1
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Janero DR. Current strategic trends in drug discovery: the present as prologue. Expert Opin Drug Discov 2024; 19:147-159. [PMID: 37936504 DOI: 10.1080/17460441.2023.2275640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/23/2023] [Indexed: 11/09/2023]
Abstract
INTRODUCTION Escalating costs and inherent uncertainties associated with drug discovery invite initiatives to improve its efficiency and de-risk campaigns for inventing better therapeutics. One such initiative involves recognizing and exploiting current approaches in therapeutics invention with molecular mechanisms of action that hold promise for designing and targeting new chemical entities as drugs. AREAS COVERED This perspective considers the current contextual framework around three drug-discovery approaches and evaluates their potential to help identify new targets/modalities in small-molecule molecular pharmacology: diversifying ligand-directed phenotypes for G protein-coupled receptor (GPCR) pharmacotherapeutic signaling; developing therapeutic-protein degraders and stabilizers for proximity-inducing pharmacology; and mining organelle biology for druggable therapeutic targets. EXPERT OPINION The contemporary drug-discovery approaches examined appear generalizable and versatile to have applications in therapeutics invention beyond those case studies discussed herein. Accordingly, they may be considered strategic trends worthy of note in advancing the field toward novel ways of addressing pharmacotherapeutically unmet medical needs.
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Affiliation(s)
- David R Janero
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, and Health Sciences Entrepreneurs, Northeastern University, Boston, MA, USA
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2
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Wingert B, Doruker P, Bahar I. Activation and Speciation Mechanisms in Class A GPCRs. J Mol Biol 2022; 434:167690. [PMID: 35728652 PMCID: PMC10129049 DOI: 10.1016/j.jmb.2022.167690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 01/03/2023]
Abstract
Accurate development of allosteric modulators of GPCRs require a thorough assessment of their sequence, structure, and dynamics, toward gaining insights into their mechanisms of actions shared by family members, as well as dynamic features that distinguish subfamilies. Building on recent progress in the characterization of the signature dynamics of proteins, we analyzed here a dataset of 160 Class A GPCRs to determine their sequence similarities, structural landscape, and dynamic features across different species (human, bovine, mouse, squid, and rat), different activation states (active/inactive), and different subfamilies. The two dominant directions of variability across experimentally resolved structures, identified by principal component analysis of the dataset, shed light to cooperative mechanisms of activation, subfamily differentiation, and speciation of Class A GPCRs. The analysis reveals the functional significance of the conformational flexibilities of specific structural elements, including: the dominant role of the intracellular loop 3 (ICL3) together with the cytoplasmic ends of the adjoining helices TM5 and TM6 in enabling allosteric activation; the role of particular structural motifs at the extracellular loop 2 (ECL2) connecting TM4 and TM5 in binding ligands specific to different subfamilies; or even the differentiation of the N-terminal conformation across different species. Detailed analyses of the modes of motions accessible to the members of the dataset and their variations across members demonstrate how the active and inactive states of GPCRs obey distinct conformational dynamics. The collective fluctuations of the GPCRs are robustly defined in the active state, while the inactive conformers exhibit broad variance among members.
