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Bhatt M, Gauthier-Manuel L, Lazzarin E, Zerlotti R, Ziegler C, Bazzone A, Stockner T, Bossi E. A comparative review on the well-studied GAT1 and the understudied BGT-1 in the brain. Front Physiol 2023; 14:1145973. [PMID: 37123280 PMCID: PMC10137170 DOI: 10.3389/fphys.2023.1145973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/30/2023] [Indexed: 05/02/2023] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system (CNS). Its homeostasis is maintained by neuronal and glial GABA transporters (GATs). The four GATs identified in humans are GAT1 (SLC6A1), GAT2 (SLC6A13), GAT3 (SLC6A11), and betaine/GABA transporter-1 BGT-1 (SLC6A12) which are all members of the solute carrier 6 (SLC6) family of sodium-dependent transporters. While GAT1 has been investigated extensively, the other GABA transporters are less studied and their role in CNS is not clearly defined. Altered GABAergic neurotransmission is involved in different diseases, but the importance of the different transporters remained understudied and limits drug targeting. In this review, the well-studied GABA transporter GAT1 is compared with the less-studied BGT-1 with the aim to leverage the knowledge on GAT1 to shed new light on the open questions concerning BGT-1. The most recent knowledge on transporter structure, functions, expression, and localization is discussed along with their specific role as drug targets for neurological and neurodegenerative disorders. We review and discuss data on the binding sites for Na+, Cl-, substrates, and inhibitors by building on the recent cryo-EM structure of GAT1 to highlight specific molecular determinants of transporter functions. The role of the two proteins in GABA homeostasis is investigated by looking at the transport coupling mechanism, as well as structural and kinetic transport models. Furthermore, we review information on selective inhibitors together with the pharmacophore hypothesis of transporter substrates.
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Affiliation(s)
- Manan Bhatt
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
| | - Laure Gauthier-Manuel
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | - Erika Lazzarin
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
| | - Rocco Zerlotti
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Christine Ziegler
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | | | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
- *Correspondence: Thomas Stockner, ; Elena Bossi,
| | - Elena Bossi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
- *Correspondence: Thomas Stockner, ; Elena Bossi,
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2
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Kickinger S, Lie MEK, Suemasa A, Al-Khawaja A, Fujiwara K, Watanabe M, Wilhelmsen KS, Falk-Petersen CB, Frølund B, Shuto S, Ecker GF, Wellendorph P. Molecular Determinants and Pharmacological Analysis for a Class of Competitive Non-transported Bicyclic Inhibitors of the Betaine/GABA Transporter BGT1. Front Chem 2021; 9:736457. [PMID: 34595152 PMCID: PMC8476755 DOI: 10.3389/fchem.2021.736457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 08/30/2021] [Indexed: 11/17/2022] Open
Abstract
The betaine/GABA transporter 1 (BGT1) is a member of the GABA transporter (GAT) family with still elusive function, largely due to a lack of potent and selective tool compounds. Based on modeling, we here present the design, synthesis and pharmacological evaluation of five novel conformationally restricted cyclic GABA analogs related to the previously reported highly potent and selective BGT1 inhibitor (1S,2S,5R)-5-aminobicyclo[3.1.0]hexane-2-carboxylic acid (bicyclo-GABA). Using [3H]GABA radioligand uptake assays at the four human GATs recombinantly expressed in mammalian cell lines, we identified bicyclo-GABA and its N-methylated analog (2) as the most potent and selective BGT1 inhibitors. Additional pharmacological characterization in a fluorescence-based membrane potential assay showed that bicyclo-GABA and 2 are competitive inhibitors, not substrates, at BGT1, which was validated by a Schild analysis for bicyclo-GABA (pKB value of 6.4). To further elaborate on the selectivity profile both compounds were tested at recombinant α1β2γ2 GABAA receptors. Whereas bicyclo-GABA showed low micromolar agonistic activity, the N-methylated 2 was completely devoid of activity at GABAA receptors. To further reveal the binding mode of bicyclo-GABA and 2 binding hypotheses of the compounds were obtained from in silico-guided mutagenesis studies followed by pharmacological evaluation at selected BGT1 mutants. This identified the non-conserved BGT1 residues Q299 and E52 as the molecular determinants driving BGT1 activity and selectivity. The binding mode of bicyclo-GABA was further validated by the introduction of activity into the corresponding GAT3 mutant L314Q (38 times potency increase cf. wildtype). Altogether, our data reveal the molecular determinants for the activity of bicyclic GABA analogs, that despite their small size act as competitive inhibitors of BGT1. These compounds may serve as valuable tools to selectively and potently target BGT1 in order to decipher its elusive pharmacological role in the brain and periphery such as the liver and kidneys.
