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Díaz-Piña DA, Rivera-Ramírez N, García-López G, Díaz NF, Molina-Hernández A. Calcium and Neural Stem Cell Proliferation. Int J Mol Sci 2024; 25:4073. [PMID: 38612887 PMCID: PMC11012558 DOI: 10.3390/ijms25074073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/31/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
Intracellular calcium plays a pivotal role in central nervous system (CNS) development by regulating various processes such as cell proliferation, migration, differentiation, and maturation. However, understanding the involvement of calcium (Ca2+) in these processes during CNS development is challenging due to the dynamic nature of this cation and the evolving cell populations during development. While Ca2+ transient patterns have been observed in specific cell processes and molecules responsible for Ca2+ homeostasis have been identified in excitable and non-excitable cells, further research into Ca2+ dynamics and the underlying mechanisms in neural stem cells (NSCs) is required. This review focuses on molecules involved in Ca2+ entrance expressed in NSCs in vivo and in vitro, which are crucial for Ca2+ dynamics and signaling. It also discusses how these molecules might play a key role in balancing cell proliferation for self-renewal or promoting differentiation. These processes are finely regulated in a time-dependent manner throughout brain development, influenced by extrinsic and intrinsic factors that directly or indirectly modulate Ca2+ dynamics. Furthermore, this review addresses the potential implications of understanding Ca2+ dynamics in NSCs for treating neurological disorders. Despite significant progress in this field, unraveling the elements contributing to Ca2+ intracellular dynamics in cell proliferation remains a challenging puzzle that requires further investigation.
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Affiliation(s)
- Dafne Astrid Díaz-Piña
- Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Montes Urales 800, Miguel Hidalgo, Ciudad de México 11000, Mexico
- Facultad de Medicina, Circuito Exterior Universitario, Universidad Nacional Autónoma de México Universitario, Copilco Universidad, Coyoacán, Ciudad de México 04360, Mexico
| | - Nayeli Rivera-Ramírez
- Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Montes Urales 800, Miguel Hidalgo, Ciudad de México 11000, Mexico
| | - Guadalupe García-López
- Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Montes Urales 800, Miguel Hidalgo, Ciudad de México 11000, Mexico
| | - Néstor Fabián Díaz
- Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Montes Urales 800, Miguel Hidalgo, Ciudad de México 11000, Mexico
| | - Anayansi Molina-Hernández
- Departamento de Fisiología y Desarrollo Celular, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Montes Urales 800, Miguel Hidalgo, Ciudad de México 11000, Mexico
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2
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Zhao N, Wu W, Wang Y, Song K, Chen G, Chen Y, Wang R, Xu J, Cui K, Chen H, Tan W, Zhang J, Xiao Z. DNA-modularized construction of bivalent ligands precisely regulates receptor binding and activation. Chem 2023. [DOI: 10.1016/j.chempr.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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3
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Khajehali E, Valant C, Jörg M, Tobin AB, Conn PJ, Lindsley CW, Sexton PM, Scammells PJ, Christopoulos A. Probing the binding site of novel selective positive allosteric modulators at the M 1 muscarinic acetylcholine receptor. Biochem Pharmacol 2018; 154:243-254. [PMID: 29777683 PMCID: PMC6066355 DOI: 10.1016/j.bcp.2018.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/15/2018] [Indexed: 12/12/2022]
Abstract
