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He L, Duan X, Li S, Zhang R, Dai X, Lu M. Unveiling the role of astrocytes in postoperative cognitive dysfunction. Ageing Res Rev 2024; 95:102223. [PMID: 38325753 DOI: 10.1016/j.arr.2024.102223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/09/2024]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder, characterized by progressive cognitive decline and the accumulation of amyloid-beta plaques, tau tangles, and neuroinflammation in the brain. Postoperative cognitive dysfunction (POCD) is a prevalent and debilitating condition characterized by cognitive decline following neuroinflammation and oxidative stress induced by procedures. POCD and AD are two conditions that share similarities in the underlying mechanisms and pathophysiology. Compared to normal aging individuals, individuals with POCD are at a higher risk for developing AD. Emerging evidence suggests that astrocytes, the most abundant glial cells in the central nervous system, play a critical role in the pathogenesis of these conditions. Comprehensive functions of astrocyte in AD has been extensively explored, but very little is known about POCD may experience late-onset AD pathogenesis. Herein, in this context, we mainly explore the multifaceted roles of astrocytes in the context of POCD, highlighting their involvement in neuroinflammation, neurotransmitter regulation, synaptic plasticity and neurotrophic support, and discuss how POCD may augment the onset of AD. Additionally, we discuss potential therapeutic strategies targeting astrocytes to mitigate or prevent POCD, which hold promise for improving the quality of life for patients undergoing surgeries and against AD in the future.
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Affiliation(s)
- Liang He
- Department of Anesthesiology, Yan'an Hospital of Kunming City, Kunming 650051, China.
| | - Xiyuan Duan
- Department of Anesthesiology, Yan'an Hospital of Kunming City, Kunming 650051, China
| | - Shikuo Li
- Department of Anesthesiology, Yan'an Hospital of Kunming City, Kunming 650051, China
| | - Ruqiang Zhang
- Department of Anesthesiology, Yan'an Hospital of Kunming City, Kunming 650051, China
| | - Xulei Dai
- Department of Clinical Laboratory Science, Xingtai Medical College, Xingtai 050054, China
| | - Meilin Lu
- Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming 650032, China.
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2
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Calaza MI, Sayago FJ, Laborda P, Cativiela C. Synthesis of [c]-Fused Bicyclic Proline Analogues. European J Org Chem 2015. [DOI: 10.1002/ejoc.201403121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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3
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Probing for Improved Potency and In Vivo Bioavailability of Excitatory Amino Acid Transporter Subtype 1 Inhibitors UCPH-101 and UCPH-102: Design, Synthesis and Pharmacological Evaluation of Substituted 7-Biphenyl Analogs. Neurochem Res 2014; 39:1964-79. [DOI: 10.1007/s11064-014-1264-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/19/2014] [Accepted: 02/20/2014] [Indexed: 02/02/2023]
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4
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Itoh M, Hiroi T, Nishibori N, Sagara T, Her S, Lee MS, Morita K. Trichostatin A enhances glutamate transporter GLT-1 mRNA levels in C6 glioma cells via neurosteroid-mediated cell differentiation. J Mol Neurosci 2012; 49:21-7. [PMID: 22711563 DOI: 10.1007/s12031-012-9842-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 06/11/2012] [Indexed: 01/03/2023]
Abstract
The neurotoxic effects of excitatory amino acids (EAAs) are suggested to be connected with the chronic loss of neuronal cells, thereby being responsible for the age-related neurodegenerative diseases. Therefore, it seems conceivable that the excitatory amino acid transporters may contribute to the protection of neuronal cells against the excitotoxic damage by facilitating the removal of EAAs from the brain tissue. On the other hand, previous studies have suggested that glial cell differentiation may be involved in the protection and recovery of neural function probably through the elevation of BDNF gene expression in the brain. Based on these findings, histone deacetylase (HDAC) inhibitors are assumed to induce glutamate transporter-1 (GLT-1) gene expression probably through the promotion of glial cell differentiation. Then, we examined the effects of HDAC inhibitors on GLT-1 mRNA levels in rat C6 glioma cells and found that trichostatin A can induce GLT-1 gene transcription following steroid 5α-reductase and GFAP gene expression. Therefore, it seems conceivable that glial cell differentiation may play a potential role in the removal of EAAs probably through the expression of GLT-1, thereby being involved in the protection of neuronal cells against the chronic excitotoxic insults in the brain.