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Affiliation(s)
- Stefanie Kickinger
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Pharmaceutical Science, University of Vienna, Vienna, Austria
| | - Maria E K Lie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Akihiro Suemasa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Anas Al-Khawaja
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Koichi Fujiwara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Mizuki Watanabe
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Kristine S Wilhelmsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christina B Falk-Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Satoshi Shuto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Gerhard F Ecker
- Department of Pharmaceutical Science, University of Vienna, Vienna, Austria
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Gryzło B, Zaręba P, Malawska K, Mazur G, Rapacz A, Ła̧tka K, Höfner GC, Latacz G, Bajda M, Sałat K, Wanner KT, Malawska B, Kulig K. Novel Functionalized Amino Acids as Inhibitors of GABA Transporters with Analgesic Activity. ACS Chem Neurosci 2021; 12:3073-3100. [PMID: 34347423 PMCID: PMC8397297 DOI: 10.1021/acschemneuro.1c00351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
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Neuropathic pain
resistance to pharmacotherapy has encouraged researchers
to develop effective therapies for its treatment. γ-Aminobutyric
acid (GABA) transporters 1 and 4 (mGAT1 and mGAT4) have been increasingly
recognized as promising drug targets for neuropathic pain (NP) associated
with imbalances in inhibitory neurotransmission. In this context,
we designed and synthesized new functionalized amino acids as inhibitors
of GABA uptake and assessed their activities toward all four mouse
GAT subtypes (mGAT1–4). According to the obtained results,
compounds 2RS,4RS-39c (pIC50 (mGAT4) = 5.36), 50a (pIC50 (mGAT2) = 5.43), and 56a (with moderate subtype selectivity
that favored mGAT4, pIC50 (mGAT4) = 5.04) were of particular
interest and were therefore evaluated for their cytotoxic and hepatotoxic
effects. In a set of in vivo experiments, both compounds 50a and 56a showed antinociceptive properties
in three rodent models of NP, namely, chemotherapy-induced neuropathic
pain models (the oxaliplatin model and the paclitaxel model) and the
diabetic neuropathic pain model induced by streptozotocin; however
compound 56a demonstrated predominant activity. Since
impaired motor coordination is also observed in neuropathic pain conditions,
we have pointed out that none of the test compounds induced motor
deficits in the rotarod test.
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Affiliation(s)
- Beata Gryzło
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Paula Zaręba
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Katarzyna Malawska
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Gabriela Mazur
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Anna Rapacz
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Kamil Ła̧tka
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Georg C. Höfner
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München Butenandtstraße 5-13, 81377 Munich, Germany
| | - Gniewomir Latacz
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Marek Bajda
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Kinga Sałat
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Klaus T. Wanner
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München Butenandtstraße 5-13, 81377 Munich, Germany
| | - Barbara Malawska
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
| | - Katarzyna Kulig
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Kraków, Poland
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4
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Zaręba P, Sałat K, Höfner GC, Łątka K, Bajda M, Latacz G, Kotniewicz K, Rapacz A, Podkowa A, Maj M, Jóźwiak K, Filipek B, Wanner KT, Malawska B, Kulig K. Development of tricyclic N-benzyl-4-hydroxybutanamide derivatives as inhibitors of GABA transporters mGAT1-4 with anticonvulsant, antinociceptive, and antidepressant activity. Eur J Med Chem 2021; 221:113512. [PMID: 34015586 DOI: 10.1016/j.ejmech.2021.113512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 01/04/2023]
Abstract