Subtype-selective allosteric modulation of the M1 muscarinic acetylcholine (ACh) receptor (M1 mAChR) is an attractive approach for the treatment of numerous disorders, including cognitive deficits. The discovery of benzyl quinolone carboxylic acid, BQCA, a selective M1 mAChR positive allosteric modulator (PAM), spurred the subsequent development of newer generation M1 PAMs representing diverse chemical scaffolds, different pharmacodynamic properties and, in some instances, improved pharmacokinetics. Key exemplar molecules from such efforts include PF-06767832 (N-((3R,4S)-3-hydroxytetrahydro-2H-pyran-4-yl)-5-methyl-4-(4-(thiazol-4-yl)benzyl)pyridine-2-carboxamide), VU6004256 (4,6-difluoro-N-(1S,2S)-2-hydroxycyclohexyl-1-((6-(1-methyl-1H-pyrazol-4-yl)pyridine-3-yl)methyl)-1H-indole-3-carboxamide) and MIPS1780 (3-(2-hydroxycyclohexyl)-6-(2-((4-(1-methyl-1H-pyrazol-4-yl)-benzyl)oxy)phenyl)pyrimidin-4(3H)-one). Given these diverse scaffolds and pharmacodynamics, the current study combined pharmacological analysis and site-directed mutagenesis to explore the potential binding site and function of newer M1 mAChR PAMs relative to BQCA. Interestingly, the mechanism of action of the novel PAMs was consistent with a common model of allostery, as previously described for BQCA. Key residues involved in the activity of BQCA, including Y179 in the second extracellular loop (ECL) and W4007.35 in transmembrane domain (TM) 7, were critical for the activity of all PAMs tested. Overall, our data indicate that structurally distinct PAMs share a similar binding site with BQCA, specifically, an extracellular allosteric site defined by residues in TM2, TM7 and ECL2. These findings provide valuable insights into the structural basis underlying modulator binding, cooperativity and signaling at the M1 mAChR, which is essential for the rational design of PAMs with tailored pharmacological properties.
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Affiliation(s)
- Elham Khajehali
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Manuela Jörg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Andrew B Tobin
- Centre for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - P Jeffrey Conn
- Department of Chemistry, Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232, United States
| | - Craig W Lindsley
- Department of Chemistry, Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232, United States
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia.
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4
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Fu Z, Ogura T, Luo W, Lin W. ATP and Odor Mixture Activate TRPM5-Expressing Microvillous Cells and Potentially Induce Acetylcholine Release to Enhance Supporting Cell Endocytosis in Mouse Main Olfactory Epithelium. Front Cell Neurosci 2018; 12:71. [PMID: 29615870 PMCID: PMC5869921 DOI: 10.3389/fncel.2018.00071] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
The main olfactory epithelium (MOE) functions to detect odor molecules, provide an epithelial surface barrier, and remove xenobiotics from inhaled air. Mechanisms coordinating the activities of different cell types within the MOE to maintain these functions are poorly understood. Previously, we showed that superficially located microvillous cells (MCs) in the MOE expressing transient receptor potential channel M5 (TRPM5) are cholinergic and chemoresponsive and that they play an important role in maintaining odor responses and olfactory-guided behavior under challenging chemical environment. Here we investigated TRPM5-MC activation and subsequent paracrine regulation. Ca2+ imaging showed that TRPM5-MCs dose-dependently increase their intracellular Ca2+ levels in response to ATP, an important signaling molecule for airway mucociliary movement, and to an odor mixture. Pharmacological examination showed that the ATP responses are primarily mediated by P2X purinergic receptors. Interestingly, using the endocytosis dye pHrodo Red dextran, we found that chemical-activated TRPM5-MCs significantly increase the number of pHrodo-labeled puncta compared to controls without stimulation and compared to cells that do not respond to ATP or to the odor mixture. These results indicate potential vesicle recycling after release of the signaling molecule acetylcholine (ACh). Interestingly, TRPM5 knockout (KO) results in a decrease in ATP-induced pHrodo internalization. We further investigated cholinergic regulation of neighboring supporting cells (SCs). We found that ACh strongly elevates intracellular Ca2+ and potentiates pHrodo endocytosis in SCs. The ACh effects are diminished in the presence of atropine or M3 muscarinic receptor antagonist and in SCs lacking M3 receptors. Collectively, these data suggest that TRPM5-MCs may regulate the MOE’s multicellular network activity via cholinergic paracrine signaling for functional maintenance and adaptive plasticity.
