilized; a novel method compared to previously published research, and in a reproducible fashion copying the methods used in the existing literature. Nonetheless, activation of neither EAAT2 nor EAAT3 could be observed in these assays. Furthermore, no evidence of GT949 binding or stabilization of purified EAAT2 could be observed in a thermal shift assay. To conclude, based on experimental evidence in the present study GT949 requires specific assay conditions, which are difficult to reproduce, and the compound cannot simply be classified as an activator of EAAT2 based on the presented evidence. Hence, further research is required to develop the tools needed to identify new EAAT modulators and use their potential as a therapeutic target.
Collapse
Affiliation(s)
- Lieve van Veggel
- Department
of Neuroscience, BIOMED Biomedical Research Institute, Faculty of
Medicine and Life Sciences, Hasselt University, 3590 Hasselt, Belgium
- Department
of Psychiatry and Neuropsychology, Division of Translational Neuroscience,
European Graduate School of Neuroscience, School for Mental Health
and Neuroscience, Maastricht University, 6200 Maastricht, The Netherlands
- University
MS Center (UMSC), 3900 Hasselt-Pelt, Belgium
| | - Tamara A.M. Mocking
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
| | - Hubert J. Sijben
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
| | - Rongfang Liu
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
| | - Marina Gorostiola González
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
| | - Majlen A. Dilweg
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
| | - Jeroen Royakkers
- Sensor
Engineering
Department, Faculty of Science and Engineering, Maastricht University, 6200 Maastricht, The Netherlands
| | - Anna Li
- Centre
for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, OX3 7BN Oxford, U.K.
| | - Vijay Kumar
- Centre
for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, OX3 7BN Oxford, U.K.
| | - Yin Yao Dong
- Nuffield
Department of Clinical Neurosciences, Weatherall Institute of Molecular
Medicine, University of Oxford, OX3 7BN Oxford, U.K.
| | - Alex Bullock
- Centre
for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, OX3 7BN Oxford, U.K.
| | - David B. Sauer
- Centre
for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, OX3 7BN Oxford, U.K.
| | - Hanne Diliën
- Sensor
Engineering
Department, Faculty of Science and Engineering, Maastricht University, 6200 Maastricht, The Netherlands
| | - Gerard J.P. van Westen
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
| | - Rudy Schreiber
- Section
of Psychopharmacology, Neuropsychology and Psychopharmacology, Faculty
of Psychology and Neuroscience, Maastricht
University, 6200 Maastricht, The Netherlands
| | - Laura H. Heitman
- Leiden
Academic Centre for Drug Research (LACDR), Division of Drug Discovery
and Safety, Leiden University, 2333 Leiden, The Netherlands
- Oncode
Institute, Einsteinweg
55, 2333 Leiden, The Netherlands
| | - Tim Vanmierlo
- Department
of Neuroscience, BIOMED Biomedical Research Institute, Faculty of
Medicine and Life Sciences, Hasselt University, 3590 Hasselt, Belgium
- Department
of Psychiatry and Neuropsychology, Division of Translational Neuroscience,
European Graduate School of Neuroscience, School for Mental Health
and Neuroscience, Maastricht University, 6200 Maastricht, The Netherlands
- University
MS Center (UMSC), 3900 Hasselt-Pelt, Belgium
| |
Collapse
|
2
|
Pan Y, Liu Z, Zou P, Chen Y, Chen Y. Hypervalent Iodine Reagents Enable C(sp 2)-H Amidation of (Hetero)arenes with Iminophenylacetic Acids. Org Lett 2022; 24:6681-6685. [PMID: 36043941 DOI: 10.1021/acs.orglett.2c02751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sulfonamide-containing (hetero)arenes are widely present in bioactive molecules. Here, we report the sulfonamidyl (hetero)arenes synthesis by the C(sp2)-H amidation from bench-stable amidyl-iminophenylacetic acids. The hypervalent iodine reagents covalently activated iminophenylacetic acids for the facile sulfonamidyl radical generation under mild photocatalytic oxidative conditions. Diversified indoles, pyrroles, imidazopyridines, and fused arenes underwent the C(sp2)-H amidation with excellent chemoselectivity and regioselectivity. This reaction performs well under neutral aqueous conditions with potential biological applications.