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Affiliation(s)
- Bentley Wingert
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Pemra Doruker
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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3
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Garai S, Schaffer PC, Laprairie RB, Janero DR, Pertwee RG, Straiker A, Thakur GA. Design, synthesis, and pharmacological profiling of cannabinoid 1 receptor allosteric modulators: Preclinical efficacy of C2-group GAT211 congeners for reducing intraocular pressure. Bioorg Med Chem 2021; 50:116421. [PMID: 34634617 DOI: 10.1016/j.bmc.2021.116421] [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] [Received: 07/01/2021] [Revised: 09/03/2021] [Accepted: 09/14/2021] [Indexed: 11/28/2022]
Abstract
Allosteric modulators of cannabinoid 1 receptor (CB1R) show translational promise over orthosteric ligands due to their potential to elicit therapeutic benefit without cannabimimetic side effects. The prototypic 2-phenylindole CB1R allosteric modulator, GAT211 (1), demonstrates preclinical efficacy in various disease models. The limited systematic structure-activity relationship (SAR) data at the C2 position of the indole ring within GAT211 invites the opportunity for further modifications to improve GAT211's pharmacological profile while serving to amplify and variegate this library of therapeutically attractive agents. These considerations prompted this focused SAR study in which we substituted the GAT211 C2-phenyl ring with heteroaromatic substituents. The synthesized GAT211 analogs were then evaluated in vitro as CB1R allosteric modulators in cAMP and β-arrestin2 assays with CP55,940 as the orthosteric ligand. Furan and thiophene rings (15c-f and 15m) were the best-tolerated substituents at the C2 position of GAT211 for engagement with human CB1R (hCB1R). The SAR around the novel ligands reported allowed direct experimental characterization of the interaction profile of that pharmacophore with its binding domain in functional, human CB1R, thus offering guidance for accessing subsequent-generation hCB1R allosteric modulators as potential therapeutics. The most potent analog, 15d, markedly promoted orthosteric ligand binding to hCB1R. Pharmacological profiling in the GTPγS and mouse vas deferens assays demonstrated that 15d behaves as a CB1R agonist-positive allosteric modulator (ago-PAM), as confirmed electrophysiologically in autoptic neurons. In vivo, 15d was efficacious as a topical agent that significantly reduced intraocular pressure (IOP) in the ocular normotensive murine model of glaucoma. Since elevated IOP is a decisive risk factor for glaucoma and attendant vision loss, our data support the proposition that the 2-phenylindole class of CB1R ago-PAMs has therapeutic potential for glaucoma and other diseases where potentiation of CB1R signaling may be therapeutic.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, SK S7N2Z4, Canada
| | - David R Janero
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK
| | - Alex Straiker
- Program in Neuroscience, Indiana University, Bloomington, Indiana Gill Center for Biomolecular Science, Bloomington, IN 47405, United States
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
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Garai S, Leo LM, Szczesniak AM, Hurst DP, Schaffer PC, Zagzoog A, Black T, Deschamps JR, Miess E, Schulz S, Janero DR, Straiker A, Pertwee RG, Abood ME, Kelly MEM, Reggio PH, Laprairie RB, Thakur GA. Discovery of a Biased Allosteric Modulator for Cannabinoid 1 Receptor: Preclinical Anti-Glaucoma Efficacy. J Med Chem 2021; 64:8104-8126. [PMID: 33826336 DOI: 10.1021/acs.jmedchem.1c00040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We apply the magic methyl effect to improve the potency/efficacy of GAT211, the prototypic 2-phenylindole-based cannabinoid type-1 receptor (CB1R) agonist-positive allosteric modulator (ago-PAM). Introducing a methyl group at the α-position of nitro group generated two diastereomers, the greater potency and efficacy of erythro, (±)-9 vs threo, (±)-10 constitutes the first demonstration of diastereoselective CB1R-allosteric modulator interaction. Of the (±)-9 enantiomers, (-)-(S,R)-13 evidenced improved potency over GAT211 as a CB1R ago-PAM, whereas (+)-(R,S)-14 was a CB1R allosteric agonist biased toward G protein- vs β-arrestin1/2-dependent signaling. (-)-(S,R)-13 and (+)-(R,S)-14 were devoid of undesirable side effects (triad test), and (+)-(R,S)-14 reduced intraocular pressure with an unprecedentedly long duration of action in a murine glaucoma model. (-)-(S,R)-13 docked into both a CB1R extracellular PAM and intracellular allosteric-agonist site(s), whereas (+)-(R,S)-14 preferentially engaged only the latter. Exploiting G-protein biased CB1R-allosteric modulation can offer safer therapeutic candidates for glaucoma and, potentially, other diseases.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Luciana M Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Anna-Maria Szczesniak
