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Dengler DG, Harikumar KG, Yen A, Sergienko EA, Miller LJ. Mechanism of Action and Structure-Activity Relationships of Tetracyclic Small Molecules Acting as Universal Positive Allosteric Modulators of the Cholecystokinin Receptor. MEMBRANES 2023; 13:150. [PMID: 36837653 PMCID: PMC9964746 DOI: 10.3390/membranes13020150] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
As part of an ongoing effort to develop a drug targeting the type 1 cholecystokinin receptor (CCK1R) to help prevent and/or treat obesity, we recently performed a high throughput screening effort of small molecules seeking candidates that enhanced the action of the natural agonist, CCK, thus acting as positive allosteric modulators without exhibiting intrinsic agonist action. Such probes would be expected to act in a temporally finite way to enhance CCK action to induce satiety during and after a meal and potentially even modulate activity at the CCK1R in a high cholesterol environment present in some obese patients. The current work focuses on the best scaffold, representing tetracyclic molecules identified through high throughput screening we previously reported. Extensive characterization of the two top "hits" from the previous effort demonstrated them to fulfill the desired pharmacologic profile. We undertook analog-by-catalog expansion of this scaffold using 65 commercially available analogs. In this effort, we were able to eliminate an off-target effect observed for this scaffold while retaining its activity as a positive allosteric modulator of CCK1R in both normal and high cholesterol membrane environments. These insights should be useful in the rational medicinal chemical enhancement of this scaffold and in the future development of candidates to advance to pre-clinical proof-of-concept and to clinical trials.
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Affiliation(s)
- Daniela G. Dengler
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Kaleeckal G. Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Alice Yen
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Eduard A. Sergienko
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Laurence J. Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ 85259, USA
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2
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Dengler DG, Sun Q, Harikumar KG, Miller LJ, Sergienko EA. Screening for positive allosteric modulators of cholecystokinin type 1 receptor potentially useful for management of obesity. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:384-394. [PMID: 35850480 PMCID: PMC9580343 DOI: 10.1016/j.slasd.2022.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Obesity has become a prevailing health burden globally and particularly in the US. It is associated with many health problems, including cardiovascular disease, diabetes and poorer mental health. Hence, there is a high demand to find safe and effective therapeutics for sustainable weight loss. Cholecystokinin (CCK) has been implicated as one of the first gastrointestinal hormones to reduce overeating and suppress appetite by activating the type 1 cholecystokinin receptor (CCK1R). Several drug development campaigns have focused on finding CCK1R-specific agonists, which showed promising efficacy for reducing meal size and weight, but fell short on FDA approval, likely due to side effects associated with potent, long-lasting activation of CCK1Rs. Positive allosteric modulators (PAMs) without inherent agonist activity have been proposed to overcome the shortcomings of traditional, orthosteric agonists and restore CCK1R signaling in failing physiologic systems. However, drug discovery campaigns searching for such novel acting CCK1R agents remain limited. Here we report a high-throughput screening effort and the establishment of a testing funnel, which led to the identification of novel CCK1R modulators. We utilized IP-One accumulation to develop robust functional equilibrium assays tailored to either detect PAMs, agonists or non-specific activators. In addition, we established the CCK1R multiplex PAM assay as a novel method to evaluate functional selectivity capable of recording CCK1R-induced cAMP accumulation and β-arrestin recruitment in the same well. This selection and arrangement of methods enabled the discovery of three scaffolds, which we characterized and validated in an array of functional and binding assays. We found two hits incorporating a tetracyclic scaffold that significantly enhanced CCK signaling at CCK1Rs without intrinsically activating CCK1Rs in an overexpressing system. Our results demonstrate that a well-thought-out testing funnel can identify small molecules with a distinct pharmacological profile and provides an important milestone for the development of novel potential treatments of obesity.
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Affiliation(s)
- Daniela G Dengler
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
| | - Qing Sun
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Kaleeckal G Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona, USA
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona, USA.
| | - Eduard A Sergienko
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
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3
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Piper NBC, Whitfield EA, Stewart GD, Xu X, Furness SGB. Targeting appetite and satiety in diabetes and obesity, via G protein-coupled receptors. Biochem Pharmacol 2022; 202:115115. [PMID: 35671790 DOI: 10.1016/j.bcp.2022.115115] [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: 02/28/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 11/17/2022]
Abstract
Type 2 diabetes and obesity have reached pandemic proportions throughout the world, so much so that the World Health Organisation coined the term "Globesity" to help encapsulate the magnitude of the problem. G protein-coupled receptors (GPCRs) are highly tractable drug targets due to their wide involvement in all aspects of physiology and pathophysiology, indeed, GPCRs are the targets of approximately 30% of the currently approved drugs. GPCRs are also broadly involved in key physiologies that underlie type 2 diabetes and obesity including feeding reward, appetite and satiety, regulation of blood glucose levels, energy homeostasis and adipose function. Despite this, only two GPCRs are the target of approved pharmaceuticals for treatment of type 2 diabetes and obesity. In this review we discuss the role of these, and select other candidate GPCRs, involved in various facets of type 2 diabetic or obese pathophysiology, how they might be targeted and the potential reasons why pharmaceuticals against these targets have not progressed to clinical use. Finally, we provide a perspective on the current development pipeline of anti-obesity drugs that target GPCRs.