γ-Aminobutyric acid (GABA) neurotransmission has a significant impact on the proper functioning of the central nervous system. Numerous studies have indicated that inhibitors of the GABA transporters mGAT1-4 offer a promising strategy for the treatment of several neurological disorders, including epilepsy, neuropathic pain, and depression. Following our previous results, herein, we report the synthesis, biological evaluation, and structure-activity relationship studies supported by molecular docking and molecular dynamics of a new series of N-benzyl-4-hydroxybutanamide derivatives regarding their inhibitory potency toward mGAT1-4. This study allowed us to identify compound 23a (N-benzyl-4-hydroxybutanamide bearing a dibenzocycloheptatriene moiety), a nonselective GAT inhibitor with a slight preference toward mGAT4 (pIC50 = 5.02 ± 0.11), and compound 24e (4-hydroxy-N-[(4-methylphenyl)-methyl]butanamide bearing a dibenzocycloheptadiene moiety) with relatively high inhibitory activity toward mGAT2 (pIC50 = 5.34 ± 0.09). In a set of in vivo experiments, compound 24e successively showed predominant anticonvulsant activity and antinociception in the formalin model of tonic pain. In contrast, compound 23a showed significant antidepressant-like properties in mice. These results were consistent with the available literature data, which indicates that, apart from seizure control, GABAergic neurotransmission is also involved in the pathophysiology of several psychiatric diseases, however alternative mechanisms underlying this action cannot be excluded. Finally, it is worth noting that the selected compounds showed unimpaired locomotor skills that have been indicated to give reliable results in behavioral assays.
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Affiliation(s)
- Paula Zaręba
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland.
| | - Kinga Sałat
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Georg C Höfner
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München Butenandtstr, 5-13, 81377, Munich, Germany
| | - Kamil Łątka
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Marek Bajda
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Gniewomir Latacz
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Krzysztof Kotniewicz
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Anna Rapacz
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Adrian Podkowa
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Maciej Maj
- Department of Biopharmacy, Medical University of Lublin, ul. W. Chodzki 4a, 20-093, Lublin, Poland
| | - Krzysztof Jóźwiak
- Department of Biopharmacy, Medical University of Lublin, ul. W. Chodzki 4a, 20-093, Lublin, Poland
| | - Barbara Filipek
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Klaus T Wanner
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München Butenandtstr, 5-13, 81377, Munich, Germany
| | - Barbara Malawska
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
| | - Katarzyna Kulig
- Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St, 30-688, Kraków, Poland
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5
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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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6
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Lie MEK, Kickinger S, Skovgaard-Petersen J, Ecker GF, Clausen RP, Schousboe A, White HS, Wellendorph P. Pharmacological Characterization of a Betaine/GABA Transporter 1 (BGT1) Inhibitor Displaying an Unusual Biphasic Inhibition Profile and Anti-seizure Effects. Neurochem Res 2020; 45:1551-1565. [PMID: 32248400 PMCID: PMC7297817 DOI: 10.1007/s11064-020-03017-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/09/2020] [Accepted: 03/18/2020] [Indexed: 12/01/2022]
Abstract
Focal epileptic seizures can in some patients be managed by inhibiting γ-aminobutyric acid (GABA) uptake via the GABA transporter 1 (GAT1) using tiagabine (Gabitril®). Synergistic anti-seizure effects achieved by inhibition of both GAT1 and the betaine/GABA transporter (BGT1) by tiagabine and EF1502, compared to tiagabine alone, suggest BGT1 as a target in epilepsy. Yet, selective BGT1 inhibitors are needed for validation of this hypothesis. In that search, a series of BGT1 inhibitors typified by (1R,2S)-2-((4,4-bis(3-methylthiophen-2-yl)but-3-en-yl)(methyl)amino)cyclohexanecarboxylic acid (SBV2-114) was developed. A thorough pharmacological characterization of SBV2-114 using a cell-based [3H]GABA uptake assay at heterologously expressed BGT1, revealed an elusive biphasic inhibition profile with two IC50 values (4.7 and 556 μM). The biphasic profile was common for this structural class of compounds, including EF1502, and was confirmed in the MDCK II cell line endogenously expressing BGT1. The possibility of two binding sites for SBV2-114 at BGT1 was assessed by computational docking studies and examined by mutational studies. These investigations confirmed that the conserved residue Q299 in BGT1 is involved in, but not solely responsible for the biphasic inhibition profile of SBV2-114. Animal studies revealed anti-seizure effects of SBV2-114 in two mouse models, supporting a function of BGT1 in epilepsy. However, as SBV2-114 is apparent to be rather non-selective for BGT1, the translational relevance of this observation is unknown. Nevertheless, SBV2-114 constitutes a valuable tool compound to study the molecular mechanism of an emerging biphasic profile of BGT1-mediated GABA transport and the putative involvement of two binding sites for this class of compounds.