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Affiliation(s)
- Mari Itoh
- Laboratory of Neuropharmacology, Department of Nursing, Shikoku University School of Health Sciences, Ohjin, Tokushima 771-1192, Japan
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5
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Luethi E, Nguyen KT, Bürzle M, Blum LC, Suzuki Y, Hediger M, Reymond JL. Identification of selective norbornane-type aspartate analogue inhibitors of the glutamate transporter 1 (GLT-1) from the chemical universe generated database (GDB). J Med Chem 2010; 53:7236-50. [PMID: 20812729 DOI: 10.1021/jm100959g] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A variety of conformationally constrained aspartate and glutamate analogues inhibit the glutamate transporter 1 (GLT-1, also known as EAAT2). To expand the search for such analogues, a virtual library of aliphatic aspartate and glutamate analogues was generated starting from the chemical universe database GDB-11, which contains 26.4 million possible molecules up to 11 atoms of C, N, O, F, resulting in 101026 aspartate analogues and 151285 glutamate analogues. Virtual screening was realized by high-throughput docking to the glutamate binding site of the glutamate transporter homologue from Pyrococcus horikoshii (PDB code: 1XFH ) using Autodock. Norbornane-type aspartate analogues were selected from the top-scoring virtual hits and synthesized. Testing and optimization led to the identification of (1R*,2R*,3S*,4R*,6R*)-2-amino-6-phenethyl-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid as a new inhibitor of GLT-1 with IC(50) = 1.4 μM against GLT-1 and no inhibition of the related transporter EAAC1. The systematic diversification of known ligands by enumeration with help of GDB followed by virtual screening, synthesis, and testing as exemplified here provides a general strategy for drug discovery.
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Affiliation(s)
- Erika Luethi
- Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland
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6
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Zheng X, Diao L, Ekins S, Polli JE. Why we should be vigilant: drug cytotoxicity observed with in vitro transporter inhibition studies. Biochem Pharmacol 2010; 80:1087-92. [PMID: 20599790 DOI: 10.1016/j.bcp.2010.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 06/11/2010] [Accepted: 06/15/2010] [Indexed: 01/11/2023]
Abstract
From routine in vitro drug-transporter inhibition assays, observed inhibition is typically assumed from direct interaction with the transporter. Other mechanisms that possibly reduce substrate uptake are not frequently fully examined. The objective of this study was to investigate the association of transporter inhibition with drug cytotoxicity. From a pool of drugs that were identified as known ASBT or OCTN2 inhibitors, 21 drugs were selected to screen inhibitory potency of their prototypical substrate and cytotoxicity against three human sodium-dependent solute carrier (SLC) transporters: apical sodium-dependent bile acid transporter (ASBT), organic cation/carnitine transporter (OCTN2), and the excitatory amino acid transporter 4 (EAAT4) in stable cell lines. Twenty drugs showed apparent inhibition in OCTN2-MDCK and ASBT-MDCK. Four dihydropyridine calcium channel blockers were cytotoxic to MDCK cells, and the observed cytotoxicity of three of them accounted for their apparent OCTN2 inhibition, and consequently were classified as non-OCTN2 inhibitors. Meanwhile, since their cytotoxicity only moderately contributed to ASBT inhibition, these three were still considered ASBT inhibitors. Four other drugs showed apparent inhibition in EAAT4-HEK cells, and cytotoxicity of three drugs corresponded with their inhibition of this transporter. Therefore, cytotoxicity significantly affected EAAT4 observations. Results showed the potential of cytotoxicity as a mechanism that can account for apparent in vitro transporter inhibition. Drug cytotoxicity varied in different cell lines, which could increase false positives for pharmacophore development.
