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van der Westhuizen ET, Choy KHC, Valant C, McKenzie-Nickson S, Bradley SJ, Tobin AB, Sexton PM, Christopoulos A. Fine Tuning Muscarinic Acetylcholine Receptor Signaling Through Allostery and Bias. Front Pharmacol 2021; 11:606656. [PMID: 33584282 PMCID: PMC7878563 DOI: 10.3389/fphar.2020.606656] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/30/2020] [Indexed: 12/18/2022] Open
Abstract
The M1 and M4 muscarinic acetylcholine receptors (mAChRs) are highly pursued drug targets for neurological diseases, in particular for Alzheimer's disease and schizophrenia. Due to high sequence homology, selective targeting of any of the M1-M5 mAChRs through the endogenous ligand binding site has been notoriously difficult to achieve. With the discovery of highly subtype selective mAChR positive allosteric modulators in the new millennium, selectivity through targeting an allosteric binding site has opened new avenues for drug discovery programs. However, some hurdles remain to be overcome for these promising new drug candidates to progress into the clinic. One challenge is the potential for on-target side effects, such as for the M1 mAChR where over-activation of the receptor by orthosteric or allosteric ligands can be detrimental. Therefore, in addition to receptor subtype selectivity, a drug candidate may need to exhibit a biased signaling profile to avoid such on-target adverse effects. Indeed, recent studies in mice suggest that allosteric modulators for the M1 mAChR that bias signaling toward specific pathways may be therapeutically important. This review brings together details on the signaling pathways activated by the M1 and M4 mAChRs, evidence of biased agonism at these receptors, and highlights pathways that may be important for developing new subtype selective allosteric ligands to achieve therapeutic benefit.
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Affiliation(s)
- Emma T. van der Westhuizen
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - K. H. Christopher Choy
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Simon McKenzie-Nickson
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Sophie J. Bradley
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Andrew B. Tobin
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Patrick M. Sexton
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
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2
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Volpato D, Kauk M, Messerer R, Bermudez M, Wolber G, Bock A, Hoffmann C, Holzgrabe U. The Role of Orthosteric Building Blocks of Bitopic Ligands for Muscarinic M1 Receptors. ACS OMEGA 2020; 5:31706-31715. [PMID: 33344823 PMCID: PMC7745449 DOI: 10.1021/acsomega.0c04220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/16/2020] [Indexed: 05/13/2023]
Abstract
The muscarinic M1 acetylcholine receptor is an important drug target for the treatment of various neurological disorders. Designing M1 receptor-selective drugs has proven challenging, mainly due to the high conservation of the acetylcholine binding site among muscarinic receptor subtypes. Therefore, less conserved and topographically distinct allosteric binding sites have been explored to increase M1 receptor selectivity. In this line, bitopic ligands, which target orthosteric and allosteric binding sites simultaneously, may provide a promising strategy. Here, we explore the allosteric, M1-selective BQCAd scaffold derived from BQCA as a starting point for the design, synthesis, and pharmacological evaluation of a series of novel bitopic ligands in which the orthosteric moieties and linker lengths are systematically varied. Since β-arrestin recruitment seems to be favorable to therapeutic implication, all the compounds were investigated by G protein and β-arrestin assays. Some bitopic ligands are partial to full agonists for G protein activation, some activate β-arrestin recruitment, and the degree of β-arrestin recruitment varies according to the respective modification. The allosteric BQCAd scaffold controls the positioning of the orthosteric ammonium group of all ligands, suggesting that this interaction is essential for stimulating G protein activation. However, β-arrestin recruitment is not affected. The novel set of bitopic ligands may constitute a toolbox to study the requirements of β-arrestin recruitment during ligand design for therapeutic usage.
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Affiliation(s)
- Daniela Volpato
- Department
of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Michael Kauk
- Institute
for Molecular Cell Biology, CMB-Center for Molecular Biomedicine,
University Hospital Jena, Friedrich-Schiller University Jena, Hans-Knöll-Straße 2, 07745 Jena, Germany
| | - Regina Messerer
- Department
of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Marcel Bermudez
- Institute
of Pharmacy, Freie Universitaet Berlin, Königin-Luise-Str. 2-4 in 14195 Berlin-Dahlem, Germany
| | - Gerhard Wolber
- Institute
of Pharmacy, Freie Universitaet Berlin, Königin-Luise-Str. 2-4 in 14195 Berlin-Dahlem, Germany
| | - Andreas Bock
- Max
Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Carsten Hoffmann
- Institute
for Molecular Cell Biology, CMB-Center for Molecular Biomedicine,
University Hospital Jena, Friedrich-Schiller University Jena, Hans-Knöll-Straße 2, 07745 Jena, Germany
| | - Ulrike Holzgrabe
- Department
of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
- . Tel.: +49 931 31-85460
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3
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Wold EA, Chen J, Cunningham KA, Zhou J. Allosteric Modulation of Class A GPCRs: Targets, Agents, and Emerging Concepts. J Med Chem 2019; 62:88-127. [PMID: 30106578 PMCID: PMC6556150 DOI: 10.1021/acs.jmedchem.8b00875] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
G-protein-coupled receptors (GPCRs) have been tractable drug targets for decades with over one-third of currently marketed drugs targeting GPCRs. Of these, the class A GPCR superfamily is highly represented, and continued drug discovery for this family of receptors may provide novel therapeutics for a vast range of diseases. GPCR allosteric modulation is an innovative targeting approach that broadens the available small molecule toolbox and is proving to be a viable drug discovery strategy, as evidenced by recent FDA approvals and clinical trials. Numerous class A GPCR allosteric modulators have been discovered recently, and emerging trends such as the availability of GPCR crystal structures, diverse functional assays, and structure-based computational approaches are improving optimization and development. This Perspective provides an update on allosterically targeted class A GPCRs and their disease indications and the medicinal chemistry approaches toward novel allosteric modulators and highlights emerging trends and opportunities in the field.