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Affiliation(s)
- Maria E K Lie
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Stefanie Kickinger
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | | | - Gerhard F Ecker
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Rasmus P Clausen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - H Steve White
- Department of Pharmacy, University of Washington, Washington, USA
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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7
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Zaręba P, Gryzło B, Malawska K, Sałat K, Höfner GC, Nowaczyk A, Fijałkowski Ł, Rapacz A, Podkowa A, Furgała A, Żmudzki P, Wanner KT, Malawska B, Kulig K. Novel mouse GABA uptake inhibitors with enhanced inhibitory activity toward mGAT3/4 and their effect on pain threshold in mice. Eur J Med Chem 2020; 188:111920. [DOI: 10.1016/j.ejmech.2019.111920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 11/16/2019] [Accepted: 11/27/2019] [Indexed: 12/12/2022]
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8
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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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9
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Tóth K, Höfner G, Wanner KT. Synthesis and biological evaluation of novel N-substituted nipecotic acid derivatives with a cis-alkene spacer as GABA uptake inhibitors. Bioorg Med Chem 2019; 27:822-831. [DOI: 10.1016/j.bmc.2019.01.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/15/2019] [Accepted: 01/23/2019] [Indexed: 10/27/2022]
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10
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Nowaczyk A, Fijałkowski Ł, Kowalska M, Podkowa A, Sałat K. Studies on the Activity of Selected Highly Lipophilic Compounds toward hGAT1 Inhibition. Part II. ACS Chem Neurosci 2019; 10:337-347. [PMID: 30222312 DOI: 10.1021/acschemneuro.8b00282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In this paper, we describe the latest results involving molecular modeling and pharmacodynamic studies of the selected highly lipophilic compounds acting by human GABA transporter 1 (hGAT1) inhibition. The chemical interaction of 17 GABA analogues with a model of hGAT1 is described using the molecular docking method. The biological role of GAT1 is related to the regulation of GABA level in the central nervous system and GAT1 inhibition plays an important role in the control of seizure threshold. To confirm that GAT1 can be also a molecular target for drugs used to treat other neurological and psychiatric diseases (e.g., pain and anxiety), in the in vivo part of this study, potential antinociceptive and anxiolytic-like properties of tiagabine, a selective GAT1 inhibitor, are described.
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Affiliation(s)
- Alicja Nowaczyk
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland
| | - Łukasz Fijałkowski
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland
| | - Magdalena Kowalska
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland
| | - Adrian Podkowa
- Chair of Inorganic and Analytical Chemistry, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Kraków, Poland
| | - Kinga Sałat
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland
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11
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Hauke TJ, Höfner G, Wanner KT. Generation and screening of pseudostatic hydrazone libraries derived from 5-substituted nipecotic acid derivatives at the GABA transporter mGAT4. Bioorg Med Chem 2019; 27:144-152. [DOI: 10.1016/j.bmc.2018.11.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/29/2018] [Accepted: 11/20/2018] [Indexed: 10/27/2022]
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12
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Tóth K, Höfner G, Wanner KT. Synthesis and biological evaluation of novel N-substituted nipecotic acid derivatives with a trans-alkene spacer as potent GABA uptake inhibitors. Bioorg Med Chem 2018; 26:5944-5961. [DOI: 10.1016/j.bmc.2018.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 12/13/2022]
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13
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Suemasa A, Watanabe M, Kobayashi T, Suzuki H, Fukuda H, Minami M, Shuto S. Design and synthesis of cyclopropane-based conformationally restricted GABA analogues as selective inhibitors for betaine/GABA transporter 1. Bioorg Med Chem Lett 2018; 28:3395-3399. [DOI: 10.1016/j.bmcl.2018.08.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 08/25/2018] [Accepted: 08/25/2018] [Indexed: 12/26/2022]
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14
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Nowaczyk A, Fijałkowski Ł, Zaręba P, Sałat K. Docking and pharmacodynamic studies on hGAT1 inhibition activity in the presence of selected neuronal and astrocytic inhibitors. Part I. J Mol Graph Model 2018; 85:171-181. [PMID: 30219588 DOI: 10.1016/j.jmgm.2018.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/11/2018] [Accepted: 09/02/2018] [Indexed: 12/30/2022]
Abstract