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Affiliation(s)
- Xiaowan Zheng
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, 20 N. Pine Street, Baltimore, MD 21201, United States
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7
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8
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Synthesis of new β- and γ-benzyloxy-S-glutamic acid derivatives and evaluation of their activity as inhibitors of excitatory amino acid transporters. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.05.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Sagot E, Jensen AA, Pickering DS, Pu X, Umberti M, Stensbøl TB, Nielsen B, Assaf Z, Aboab B, Bolte J, Gefflaut T, Bunch L. Chemo-enzymatic synthesis of (2S,4R)-2-amino-4-(3-(2,2-diphenylethylamino)-3-oxopropyl)pentanedioic acid: a novel selective inhibitor of human excitatory amino acid transporter subtype 2. J Med Chem 2008; 51:4085-92. [PMID: 18578477 DOI: 10.1021/jm800091e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the mammalian central nervous system (CNS), the action of sodium dependent excitatory amino acid transporters (EAATs) is responsible for termination of glutamatergic neurotransmission by reuptake of ( S) -glutamate (Glu) from the synaptic cleft. Five EAAT subtypes have been identified, of which EAAT1-4 are present in the CNS, while EAAT5 is localized exclusively in the retina. In this study, we have used an enantioselective chemo-enzymatic strategy to synthesize 10 new Glu analogues 2a- k ( 2d is exempt) with different functionalities in the 4 R-position and characterized their pharmacological properties at the human EAAT1-3. In particular, one compound, 2k, displayed a significant preference as inhibitor of the EAAT2 subtype over EAAT1,3. The compound also displayed very low affinities toward ionotropic and metabotropic Glu receptors, making it the most selective EAAT2 inhibitor described so far.
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Affiliation(s)
- Emanuelle Sagot
- Departement de Chimie, Universite Blaise Pascal, 63177 Aubiere Cedex, France
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10
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Synthesis of enantiomerically pure HIP-A and HIP-B and investigation of their activity as inhibitors of excitatory amino acid transporters. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Pedretti A, De Luca L, Sciarrillo C, Vistoli G. Fragmental Modeling of Human Glutamate Transporter EAAT1 and Analysis of its Binding Modes by Docking and Pharmacophore Mapping. ChemMedChem 2008; 3:79-90. [DOI: 10.1002/cmdc.200700197] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Tilleux S, Hermans E. Neuroinflammation and regulation of glial glutamate uptake in neurological disorders. J Neurosci Res 2007; 85:2059-70. [PMID: 17497670 DOI: 10.1002/jnr.21325] [Citation(s) in RCA: 284] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Oxidative stress, neuroinflammation, and excitotoxicity are frequently considered distinct but common hallmarks of several neurological disorders, including Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and Alzheimer's disease. Although neuron degeneration and death are the ultimate consequences of these pathological processes, it is now widely accepted that alterations in the function of surrounding glial cells are key features in the progression of these diseases. In response to alteration in their local environment, microglia, commonly considered the resident immune cells of the nervous parenchyma, become activated and release a variety of soluble factors. Among these, proinflammatory cytokines and free radicals actively participate in the degenerative insults. In addition, excitotoxic neuronal damage resulting from excessive glutamate is frequently associated with impaired handling of extracellular glutamate by gliotic astrocytes. Although several research projects have focused on the biochemical mechanisms of the regulation of glial glutamate transporters, a relationship between activation of microglia and modulation of astrocytic glutamate uptake is now suggested. The aim of this review is to summarize and discuss the data showing an influence of inflammatory mediators and related free radicals on the expression and activity of glial glutamate transporters.