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Affiliation(s)
- Ziying Fu
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Wangmei Luo
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
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5
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Radu BM, Osculati AMM, Suku E, Banciu A, Tsenov G, Merigo F, Di Chio M, Banciu DD, Tognoli C, Kacer P, Giorgetti A, Radu M, Bertini G, Fabene PF. All muscarinic acetylcholine receptors (M 1-M 5) are expressed in murine brain microvascular endothelium. Sci Rep 2017; 7:5083. [PMID: 28698560 PMCID: PMC5506046 DOI: 10.1038/s41598-017-05384-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 05/30/2017] [Indexed: 12/25/2022] Open
Abstract
Clinical and experimental studies indicate that muscarinic acetylcholine receptors are potential pharmacological targets for the treatment of neurological diseases. Although these receptors have been described in human, bovine and rat cerebral microvascular tissue, a subtype functional characterization in mouse brain endothelium is lacking. Here, we show that all muscarinic acetylcholine receptors (M1-M5) are expressed in mouse brain microvascular endothelial cells. The mRNA expression of M2, M3, and M5 correlates with their respective protein abundance, but a mismatch exists for M1 and M4 mRNA versus protein levels. Acetylcholine activates calcium transients in brain endothelium via muscarinic, but not nicotinic, receptors. Moreover, although M1 and M3 are the most abundant receptors, only a small fraction of M1 is present in the plasma membrane and functions in ACh-induced Ca2+ signaling. Bioinformatic analyses performed on eukaryotic muscarinic receptors demonstrate a high degree of conservation of the orthosteric binding site and a great variability of the allosteric site. In line with previous studies, this result indicates muscarinic acetylcholine receptors as potential pharmacological targets in future translational studies. We argue that research on drug development should especially focus on the allosteric binding sites of the M1 and M3 receptors.
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Affiliation(s)
- Beatrice Mihaela Radu
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy.,Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, 050095, Romania
| | | | - Eda Suku
- Department of Biotechnology, University of Verona, Verona, 37134, Italy
| | - Adela Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, 050095, Romania.,Engineering Faculty, Constantin Brancusi' University, Calea Eroilor 30, Targu Jiu, 210135, Romania
| | - Grygoriy Tsenov
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy
| | - Flavia Merigo
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy
| | - Marzia Di Chio
- Department of Public Health and Community Medicine, University of Verona, Verona, 37134, Italy
| | - Daniel Dumitru Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, 050095, Romania
| | - Cristina Tognoli
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy
| | - Petr Kacer
- National Institute of Mental Health, Klecany, 25067, Czech Republic
| | | | - Mihai Radu
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy. .,Department of Life and Environmental Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, PO Box MG-6, Reactorului 30, Magurele, 077125, Romania.
| | - Giuseppe Bertini
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy
| | - Paolo Francesco Fabene
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy
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6
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Bradley SJ, Tobin AB. Design of Next-Generation G Protein-Coupled Receptor Drugs: Linking Novel Pharmacology and In Vivo Animal Models. Annu Rev Pharmacol Toxicol 2016; 56:535-59. [PMID: 26738479 DOI: 10.1146/annurev-pharmtox-011613-140012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite the fact that G protein-coupled receptors (GPCRs) are the most successful drug targets in history, this supergene family of cell surface receptors has yet to be fully exploited as targets in the treatment of human disease. Here, we present optimism that this may change in the future by reviewing the substantial progress made in the understanding of GPCR molecular pharmacology that has generated an extensive toolbox of ligand types that include orthosteric, allosteric, and bitopic ligands, many of which show signaling bias. We discuss how combining these advances with recently described transgenic, chemical genetic, and optogenetic animal models will provide the framework to allow for the rational design of next-generation GPCR drugs that possess increased therapeutic efficacy and decreased adverse/toxic responses.