Collapse
Affiliation(s)
- Yue Pan
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China.,Department of Chemistry, Shanghai University, 99 Shangda Road, Shanghai 200444 China
| | - Zhengyi Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China
| | - Peng Zou
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China
| | - Yali Chen
- Department of Chemistry, Shanghai University, 99 Shangda Road, Shanghai 200444 China
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 China.,School of Physical Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210 China.,School of Chemistry and Material Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou 310024, China
| |
Collapse
|
3
|
Piepgras J, Rohrbeck A, Just I, Bittner S, Ahnert-Hilger G, Höltje M. Enhancement of Phosphorylation and Transport Activity of the Neuronal Glutamate Transporter Excitatory Amino Acid Transporter 3 by C3bot and a 26mer C3bot Peptide. Front Cell Neurosci 2022; 16:860823. [PMID: 35783090 PMCID: PMC9240211 DOI: 10.3389/fncel.2022.860823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
In primary murine hippocampal neurons we investigated the regulation of EAAT3-mediated glutamate transport by the Clostridium botulinum C3 transferase C3bot and a 26mer peptide derived from full length protein. Incubation with either enzyme-competent C3bot or enzyme-deficient C3bot156–181 peptide resulted in the upregulation of glutamate uptake by up to 22% compared to untreated cells. A similar enhancement of glutamate transport was also achieved by the classical phorbol-ester-mediated activation of protein kinase C subtypes. Yet comparable, effects elicited by C3 preparations seemed not to rely on PKCα, γ, ε, or ζ activation. Blocking of tyrosine phosphorylation by tyrosine kinase inhibitors prevented the observed effect mediated by C3bot and C3bot 26mer. By using biochemical and molecular biological assays we could rule out that the observed C3bot and C3bot 26mer-mediated effects solely resulted from enhanced transporter expression or translocation to the neuronal surface but was rather mediated by transporter phosphorylation at tyrosine residues that was found to be significantly enhanced following incubation with either full length protein or the 26mer C3 peptide.
Collapse
Affiliation(s)
- Johannes Piepgras
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine-Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Astrid Rohrbeck
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School, Hanover, Germany
| | - Stefan Bittner
- Department of Neurology, Focus Program Translational Neuroscience and Immunotherapy, Rhine-Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gudrun Ahnert-Hilger
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, University of Göttingen, Göttingen, Germany
| | - Markus Höltje
- Institut für Integrative Neuroanatomie, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- *Correspondence: Markus Höltje,
| |
Collapse
|
4
|
Huttunen J, Adla SK, Markowicz-Piasecka M, Huttunen KM. Increased/Targeted Brain (Pro)Drug Delivery via Utilization of Solute Carriers (SLCs). Pharmaceutics 2022; 14:pharmaceutics14061234. [PMID: 35745806 PMCID: PMC9228667 DOI: 10.3390/pharmaceutics14061234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 02/04/2023] Open
Abstract
Membrane transporters have a crucial role in compounds’ brain drug delivery. They allow not only the penetration of a wide variety of different compounds to cross the endothelial cells of the blood–brain barrier (BBB), but also the accumulation of them into the brain parenchymal cells. Solute carriers (SLCs), with nearly 500 family members, are the largest group of membrane transporters. Unfortunately, not all SLCs are fully characterized and used in rational drug design. However, if the structural features for transporter interactions (binding and translocation) are known, a prodrug approach can be utilized to temporarily change the pharmacokinetics and brain delivery properties of almost any compound. In this review, main transporter subtypes that are participating in brain drug disposition or have been used to improve brain drug delivery across the BBB via the prodrug approach, are introduced. Moreover, the ability of selected transporters to be utilized in intrabrain drug delivery is discussed. Thus, this comprehensive review will give insights into the methods, such as computational drug design, that should be utilized more effectively to understand the detailed transport mechanisms. Moreover, factors, such as transporter expression modulation pathways in diseases that should be taken into account in rational (pro)drug development, are considered to achieve successful clinical applications in the future.