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Dow P Hurst
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Tallan Black
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Jeffrey R Deschamps
- Naval Research Laboratory, Code 6930, 4555 Overlook Avenue, Washington, District of Columbia 20375, United States
| | - Elke Miess
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - Stefan Schulz
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Alex Straiker
- The Gill Center and the Department of Psychological & Brain Sciences, Indiana University, 1101 E. 10th St, Bloomington, Indiana 47405, United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, U.K
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Melanie E M Kelly
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Patricia H Reggio
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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Haspula D, Clark MA. Cannabinoid Receptors: An Update on Cell Signaling, Pathophysiological Roles and Therapeutic Opportunities in Neurological, Cardiovascular, and Inflammatory Diseases. Int J Mol Sci 2020; 21:E7693. [PMID: 33080916 PMCID: PMC7590033 DOI: 10.3390/ijms21207693] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/16/2022] Open
Abstract
The identification of the human cannabinoid receptors and their roles in health and disease, has been one of the most significant biochemical and pharmacological advancements to have occurred in the past few decades. In spite of the major strides made in furthering endocannabinoid research, therapeutic exploitation of the endocannabinoid system has often been a challenging task. An impaired endocannabinoid tone often manifests as changes in expression and/or functions of type 1 and/or type 2 cannabinoid receptors. It becomes important to understand how alterations in cannabinoid receptor cellular signaling can lead to disruptions in major physiological and biological functions, as they are often associated with the pathogenesis of several neurological, cardiovascular, metabolic, and inflammatory diseases. This review focusses mostly on the pathophysiological roles of type 1 and type 2 cannabinoid receptors, and it attempts to integrate both cellular and physiological functions of the cannabinoid receptors. Apart from an updated review of pre-clinical and clinical studies, the adequacy/inadequacy of cannabinoid-based therapeutics in various pathological conditions is also highlighted. Finally, alternative strategies to modulate endocannabinoid tone, and future directions are also emphasized.
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Affiliation(s)
- Dhanush Haspula
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
| | - Michelle A. Clark
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
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6
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Focused structure-activity relationship profiling around the 2-phenylindole scaffold of a cannabinoid type-1 receptor agonist-positive allosteric modulator: site-III aromatic-ring congeners with enhanced activity and solubility. Bioorg Med Chem 2020; 28:115727. [PMID: 33065437 DOI: 10.1016/j.bmc.2020.115727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/06/2020] [Accepted: 08/19/2020] [Indexed: 12/31/2022]
Abstract
Specific tuning of cannabinoid 1 receptor (CB1R) activity by small-molecule allosteric modulators is a therapeutic modality with multiple properties inherently advantageous to therapeutic applications. We previously generated a library of unique CB1R positive allosteric modulators (PAMs) derived from GAT211, which has three pharmacophoric sites critical to its ago-PAM activity. To elaborate our CB1R PAM library, we report the rational design and molecular-pharmacology profiling of several 2-phenylindole analogs modified at the "site-III" aromatic ring. The comprehensive structure-activity relationship (SAR) investigation demonstrates that attaching small lipophilic functional groups on the ortho-position of the GAT211 site-III phenyl ring could markedly enhance CB1R ago-PAM activity. Select site-III modifications also improved GAT211's water solubility. The SAR reported both extends the structural diversity of this compound class and demonstrates the utility of GAT211's site-III for improving the parent compound's drug-like properties of potency and/or aqueous solubility.