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Affiliation(s)
- Eric A. Wold
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jianping Chen
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Kathryn A. Cunningham
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
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4
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Davoren JE, Garnsey M, Pettersen B, Brodney MA, Edgerton JR, Fortin JP, Grimwood S, Harris AR, Jenkinson S, Kenakin T, Lazzaro JT, Lee CW, Lotarski SM, Nottebaum L, O’Neil SV, Popiolek M, Ramsey S, Steyn SJ, Thorn CA, Zhang L, Webb D. Design and Synthesis of γ- and δ-Lactam M1 Positive Allosteric Modulators (PAMs): Convulsion and Cholinergic Toxicity of an M1-Selective PAM with Weak Agonist Activity. J Med Chem 2017; 60:6649-6663. [DOI: 10.1021/acs.jmedchem.7b00597] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
| | | | | | | | | | | | | | | | - Stephen Jenkinson
- Drug Safety
Research and Development, Pfizer Worldwide Research and Development, La Jolla, California 92121, United States
| | - Terry Kenakin
- Department
of Pharmacology, University of North Carolina School of Medicine, Chapel
Hill, North Carolina 27599, United States
| | | | | | | | - Lisa Nottebaum
- Drug Safety
Research and Development, Pfizer Worldwide Research and Development, La Jolla, California 92121, United States
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5
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Panarese JD, Cho HP, Adams JJ, Nance KD, Garcia-Barrantes PM, Chang S, Morrison RD, Blobaum AL, Niswender CM, Stauffer SR, Conn PJ, Lindsley CW. Further optimization of the M1 PAM VU0453595: Discovery of novel heterobicyclic core motifs with improved CNS penetration. Bioorg Med Chem Lett 2016; 26:3822-5. [PMID: 27173801 PMCID: PMC5082649 DOI: 10.1016/j.bmcl.2016.04.083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 01/28/2023]
Abstract
This Letter describes the continued chemical optimization of the VU0453595 series of M1 positive allosteric modulators (PAMs). By surveying alternative 5,6- and 6,6-heterobicylic cores for the 6,7-dihydro-5H-pyrrolo[3,4-b]pyridine-5-one core of VU453595, we found new cores that engendered not only comparable or improved M1 PAM potency, but significantly improved CNS distribution (Kps 0.3-3.1). Moreover, this campaign provided fundamentally distinct M1 PAM chemotypes, greatly expanding the available structural diversity for this valuable CNS target, devoid of hydrogen-bond donors.
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Affiliation(s)
- Joseph D Panarese
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hykeyung P Cho
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jeffrey J Adams
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kellie D Nance
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Pedro M Garcia-Barrantes
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sichen Chang
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ryan D Morrison
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Anna L Blobaum
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Colleen M Niswender
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Shaun R Stauffer
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Craig W Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.
