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Nguyen HTM, van der Westhuizen ET, Langmead CJ, Tobin AB, Sexton PM, Christopoulos A, Valant C. Opportunities and challenges for the development of M 1 muscarinic receptor positive allosteric modulators in the treatment for neurocognitive deficits. Br J Pharmacol 2024; 181:2114-2142. [PMID: 36355830 DOI: 10.1111/bph.15982] [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: 07/06/2022] [Revised: 09/22/2022] [Accepted: 10/18/2022] [Indexed: 11/12/2022] Open
Abstract
Targeting allosteric sites of M1 muscarinic acetylcholine receptors (M1 receptors) is a promising strategy to treat neurocognitive disorders, such as Alzheimer's disease and schizophrenia. Indeed, the last two decades have seen an impressive body of work focussing on the design and development of positive allosteric modulators (PAMs) for the M1 receptor. This has led to the identification of a structurally diverse range of highly selective M1 PAMs. In preclinical models, M1 PAMs have shown rescue of cognitive deficits and improvement of endpoints predictive of symptom domains of schizophrenia. Yet, to date only a few M1 PAMs have reached early-stage clinical trials, with many of them failing to progress further due to on-target mediated cholinergic adverse effects that have plagued the development of this class of ligand. This review covers the recent preclinical and clinical studies in the field of M1 receptor drug discovery for the treatment of Alzheimer's disease and schizophrenia, with a specific focus on M1 PAM, highlighting both the undoubted potential but also key challenges for the successful translation of M1 PAMs from bench-side to bedside. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Huong T M Nguyen
- Drug Discovery Biology, Monash University, Parkville, Melbourne, VIC, Australia
- Department of Biochemistry, Hanoi University of Pharmacy, Hanoi, Vietnam
| | | | - Christopher J Langmead
- Drug Discovery Biology, Monash University, Parkville, Melbourne, VIC, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Melbourne, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash University, Parkville, Melbourne, VIC, Australia
| | - Andrew B Tobin
- Centre for Translational Pharmacology, University of Glasgow, Glasgow, UK
| | - Patrick M Sexton
- Drug Discovery Biology, Monash University, Parkville, Melbourne, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash University, Parkville, Melbourne, VIC, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash University, Parkville, Melbourne, VIC, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Melbourne, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash University, Parkville, Melbourne, VIC, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash University, Parkville, Melbourne, VIC, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Melbourne, VIC, Australia
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2
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Michel MC. Introduction: A Short History of Adrenoceptor Research. Handb Exp Pharmacol 2024. [PMID: 38797750 DOI: 10.1007/164_2024_718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
This chapter provides a short history of adrenoceptor research starting from the initial discovery of adrenaline. It covers the evolving classification of adrenoceptor subtypes, the cloning of these subtypes from multiple species, and factors such as adrenoceptor regulation, inverse agonism and biased agonism. More details on many of these aspects are provided in other chapters of this volume of Handbook of Experimental Pharmacology.
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Affiliation(s)
- Martin C Michel
- Department of Pharmacology, University Medical Center, Johannes Gutenberg University, Mainz, Germany.
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3
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Szczurowska E, Szánti-Pintér E, Randáková A, Jakubík J, Kudova E. Allosteric Modulation of Muscarinic Receptors by Cholesterol, Neurosteroids and Neuroactive Steroids. Int J Mol Sci 2022; 23:13075. [PMID: 36361865 PMCID: PMC9656441 DOI: 10.3390/ijms232113075] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/24/2023] Open
Abstract
Muscarinic acetylcholine receptors are membrane receptors involved in many physiological processes. Malfunction of muscarinic signaling is a cause of various internal diseases, as well as psychiatric and neurologic conditions. Cholesterol, neurosteroids, neuroactive steroids, and steroid hormones are molecules of steroid origin that, besides having well-known genomic effects, also modulate membrane proteins including muscarinic acetylcholine receptors. Here, we review current knowledge on the allosteric modulation of muscarinic receptors by these steroids. We give a perspective on the research on the non-genomic effects of steroidal compounds on muscarinic receptors and drug development, with an aim to ultimately exploit such knowledge.
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Affiliation(s)
- Ewa Szczurowska
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo Namesti 2, Prague 6, 166 10 Prague, Czech Republic
| | - Eszter Szánti-Pintér
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo Namesti 2, Prague 6, 166 10 Prague, Czech Republic
| | - Alena Randáková
- Institute of Physiology, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Jan Jakubík
- Institute of Physiology, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo Namesti 2, Prague 6, 166 10 Prague, Czech Republic
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4
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Myslivecek J. Multitargeting nature of muscarinic orthosteric agonists and antagonists. Front Physiol 2022; 13:974160. [PMID: 36148314 PMCID: PMC9486310 DOI: 10.3389/fphys.2022.974160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/01/2022] [Indexed: 11/16/2022] Open
Abstract
Muscarinic receptors (mAChRs) are typical members of the G protein-coupled receptor (GPCR) family and exist in five subtypes from M1 to M5. Muscarinic receptor subtypes do not sufficiently differ in affinity to orthosteric antagonists or agonists; therefore, the analysis of receptor subtypes is complicated, and misinterpretations can occur. Usually, when researchers mainly specialized in CNS and peripheral functions aim to study mAChR involvement in behavior, learning, spinal locomotor networks, biological rhythms, cardiovascular physiology, bronchoconstriction, gastrointestinal tract functions, schizophrenia, and Parkinson’s disease, they use orthosteric ligands and they do not use allosteric ligands. Moreover, they usually rely on manufacturers’ claims that could be misleading. This review aimed to call the attention of researchers not deeply focused on mAChR pharmacology to this fact. Importantly, limited selective binding is not only a property of mAChRs but is a general attribute of most neurotransmitter receptors. In this review, we want to give an overview of the most common off-targets for established mAChR ligands. In this context, an important point is a mention the tremendous knowledge gap on off-targets for novel compounds compared to very well-established ligands. Therefore, we will summarize reported affinities and give an outline of strategies to investigate the subtype’s function, thereby avoiding ambiguous results. Despite that, the multitargeting nature of drugs acting also on mAChR could be an advantage when treating such diseases as schizophrenia. Antipsychotics are a perfect example of a multitargeting advantage in treatment. A promising strategy is the use of allosteric ligands, although some of these ligands have also been shown to exhibit limited selectivity. Another new direction in the development of muscarinic selective ligands is functionally selective and biased agonists. The possible selective ligands, usually allosteric, will also be listed. To overcome the limited selectivity of orthosteric ligands, the recommended process is to carefully examine the presence of respective subtypes in specific tissues via knockout studies, carefully apply “specific” agonists/antagonists at appropriate concentrations and then calculate the probability of a specific subtype involvement in specific functions. This could help interested researchers aiming to study the central nervous system functions mediated by the muscarinic receptor.