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Affiliation(s)
- Sophie J Bradley
- MRC Toxicology Unit, University of Leicester, Leicester LE1 9HN United Kingdom; ,
| | - Andrew B Tobin
- MRC Toxicology Unit, University of Leicester, Leicester LE1 9HN United Kingdom; ,
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7
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Thomas T, Chalmers DK, Yuriev E. Homology Modeling and Docking Evaluation of Human Muscarinic Acetylcholine Receptors. NEUROMETHODS 2016. [DOI: 10.1007/978-1-4939-2858-3_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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8
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Christopoulos A. Advances in G protein-coupled receptor allostery: from function to structure. Mol Pharmacol 2014; 86:463-78. [PMID: 25061106 DOI: 10.1124/mol.114.094342] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
It is now widely accepted that G protein-coupled receptors (GPCRs) are highly dynamic proteins that adopt multiple active states linked to distinct functional outcomes. Furthermore, these states can be differentially stabilized not only by orthosteric ligands but also by allosteric ligands acting at spatially distinct binding sites. The key pharmacologic characteristics of GPCR allostery include improved selectivity due to either greater sequence divergence between receptor subtypes and/or subtype-selective cooperativity, a ceiling level to the effect, probe dependence (whereby the magnitude and direction of the allosteric effect change with the nature of the interacting ligands), and the potential for biased signaling. Recent chemical biology developments are beginning to demonstrate how the incorporation of analytical pharmacology and operational modeling into the experimental workflow can enrich structure-activity studies of allostery and bias, and have also led to the discovery of a new class of hybrid orthosteric/allosteric (bitopic) molecules. The potential for endogenous allosteric modulators to play a role in physiology and disease remains to be fully appreciated but will likely represent an important area for future studies. Finally, breakthroughs in structural and computational biology are beginning to unravel the mechanistic basis of GPCR allosteric modulation at the molecular level.
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Affiliation(s)
- Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
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9
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Keov P, López L, Devine SM, Valant C, Lane JR, Scammells PJ, Sexton PM, Christopoulos A. Molecular mechanisms of bitopic ligand engagement with the M1 muscarinic acetylcholine receptor. J Biol Chem 2014; 289:23817-37. [PMID: 25006252 DOI: 10.1074/jbc.m114.582874] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
TBPB and 77-LH-28-1 are selective agonists of the M1 muscarinic acetylcholine receptor (mAChR) that may gain their selectivity through a bitopic mechanism, interacting concomitantly with the orthosteric site and part of an allosteric site. The current study combined site-directed mutagenesis, analytical pharmacology,and molecular modeling to gain further insights into the structural basis underlying binding and signaling by these agonists. Mutations within the orthosteric binding site caused similar reductions in affinity and signaling efficacy for both selective and prototypical orthosteric ligands. In contrast, the mutation of residues within transmembrane helix (TM) 2 and the second extracellular loop (ECL2) discriminated between the different classes of ligand. In particular, ECL2 appears to be involved in the selective binding of bitopic ligands and in coordinating biased agonism between intracellular calcium mobilization and ERK1/2 phosphorylation. Molecular modeling of the interaction between TBPB and the M1 mAChR revealed a binding pose predicted to extend from the orthosteric site up toward a putative allosteric site bordered by TM2, TM3, and TM7, thus consistent with a bitopic mode of binding. Overall, these findings provide valuable structural and mechanistic insights into bitopic ligand actions and receptor activation and support a role for ECL2 in dictating the active states that can be adopted by a G protein-coupled receptor. This may enable greater selective ligand design and development for mAChRs and facilitate improved identification of bitopic ligands.