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6
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Davoren JE, Lee CW, Garnsey M, Brodney MA, Cordes J, Dlugolenski K, Edgerton JR, Harris AR, Helal CJ, Jenkinson S, Kauffman GW, Kenakin TP, Lazzaro JT, Lotarski SM, Mao Y, Nason DM, Northcott C, Nottebaum L, O’Neil SV, Pettersen B, Popiolek M, Reinhart V, Salomon-Ferrer R, Steyn SJ, Webb D, Zhang L, Grimwood S. Discovery of the Potent and Selective M1 PAM-Agonist N-[(3R,4S)-3-Hydroxytetrahydro-2H-pyran-4-yl]-5-methyl-4-[4-(1,3-thiazol-4-yl)benzyl]pyridine-2-carboxamide (PF-06767832): Evaluation of Efficacy and Cholinergic Side Effects. J Med Chem 2016; 59:6313-28. [DOI: 10.1021/acs.jmedchem.6b00544] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Stephen Jenkinson
- Drug
Safety Research and Development, Pfizer Worldwide Research and Development, La Jolla, California 92121, United States
| | | | - Terrence P. Kenakin
- Department
of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, United States
| | | | | | | | | | | | - Lisa Nottebaum
- Drug
Safety Research and Development, Pfizer Worldwide Research and Development, La Jolla, California 92121, United States
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7
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Mistry SN, Jörg M, Lim H, Vinh NB, Sexton PM, Capuano B, Christopoulos A, Lane JR, Scammells PJ. 4-Phenylpyridin-2-one Derivatives: A Novel Class of Positive Allosteric Modulator of the M1 Muscarinic Acetylcholine Receptor. J Med Chem 2015; 59:388-409. [DOI: 10.1021/acs.jmedchem.5b01562] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Shailesh N. Mistry
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Manuela Jörg
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Herman Lim
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Natalie B. Vinh
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Patrick M. Sexton
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Ben Capuano
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Arthur Christopoulos
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - J. Robert Lane
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
| | - Peter J. Scammells
- Medicinal
Chemistry and ‡Drug Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria Australia
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8
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Han C, Chatterjee A, Noetzel MJ, Panarese JD, Smith E, Chase P, Hodder P, Niswender C, Conn PJ, Lindsley CW, Stauffer SR. Discovery and SAR of muscarinic receptor subtype 1 (M1) allosteric activators from a molecular libraries high throughput screen. Part 1: 2,5-dibenzyl-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones as positive allosteric modulators. Bioorg Med Chem Lett 2014; 25:384-8. [PMID: 25435150 DOI: 10.1016/j.bmcl.2014.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 10/29/2014] [Accepted: 11/03/2014] [Indexed: 12/18/2022]
Abstract
Results from a 2012 high-throughput screen of the NIH Molecular Libraries Small Molecule Repository (MLSMR) against the human muscarinic receptor subtype 1 (M1) for positive allosteric modulators is reported. A content-rich screen utilizing an intracellular calcium mobilization triple-addition protocol allowed for assessment of all three modes of pharmacology at M1, including agonist, positive allosteric modulator, and antagonist activities in a single screening platform. We disclose a dibenzyl-2H-pyrazolo[4,3-c]quinolin-3(5H)-one hit (DBPQ, CID 915409) and examine N-benzyl pharmacophore/SAR relationships versus previously reported quinolin-3(5H)-ones and isatins, including ML137. SAR and consideration of recently reported crystal structures, homology modeling, and structure-function relationships using point mutations suggests a shared binding mode orientation at the putative common allosteric binding site directed by the pendant N-benzyl substructure.
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Affiliation(s)
- Changho Han
- 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
| | - Arindam Chatterjee
- 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
| | - Meredith J Noetzel
- 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
| | - Joseph D Panarese
- 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
| | - Emery Smith
- The Scripps Research Institutes Molecular Screening Center, Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, USA
| | - Peter Chase
- The Scripps Research Institutes Molecular Screening Center, Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, USA
| | | | - Colleen 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
| | - 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
| | - Shaun R Stauffer
- 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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9
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Abdul-Ridha A, Lane JR, Mistry SN, López L, Sexton PM, Scammells PJ, Christopoulos A, Canals M. Mechanistic insights into allosteric structure-function relationships at the M1 muscarinic acetylcholine receptor. J Biol Chem 2014; 289:33701-11. [PMID: 25326383 DOI: 10.1074/jbc.m114.604967] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Benzylquinolone carboxylic acid (BQCA) is the first highly selective positive allosteric modulator (PAM) for the M1 muscarinic acetylcholine receptor (mAChR), but it possesses low affinity for the allosteric site on the receptor. More recent drug discovery efforts identified 3-((1S,2S)-2-hydroxycyclohexyl)-6-((6-(1-methyl-1H-pyrazol-4-yl)pyridin-3-yl)methyl)benzo[h]quinazolin-4(3H)-one (referred to herein as benzoquinazolinone 12) as a more potent M1 mAChR PAM with a structural ancestry originating from BQCA and related compounds. In the current study, we optimized the synthesis of and fully characterized the pharmacology of benzoquinazolinone 12, finding that its improved potency derived from a 50-fold increase in allosteric site affinity as compared with BQCA, while retaining a similar level of positive cooperativity with acetylcholine. We then utilized site-directed mutagenesis and molecular modeling to validate the allosteric binding pocket we previously described for BQCA as a shared site for benzoquinazolinone 12 and provide a molecular basis for its improved activity at the M1 mAChR. This includes a key role for hydrophobic and polar interactions with residues Tyr-179, in the second extracellular loop (ECL2) and Trp-400(7.35) in transmembrane domain (TM) 7. Collectively, this study highlights how the properties of affinity and cooperativity can be differentially modified on a common structural scaffold and identifies molecular features that can be exploited to tailor the development of M1 mAChR-targeting PAMs.
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Affiliation(s)
| | | | - Shailesh N Mistry
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
| | - Laura López
- From the Departments of Drug Discovery Biology and
| | | | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
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