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5
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Drug Design Targeting the Muscarinic Receptors and the Implications in Central Nervous System Disorders. Biomedicines 2022; 10:biomedicines10020398. [PMID: 35203607 PMCID: PMC8962391 DOI: 10.3390/biomedicines10020398] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 11/16/2022] Open
Abstract
There is substantial evidence that cholinergic system function impairment plays a significant role in many central nervous system (CNS) disorders. During the past three decades, muscarinic receptors (mAChRs) have been implicated in various pathologies and have been prominent targets of drug-design efforts. However, due to the high sequence homology of the orthosteric binding site, many drug candidates resulted in limited clinical success. Although several advances in treating peripheral pathologies have been achieved, targeting CNS pathologies remains challenging for researchers. Nevertheless, significant progress has been made in recent years to develop functionally selective orthosteric and allosteric ligands targeting the mAChRs with limited side effect profiles. This review highlights past efforts and focuses on recent advances in drug design targeting these receptors for Alzheimer’s disease (AD), schizophrenia (SZ), and depression.
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Burger WAC, Gentry PR, Berizzi AE, Vuckovic Z, van der Westhuizen ET, Thompson G, Yeasmin M, Lindsley CW, Sexton PM, Langmead CJ, Tobin AB, Christopoulos A, Valant C, Thal DM. Identification of a Novel Allosteric Site at the M 5 Muscarinic Acetylcholine Receptor. ACS Chem Neurosci 2021; 12:3112-3123. [PMID: 34351123 DOI: 10.1021/acschemneuro.1c00383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The M5 muscarinic acetylcholine receptor (mAChR) has emerged as an exciting therapeutic target for the treatment of addiction and behavioral disorders. This has been in part due to promising preclinical studies with the M5 mAChR selective negative allosteric modulator (NAM), ML375. The binding site of ML375 remains unknown, however, making it difficult to develop improved M5 mAChR selective modulators. To determine the possible location of the ML375 binding site, we used radioligand binding and functional assays to show that ML375 does not interact with the well-characterized "common" mAChR allosteric site located in the receptor's extracellular vestibule, nor a previously proposed second allosteric site recognized by the modulator, amiodarone. Molecular docking was used to predict potential allosteric sites within the transmembrane (TM) domain of the M5 mAChR. These predicted sites were assessed using M5-M2 mAChR receptor chimeras and further targeted with site-directed mutagenesis, which enabled the identification of a putative binding site for ML375 at the interface of TMs 2-4. Collectively, these results identify a third allosteric site at the M5 mAChR and highlight the ability of allosteric modulators to selectively target highly conserved proteins.
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Affiliation(s)
- Wessel A. C. Burger
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Patrick R. Gentry
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Alice E. Berizzi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Ziva Vuckovic
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Emma T. van der Westhuizen
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Geoff Thompson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Mahmuda Yeasmin
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Craig W. Lindsley
- Department of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Chemistry, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Patrick M. Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Christopher J. Langmead
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Andrew B. Tobin
- The 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
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - David M. Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
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7
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Dolejší E, Chetverikov N, Szánti-Pintér E, Nelic D, Randáková A, Doležal V, El-Fakahany EE, Kudová E, Jakubík J. Neuroactive steroids, WIN-compounds and cholesterol share a common binding site on muscarinic acetylcholine receptors. Biochem Pharmacol 2021; 192:114699. [PMID: 34324870 DOI: 10.1016/j.bcp.2021.114699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/20/2021] [Accepted: 07/20/2021] [Indexed: 02/06/2023]
Abstract
Endogenous neurosteroids and their synthetic analogues-neuroactive steroids-have been found to bind to muscarinic acetylcholine receptors and allosterically modulate acetylcholine binding and function. Using radioligand binding experiments we investigated their binding mode. We show that neuroactive steroids bind to two binding sites on muscarinic receptors. Their affinity for the high-affinity binding site is about 100 nM. Their affinity for the low-affinity binding site is about 10 µM. The high-affinity binding occurs at the same site as binding of steroid-based WIN-compounds that is different from the common allosteric binding site for alcuronium or gallamine that is located between the second and third extracellular loop of the receptor. This binding site is also different from the allosteric binding site for the structurally related aminosteroid-based myorelaxants pancuronium and rapacuronium. Membrane cholesterol competes with neurosteroids/neuroactive steroids binding to both high- and low-affinity binding site, indicating that both sites are oriented towards the cell membrane..
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Affiliation(s)
- Eva Dolejší
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | | | - Eszter Szánti-Pintér
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Dominik Nelic
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Alena Randáková
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Vladimír Doležal
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Esam E El-Fakahany
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis, MN 55455, USA
| | - Eva Kudová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.
| | - Jan Jakubík
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
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8
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Zhang Y, Zhang S, Xu G, Li M, Tang C, Fan W. Cu-Catalyzed carbamoylation versus amination of quinoline N-oxide with formamides. Org Biomol Chem 2019; 17:309-314. [DOI: 10.1039/c8ob02844c] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Carbamoylation and amination of quinoline with formamides was developed via copper-catalyzed C–C and C–N bond formations.
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Affiliation(s)
- Yan Zhang
- School of Pharmaceutical Science
- Jiangnan University
- Wuxi 214122
- P. R. China
| | - Shiwei Zhang
- School of Pharmaceutical Science
- Jiangnan University
- Wuxi 214122
- P. R. China
| | - Guangxing Xu
- School of Pharmaceutical Science
- Jiangnan University
- Wuxi 214122
- P. R. China
| | - Min Li
- School of Pharmaceutical Science
- Jiangnan University
- Wuxi 214122
- P. R. China
| | - Chunlei Tang
- School of Pharmaceutical Science
- Jiangnan University
- Wuxi 214122
- P. R. China
| | - Weizheng Fan
- School of Pharmaceutical Science
- Jiangnan University
- Wuxi 214122
- P. R. China
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9
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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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10
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Bock A, Schrage R, Mohr K. Allosteric modulators targeting CNS muscarinic receptors. Neuropharmacology 2017; 136:427-437. [PMID: 28935216 DOI: 10.1016/j.neuropharm.2017.09.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 12/21/2022]
Abstract
Muscarinic acetylcholine receptors are G protein-coupled receptors (GPCRs) which are broadly expressed in the central nervous system (CNS) and other tissues in the periphery. They emerge as important drug targets for a number of diseases including Alzheimer's disease, Parkinson's disease, and schizophrenia. Muscarinic receptors are divided into five subtypes (M1-M5) of which M1-M4 have been crystalized. All subtypes possess at least one allosteric binding site which is located in the extracellular region of the receptor on top of the ACh (i.e. orthosteric) binding site. The former can be specifically targeted by chemical compounds (mostly small molecules) and binding of such allosteric modulators affects the affinity and/or efficacy of orthosteric ligands. This allows highly specific modulation of GPCR function and, from a drug discovery point of view, may be advantageous in terms of subtype selectivity and biased signaling. There is a plethora of allosteric modulators for all five muscarinic receptor subtypes. This review presents the basic principles of allosteric modulation of GPCRs on both the molecular and structural level focusing on allosteric modulators of the muscarinic receptor family. Further we discuss dualsteric (i.e. bitopic orthosteric/allosteric) ligands emphasizing their potential in modulating muscarinic receptor dynamics and signaling. The common mechanisms of muscarinic receptor allosteric modulation have been proven to be generalizable and are at play at many, if not all GPCRs. Given this paradigmatic role of muscarinic receptors we suggest that also new developments in muscarinic allosteric modulation may also be extended to other members of the GPCR superfamily. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
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Affiliation(s)
- Andreas Bock
- Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany; Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany.