Inhibition of 4-aminobutanoic acid (GABA) uptake is a strategy for enhancing GABA transmission. The utility of this approach is demonstrated by the successful development of such agents for the treatment of epilepsy and pain. Existing reports on acute brain slice preparations indicate the intersecting of complementary channels and receptors sets between astrocytes and neurons cells. Thorough analysis of astroglial cells by means of molecular and functional studies demonstrated their active modulatory role in intercellular communication. The chemical interactions between sixteen GABA analogues and isoform of hGAT1 is outlined in the light of molecular docking results. In the in vivo part antinociceptive properties of racemic nipecotic acid, its R and S enantiomers and isonipecotic acid, each administered intraperitoneally at 3 fixed doses (10, 30 and 100 mg/kg), were assessed in a thermally-induced acute pain model i.e. the mouse hot plate test. Docking analyses provided complex binding energies, specific h-bond components, and h-bond properties, such as energies, distances and angles. In vivo tests revealed statistically significant antinociceptive properties of isonipecotic acid (10 and 30 mg/kg), R-nipecotic acid (30 and 100 mg/kg) and S-nipecotic acid (100 mg/kg) in mice. The docking data endorse the hypothesis of correlation between the strength of their chemical interactions with hGAT1 and analgesic action of studied compounds.
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Affiliation(s)
- Alicja Nowaczyk
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland.
| | - Łukasz Fijałkowski
- Department of Organic Chemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland.
| | - Paula Zaręba
- Department of Physicochemical Drug Analysis, Chair of Pharmaceutical Chemistry, Jagiellonian University Medical College, 9 Medyczna St., 30 - 688, Krakow, Poland.
| | - Kinga Sałat
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30 - 688, Krakow, Poland.
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15
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Tóth K, Höfner G, Wanner KT. Synthesis and biological evaluation of novel N-substituted nipecotic acid derivatives with an alkyne spacer as GABA uptake inhibitors. Bioorg Med Chem 2018; 26:3668-3687. [DOI: 10.1016/j.bmc.2018.05.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/25/2018] [Accepted: 05/30/2018] [Indexed: 12/14/2022]
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16
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Jørgensen L, Al-Khawaja A, Kickinger S, Vogensen SB, Skovgaard-Petersen J, Rosenthal E, Borkar N, Löffler R, Madsen KK, Bräuner-Osborne H, Schousboe A, Ecker GF, Wellendorph P, Clausen RP. Structure–Activity Relationship, Pharmacological Characterization, and Molecular Modeling of Noncompetitive Inhibitors of the Betaine/γ-Aminobutyric Acid Transporter 1 (BGT1). J Med Chem 2017; 60:8834-8846. [DOI: 10.1021/acs.jmedchem.7b00924] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Lars Jørgensen
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Anas Al-Khawaja
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Stefanie Kickinger
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Stine B. Vogensen
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jonas Skovgaard-Petersen
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Emil Rosenthal
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Nrupa Borkar
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Rebekka Löffler
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Karsten K. Madsen
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Gerhard F. Ecker
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Petrine Wellendorph
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Rasmus P. Clausen
- Department of Drug
Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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17
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Wellendorph P, Jacobsen J, Skovgaard-Petersen J, Jurik A, Vogensen SB, Ecker G, Schousboe A, Krogsgaard-Larsen P, Clausen RP. γ-Aminobutyric Acid and Glycine Neurotransmitter Transporters. METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2017. [DOI: 10.1002/9783527679430.ch4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Petrine Wellendorph
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
| | - Julie Jacobsen
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
| | - Jonas Skovgaard-Petersen
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
| | - Andreas Jurik
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14, A-1090 Vienna Austria
| | - Stine B. Vogensen
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
| | - Gerhard Ecker
- University of Vienna; Department of Pharmaceutical Chemistry; Althanstrasse 14, A-1090 Vienna Austria
| | - Arne Schousboe
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
| | - Povl Krogsgaard-Larsen
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
| | - Rasmus P. Clausen
- University of Copenhagen; Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology; Universitetsparken 2, DK-2100 Copenhagen Denmark
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18