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Affiliation(s)
- Peter Keov
- From the Drug Discovery Biology Theme and Department of Pharmacology and
| | - Laura López
- From the Drug Discovery Biology Theme and Department of Pharmacology and
| | - Shane M Devine
- the Medicinal Chemistry Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Celine Valant
- From the Drug Discovery Biology Theme and Department of Pharmacology and
| | - J Robert Lane
- From the Drug Discovery Biology Theme and Department of Pharmacology and
| | - Peter J Scammells
- the Medicinal Chemistry Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Patrick M Sexton
- From the Drug Discovery Biology Theme and Department of Pharmacology and
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10
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Allosteric modulation and functional selectivity of G protein-coupled receptors. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 10:e237-43. [PMID: 24050274 DOI: 10.1016/j.ddtec.2012.08.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Agonists of a single G protein-coupled receptor (GPCR) may activate distinct signaling pathways. Functional selectivity, an emerging concept with therapeutic relevance for GPCRs, may be due to conformational selection or stabilization with respect to particular agonists, receptor dimerization, variable expression levels of GPCRs and downstream signaling molecules, and allosteric modulation. Allosteric modulators may have potential advantages over orthosteric ligands, including greater selectivity and safety. This review focuses on functional selectivity resulting from allosteric modulation.
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11
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Keov P, Valant C, Devine SM, Lane JR, Scammells PJ, Sexton PM, Christopoulos A. Reverse Engineering of the Selective Agonist TBPB Unveils Both Orthosteric and Allosteric Modes of Action at the M1 Muscarinic Acetylcholine Receptor. Mol Pharmacol 2013; 84:425-37. [DOI: 10.1124/mol.113.087320] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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12
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Lane JR, Sexton PM, Christopoulos A. Bridging the gap: bitopic ligands of G-protein-coupled receptors. Trends Pharmacol Sci 2013. [DOI: 10.1016/j.tips.2012.10.003] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Sheffler DJ, Sevel C, Le U, Lovell KM, Tarr JC, Carrington SJS, Cho HP, Digby GJ, Niswender CM, Conn PJ, Hopkins CR, Wood MR, Lindsley CW. Further exploration of M₁ allosteric agonists: subtle structural changes abolish M₁ allosteric agonism and result in pan-mAChR orthosteric antagonism. Bioorg Med Chem Lett 2013; 23:223-7. [PMID: 23200253 PMCID: PMC3525729 DOI: 10.1016/j.bmcl.2012.10.132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/18/2012] [Accepted: 10/29/2012] [Indexed: 01/22/2023]
Abstract
This letter describes the further exploration of two series of M(1) allosteric agonists, TBPB and VU0357017, previously reported from our lab. Within the TPBP scaffold, either electronic or steric perturbations to the central piperidine ring led to a loss of selective M(1) allosteric agonism and afforded pan-mAChR antagonism, which was demonstrated to be mediated via the orthosteric site. Additional SAR around a related M(1) allosteric agonist family (VU0357017) identified similar, subtle 'molecular switches' that modulated modes of pharmacology from allosteric agonism to pan-mAChR orthosteric antagonism. Therefore, all of these ligands are best classified as bi-topic ligands that possess high affinity binding at an allosteric site to engender selective M(1) activation, but all bind, at higher concentrations, to the orthosteric ACh site, leading to non-selective orthosteric site binding and mAChR antagonism.