| | - Ramona Schrage
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
| | - Klaus Mohr
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
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11
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Boulos JF, Jakubik J, Boulos JM, Randakova A, Momirov J. Synthesis of novel and functionally selective non-competitive muscarinic antagonists as chemical probes. Chem Biol Drug Des 2017. [PMID: 28646631 DOI: 10.1111/cbdd.13059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Muscarinic receptors are known to play important biological roles and are drug targets for several human diseases. In a pilot study, novel muscarinic antagonists were synthesized and used as chemical probes to obtain additional information of the muscarinic pharmacophore. The design of these ligands made use of current orthosteric and allosteric models of drug-receptor interactions together with chemical motifs known to achieve muscarinic receptor selectivity. This approach has led to the discovery of several non-competitive muscarinic ligands that strongly bind at a secondary receptor site. These compounds were found to be non-competitive antagonists that completely abolished carbachol activation in functional assays. Several of these compounds antagonized functional response to carbachol with great potency at M1 and M4 than at the rest of receptor subtypes.
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Affiliation(s)
- John F Boulos
- Department of Physical Sciences, Barry University, Miami Shores, FL, USA
| | - Jan Jakubik
- Department of Neurochemistry, Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - John M Boulos
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA
| | - Alena Randakova
- Department of Neurochemistry, Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jelena Momirov
- Department of Physical Sciences, Barry University, Miami Shores, FL, USA
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12
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13
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Keller M, Tränkle C, She X, Pegoli A, Bernhardt G, Buschauer A, Read RW. M2 Subtype preferring dibenzodiazepinone-type muscarinic receptor ligands: Effect of chemical homo-dimerization on orthosteric (and allosteric?) binding. Bioorg Med Chem 2015; 23:3970-90. [PMID: 25650309 DOI: 10.1016/j.bmc.2015.01.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/21/2014] [Accepted: 01/07/2015] [Indexed: 10/24/2022]
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14
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Gentry PR, Sexton PM, Christopoulos A. Novel Allosteric Modulators of G Protein-coupled Receptors. J Biol Chem 2015; 290:19478-88. [PMID: 26100627 DOI: 10.1074/jbc.r115.662759] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are allosteric proteins, because their signal transduction relies on interactions between topographically distinct, yet conformationally linked, domains. Much of the focus on GPCR allostery in the new millennium, however, has been on modes of targeting GPCR allosteric sites with chemical probes due to the potential for novel therapeutics. It is now apparent that some GPCRs possess more than one targetable allosteric site, in addition to a growing list of putative endogenous modulators. Advances in structural biology are also shedding new insights into mechanisms of allostery, although the complexities of candidate allosteric drugs necessitate rigorous biological characterization.
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Affiliation(s)
- Patrick R Gentry
- From Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Victoria 3052, Australia
| | - Patrick M Sexton
- From Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Victoria 3052, Australia
| | - Arthur Christopoulos
- From Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, Victoria 3052, Australia
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15
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Chen X, Klöckner J, Holze J, Zimmermann C, Seemann WK, Schrage R, Bock A, Mohr K, Tränkle C, Holzgrabe U, Decker M. Rational Design of Partial Agonists for the Muscarinic M1 Acetylcholine Receptor. J Med Chem 2014; 58:560-76. [DOI: 10.1021/jm500860w] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Xinyu Chen
- Institute of Pharmacy
and Food Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute of Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Jessika Klöckner
- Institute of Pharmacy
and Food Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Janine Holze
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
| | - Cornelia Zimmermann
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
| | - Wiebke K. Seemann
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | - Ramona Schrage
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
| | - Andreas Bock
- Institute of Pharmacology and Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Klaus Mohr
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
| | - Christian Tränkle
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Strasse 3, 53121 Bonn, Germany
| | - Ulrike Holzgrabe
- Institute of Pharmacy
and Food Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Michael Decker
- Institute of Pharmacy
and Food Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute of Pharmacy, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
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16
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Muscarinic acetylcholine receptors: novel opportunities for drug development. Nat Rev Drug Discov 2014; 13:549-60. [PMID: 24903776 DOI: 10.1038/nrd4295] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The muscarinic acetylcholine receptors are a subfamily of G protein-coupled receptors that regulate numerous fundamental functions of the central and peripheral nervous system. The past few years have witnessed unprecedented new insights into muscarinic receptor physiology, pharmacology and structure. These advances include the first structural views of muscarinic receptors in both inactive and active conformations, as well as a better understanding of the molecular underpinnings of muscarinic receptor regulation by allosteric modulators. These recent findings should facilitate the development of new muscarinic receptor subtype-selective ligands that could prove to be useful for the treatment of many severe pathophysiological conditions.
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Schober DA, Croy CH, Xiao H, Christopoulos A, Felder CC. Development of a radioligand, [(3)H]LY2119620, to probe the human M(2) and M(4) muscarinic receptor allosteric binding sites. Mol Pharmacol 2014; 86:116-23. [PMID: 24807966 DOI: 10.1124/mol.114.091785] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In this study, we characterized a muscarinic acetylcholine receptor (mAChR) potentiator, LY2119620 (3-amino-5-chloro-N-cyclopropyl-4-methyl-6-[2-(4-methylpiperazin-1-yl)-2-oxoethoxy]thieno[2,3-b]pyridine-2-carboxamide) as a novel probe of the human M2 and M4 allosteric binding sites. Since the discovery of allosteric binding sites on G protein-coupled receptors, compounds targeting these novel sites have been starting to emerge. For example, LY2033298 (3-amino-5-chloro-6-methoxy-4-methyl-thieno(2,3-b)pyridine-2-carboxylic acid cyclopropylamid) and a derivative of this chemical scaffold, VU152100 (3-amino-N-(4-methoxybenzyl)-4,6-dimethylthieno[2,3-b]pyridine carboxamide), bind to the human M4 mAChR allosteric pocket. In the current study, we characterized LY2119620, a compound similar in structure to LY2033298 and binds to the same allosteric site on the human M4 mAChRs. However, LY2119620 also binds to an allosteric site on the human M2 subtype. [(3)H]NMS ([(3)H]N-methylscopolamine) binding experiments confirm that LY2119620 does not compete for the orthosteric binding pocket at any of the five muscarinic receptor subtypes. Dissociation kinetic studies using [(3)H]NMS further support that LY2119620 binds allosterically to the M2 and M4 mAChRs and was positively cooperative with muscarinic orthosteric agonists. To probe directly the allosteric sites on M2 and M4, we radiolabeled LY2119620. Cooperativity binding of [(3)H]LY2119620 with mAChR orthosteric agonists detects significant changes in Bmax values with little change in Kd, suggesting a G protein-dependent process. Furthermore, [(3)H]LY2119620 was displaced by compounds of similar chemical structure but not by previously described mAChR allosteric compounds such as gallamine or WIN 62,577 (17-β-hydroxy-17-α-ethynyl-δ-4-androstano[3,2-b]pyrimido[1,2-a]benzimidazole). Our results therefore demonstrate the development of a radioligand, [(3)H]LY2119620 to probe specifically the human M2 and M4 muscarinic receptor allosteric binding sites.