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Damgaard M, Haugaard AS, Kickinger S, Al-Khawaja A, Lie MEK, Ecker GF, Clausen RP, Frølund B. Development of Non-GAT1-Selective Inhibitors: Challenges and Achievements. ADVANCES IN NEUROBIOLOGY 2017; 16:315-332. [DOI: 10.1007/978-3-319-55769-4_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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19
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Astrocytic GABA Transporters: Pharmacological Properties and Targets for Antiepileptic Drugs. ADVANCES IN NEUROBIOLOGY 2017; 16:283-296. [PMID: 28828616 DOI: 10.1007/978-3-319-55769-4_14] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inactivation of GABA-mediated neurotransmission is achieved by high-affinity transporters located at both GABAergic neurons and the surrounding astrocytes. Early studies of the pharmacological properties of neuronal and glial GABA transporters suggested that different types of transporters might be expressed in the two cell types, and such a scenario was confirmed by the cloning of four distinctly different GABA transporters from a number of different species. These GABA-transport entities have been extensively characterized using a large number of GABA analogues of restricted conformation, and several of these compounds have been shown to exhibit pronounced anticonvulsant activity in a variety of animal seizure models. As proof of concept of the validity of this drug development approach, one GABA-transport inhibitor, tiagabine, has been developed as a clinically active antiepileptic drug. This review provides a detailed account of efforts to design new subtype-selective GABA-transport inhibitors aiming at identifying novel antiepileptic drug candidates.
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Glial GABA Transporters as Modulators of Inhibitory Signalling in Epilepsy and Stroke. ADVANCES IN NEUROBIOLOGY 2017; 16:137-167. [PMID: 28828609 DOI: 10.1007/978-3-319-55769-4_7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Imbalances in GABA-mediated tonic inhibition are involved in several pathophysiological conditions. A classical way of controlling tonic inhibition is through pharmacological intervention with extrasynaptic GABAA receptors that sense ambient GABA and mediate a persistent GABAergic conductance. An increase in tonic inhibition may, however, also be obtained indirectly by inhibiting glial GABA transporters (GATs). These are sodium-coupled membrane transport proteins that normally act to terminate GABA neurotransmitter action by taking up GABA into surrounding astrocytes. The aim of the review is to provide an overview of glial GATs in regulating tonic inhibition, especially in epilepsy and stroke. This entails a comprehensive summary of changes known to occur in GAT expression levels and signalling following epileptic and ischemic insults. Further, we discuss the accumulating pharmacological evidence for targeting GATs in these diseases.
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21
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Jiang Y, Liu Z, Holenz J, Yang H. Competitive Intelligence–based Lead Generation and Fast Follower Approaches. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/9783527677047.ch08] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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22
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23
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Vogensen SB, Jørgensen L, Madsen KK, Jurik A, Borkar N, Rosatelli E, Nielsen B, Ecker GF, Schousboe A, Clausen RP. Structure activity relationship of selective GABA uptake inhibitors. Bioorg Med Chem 2015; 23:2480-8. [DOI: 10.1016/j.bmc.2015.03.060] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/12/2015] [Accepted: 03/19/2015] [Indexed: 10/23/2022]
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24
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Jurik A, Zdrazil B, Holy M, Stockner T, Sitte HH, Ecker GF. A binding mode hypothesis of tiagabine confirms liothyronine effect on γ-aminobutyric acid transporter 1 (GAT1). J Med Chem 2015; 58:2149-58. [PMID: 25679268 PMCID: PMC4360375 DOI: 10.1021/jm5015428] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
Elevating
GABA levels in the synaptic cleft by inhibiting its reuptake
carrier GAT1 is an established approach for the treatment of CNS disorders
like epilepsy. With the increasing availability of crystal structures
of transmembrane transporters, structure-based approaches to elucidate
the molecular basis of ligand–transporter interaction also
become feasible. Experimental data guided docking of derivatives of
the GAT1 inhibitor tiagabine into a protein homology model of GAT1
allowed derivation of a common binding mode for this class of inhibitors
that is able to account for the distinct structure–activity
relationship pattern of the data set. Translating essential binding
features into a pharmacophore model followed by in silico screening
of the DrugBank identified liothyronine as a drug potentially exerting
a similar effect on GAT1. Experimental testing further confirmed the
GAT1 inhibiting properties of this thyroid hormone.