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7
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Garai S, Kulkarni PM, Schaffer PC, Leo LM, Brandt AL, Zagzoog A, Black T, Lin X, Hurst DP, Janero DR, Abood ME, Zimmowitch A, Straiker A, Pertwee RG, Kelly M, Szczesniak AM, Denovan-Wright EM, Mackie K, Hohmann AG, Reggio PH, Laprairie RB, Thakur GA. Application of Fluorine- and Nitrogen-Walk Approaches: Defining the Structural and Functional Diversity of 2-Phenylindole Class of Cannabinoid 1 Receptor Positive Allosteric Modulators. J Med Chem 2020; 63:542-568. [PMID: 31756109 DOI: 10.1021/acs.jmedchem.9b01142] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cannabinoid 1 receptor (CB1R) allosteric ligands hold a far-reaching therapeutic promise. We report the application of fluoro- and nitrogen-walk approaches to enhance the drug-like properties of GAT211, a prototype CB1R allosteric agonist-positive allosteric modulator (ago-PAM). Several analogs exhibited improved functional potency (cAMP, β-arrestin 2), metabolic stability, and aqueous solubility. Two key analogs, GAT591 (6r) and GAT593 (6s), exhibited augmented allosteric-agonist and PAM activities in neuronal cultures, improved metabolic stability, and enhanced orthosteric agonist binding (CP55,940). Both analogs also exhibited good analgesic potency in the CFA inflammatory-pain model with longer duration of action over GAT211 while being devoid of adverse cannabimimetic effects. Another analog, GAT592 (9j), exhibited moderate ago-PAM potency and improved aqueous solubility with therapeutic reduction of intraocular pressure in murine glaucoma models. The SAR findings and the enhanced allosteric activity in this class of allosteric modulators were accounted for in our recently developed computational model for CB1R allosteric activation and positive allosteric modulation.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Pushkar M Kulkarni
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Luciana M Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine , Temple University , Philadelphia , Pennsylvania 19140 , United States
| | - Asher L Brandt
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Tallan Black
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Xiaoyan Lin
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Dow P Hurst
- Center for Drug Discovery , University of North Carolina Greensboro , Greensboro , North Carolina 27402 , United States
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Department of Chemistry and Chemical Biology, College of Science, and Health Sciences Entrepreneurs , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine , Temple University , Philadelphia , Pennsylvania 19140 , United States
| | - Anaelle Zimmowitch
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Alex Straiker
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , Aberdeen AB25 2ZD , Scotland, U.K
| | - Melanie Kelly
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Anna-Maria Szczesniak
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Eileen M Denovan-Wright
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Ken Mackie
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Andrea G Hohmann
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Patricia H Reggio
- Center for Drug Discovery , University of North Carolina Greensboro , Greensboro , North Carolina 27402 , United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada.,Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
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Allosteric Modulation of Cannabinoid Receptor 1-Current Challenges and Future Opportunities. Int J Mol Sci 2019; 20:ijms20235874. [PMID: 31771126 PMCID: PMC6928801 DOI: 10.3390/ijms20235874] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023] Open
Abstract
The cannabinoid receptor type 1 (CB1R), a G protein-coupled receptor (GPCR), plays an essential role in the control of many physiological processes such as hunger, memory loss, gastrointestinal activity, catalepsy, fear, depression, and chronic pain. Therefore, it is an attractive target for drug discovery to manage pain, neurodegenerative disorders, obesity, and substance abuse. However, the psychoactive adverse effects, generated by CB1R activation in the brain, limit the use of the orthosteric CB1R ligands as drugs. The discovery of CB1R allosteric modulators during the last decade provided new tools to target the CB1R. Moreover, application of the site-directed mutagenesis in combination with advanced physical methods, especially X-ray crystallography and computational modeling, has opened new horizons for understanding the complexity of the structure, function, and activity of cannabinoid receptors. In this paper, we present the latest advances in research on the CB1R, its allosteric modulation and allosteric ligands, and their translational potential. We focused on structural essentials of the cannabinoid 1 receptor- ligand (drug) interactions, as well as modes of CB1R signaling regulation.
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9
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Hurst DP, Garai S, Kulkarni PM, Schaffer PC, Reggio PH, Thakur GA. Identification of CB1 Receptor Allosteric Sites Using Force-Biased MMC Simulated Annealing and Validation by Structure-Activity Relationship Studies. ACS Med Chem Lett 2019; 10:1216-1221. [PMID: 31413808 DOI: 10.1021/acsmedchemlett.9b00256] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/10/2019] [Indexed: 02/02/2023] Open
Abstract
Positive allosteric modulation of the cannabinoid 1 receptor (CB1R) has demonstrated distinct therapeutic advantages that address several limitations associated with orthosteric agonism and has opened a promising therapeutic avenue for further drug development. To advance the development of CB1R positive allosteric modulators, it is important to understand the molecular architecture of CB1R allosteric site(s). The goal of this work was to use Force-Biased MMC Simulated Annealing to identify binding sites for GAT228 (R), a partial allosteric agonist, and GAT229 (S), a positive allosteric modulator (PAM) at the CB1R. Our studies suggest that GAT228 binds in an intracellular (IC) TMH1-2-4 exosite that would allow this compound to act as a CB1 allosteric agonist as well as a CB1 PAM. In contrast, GAT229 binds at the extracellular (EC) ends of TMH2/3, just beneath the EC1 loop. At this site, this compound can act as CB1 PAM only. Finally, these results were successfully validated through the synthesis and biochemical evaluation of a focused library of compounds.