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Affiliation(s)
- Douglas J. Sheffler
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Christian Sevel
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Uyen Le
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Kimberly M. Lovell
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - James C. Tarr
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Sheridan J. S. Carrington
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hyekyung P. Cho
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Gregory J. Digby
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Colleen M. Niswender
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
| | - Corey R. Hopkins
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Michael R. Wood
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Craig W. Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
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14
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Digby GJ, Utley TJ, Lamsal A, Sevel C, Sheffler DJ, Lebois EP, Bridges TM, Wood MR, Niswender CM, Lindsley CW, Conn PJ. Chemical modification of the M(1) agonist VU0364572 reveals molecular switches in pharmacology and a bitopic binding mode. ACS Chem Neurosci 2012; 3:1025-36. [PMID: 23259038 PMCID: PMC3526969 DOI: 10.1021/cn300103e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 09/08/2012] [Indexed: 02/08/2023] Open
Abstract
We previously reported the discovery of VU0364572 and VU0357017 as M(1)-selective agonists that appear to activate M(1) through actions at an allosteric site. Previous studies have revealed that chemical scaffolds for many allosteric modulators contain molecular switches that allow discovery of allosteric antagonists and allosteric agonists or positive allosteric modulators (PAMs) based on a single chemical scaffold. Based on this, we initiated a series of studies to develop selective M(1) allosteric antagonists based on the VU0364572 scaffold. Interestingly, two lead antagonists identified in this series, VU0409774 and VU0409775, inhibited ACh-induced Ca(2+) responses at rat M(1-5) receptor subtypes, suggesting they are nonselective muscarinic antagonists. VU0409774 and VU0409775 also completely displaced binding of the nonselective radioligand [(3)H]-NMS at M(1) and M(3) mAChRs with affinities similar to their functional IC(50) values. Finally, Schild analysis revealed that these compounds inhibit M(1) responses through a fully competitive interaction at the orthosteric binding site. This surprising finding prompted further studies to determine whether agonist activity of VU0364572 and VU0357017 may also engage in previously unappreciated actions at the orthosteric site on M(1). Surprisingly, both VU0364572 and VU0357017 completely displaced [(3)H]-NMS binding to the orthosteric site of M(1)-M(5) receptors at high concentrations. Furthermore, evaluation of agonist activity in systems with varying levels of receptor reserve and Furchgott analysis using a cell line expressing M(1) under control of an inducible promotor was consistent with an action of these compounds as weak orthosteric partial agonists of M(1). However, consistent with previous studies suggesting actions at a site that is distinct from the orthosteric binding site, VU0364572 or VU0357017 slowed the rate of [(3)H]-NMS dissociation from CHO-rM(1) membranes. Together, these results suggest that VU0364572 and VU0357017 act as bitopic ligands and that novel antagonists in this series act as competitive orthosteric site antagonists.
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Affiliation(s)
- Gregory J Digby
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Abdul-Ridha A, Lane JR, Sexton PM, Canals M, Christopoulos A. Allosteric modulation of a chemogenetically modified G protein-coupled receptor. Mol Pharmacol 2012. [PMID: 23197649 DOI: 10.1124/mol.112.083006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetically modified muscarinic acetylcholine receptors (mAChRs) that have minimal responsiveness to acetylcholine (ACh) but are potently and efficaciously activated by an otherwise inert synthetic ligand, clozapine-N-oxide (CNO). DREADDs have been used as tools for selectively modulating signal transduction pathways in vitro and in vivo. Recent comprehensive studies have validated how the pharmacology of a CNO-bound DREADD mirrors that of an ACh-bound wild-type (WT) mAChR. However, nothing is known about whether this equivalence extends to the allosteric modulation of DREADDs by small molecules. To address this, we investigated the actions at an M(1) DREADD of benzyl quinolone carboxylic acid (BQCA), a positive allosteric modulator of ACh binding and function that is known to behave according to a simple two-state mechanism at the WT receptor. We found that allosteric modulation of the CNO-bound DREADD receptor is not equivalent to the corresponding modulation of the ACh-bound WT receptor. We also found that BQCA engenders stimulus bias at the M(1) DREADD, having differential types of cooperativity depending on the signaling pathway. Furthermore, the modulation of ACh itself by BQCA at the DREADD is not compatible with the two-state model that we previously applied to the M(1) WT receptor.