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Affiliation(s)
- Andreas Jurik
- University of Vienna , Department of Pharmaceutical Chemistry, Division of Drug Design and Medicinal Chemistry, Althanstraße 14, 1090 Vienna, Austria
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25
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Madsen KK, Hansen GH, Danielsen EM, Schousboe A. The subcellular localization of GABA transporters and its implication for seizure management. Neurochem Res 2014; 40:410-9. [PMID: 25519681 DOI: 10.1007/s11064-014-1494-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 11/27/2014] [Accepted: 12/01/2014] [Indexed: 10/24/2022]
Abstract
The ability to modulate the synaptic GABA levels has been demonstrated by using the clinically effective and selective GAT1 inhibitor tiagabine [(R)-N-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]nipecotic acid]. N-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]-3-hydroxy-4-(methylamino)-4,5,6,7-tetrahydrobenzo[d]isoxazol-3-ol (EF1502) which not only inhibits GAT1 like tiagabine but also BGT1 has been shown to modulate extrasynaptic GABA levels. The simultaneous inhibition of synaptic and extrasynaptic GABA transporters using tiagabine and EF1502, respectively has been demonstrated to exert a synergistic anticonvulsant effect in several seizure models in mice. The pharmacological profile of these and similar compounds has been thoroughly investigated in in vitro systems, comparing the GAT subtype selectivity with the ability to inhibit GABA uptake in primary cultures of neurons and astrocytes. However, an exact explanation has not yet been found. In the present study, the ability of GATs to form homo and/or heterodimers was investigated as well as to which membrane micro environment the GATs reside. To investigate dimerization of GATs, fusion proteins of GATs tagged with either yellow fluorescent protein or cerulean fluorescent protein were made and fluorescence resonance energy transfer (FRET) was measured. It was found that GATs form both homo- and hetero-dimers in N2A and HEK-293 cells. Microdomain localization of GATs as investigated by detergent resistant membrane fractions after treatment of tissue with Brij-98 or Triton X-100 revealed that BGT1 and GAT1 mostly localize to non-membrane rafts independent of the detergent used. However, GAT3 localizes to membrane rafts when using Brij-98. Taken together, these results suggest that the observed hetero dimerization of GATs in the FRET study is unlikely to have functional implications since the GATs are located to very different cellular compartments and cell types.
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Affiliation(s)
- Karsten K Madsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark,
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26
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Kern FT, Wanner KT. Generation and Screening of Oxime Libraries Addressing the Neuronal GABA Transporter GAT1. ChemMedChem 2014; 10:396-410. [DOI: 10.1002/cmdc.201402376] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Indexed: 01/03/2023]
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27
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Kobayashi T, Suemasa A, Igawa A, Ide S, Fukuda H, Abe H, Arisawa M, Minami M, Shuto S. Conformationally Restricted GABA with Bicyclo[3.1.0]hexane Backbone as the First Highly Selective BGT-1 Inhibitor. ACS Med Chem Lett 2014; 5:889-93. [PMID: 25147609 DOI: 10.1021/ml500134k] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/16/2014] [Indexed: 11/29/2022] Open
Abstract
On the basis of the three-dimensional diversity-oriented conformational restriction strategy using key chiral cyclopropane units, we previously identified 3 ((2S,3R)-4-amino-3,4-methanobutyric acid) with a chiral trans-cyclopropane structure as a γ-aminobutyric acid (GABA) transporter inhibitor selective for GABA transporter (GAT) subtypes GAT-3 and BGT-1 (betaine/GABA transporter-1). Further conformational restriction of 3 with the rigid bicyclo[3.1.0]hexane backbone led to the successful development of the first highly potent and selective BGT-1 inhibitor 4 (IC50 = 0.59 μM). The bioactive conformation of 3 for BGT-1 was also identified.