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Affiliation(s)
- Douglas A Schober
- Lilly Neuroscience, Lilly Research Laboratories, Eli Lilly and Co., Lilly Corporate Center, Indianapolis, Indiana (D.A.S., C.H.C., H.X., C.C.F.); and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (A.C.)
| | - Carrie H Croy
- Lilly Neuroscience, Lilly Research Laboratories, Eli Lilly and Co., Lilly Corporate Center, Indianapolis, Indiana (D.A.S., C.H.C., H.X., C.C.F.); and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (A.C.)
| | - Hongling Xiao
- Lilly Neuroscience, Lilly Research Laboratories, Eli Lilly and Co., Lilly Corporate Center, Indianapolis, Indiana (D.A.S., C.H.C., H.X., C.C.F.); and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (A.C.)
| | - Arthur Christopoulos
- Lilly Neuroscience, Lilly Research Laboratories, Eli Lilly and Co., Lilly Corporate Center, Indianapolis, Indiana (D.A.S., C.H.C., H.X., C.C.F.); and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (A.C.)
| | - Christian C Felder
- Lilly Neuroscience, Lilly Research Laboratories, Eli Lilly and Co., Lilly Corporate Center, Indianapolis, Indiana (D.A.S., C.H.C., H.X., C.C.F.); and Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (A.C.)
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Evaluation of 1,2,5-thiadiazoles as modulators of M1/M5 muscarinic receptor subtypes. Bioorg Med Chem 2014; 22:1838-44. [DOI: 10.1016/j.bmc.2014.01.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 01/20/2014] [Accepted: 01/30/2014] [Indexed: 11/21/2022]
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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20
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Davie BJ, Christopoulos A, Scammells PJ. Development of M1 mAChR allosteric and bitopic ligands: prospective therapeutics for the treatment of cognitive deficits. ACS Chem Neurosci 2013; 4:1026-48. [PMID: 23659787 PMCID: PMC3715844 DOI: 10.1021/cn400086m] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/09/2013] [Indexed: 12/22/2022] Open
Abstract
Since the cholinergic hypothesis of memory dysfunction was first reported, extensive research efforts have focused on elucidating the mechanisms by which this intricate system contributes to the regulation of processes such as learning, memory, and higher executive function. Several cholinergic therapeutic targets for the treatment of cognitive deficits, psychotic symptoms, and the underlying pathophysiology of neurodegenerative disorders, such as Alzheimer's disease and schizophrenia, have since emerged. Clinically approved drugs now exist for some of these targets; however, they all may be considered suboptimal therapeutics in that they produce undesirable off-target activity leading to side effects, fail to address the wide variety of symptoms and underlying pathophysiology that characterize these disorders, and/or afford little to no therapeutic effect in subsets of patient populations. A promising target for which there are presently no approved therapies is the M1 muscarinic acetylcholine receptor (M1 mAChR). Despite avid investigation, development of agents that selectively activate this receptor via the orthosteric site has been hampered by the high sequence homology of the binding site between the five muscarinic receptor subtypes and the wide distribution of this receptor family in both the central nervous system (CNS) and the periphery. Hence, a plethora of ligands targeting less structurally conserved allosteric sites of the M1 mAChR have been investigated. This Review aims to explain the rationale behind allosterically targeting the M1 mAChR, comprehensively summarize and critically evaluate the M1 mAChR allosteric ligand literature to date, highlight the challenges inherent in allosteric ligand investigation that are impeding their clinical advancement, and discuss potential methods for resolving these issues.
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Affiliation(s)
- Briana J. Davie
- Medicinal
Chemistry and Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal
Parade, Parkville VIC 3052, Australia
| | - Arthur Christopoulos
- Medicinal
Chemistry and Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal
Parade, Parkville VIC 3052, Australia
| | - Peter J. Scammells
- Medicinal
Chemistry and Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal
Parade, Parkville VIC 3052, Australia
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21
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Odagaki Y, Kinoshita M, Toyoshima R. Pharmacological characterization of M1 muscarinic acetylcholine receptor-mediated Gq activation in rat cerebral cortical and hippocampal membranes. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:937-47. [DOI: 10.1007/s00210-013-0887-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/27/2013] [Indexed: 11/30/2022]
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Daval SB, Kellenberger E, Bonnet D, Utard V, Galzi JL, Ilien B. Exploration of the orthosteric/allosteric interface in human M1 muscarinic receptors by bitopic fluorescent ligands. Mol Pharmacol 2013; 84:71-85. [PMID: 23604140 DOI: 10.1124/mol.113.085670] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bitopic binding properties apply to a variety of muscarinic compounds that span and simultaneously bind to both the orthosteric and allosteric receptor sites. We provide evidence that fluorescent pirenzepine derivatives, with the M1 antagonist fused to the boron-dipyrromethene [Bodipy (558/568)] fluorophore via spacers of varying lengths, exhibit orthosteric/allosteric binding properties at muscarinic M1 receptors. This behavior was inferred from a combination of functional, radioligand, and fluorescence resonance energy transfer binding experiments performed under equilibrium and kinetic conditions on enhanced green fluorescent protein-fused M1 receptors. Although displaying a common orthosteric component, the fluorescent compounds inherit bitopic properties from a linker-guided positioning of their Bodipy moiety within the M1 allosteric vestibule. Depending on linker length, the fluorophore is allowed to reach neighboring allosteric domains, overlapping or not with the classic gallamine site, but distinct from the allosteric indolocarbazole "WIN" site. Site-directed mutagenesis, as well as molecular modeling and ligand docking studies based on recently solved muscarinic receptor structures, further support the definition of two groups of Bodipy-pirenzepine derivatives exhibiting distinct allosteric binding poses. Thus, the linker may dictate pharmacological outcomes for bitopic molecules that are hardly predictable from the properties of individual orthosteric and allosteric building blocks. Our findings also demonstrate that the fusion of a fluorophore to an orthosteric ligand is not neutral, as it may confer, unless carefully controlled, unexpected properties to the resultant fluorescent tracer. Altogether, this study illustrates the importance of a "multifacet" experimental approach to unravel and validate bitopic ligand binding mechanisms.