Collapse
Affiliation(s)
- Johanna Huttunen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (J.H.); (S.K.A.)
| | - Santosh Kumar Adla
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (J.H.); (S.K.A.)
- Institute of Organic Chemistry and Biochemistry (IOCB), Czech Academy of Sciences, Flemingovo Namesti 542/2, 160 00 Prague, Czech Republic
| | - Magdalena Markowicz-Piasecka
- Department of Pharmaceutical Chemistry, Drug Analysis and Radiopharmacy, Medical University of Lodz, ul. Muszyńskiego 1, 90-151 Lodz, Poland;
| | - Kristiina M. Huttunen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; (J.H.); (S.K.A.)
- Correspondence:
| |
Collapse
|
5
|
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.
Collapse
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,
| |
Collapse
|
6
|
Recent developments in ligands and chemical probes targeting solute carrier transporters. Curr Opin Chem Biol 2021; 62:53-63. [PMID: 33689964 DOI: 10.1016/j.cbpa.2021.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/12/2021] [Accepted: 01/31/2021] [Indexed: 12/30/2022]
Abstract
Solute carrier (SLC) membrane transporters remain a largely unexploited target class, despite their central roles in cell identity and metabolism. This gap is reflected in the lack of high-quality chemical ligands or probes and in the small number of compounds that have progressed toward clinical development. In this review, we discuss recent advancements in SLC ligand discovery as well as new candidates that have been added to the investigational toolkit, with a particular focus on first-in-class ligands and the cognate discovery strategies. The availability of new probes expands the opportunity to elucidate the functions of SLCs and their relevance in physiology and explores any future potential of SLC druggability.
Collapse
|
7
|
Kahya U, Köseer AS, Dubrovska A. Amino Acid Transporters on the Guard of Cell Genome and Epigenome. Cancers (Basel) 2021; 13:E125. [PMID: 33401748 PMCID: PMC7796306 DOI: 10.3390/cancers13010125] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/26/2020] [Accepted: 12/27/2020] [Indexed: 02/06/2023] Open
Abstract
Tumorigenesis is driven by metabolic reprogramming. Oncogenic mutations and epigenetic alterations that cause metabolic rewiring may also upregulate the reactive oxygen species (ROS). Precise regulation of the intracellular ROS levels is critical for tumor cell growth and survival. High ROS production leads to the damage of vital macromolecules, such as DNA, proteins, and lipids, causing genomic instability and further tumor evolution. One of the hallmarks of cancer metabolism is deregulated amino acid uptake. In fast-growing tumors, amino acids are not only the source of energy and building intermediates but also critical regulators of redox homeostasis. Amino acid uptake regulates the intracellular glutathione (GSH) levels, endoplasmic reticulum stress, unfolded protein response signaling, mTOR-mediated antioxidant defense, and epigenetic adaptations of tumor cells to oxidative stress. This review summarizes the role of amino acid transporters as the defender of tumor antioxidant system and genome integrity and discusses them as promising therapeutic targets and tumor imaging tools.
Collapse
Affiliation(s)
- Uğur Kahya
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (U.K.); (A.S.K.)
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, 01328 Dresden, Germany
| | - Ayşe Sedef Köseer
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (U.K.); (A.S.K.)
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, 01328 Dresden, Germany
- National Center for Tumor Diseases (NCT), Partner Site Dresden and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Anna Dubrovska
- OncoRay–National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01309 Dresden, Germany; (U.K.); (A.S.K.)
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, 01328 Dresden, Germany
- National Center for Tumor Diseases (NCT), Partner Site Dresden and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden and German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|