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Affiliation(s)
- Dow P. Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro North Carolina 27412, United States
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Pushkar M. Kulkarni
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Peter C. Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro North Carolina 27412, United States
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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10
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Nguyen T, Gamage TF, Decker AM, German N, Langston TL, Farquhar CE, Kenakin TP, Wiley JL, Thomas BF, Zhang Y. Diarylureas Containing 5-Membered Heterocycles as CB 1 Receptor Allosteric Modulators: Design, Synthesis, and Pharmacological Evaluation. ACS Chem Neurosci 2019; 10:518-527. [PMID: 30188693 DOI: 10.1021/acschemneuro.8b00396] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Allosteric modulators have attracted significant interest as an alternate strategy to modulate CB1 receptor signaling for therapeutic benefits that may avoid the adverse effects associated with orthosteric ligands. Here we extended our previous structure-activity relationship studies on the diarylurea-based CB1 negative allosteric modulators (NAMs) by introducing five-membered heterocycles to replace the 5-pyrrolidinylpyridinyl group in PSNCBAM-1 (1), one of the first generation CB1 allosteric modulators. Many of these compounds had comparable potency to 1 in blocking the CB1 agonist CP55,940 stimulated calcium mobilization and [35S]GTP-γ-S binding. Similar to 1, most compounds showed positive cooperativity by increasing [3H]CP55,940 binding, consistent with the positive allosteric modulator (PAM)-antagonist mechanism. Interestingly, these compounds exhibited differences in ability to increase specific binding of [3H]CP55,940 and decrease binding of the antagonist [3H]SR141716. In saturation binding studies, only increases in [3H]CP55,940 Bmax, but not Kd, were observed, suggesting that these compounds stabilize low affinity receptors into a high affinity state. Among the series, the 2-pyrrolyl analogue (13) exhibited greater potency than 1 in the [35S]GTP-γ-S binding assay and significantly enhanced the maximum binding level in the [3H]CP5,5940 binding assay, indicating greater CB1 receptor affinity and/or cooperativity.
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Affiliation(s)
- Thuy Nguyen
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Thomas F. Gamage
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Ann M. Decker
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Nadezhda German
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Tiffany L. Langston
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Charlotte E. Farquhar
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Terry P. Kenakin
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Jenny L. Wiley
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Brian F. Thomas
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
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11
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Immadi SS, Dopart R, Wu Z, Fu B, Kendall DA, Lu D. Exploring 6-Azaindole and 7-Azaindole Rings for Developing Cannabinoid Receptor 1 Allosteric Modulators. Cannabis Cannabinoid Res 2018; 3:252-258. [PMID: 30547095 PMCID: PMC6290480 DOI: 10.1089/can.2018.0046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Introduction and Objective: Org27569 is a prototypical allosteric modulator of the cannabinoid receptor 1 (CB1). It belongs to the indole-2-carboxamide scaffold and has been intensively investigated in pharmacology and in structure-activity relationship (SAR) studies. Although azaindoles are rare in natural products and differ only by the presence of an extra ring nitrogen, they were demonstrated as valuable bioisosteres in many pharmacologically important molecules. To extend the SAR investigation of the indole-2-carboxamide class of CB1 allosteric modulators, azaindole (pyrrolopyridine) rings were used to replace the indole ring of Org27569 analogs to explore the potential of azaindole-2-carboxamides as CB1 allosteric modulators. Using 6- and 7-azaindole in lieu of the indole moiety within this class of CB1 allosteric modulators indeed improved the aqueous solubility. Materials and Methods: We synthesized 6- and 7-azaindole-2-carboxamides and their indole-2-carboxamide counterparts. The molecules were evaluated by [3H]CP55,940 binding and [35S]GTPγS binding assays for their allosteric modulation of the CB1 receptor. Results: The 7-azaindole-2-carboxamides lost the ability to bind to the CB1 receptor. The 6-azaindole-2-carboxamides (e.g., 3c and 3d) showed markedly reduced binding affinities to the CB1 receptor in comparison with their indole-2-carboxamide counterparts. However, they behaved similarly as indole-2-carboxamides in potentiating the orthosteric agonist binding and inhibiting the orthosteric agonist-induced G-protein coupling. The results indicated that some azaindole scaffolds (e.g., 6-azaindole) are worth further exploration, whereas the 7-azaindole ring is not a viable bioisostere of the indole ring in the Org27569 class of CB1 allosteric modulators.