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Affiliation(s)
- Sandrine B Daval
- Unité Biotechnologie et Signalisation cellulaire, UMR 7242 CNRS, Université de Strasbourg, Ecole Supérieure de Biotechnologie de Strasbourg, 300 Bvd S. Brant - BP 10413, 67412 Illkirch, France
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23
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Shivnaraine RV, Huang XP, Seidenberg M, Ellis J, Wells JW. Heterotropic cooperativity within and between protomers of an oligomeric M(2) muscarinic receptor. Biochemistry 2012; 51:4518-40. [PMID: 22551249 DOI: 10.1021/bi3000287] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
At least four allosteric sites have been found to mediate the dose-dependent effects of gallamine on the binding of [(3)H]quinuclidinylbenzilate (QNB) and N-[(3)H]methylscopolamine (NMS) to M(2) muscarinic receptors in membranes and solubilized preparations from porcine atria, CHO cells, and Sf9 cells. The rate of dissociation of [(3)H]QNB was affected in a bell-shaped manner with at least one Hill coefficient (n(H)) greater than 1, indicating that at least three allosteric sites are involved. The level of binding of [(3)H]QNB was decreased in a biphasic manner, revealing at least two allosteric sites; binding of [(3)H]NMS was affected in a triphasic, serpentine manner, revealing at least three sites, and values of n(H) >1 pointed to at least four sites. Several lines of evidence indicate that all effects of gallamine were allosteric in nature and could be observed at equilibrium. The rates of equilibration and dissociation suggest that the receptor was predominately oligomeric, and the heterogeneity revealed by gallamine can be attributed to differences in its affinity for the constituent protomers of a tetramer. Those differences appear to arise from inter- and intramolecular cooperativity between gallamine and the radioligand.
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Affiliation(s)
- Rabindra V Shivnaraine
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
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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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Heitman LH, Kleinau G, Brussee J, Krause G, Ijzerman AP. Determination of different putative allosteric binding pockets at the lutropin receptor by using diverse drug-like low molecular weight ligands. Mol Cell Endocrinol 2012; 351:326-36. [PMID: 22269095 DOI: 10.1016/j.mce.2012.01.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 01/09/2012] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
Abstract
The lutropin/choriogonadotrophin receptor (LHCGR) is a family A G protein-coupled receptor (GPCR) which binds the endogenous hormone-ligands at the large extracellular domain. In contrast, several drug-like low-molecular-weight ligands (LMWs) have been reported to interact allosterically within the seven transmembrane domain (7TMD) of the LHCGR. Here, we were interested to study the putative allosteric LHCGR binding region with focus on the determination of two pockets for LMW ligands. A library of compounds was screened for their ability to modify the binding of an allosteric radiolabeled LMW agonist [³H]Org 43553. Further experimental and computational studies revealed that the putative binding pocket for a newly identified allosteric enhancer (LUF5419) and a previously described allosteric inhibitor (LUF5771) are overlapping and that this site is different from the Org 43553 binding site. The present study showed that these compounds are useful tools to reveal details on different allosteric binding sites located within the 7TMD of the LHCGR.
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Affiliation(s)
- Laura H Heitman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, University of Leiden, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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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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27
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Influence of MT7 toxin on the oligomerization state of the M1 muscarinic receptor1. Biol Cell 2012; 102:409-20. [DOI: 10.1042/bc20090171] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
There has been great interest in the structure-function relationships of the muscarinic acetylcholine receptors (mAChRs) because these prototypical Family A/class 1 G protein-coupled receptors (GPCRs) are attractive therapeutic targets for both peripheral and central nervous system disorders. A multitude of drugs that act at the mAChRs have been identified over the years, but many of these show minimal selectivity for any one of the five mAChR subtypes over the others, which has hampered their development into therapeutics due to adverse side effects. The lack of drug specificity is primarily due to high sequence similarity in this family of receptor, especially in the orthosteric binding pocket. Thus, there remains an ongoing need for a molecular understanding of how mAChRs bind their ligands, and how selectivity in binding and activation can be achieved. Unfortunately, there remains a paucity of solved high-resolution structures of GPCRs, including the mAChRs, and thus most of our knowledge of structure-function mechanisms related to this receptor family to date has been obtained indirectly through approaches such as mutagenesis. Nonetheless, such studies have revealed a wealth of information that has led to novel insights and may be used to guide future rational drug design campaigns.
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29
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Levit A, Yarnitzky T, Wiener A, Meidan R, Niv MY. Modeling of human prokineticin receptors: interactions with novel small-molecule binders and potential off-target drugs. PLoS One 2011; 6:e27990. [PMID: 22132188 PMCID: PMC3221691 DOI: 10.1371/journal.pone.0027990] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 10/29/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND AND MOTIVATION The Prokineticin receptor (PKR) 1 and 2 subtypes are novel members of family A GPCRs, which exhibit an unusually high degree of sequence similarity. Prokineticins (PKs), their cognate ligands, are small secreted proteins of ∼80 amino acids; however, non-peptidic low-molecular weight antagonists have also been identified. PKs and their receptors play important roles under various physiological conditions such as maintaining circadian rhythm and pain perception, as well as regulating angiogenesis and modulating immunity. Identifying binding sites for known antagonists and for additional potential binders will facilitate studying and regulating these novel receptors. Blocking PKRs may serve as a therapeutic tool for various diseases, including acute pain, inflammation and cancer. METHODS AND RESULTS Ligand-based pharmacophore models were derived from known antagonists, and virtual screening performed on the DrugBank dataset identified potential human PKR (hPKR) ligands with novel scaffolds. Interestingly, these included several HIV protease inhibitors for which endothelial cell dysfunction is a documented side effect. Our results suggest that the side effects might be due to inhibition of the PKR signaling pathway. Docking of known binders to a 3D homology model of hPKR1 is in agreement with the well-established canonical TM-bundle binding site of family A GPCRs. Furthermore, the docking results highlight residues that may form specific contacts with the ligands. These contacts provide structural explanation for the importance of several chemical features that were obtained from the structure-activity analysis of known binders. With the exception of a single loop residue that might be perused in the future for obtaining subtype-specific regulation, the results suggest an identical TM-bundle binding site for hPKR1 and hPKR2. In addition, analysis of the intracellular regions highlights variable regions that may provide subtype specificity.
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Affiliation(s)
- Anat Levit
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Talia Yarnitzky
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ayana Wiener
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Rina Meidan
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Masha Y. Niv
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
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Congreve M, Langmead CJ, Mason JS, Marshall FH. Progress in structure based drug design for G protein-coupled receptors. J Med Chem 2011; 54:4283-311. [PMID: 21615150 PMCID: PMC3308205 DOI: 10.1021/jm200371q] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Indexed: 12/12/2022]
Affiliation(s)
- Miles Congreve
- Heptares Therapeutics Limited, BioPark, Welwyn Garden City, Hertfordshire, UK.