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Affiliation(s)
- Takaaki Kobayashi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Akihiro Suemasa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Arisa Igawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Soichiro Ide
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Hayato Fukuda
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Hiroshi Abe
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Mitsuhiro Arisawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Masabumi Minami
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Satoshi Shuto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12,
Nishi-6, Kita-ku, Sapporo 060-0812, Japan
- Center for Research
and Education on Drug Discovery, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan
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28
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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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Hiramatsu M. [Functional role for GABA transporters in the CNS]. Nihon Yakurigaku Zasshi 2014; 143:187-192. [PMID: 24717607 DOI: 10.1254/fpj.143.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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30
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Schousboe A, Madsen KK, Barker-Haliski ML, White HS. The GABA Synapse as a Target for Antiepileptic Drugs: A Historical Overview Focused on GABA Transporters. Neurochem Res 2014; 39:1980-7. [DOI: 10.1007/s11064-014-1263-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 01/18/2023]
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31
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2-Substituted 4-hydroxybutanamides as potential inhibitors of γ-aminobutyric acid transporters mGAT1–mGAT4: Synthesis and biological evaluation. Bioorg Med Chem 2013; 21:5154-67. [DOI: 10.1016/j.bmc.2013.06.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/12/2013] [Accepted: 06/16/2013] [Indexed: 11/22/2022]
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32
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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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33
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Cyclopropane-based conformational restriction of GABA by a stereochemical diversity-oriented strategy: identification of an efficient lead for potent inhibitors of GABA transports. Bioorg Med Chem 2013; 21:4938-50. [PMID: 23886812 DOI: 10.1016/j.bmc.2013.06.063] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/26/2013] [Accepted: 06/26/2013] [Indexed: 12/22/2022]
Abstract
A series of cyclopropane-based conformationally restricted γ-aminobutyric acid (GABA) analogs with stereochemical diversity, that is, the trans- and cis-2,3-methano analogs Ia and Ib and their enantiomers ent-Ia and ent-Ib, and also the trans- and cis-3,4-methano analogs IIa and IIb and their enantiomers ent-IIa and ent-Iib, were synthesized from the chiral cyclopropane units Type-a and Type-b that we developed. These analogs were systematically evaluated with four GABA transporter (GAT) subtypes. The trans-3,4-methano analog IIa had inhibitory effects on GAT3 (IC50=23.9μM) and betaine-GABA transporter1 (5.48μM), indicating its potential as an effective lead compound for the development of potent GAT inhibitors due to its hydrophilic and low molecular weight properties and excellent ligand efficiency.
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34
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Schousboe A, Bak LK, Waagepetersen HS. Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA. Front Endocrinol (Lausanne) 2013; 4:102. [PMID: 23966981 PMCID: PMC3744088 DOI: 10.3389/fendo.2013.00102] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/31/2013] [Indexed: 01/20/2023] Open
Abstract
Glutamate and GABA are the quantitatively major neurotransmitters in the brain mediating excitatory and inhibitory signaling, respectively. These amino acids are metabolically interrelated and at the same time they are tightly coupled to the intermediary metabolism including energy homeostasis. Astrocytes play a pivotal role in the maintenance of the neurotransmitter pools of glutamate and GABA since only these cells express pyruvate carboxylase, the enzyme required for de novo synthesis of the two amino acids. Such de novo synthesis is obligatory to compensate for catabolism of glutamate and GABA related to oxidative metabolism when the amino acids are used as energy substrates. This, in turn, is influenced by the extent to which the cycling of the amino acids between neurons and astrocytes may occur. This cycling is brought about by the glutamate/GABA - glutamine cycle the operation of which involves the enzymes glutamine synthetase (GS) and phosphate-activated glutaminase together with the plasma membrane transporters for glutamate, GABA, and glutamine. The distribution of these proteins between neurons and astrocytes determines the efficacy of the cycle and it is of particular importance that GS is exclusively expressed in astrocytes. It should be kept in mind that the operation of the cycle is associated with movement of ammonia nitrogen between the two cell types and different mechanisms which can mediate this have been proposed. This review is intended to delineate the above mentioned processes and to discuss quantitatively their relative importance in the homeostatic mechanisms responsible for the maintenance of optimal conditions for the respective neurotransmission processes to operate.
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Affiliation(s)
- Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Arne Schousboe, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark e-mail:
| | - Lasse K. Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helle S. Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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