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Jörg M, van der Westhuizen ET, Lu Y, Christopher Choy KH, Shackleford DM, Khajehali E, Tobin AB, Thal DM, Capuano B, Christopoulos A, Valant C, Scammells PJ. Design, synthesis and evaluation of novel 2-phenyl-3-(1H-pyrazol-4-yl)pyridine positive allosteric modulators for the M 4 mAChR. Eur J Med Chem 2023; 258:115588. [PMID: 37423123 DOI: 10.1016/j.ejmech.2023.115588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 07/11/2023]
Abstract
Translation of muscarinic acetylcholine receptor (mAChR) agonists into clinically used therapeutic agents has been difficult due to their poor subtype selectivity. M4 mAChR subtype-selective positive allosteric modulators (PAMs) may provide better therapeutic outcomes, hence investigating their detailed pharmacological properties is crucial to advancing them into the clinic. Herein, we report the synthesis and comprehensive pharmacological evaluation of M4 mAChR PAMs structurally related to 1e, Me-C-c, [11C]MK-6884 and [18F]12. Our results show that small structural changes to the PAMs can result in pronounced differences to baseline, potency (pEC50) and maximum effect (Emax) measures in cAMP assays when compared to the endogenous ligand acetylcholine (ACh) without the addition of the PAMs. Eight selected PAMs were further assessed to determine their binding affinity and potential signalling bias profile between cAMP and β-arrestin 2 recruitment. These rigorous analyses resulted in the discovery of the novel PAMs, 6k and 6l, which exhibit improved allosteric properties compared to the lead compound, and probative in vivo exposure studies in mice confirmed that they maintain the ability to cross the blood-brain barrier, making them more suitable for future preclinical assessment.
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Affiliation(s)
- Manuela Jörg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Emma T van der Westhuizen
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Yao Lu
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia; ARC Industrial Transformation Training Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - K H Christopher Choy
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - David M Shackleford
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Elham Khajehali
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, 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
| | - David M Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia; ARC Industrial Transformation Training Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Ben Capuano
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia; ARC Industrial Transformation Training Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia; Neuromedicines Discovery Centre, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia.
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia.
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Salamone S, Appendino G, Khalili A, Pollastro F, Munoz E, Unciti-Broceta JD. Agathadiol, a labdane diterpenoid from juniper berries, is a positive allosteric modulator of CB 1R. Fitoterapia 2021; 155:105059. [PMID: 34637886 DOI: 10.1016/j.fitote.2021.105059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/09/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022]
Abstract
The neutral fraction of a juniper (Juniperus communis L.) berries acetone extract could positively modulate the activity of type 1 - cannabinoid receptor (CB1R). Bioactivity-directed fractionation identified the labdane diterpenoid agathadiol (4) as a positive allosteric modulator of CB1R, while closely related analogues were inactive. Agathadiol (4) is a minor constituent of juniper, but could be more conveniently obtained by semisynthesis from agathic acid (8), a major constituent of Manila copal.
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Affiliation(s)
- Stefano Salamone
- Dipartimento di Scienze del Farmaco, Largo Donegani 2, 28100 Novara, Italy
| | - Giovanni Appendino
- Dipartimento di Scienze del Farmaco, Largo Donegani 2, 28100 Novara, Italy
| | - Adil Khalili
- Dipartimento di Scienze del Farmaco, Largo Donegani 2, 28100 Novara, Italy
| | - Federica Pollastro
- Dipartimento di Scienze del Farmaco, Largo Donegani 2, 28100 Novara, Italy; PlantaChem Srls, via Amico Canobio 4/6, 28100 Novara, Italy.
| | - Eduardo Munoz
- Instituto Maimónides de Investigación Biomédica de Córdoba, av. de Menéndez Pidal, 14004 Córdoba, Spain; Departamento de Biología Celular, Fisiología e Inmunología, Campus de Menéndez Pidal, Universidad de Córdoba, 14071 Spain Córdoba, Spain; Hospital Universitario Reina Sofía, av. de Menéndez Pidal, s/n, 14004 Córdoba, Spain.
| | - Juan D Unciti-Broceta
- Emerald Health Biotechnology, Parque Científico Tecnológico Rabanales 21, Calle Cecilia Payne, 14014 Córdoba, Spain
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Abdelkarim H, Hitchinson B, Banerjee A, Gaponenko V. Advances in NMR Methods to Identify Allosteric Sites and Allosteric Ligands. Adv Exp Med Biol 2019; 1163:171-186. [PMID: 31707704 DOI: 10.1007/978-981-13-8719-7_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
NMR allows assessment of protein structure in solution. Unlike conventional X-ray crystallography that provides snapshots of protein conformations, all conformational states are simultaneously accessible to analysis by NMR. This is a significant advantage for discovery and characterization of allosteric effects. These effects are observed when binding at one site of the protein affects another distinct site through conformational transitions. Allosteric regulation of proteins has been observed in multiple physiological processes in health and disease, providing an opportunity for the development of allosteric inhibitors. These compounds do not directly interact with the orthosteric site of the protein but influence its structure and function. In this book chapter, we provide an overview on how NMR methods are utilized to identify allosteric sites and to discover novel inhibitors, highlighting examples from the field. We also describe how NMR has contributed to understanding of allosteric mechanisms and propose that it is likely to play an important role in clarification and further development of key concepts of allostery.