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Lampropoulou E, Manioudaki M, Fousteris M, Koutsourea A, Nikolaropoulos S, Papadimitriou E. Pyrrolo[2,3-α]carbazole derivatives as topoisomerase I inhibitors that affect viability of glioma and endothelial cells in vitro and angiogenesis in vivo. Biomed Pharmacother 2011; 65:142-50. [DOI: 10.1016/j.biopha.2011.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 02/08/2011] [Indexed: 11/28/2022] Open
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Langmead CJ. Determining allosteric modulator mechanism of action: integration of radioligand binding and functional assay data. Methods Mol Biol 2011; 746:195-209. [PMID: 21607858 DOI: 10.1007/978-1-61779-126-0_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The drive to produce safer and more receptor subtype selective drugs has sparked a renewed interest in allosteric modulators of G protein-coupled receptors. The increasing use of functional assays has shown that allosteric ligands are capable of modulating both orthosteric agonist affinity and efficacy, as well as mediating receptor activation in their own right. Such a complex range of behaviours can be difficult to discern from single datasets; this chapter seeks to explain how to use radioligand binding and functional assay datasets in concert to elucidate allosteric modulator mechanism of action.
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DFT calculation of four new potential agents muscarinic of bispyridinium type: structure, synthesis, biological activity, hydration, and relations with the potents W84 and DUO-3O. J Comput Aided Mol Des 2010; 25:145-61. [DOI: 10.1007/s10822-010-9406-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 12/05/2010] [Indexed: 10/18/2022]
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Peace AG, Shewan DA. New perspectives in cyclic AMP-mediated axon growth and guidance: The emerging epoch of Epac. Brain Res Bull 2010; 84:280-8. [PMID: 20851749 DOI: 10.1016/j.brainresbull.2010.09.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 09/03/2010] [Accepted: 09/06/2010] [Indexed: 11/18/2022]
Abstract
In the search for a cure to brain and spinal cord injury much has been learned about the inhibitory environment of the central nervous system (CNS), and yet a clinical therapy remains elusive. In recent years great advances have been made in understanding intracellular molecular mechanisms that transduce cell surface receptor-mediated signals that neurons receive from their environment. Many of these signalling pathways share common mechanisms, which presents the possibility that manipulating activities of key cell signalling molecules such as those regulated by 3'-5'-cyclic adenosine monophosphate (cAMP) might allow axons to simultaneously overcome the inhibitory effects of a number of extracellular ligands. The identification of Epac, a novel direct intracellular target for cAMP, has opened up a new avenue of research that is beginning to explain how cAMP can mediate a range of neuronal functions including distinct axon growth and guidance decisions. With current research tools that allow more specific activation of proteins or knock-down of their expression, as well as quantitation of protein activities in live cells, it is already becoming clear that Epac plays highly important roles in the development and function of the nervous system. Here, we focus on emerging evidence that Epac mediates cAMP-regulated axon growth and chemoattraction, and thus represents a novel target for overcoming axon growth inhibition and promoting CNS regeneration.
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Affiliation(s)
- Andrew G Peace
- Institute of Medical Sciences, School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, United Kingdom.
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Jakubík J, El-Fakahany EE. Allosteric Modulation of Muscarinic Acetylcholine Receptors. Pharmaceuticals (Basel) 2010; 3:2838-2860. [PMID: 27713379 PMCID: PMC4034100 DOI: 10.3390/ph3092838] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 08/17/2010] [Accepted: 08/18/2010] [Indexed: 11/16/2022] Open
Abstract
An allosteric modulator is a ligand that binds to an allosteric site on the receptor and changes receptor conformation to produce increase (positive cooperativity) or decrease (negative cooperativity) in the binding or action of an orthosteric agonist (e.g., acetylcholine). Since the identification of gallamine as the first allosteric modulator of muscarinic receptors in 1976, this unique mode of receptor modulation has been intensively studied by many groups. This review summarizes over 30 years of research on the molecular mechanisms of allosteric interactions of drugs with the receptor and for new allosteric modulators of muscarinic receptors with potential therapeutic use. Identification of positive modulators of acetylcholine binding and function that enhance neurotransmission and the discovery of highly selective allosteric modulators are mile-stones on the way to novel therapeutic agents for the treatment of schizophrenia, Alzheimer’s disease and other disorders involving impaired cognitive function.
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Affiliation(s)
- Jan Jakubík
- Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 00 Praha, Czech Republic.
| | - Esam E El-Fakahany
- Division of Neuroscience Research in Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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De Amici M, Dallanoce C, Holzgrabe U, Tränkle C, Mohr K. Allosteric ligands for G protein-coupled receptors: a novel strategy with attractive therapeutic opportunities. Med Res Rev 2010; 30:463-549. [PMID: 19557759 DOI: 10.1002/med.20166] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Allosteric receptor ligands bind to a recognition site that is distinct from the binding site of the endogenous messenger molecule. As a consequence, allosteric agents may attach to receptors that are already transmitter-bound. Ternary complex formation opens an avenue to qualitatively new drug actions at G protein-coupled receptors (GPCRs), in particular receptor subtype selective potentiation of endogenous transmitter action. Consequently, suitable exploitation of allosteric recognition sites as alternative molecular targets could pave the way to a drug discovery paradigm different from those aimed at mimicking or blocking the effects of endogenous (orthosteric) receptor activators. The number of allosteric ligands reported to modulate GPCR function is steadily increasing and some have already reached routine clinical use. This review aims at introducing into this fascinating field of drug discovery and at providing an overview about the achievements that have already been made. Various case examples will be discussed in the framework of GPCR classification (family A, B, and C receptors). In addition, the behavior at muscarinic receptors of hybrid derivatives incorporating both an allosteric and an orthosteric fragment in a common molecular skeleton will be illustrated.
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Affiliation(s)
- Marco De Amici
- Department of Pharmaceutical Sciences Pietro Pratesi, University of Milan, via Mangiagalli 25, 20133 Milano, Italy.
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Stahl E, Ellis J. Novel allosteric effects of amiodarone at the muscarinic M5 receptor. J Pharmacol Exp Ther 2010; 334:214-22. [PMID: 20348203 DOI: 10.1124/jpet.109.165316] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Allosteric sites on muscarinic receptors may present superior therapeutic targets for several central nervous system disorders, due to the potential of allosteric ligands to provide more selective modulation and to preserve the spatiotemporal patterning that is characteristic of synaptic transmission. We have found that the antiarrhythmic drug amiodarone interacts allosterically with M(1) and M(5) muscarinic receptors. At both M(1) and M(5), amiodarone was only able to partially inhibit the binding of the orthosteric antagonist [(3)H]N-methylscopolamine (NMS). In addition, amiodarone was able to alter the rate of dissociation of [(3)H]NMS from M(1) and M(5) receptors. These findings suggest that NMS and amiodarone are able to bind to the receptor simultaneously. The pharmacology of the effect on NMS dissociation demonstrated that amiodarone was not interacting at the "common" site at which gallamine, obidoxime, and many other muscarinic allosteric ligands are known to bind. In functional studies, amiodarone enhanced the ability of acetylcholine (at EC(20)) to activate the M(5) receptor; however, under the same conditions, amiodarone did not enhance M(1) activation. More detailed studies at M(5) found that the effect of amiodarone was to enhance the efficacy of acetylcholine, without increasing its potency. This report describes the first demonstration of allosteric enhancement of efficacy at the M(5) receptor, and the first demonstration of enhancement of efficacy but not potency at any muscarinic receptor. In summary, amiodarone has been shown to be a novel positive allosteric modulator of muscarinic receptors that is selective for the M(5) subtype, relative to M(1).