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Affiliation(s)
- Sri Sujana Immadi
- Department of Pharmaceutical Sciences, Rangel College of Pharmacy, Health Science Center, Texas A&M University, Kingsville, Texas
| | - Rachel Dopart
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut
| | - Zhixing Wu
- Department of Pharmaceutical Sciences, Rangel College of Pharmacy, Health Science Center, Texas A&M University, Kingsville, Texas
| | - Boqiao Fu
- Department of Pharmaceutical Sciences, Rangel College of Pharmacy, Health Science Center, Texas A&M University, Kingsville, Texas
| | - Debra A. Kendall
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut
| | - Dai Lu
- Department of Pharmaceutical Sciences, Rangel College of Pharmacy, Health Science Center, Texas A&M University, Kingsville, Texas
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Gado F, Di Cesare Mannelli L, Lucarini E, Bertini S, Cappelli E, Digiacomo M, Stevenson LA, Macchia M, Tuccinardi T, Ghelardini C, Pertwee RG, Manera C. Identification of the First Synthetic Allosteric Modulator of the CB 2 Receptors and Evidence of Its Efficacy for Neuropathic Pain Relief. J Med Chem 2018; 62:276-287. [PMID: 29990428 DOI: 10.1021/acs.jmedchem.8b00368] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The direct activation of cannabinoid receptors (CBRs) results in several beneficial effects; therefore several CBRs ligands have been synthesized and tested in vitro and in vivo. However, none of them reached an advanced phase of clinical development due mainly to side effects on the CNS. Medicinal chemistry approaches are now engaged to develop allosteric modulators that might offer a novel therapeutic approach to achieve potential therapeutic benefits avoiding inherent side effects of orthosteric ligands. Here we identify the first ever synthesized positive allosteric modulator (PAM) that targets CB2Rs. The evidence for this was obtained using [3H]CP55940 and [35S]GTPγS binding assays. This finding will be useful for the characterization of allosteric binding site(s) on CB2Rs which will be essential for the further development of CB2R allosteric modulators. Moreover, the new CB2R PAM displayed antinociceptive activity in vivo in an experimental mouse model of neuropathic pain, raising the possibility that it might be a good candidate for clinical development.
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Affiliation(s)
- Francesca Gado
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Lorenzo Di Cesare Mannelli
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology , University of Florence , 50139 Florence , Italy
| | - Elena Lucarini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology , University of Florence , 50139 Florence , Italy
| | - Simone Bertini
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Elena Cappelli
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Maria Digiacomo
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Lesley A Stevenson
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , AB25 2ZD Aberdeen , Scotland, U.K
| | - Marco Macchia
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Tiziano Tuccinardi
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy.,Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology , Temple University , Philadelphia , Pennsylvania 19122 , United States
| | - Carla Ghelardini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology , University of Florence , 50139 Florence , Italy
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , AB25 2ZD Aberdeen , Scotland, U.K
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