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Affiliation(s)
- Sébastien Tilleux
- Laboratoire de Pharmacologie Expérimentale, Faculté de Médecine, Université catholique de Louvain, Brussels, Belgium
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13
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Riluzole enhances the activity of glutamate transporters GLAST, GLT1 and EAAC1. Eur J Pharmacol 2007; 578:171-6. [PMID: 18036519 DOI: 10.1016/j.ejphar.2007.10.023] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 10/11/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
Abstract
Riluzole exerts a neuroprotective effect through different mechanisms, including action on glutamatergic transmission. We investigated whether this drug affects glutamate transporter-mediated uptake, using clonal cell lines stably expressing the rat glutamate transporters GLAST, GLT1 or EAAC1. We found that riluzole significantly increased glutamate uptake in a dose-dependent manner; kinetic analysis indicated that the apparent affinity of glutamate for the transporters was significantly increased, with similar effects in the three cell lines. This may facilitate the buffering of excessive extracellular glutamate under pathological conditions suggesting that riluzole's neuroprotective action might be partly mediated by its activating effect on glutamate uptake.
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14
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Oztürk OH, Küçükatay V, Yönden Z, Ağar A, Bağci H, Delibaş N. Expressions of N-methyl-d-aspartate receptors NR2A and NR2B subunit proteins in normal and sulfite-oxidase deficient rat’s hippocampus: effect of exogenous sulfite ingestion. Arch Toxicol 2006; 80:671-9. [PMID: 16858610 DOI: 10.1007/s00204-006-0125-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 05/30/2006] [Indexed: 10/24/2022]
Abstract
Sulfites whether ingested or produced through the sulfur-containing amino acids metabolism of the animal are very active molecules and can cause cellular toxicity. Sulfite oxidase (SOX), a heme- and molybdenum containing mitochondrial enzyme, prevents mammalian cells from adverse effects of sulfite toxicity by metabolizing sulfite to sulfate. The present study was aimed to investigate effect of sulfite on the N-methyl-D-aspartate (NMDA) receptor (NMDAR) NR2A and NR2B subunits in hippocampus of normal and SOX-deficient rats. Rats were divided into four groups; (1) control group, which was given rat chow and tap water ad libitum (C), (2) sulfite group, treated with sulfite (25 mg/kg) in drinking water and commercial rat chow ad libitum (S), (3) SOX-deficient group, maintained on high-W/Mo-deficient regimen to produce SOX deficiency (D), and (4) SOX-deficient + sulfite group (DS), prepared as those in the third group and were afterwards given sulfite (25 mg/kg) additionally. Whole treatment schedule were continued for 6 weeks. Sulfite treatment caused a decrease of NR2A and NR2B subunits of the NMDAR in hippocampus of rats in S and DS groups. Interestingly, similar decrement was observed in D group, probably due to increased endogenous sulfite production. In summary, the results indicated that feeding sulfite to the rats may cause down-regulation of NMDARs by degrading NR2A and NR2B subunits of it, which may be considered as a neuro-compensatory mechanism.
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Affiliation(s)
- Oktay Hasan Oztürk
- Department of Biochemistry, Faculty of Medicine, Akdeniz University, 07070 Antalya, Turkey
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15
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Alaux S, Kusk M, Sagot E, Bolte J, Jensen AA, Bräuner-Osborne H, Gefflaut T, Bunch L. Chemoenzymatic synthesis of a series of 4-substituted glutamate analogues and pharmacological characterization at human glutamate transporters subtypes 1-3. J Med Chem 2006; 48:7980-92. [PMID: 16335922 DOI: 10.1021/jm050597z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of nine L-2,4-syn-4-alkylglutamic acid analogues (1a-i) were synthesized in high yield and high enantiomeric excess (>99% ee) from their corresponding 4-substituted ketoglutaric acids (2a-i), using the enzyme aspartate aminotransferase (AAT) from pig heart or E. coli. The synthesized compounds were evaluated as potential ligands for the glutamate transporters EAAT1, EAAT2, and EAAT3 (excitatory amino acid transporter, subtypes 1-3) in the FLIPR membrane potential (FMP) assay. We found a distinct change in the pharmacological profile when the 4-methyl group (compound 1a, an EAAT1 substrate and EAAT2,3 inhibitor) was extended to a 4-ethyl group, compound 1b, as this analogue is an inhibitor at all three subtypes, EAAT1-3. Furthermore, we conclude that both large and bulky hydrophobic substituents in the 4-position of L-2,4-syn Glu are allowed by all three glutamate transporter subtypes EAAT1-3 while maintaining inhibitory activity.