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Affiliation(s)
- Alaa Abdul-Ridha
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia
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Abstract
INTRODUCTION There is substantial evidence from preclinical and early proof-of-concept studies suggesting that selective modulation of the M(1) muscarinic receptor is efficacious in cognitive models of Alzheimer's disease (AD) and antipsychotic models of schizophrenia. For example, a number of nonselective M(1) muscarinic agonists have previously shown positive effects on cognitive function in AD patients, but were limited due to cholinergic adverse events thought to be mediated by pan activation of the M(2) to M(5) subtypes. Thus, there is a need to identify selective activators of the M(1) receptor to evaluate their potential in cognitive disorders. One strategy to confer selectivity for M(1) is the identification of allosteric agonists or positive allosteric modulators, which would target an allosteric site on the M(1) receptor rather than the highly conserved orthosteric acetylcholine binding site. AREAS COVERED This review discusses the M(1) muscarinic receptor and its potential therapeutic value in the treatment of CNS disorders such as AD and schizophrenia. Specifically, novel allosteric ligands that activate or positively modulate the M(1) receptor are examined and peer-reviewed articles associated with these patents publications are also described. EXPERT OPINION There is substantial evidence supporting activation of the M(1) receptor might be effective in treating symptoms of AD and schizophrenia, but therapeutic success has been elusive and is hypothesized to be due to the lack of selectivity among orthosteric agonists. During the past decade, allosteric modulation of GPCRs has evolved as a viable strategy toward generating subtype selective molecules. A number of novel, selective ligands in the form of allosteric agonists and positive allosteric modulators of the M(1) receptor have been identified offering the potential for clinical evaluation of M(1)-specific receptor activation.
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Affiliation(s)
- Scott D Kuduk
- Department of Medicinal Chemistry, Merck Research Laboratories , Sumneytown Pike, PO Box 4, West Point, PA 19486, USA.
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Xu J, Xu J, Chen H. Interpreting the structural mechanism of action for MT7 and human muscarinic acetylcholine receptor 1 complex by modeling protein–protein interaction. J Biomol Struct Dyn 2012; 30:30-44. [DOI: 10.1080/07391102.2012.674188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Daval SB, Valant C, Bonnet D, Kellenberger E, Hibert M, Galzi JL, Ilien B. Fluorescent derivatives of AC-42 to probe bitopic orthosteric/allosteric binding mechanisms on muscarinic M1 receptors. J Med Chem 2012; 55:2125-43. [PMID: 22329602 DOI: 10.1021/jm201348t] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two fluorescent derivatives of the M1 muscarinic selective agonist AC-42 were synthesized by coupling the lissamine rhodamine B fluorophore (in ortho and para positions) to AC42-NH(2). This precursor, prepared according to an original seven-step procedure, was included in the study together with the LRB fluorophore (alone or linked to an alkyl chain). All these compounds are antagonists, but examination of their ability to inhibit or modulate orthosteric [(3)H]NMS binding revealed that para-LRB-AC42 shared several properties with AC-42. Carefully designed experiments allowed para-LRB-AC42 to be used as a FRET tracer on EGFP-fused M1 receptors. Under equilibrium binding conditions, orthosteric ligands, AC-42, and the allosteric modulator gallamine behaved as competitors of para-LRB-AC42 binding whereas other allosteric compounds such as WIN 51,708 and N-desmethylclozapine were noncompetitive inhibitors. Finally, molecular modeling studies focused on putative orthosteric/allosteric bitopic poses for AC-42 and para-LRB-AC42 in a 3D model of the human M1 receptor.
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Affiliation(s)
- Sandrine B Daval
- Unité Biotechnologie et Signalisation Cellulaire, UMR 7242 CNRS, Ecole Supérieure de Biotechnologie de Strasbourg, Université de Strasbourg, BP 10413, 67412 Illkirch, France
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Muscarinic and nicotinic acetylcholine receptor agonists and allosteric modulators for the treatment of schizophrenia. Neuropsychopharmacology 2012; 37:16-42. [PMID: 21956443 PMCID: PMC3238081 DOI: 10.1038/npp.2011.199] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Muscarinic and nicotinic acetylcholine (ACh) receptors (mAChRs and nAChRs) are emerging as important targets for the development of novel treatments for the symptoms associated with schizophrenia. Preclinical and early proof-of-concept clinical studies have provided strong evidence that activators of specific mAChR (M(1) and M(4)) and nAChR (α(7) and α(2)β(4)) subtypes are effective in animal models of antipsychotic-like activity and/or cognitive enhancement, and in the treatment of positive and cognitive symptoms in patients with schizophrenia. While early attempts to develop selective mAChR and nAChR agonists provided important preliminary findings, these compounds have ultimately failed in clinical development due to a lack of true subtype selectivity and subsequent dose-limiting adverse effects. In recent years, there have been major advances in the discovery of highly selective activators for the different mAChR and nAChR subtypes with suitable properties for optimization as potential candidates for clinical trials. One novel strategy has been to identify ligands that activate a specific receptor subtype through actions at sites that are distinct from the highly conserved ACh-binding site, termed allosteric sites. These allosteric activators, both allosteric agonists and positive allosteric modulators, of mAChR and nAChR subtypes demonstrate unique mechanisms of action and high selectivity in vivo, and may provide innovative treatment strategies for schizophrenia.
