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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Yang X, Dilweg MA, Osemwengie D, Burggraaff L, van der Es D, Heitman LH, IJzerman AP. Design and pharmacological profile of a novel covalent partial agonist for the adenosine A 1 receptor. Biochem Pharmacol 2020; 180:114144. [PMID: 32653590 DOI: 10.1016/j.bcp.2020.114144] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/29/2022]
Abstract
Partial agonists for G protein-coupled receptors (GPCRs) provide opportunities for novel pharmacotherapies with enhanced on-target safety compared to full agonists. For the human adenosine A1 receptor (hA1AR) this has led to the discovery of capadenoson, which has been in phase IIa clinical trials for heart failure. Accordingly, the design and profiling of novel hA1AR partial agonists has become an important research focus. In this study, we report on LUF7746, a capadenoson derivative bearing an electrophilic fluorosulfonyl moiety, as an irreversibly binding hA1AR modulator. Meanwhile, a nonreactive ligand bearing a methylsulfonyl moiety, LUF7747, was designed as a control probe in our study. In a radioligand binding assay, LUF7746's apparent affinity increased to nanomolar range with longer pre-incubation time, suggesting an increasing level of covalent binding over time. Moreover, compared to the reference full agonist CPA, LUF7746 was a partial agonist in a hA1AR-mediated G protein activation assay and resistant to blockade with an antagonist/inverse agonist. An in silico structure-based docking study combined with site-directed mutagenesis of the hA1AR demonstrated that amino acid Y2717.36 was the primary anchor point for the covalent interaction. Additionally, a label-free whole-cell assay was set up to identify LUF7746's irreversible activation of an A1 receptor-mediated cell morphological response. These results led us to conclude that LUF7746 is a novel covalent hA1AR partial agonist and a valuable chemical probe for further mapping the receptor activation process. It may also serve as a prototype for a therapeutic approach in which a covalent partial agonist may cause less on-target side effects, conferring enhanced safety compared to a full agonist.
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Affiliation(s)
- Xue Yang
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands
| | - Majlen A Dilweg
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands
| | - Dion Osemwengie
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands
| | - Lindsey Burggraaff
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands
| | - Daan van der Es
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands
| | - Laura H Heitman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands
| | - Adriaan P IJzerman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300RA Leiden, The Netherlands.
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