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Affiliation(s)
- Hazem Abdelkarim
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ben Hitchinson
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Avik Banerjee
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
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Abstract
Opioid analgesics, most of which act through mu opioid receptors, have long represented valuable therapeutic agents to treat severe pain. Concerted drug development efforts for over a 100 years have resulted in a large variety of opioid analgesics used in the clinic, but all of them continue to exhibit the side effects, especially respiratory depression, that have long plagued the use of morphine. The recent explosion in fatalities resulting from overdose of prescription and synthetic opioids has dramatically increased the need for safer analgesics, but recent developments in mu receptor research have provided new strategies to develop such drugs. This chapter reviews recent advances in developing novel opioid analgesics from an understanding of mu receptor structure and function. This includes a summary of the mechanism of agonist binding deduced from the crystal structure of mu receptors. It will also highlight the development of novel agonist mechanisms, including biased agonists, bivalent ligands, and allosteric modulators of mu receptor function, and describe how receptor phosphorylation modulates these pathways. Finally, it will summarize research on the alternative pre-mRNA splicing mechanisms that produces a multiplicity of mu receptor isoforms. Many of these isoforms exhibit different pharmacological specificities and brain circuitry localization, thus providing an opportunity to develop novel drugs with increased therapeutic windows.
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Affiliation(s)
- Gavril W Pasternak
- Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Steven R Childers
- Department of Physiology/Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Ying-Xian Pan
- Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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Abstract
The human cannabinoid receptor, CB1, has been difficult to purify in a functional form, hampering structural and biophysical studies. Here, we present our approaches for obtaining pure, detergent solubilized, functional CB1. We also discuss our site-directed fluorescence labeling (SDFL) methods for identifying different structural changes that CB1 can undergo upon binding different cannabinoid ligands. To identify optimal CB1 constructs for these studies (those with the best expression levels, solubility in detergent and function), we first screened various CB1-green fluorescent protein chimeras in a mammalian expression system. Once identified, we then tagged the best candidates with the 1D4 epitope (the C-terminus of rhodopsin) and purified them using a single-step immunoaffinity process. The resulting, highly pure proteins retain their ability to activate G-protein, and are ~85% functional, as assessed by radioligand binding studies. The SDFL studies involve introducing single cysteine residues at key places in the receptor, then labeling them with a small fluorophore, bimane. The spectral properties of the bimane probe are then monitored before and after addition of cannabinoid ligands. Changes in fluorescence of the attached probe indicate regions of the receptor undergoing conformational changes upon ligand binding. Together, these approaches set the stage for a deeper understanding of the structure and function of CB1. Access to pure, functional CB1 makes subsequent structural studies possible (such as crystallography and single-particle EM analysis), and the SDFL studies enable a better structural and mechanistic understanding of this key receptor and the dynamic changes it undergoes during activation and attenuation.
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Iturriaga-Vásquez P, Alzate-Morales J, Bermudez I, Varas R, Reyes-Parada M. Multiple binding sites in the nicotinic acetylcholine receptors: An opportunity for polypharmacolgy. Pharmacol Res 2015; 101:9-17. [PMID: 26318763 DOI: 10.1016/j.phrs.2015.08.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 08/20/2015] [Accepted: 08/20/2015] [Indexed: 12/21/2022]
Abstract
For decades, the development of selective compounds has been the main goal for chemists and biologists involved in drug discovery. However, diverse lines of evidence indicate that polypharmacological agents, i.e. those that act simultaneously at various protein targets, might show better profiles than selective ligands, regarding both efficacy and side effects. On the other hand, the availability of the crystal structure of different receptors allows a detailed analysis of the main interactions between drugs and receptors in a specific binding site. Neuronal nicotinic acetylcholine receptors (nAChRs) constitute a large and diverse family of ligand-gated ion channels (LGICs) that, as a product of its modulation, regulate neurotransmitter release, which in turns produce a global neuromodulation of the central nervous system. nAChRs are pentameric protein complexes in such a way that expression of compatible subunits can lead to various receptor assemblies or subtypes. The agonist binding site, located at the extracellular region, exhibits different properties depending on the subunits that conform the receptor. In the last years, it has been recognized that nAChRs could also contain one or more allosteric sites which could bind non-classical nicotinic ligands including several therapeutically useful drugs. The presence of multiple binding sites in nAChRs offers an interesting possibility for the development of novel polypharmacological agents with a wide spectrum of actions.
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