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Decker M, Holzgrabe U. M1 muscarinic cetylcholine receptor allosteric modulators as potential therapeutic opportunities for treating Alzheimer's disease. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20025b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Bubser M, Byun N, Wood MR, Jones CK. Muscarinic receptor pharmacology and circuitry for the modulation of cognition. Handb Exp Pharmacol 2012:121-66. [PMID: 22222698 DOI: 10.1007/978-3-642-23274-9_7] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The muscarinic cholinergic system constitutes an important part of the neuronal circuitry that modulates normal cognition. Muscarinic receptor antagonists are well known to produce or exacerbate impairments in attention, learning, and memory. Conversely, both direct-acting muscarinic receptor agonists and indirect-acting muscarinic cholinergic agonists, such as acetylcholinesterase inhibitors, have shown cognition-enhancing properties, including improvements in normal cognitive function, reversal of cognitive deficits induced by muscarinic receptor antagonists, and attenuation of cognitive deficits in psychiatric and neurological disorders, such as Alzheimer's disease and schizophrenia. However, until recently, the lack of small molecule ligands that antagonize or activate specific muscarinic acetylcholine receptor (mAChR) subtypes with high selectivity has been a major obstacle in defining the relative contributions of individual mAChRs to different aspects of cognitive function and for the development of novel therapeutic agents. These limitations may be potentially overcome by the recent discovery of novel mAChR subtype-selective compounds, notably allosteric agonists and positive allosteric modulators, which exhibit greater selectivity for individual mAChR subtypes than previous mAChR orthosteric agonists. In preclinical studies, these novel ligands have shown promising efficacy in several models for the enhancement of cognition. In this chapter, we will review the muscarinic cholinergic circuitry and pharmacology of mAChR agonists and antagonists relevant to the modulation of different aspects of cognition in animals and clinical populations.
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Affiliation(s)
- Michael Bubser
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
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Valant C, Robert Lane J, Sexton PM, Christopoulos A. The best of both worlds? Bitopic orthosteric/allosteric ligands of g protein-coupled receptors. Annu Rev Pharmacol Toxicol 2011; 52:153-78. [PMID: 21910627 DOI: 10.1146/annurev-pharmtox-010611-134514] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is now acknowledged that G protein-coupled receptors, the largest class of drug targets, adopt multiple active states that can be preferentially stabilized by orthosteric ligands or allosteric modulators, thus giving rise to the phenomenon of pathway-biased signaling. In the past few years, researchers have begun to explore the potential of linking orthosteric and allosteric pharmacophores to yield bitopic hybrid ligands. This approach is an extension of the more traditional bivalent ligand concept and shares some of the same challenges, including the choice and role of the linker between the two pharmacophores and the validation of mechanism of action. Nonetheless, the promise of bitopic ligands is the generation of novel chemical tools that have improved affinity and/or selectivity profiles. Previously identified functionally selective compounds (and medicines) also may act via a bitopic mechanism, suggesting that the phenomenon is more widespread than currently appreciated.
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Affiliation(s)
- Celine Valant
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia.
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