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Affiliation(s)
- Edward Stahl
- Department of Psychiatry, Penn State University College of Medicine, Hershey, PA 17033, USA
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Morphy R. Selectively nonselective kinase inhibition: striking the right balance. J Med Chem 2010; 53:1413-37. [PMID: 20166671 DOI: 10.1021/jm901132v] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Richard Morphy
- Medicinal Chemistry Department, Schering-Plough, Newhouse, Lanarkshire, ML1 5SH, UK.
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Molecular mechanisms of action and in vivo validation of an M4 muscarinic acetylcholine receptor allosteric modulator with potential antipsychotic properties. Neuropsychopharmacology 2010; 35:855-69. [PMID: 19940843 PMCID: PMC3055367 DOI: 10.1038/npp.2009.194] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We recently identified LY2033298 as a novel allosteric potentiator of acetylcholine (ACh) at the M(4) muscarinic acetylcholine receptor (mAChR). This study characterized the molecular mode of action of this modulator in both recombinant and native systems. Radioligand-binding studies revealed that LY2033298 displayed a preference for the active state of the M(4) mAChR, manifested as a potentiation in the binding affinity of ACh (but not antagonists) and an increase in the proportion of high-affinity agonist-receptor complexes. This property accounted for the robust allosteric agonism displayed by the modulator in recombinant cells in assays of [(35)S]GTPgammaS binding, extracellular regulated kinase 1/2 phosphorylation, glycogen synthase kinase 3beta phosphorylation, and receptor internalization. We also found that the extent of modulation by LY2033298 differed depending on the signaling pathway, indicating that LY2033298 engenders functional selectivity in the actions of ACh. This property was retained in NG108-15 cells, which natively express rodent M(4) mAChRs. Functional interaction studies between LY2033298 and various orthosteric and allosteric ligands revealed that its site of action overlaps with the allosteric site used by prototypical mAChR modulators. Importantly, LY2033298 reduced [(3)H]ACh release from rat striatal slices, indicating retention of its ability to allosterically potentiate endogenous ACh in situ. Moreover, its ability to potentiate oxotremorine-mediated inhibition of condition avoidance responding in rodents was significantly attenuated in M(4) mAChR knockout mice, validating the M(4) mAChR as a key target of action of this novel allosteric ligand.
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40
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Acetylcholine (muscarinic). Br J Pharmacol 2009. [DOI: 10.1111/j.1476-5381.2009.00501_4.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Fruchart-Gaillard C, Mourier G, Marquer C, Stura E, Birdsall NJM, Servent D. Different Interactions between MT7 Toxin and the Human Muscarinic M1 Receptor in Its Free and N-Methylscopolamine-Occupied States. Mol Pharmacol 2008; 74:1554-63. [DOI: 10.1124/mol.108.050773] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
Signaling through the cyclic adenosine monophosphate-dependent protein kinase [protein kinase A (PKA)] is an important and widely studied area of signal transduction research. This signaling pathway is commonly investigated through the use of the pharmacological PKA inhibitors H89 and KT 5720. Both of these compounds are thought to block PKA actions through competitive inhibition of the adenosine triphosphate site on the PKA catalytic subunit. Recently, a number of studies have identified actions of H89 and KT 5720 that are independent of their effects on PKA. These nonspecific effects are widespread; they include actions on other protein kinases and signaling molecules and also on basic cellular functions, such as transcription. Here, I summarize the nonspecific effects of these two compounds and compare their actions with those of other PKA inhibitors.
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Affiliation(s)
- Andrew J Murray
- School of Medical Sciences, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
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Chung LY, Yap KF, Goh SH, Mustafa MR, Imiyabir Z. Muscarinic receptor binding activity of polyoxygenated flavones from Melicope subunifoliolata. PHYTOCHEMISTRY 2008; 69:1548-1554. [PMID: 18334259 DOI: 10.1016/j.phytochem.2008.01.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 01/30/2008] [Accepted: 01/31/2008] [Indexed: 05/26/2023]
Abstract
The bark extract of Melicope subunifoliolata (Stapf) T.G. Hartley showed competitive muscarinic receptor binding activity. Six polymethoxyflavones [melibentin (1); melisimplexin (3); 3,3',4',5,7-pentamethoxyflavone (4); meliternatin (5); 3,5,8-trimethoxy-3',4',6,7-bismethylenedioxyflavone (6); and isokanugin (7)] and one furanocoumarin [5-methoxy-8-geranyloxypsoralen (2)] were isolated from the bark extract. Compounds 2 and 6 were isolated for the first time from M. subunifoliolata. The methoxyflavones (compounds 1, 3, 4, 5, 6, and 7) show moderate inhibition in a muscarinic receptor binding assay, while the furanocoumarin (compound 2) is inactive. The potency of the methoxyflavones to inhibit [(3)H]NMS-muscarinic receptor binding is influenced by the position and number of methoxy substitution. The results suggest these compounds are probably muscarinic modulators, agonists or partial agonists/antagonists.
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Affiliation(s)
- L Y Chung
- Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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Heitman LH, Ye K, Oosterom J, IJzerman AP. Amiloride Derivatives and a Nonpeptidic Antagonist Bind at Two Distinct Allosteric Sites in the Human Gonadotropin-Releasing Hormone Receptor. Mol Pharmacol 2008; 73:1808-15. [DOI: 10.1124/mol.107.043521] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Gregory KJ, Sexton PM, Christopoulos A. Allosteric modulation of muscarinic acetylcholine receptors. Curr Neuropharmacol 2007; 5:157-67. [PMID: 19305798 PMCID: PMC2656816 DOI: 10.2174/157015907781695946] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 04/05/2007] [Indexed: 11/22/2022] Open
Abstract
Muscarinic acetylcholine receptors (mAChRs) are prototypical Family A G protein coupled-receptors. The five mAChR subtypes are widespread throughout the periphery and the central nervous system and, accordingly, are widely involved in a variety of both physiological and pathophysiological processes. There currently remains an unmet need for better therapeutic agents that can selectively target a given mAChR subtype to the relative exclusion of others. The main reason for the lack of such selective mAChR ligands is the high sequence homology within the acetylcholine-binding site (orthosteric site) across all mAChRs. However, the mAChRs possess at least one, and likely two, extracellular allosteric binding sites that can recognize small molecule allosteric modulators to regulate the binding and function of orthosteric ligands. Extensive studies of prototypical mAChR modulators, such as gallamine and alcuronium, have provided strong pharmacological evidence, and associated structure-activity relationships (SAR), for a "common" allosteric site on all five mAChRs. These studies are also supported by mutagenesis experiments implicating the second extracellular loop and the interface between the third extracellular loop and the top of transmembrane domain 7 as contributing to the common allosteric site. Other studies are also delineating the pharmacology of a second allosteric site, recognized by compounds such as staurosporine. In addition, allosteric agonists, such as McN-A-343, AC-42 and N-desmethylclozapine, have also been identified. Current challenges to the field include the ability to effectively detect and validate allosteric mechanisms, and to quantify allosteric effects on binding affinity and signaling efficacy to inform allosteric modulator SAR.