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Affiliation(s)
- Sebastien Alaux
- Département de Chimie, Université Blaise Pascal, 63177 Aubière Cedex, France
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16
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Bunch L, Nielsen B, Jensen AA, Bräuner-Osborne H. Rational Design and Enantioselective Synthesis of (1R,4S,5R,6S)-3-Azabicyclo[3.3.0]octane-4,6-dicarboxylic Acid A Novel Inhibitor at Human Glutamate Transporter Subtypes 1, 2, and 3. J Med Chem 2005; 49:172-8. [PMID: 16392801 DOI: 10.1021/jm0508336] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The natural product kainic acid is used as template for the rational design of a novel conformationally restricted (S)-glutamic acid (Glu) analogue, (1R,4S,5R,6S)-3-azabicyclo[3.3.0]octane-4,6-dicarboxylic acid (1a). The target structure 1a was synthesized from commercially available (S)-pyroglutaminol, in an enantioselective fashion, in 14 steps. Pharmacological characterization of 1a at human glutamate transporter subtypes 1, 2, and 3 yielded K(i) values of 127, 52, and 46 microM, respectively. Furthermore, binding studies at native ionotropic Glu (iGlu) receptors revealed low affinity for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-preferring iGlu receptors (IC(50) > 100 microM), whereas affinities for the KAIN-preferring iGlu receptors and the N-methyl-d-aspartate (NMDA)-preferring group of iGlu receptors were in the low micromolar range (IC(50) = 14 and 2.9 microM, respectively). At metabotropic Glu receptors (mGluR), EC(50) values for 1a were >1000 microM for mGluR1 and 4, representing group I and III, respectively, and approximately 1000 microM (agonist) for mGluR2, representing group II.
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Affiliation(s)
- Lennart Bunch
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
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Bräuner-Osborne H, Bunch L, Chopin N, Couty F, Evano G, Jensen AA, Kusk M, Nielsen B, Rabasso N. Azetidinic amino acids: stereocontrolled synthesis and pharmacological characterization as ligands for glutamate receptors and transporters. Org Biomol Chem 2005; 3:3926-36. [PMID: 16240010 DOI: 10.1039/b509514j] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from beta-amino alcohols through a straightforward five step sequence. The key step of this synthesis is an original anionic 4-exo-tet ring closure that forms the azetidine ring upon an intramolecular Michael addition. This reaction was proven to be reversible and to lead to a thermodynamic distribution of two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III mGlu receptors, respectively. Furthermore, azetidine analogues 35, 36, and 40 were also characterized as potential ligands at the glutamate transporter subtypes EAAT1-3 in the FLIPR Membrane Potential (FMP) assay. The (2R)-azetidines 35, 37, 39, 41 and 43 were inactive in iGlu, mGlu and EAAT assays, whereas a marked change in the pharmacological profile at the iGlu receptors was observed when a methyl group was introduced in the C-4 position, compound 36 versus t-CAA. At EAAT1-3, compound 35 was inactive, whereas azetidines 36 and 40 were both identified as inhibitors and showed selectivity for the EAAT2 subtype.
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Affiliation(s)
- Hans Bräuner-Osborne
- Department of Medicinal Chemistry, Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100, Copenhagen, Denmark
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