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Affiliation(s)
| | | | - Arthur Christopoulos
- Drug Discovery Biology Laboratory, Department of Pharmacology, Monash University, Clayton, Victoria, 3800, Australia
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Schwartz TW, Holst B. Allosteric enhancers, allosteric agonists and ago-allosteric modulators: where do they bind and how do they act? Trends Pharmacol Sci 2007; 28:366-73. [PMID: 17629958 DOI: 10.1016/j.tips.2007.06.008] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 05/22/2007] [Accepted: 06/29/2007] [Indexed: 11/24/2022]
Abstract
Many small-molecule agonists also display allosteric properties. Such ago-allosteric modulators act as co-agonists, providing additive efficacy--instead of partial antagonism--and they can affect--and often improve--the potency of the endogenous agonist. Surprisingly, the apparent binding sites of several ordinary allosteric enhancers and ago-allosteric modulators seem to overlap with those of the endogenous agonists. Different molecular scenarios are proposed to explain this discrepancy from classical allosteric models. In one scenario, the ago-allosteric modulator can interchange between different binding modes. In another, dimeric, receptor scenario, the endogenous agonist binds to one protomer while the ago-allosteric modulator binds to the other, 'allosteric' protomer. It is suggested that testing for ago-allosteric properties should be an integral part of the agonist drug discovery process because a compound that acts with--rather than against--the endogenous agonist could be an optimal agonist drug.
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Affiliation(s)
- Thue W Schwartz
- Laboratory for Molecular Pharmacology, Institute of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.
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48
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May LT, Avlani VA, Langmead CJ, Herdon HJ, Wood MD, Sexton PM, Christopoulos A. Structure-Function Studies of Allosteric Agonism at M2Muscarinic Acetylcholine Receptors. Mol Pharmacol 2007; 72:463-76. [PMID: 17525129 DOI: 10.1124/mol.107.037630] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The M2 muscarinic acetylcholine receptor (mAChR) possesses at least one binding site for allosteric modulators that is dependent on the residues (172)EDGE(175), Tyr(177), and Thr(423). However, the contribution of these residues to actions of allosteric agonists, as opposed to modulators, is unknown. We created mutant M2 mAChRs in which the charge of the (172)EDGE(175) sequence had been neutralized and each Tyr(177) and Thr(423) was substituted with alanine. Radioligand binding experiments revealed that these mutations had a profound inhibitory effect on the prototypical modulators gallamine, alcuronium, and heptane-1,7-bis-[dimethyl-3'-phthalimidopropyl]-ammonium bromide (C7/3-phth) but minimal effects on the orthosteric antagonist [3H]N-methyl scopolamine. In contrast, the allosteric agonists 4-I-[3-chlorophenyl]carbamoyloxy)-2-butynyltrimethylammnonium chloride (McN-A-343), 4-n-butyl-1-[4-(2-methylphenyl)-4-oxo-1-butyl] piperidine hydrogen chloride (AC-42), and the novel AC-42 derivative 1-[3-(4-butyl-1-piperidinyl)propyl]-3,4-dihydro-2(1H)-quinolinone (77-LH-28-1) demonstrated an increased affinity or proportion of high-affinity sites at the combined EDGE-YT mutation, indicating a different mode of binding to the prototypical modulators. Subsequent functional assays of extracellular signal-regulated kinase (ERK)1/2 phosphorylation and guanosine 5'-(gamma-[(35)S]thio)triphosphate ([(35)S]GTPgammaS) binding revealed minimal effects of the mutations on the orthosteric agonists acetylcholine (ACh) and pilocarpine but a significant increase in the efficacy of McN-A-343 and potency of 77-LH-28-1. Additional mutagenesis experiments found that these effects were predominantly mediated by Tyr(177) and Thr(423), rather than the (172)EDGE(175) sequence. The functional interaction between each of the allosteric agonists and ACh was characterized by high negative cooperativity but was consistent with an increased allosteric agonist affinity at the combined EDGE-YT mutant M2 mAChR. This study has thus revealed a differential role of critical allosteric site residues on the binding and function of allosteric agonists versus allosteric modulators of M2 mAChRs.
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Affiliation(s)
- Lauren T May
- Drug Discovery Biology Laboratory, Department of Pharmacology, Monash University, Clayton, Victoria 3800, Australia
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Gaspari RJ, Paydarfar D. Pathophysiology of respiratory failure following acute dichlorvos poisoning in a rodent model. Neurotoxicology 2007; 28:664-71. [PMID: 17350689 PMCID: PMC2041827 DOI: 10.1016/j.neuro.2007.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 01/30/2007] [Accepted: 02/02/2007] [Indexed: 10/23/2022]
Abstract
Organophosphate (OP) poisoning causes a cholinergic crisis with a wide range of clinical effects including central apnea, pulmonary bronchoconstriction and secretions, seizures, and muscle weakness. The morbidity and mortality from acute OP poisoning is attributed to respiratory failure but the relative contributions of the central and peripheral effects in producing collapse of the respiratory system are unclear. In this study we used a novel adult rat model of acute OP poisoning to analyze the pathophysiology of acute OP poisoning. We found that poisoning caused rapidly lethal central apnea. In animals sustained with mechanical ventilation, we found that following central apnea there ensued progressive pulmonary insufficiency that was variable in timing and severity. Our findings support the hypothesis that OP poisoning in this animal model causes a sequential "two hit" insult, with rapid central apnea followed by delayed impairment of pulmonary gas exchange with prominent airway secretions.
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Affiliation(s)
- Romolo J Gaspari
- Department of Emergency Medicine, University of Massachusetts School of Medicine, 55 Lake Avenue North, Worcester, MA 01655, USA.
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Abstract
The past decade has witnessed a significant growth in the identification of allosteric modulators of G protein-coupled receptors (GPCRs), i.e., ligands that interact with binding sites that are topographically distinct from the orthosteric site recognized by the receptor's endogenous agonist. Because of their ability to modulate receptor conformations in the presence of orthosteric ligand, allosteric modulators can "fine-tune" classical pharmacological responses. This is advantageous in terms of a potential for engendering greater GPCR subtype-selectivity, but represents a significant challenge for detecting and validating allosteric behaviors. Although allosteric sites need not have evolved to accommodate endogenous ligands, there are a number of examples of where such modulators have been shown to contribute to physiological or pathophysiological processes. Studies are also beginning to unravel the structural basis of allosteric modulation of GPCRs. It remains to be determined whether such modulation represents interactions within monomers versus across dimers.
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Affiliation(s)
- Lauren T May
- Department of Pharmacology, University of Melbourne, 3010 Parkville, Victoria
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