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Affiliation(s)
- Noah B C Piper
- Receptor Transducer Coupling Laboratory, School of Biomedical Sciences, Faculty of Medicine, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Emily A Whitfield
- Receptor Transducer Coupling Laboratory, School of Biomedical Sciences, Faculty of Medicine, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Gregory D Stewart
- Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology Monash University, Parkville, VIC 3052, Australia
| | - Xiaomeng Xu
- Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology Monash University, Parkville, VIC 3052, Australia
| | - Sebastian G B Furness
- Receptor Transducer Coupling Laboratory, School of Biomedical Sciences, Faculty of Medicine, University of Queensland, St. Lucia, QLD 4072, Australia; Drug Discovery Biology Laboratory, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology Monash University, Parkville, VIC 3052, Australia.
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4
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Miller LJ, Harikumar KG, Wootten D, Sexton PM. Roles of Cholecystokinin in the Nutritional Continuum. Physiology and Potential Therapeutics. Front Endocrinol (Lausanne) 2021; 12:684656. [PMID: 34149622 PMCID: PMC8206557 DOI: 10.3389/fendo.2021.684656] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Cholecystokinin is a gastrointestinal peptide hormone with important roles in metabolic physiology and the maintenance of normal nutritional status, as well as potential roles in the prevention and management of obesity, currently one of the dominant causes of direct or indirect morbidity and mortality. In this review, we discuss the roles of this hormone and its receptors in maintaining nutritional homeostasis, with a particular focus on appetite control. Targeting this action led to the development of full agonists of the type 1 cholecystokinin receptor that have so far failed in clinical trials for obesity. The possible reasons for clinical failure are discussed, along with alternative pharmacologic strategies to target this receptor for prevention and management of obesity, including development of biased agonists and allosteric modulators. Cellular cholesterol is a natural modulator of the type 1 cholecystokinin receptor, with elevated levels disrupting normal stimulus-activity coupling. The molecular basis for this is discussed, along with strategies to overcome this challenge with a corrective positive allosteric modulator. There remains substantial scope for development of drugs to target the type 1 cholecystokinin receptor with these new pharmacologic strategies and such drugs may provide new approaches for treatment of obesity.
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Affiliation(s)
- Laurence J. Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States
- *Correspondence: Laurence J. Miller,
| | - Kaleeckal G. Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States
| | - Denise Wootten
- Drug Discovery Biology theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Patrick M. Sexton
- Drug Discovery Biology theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
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5
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Desai AJ, Dong M, Harikumar KG, Miller LJ. Cholecystokinin-induced satiety, a key gut servomechanism that is affected by the membrane microenvironment of this receptor. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2016; 6:S22-S27. [PMID: 28685026 DOI: 10.1038/ijosup.2016.5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The gastrointestinal (GI) tract has a central role in nutritional homeostasis, as location for food ingestion, digestion and absorption, with the gut endocrine system responding to and regulating these events, as well as influencing appetite. One key GI hormone with the full spectrum of these activities is cholecystokinin (CCK), a peptide released from neuroendocrine I cells scattered through the proximal intestine in response to fat and protein, with effects to stimulate gall bladder contraction and pancreatic exocrine secretion, to regulate gastric emptying and intestinal transit, and to induce satiety. There has been interest in targeting the type 1 CCK receptor (CCK1R) for drug development to provide non-caloric satiation as an aid to dieting and weight loss; however, there have been concerns about CCK1R agonists related to side effects and potential trophic impact on the pancreas. A positive allosteric modulator (PAM) of CCK action at this receptor without intrinsic agonist activity could provide a safer and more effective approach to long-term administration. In addition, CCK1R stimulus-activity coupling has been shown to be negatively affected by excess membrane cholesterol, a condition described in the metabolic syndrome, thereby potentially interfering with an important servomechanism regulating appetite. A PAM targeting this receptor could also potentially correct the negative impact of cholesterol on CCK1R function. We will review the molecular basis for binding natural peptide agonist, binding and action of small molecules within the allosteric pocket, and the impact of cholesterol. Novel strategies for taking advantage of this receptor for the prevention and management of obesity will be reviewed.
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Affiliation(s)
- A J Desai
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
| | - M Dong
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
| | - K G Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
| | - L J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
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6
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Desai AJ, Henke BR, Miller LJ. Elimination of a cholecystokinin receptor agonist 'trigger' in an effort to develop positive allosteric modulators without intrinsic agonist activity. Bioorg Med Chem Lett 2015; 25:1849-55. [PMID: 25862198 DOI: 10.1016/j.bmcl.2015.03.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 01/25/2023]
Abstract
Cholecystokinin (CCK) acts at the type 1 cholecystokinin receptor (CCK1R) to elicit satiety and is a well-established drug target for obesity. To date, small molecule agonists have been developed, but have failed to demonstrate adequate efficacy in clinical trials, and concerns about side effects and potential toxicity have limited further development of full agonists. The use of positive allosteric modulators (PAMs) without intrinsic agonist activity that are active only for a brief period of time after a meal might represent a safer alternative. Here, we propose a possible novel strategy to develop such compounds by modifying the agonist 'trigger' of an existing small molecule agonist. We have studied analogues of the 1,5-benzodiazepine agonist, GI181771X, in which the N1-isopropyl agonist 'trigger' was modified. While agonist activity was greatly reduced in these compounds, they acted as negative, rather than positive modulators. The parent drug was also found to exhibit no positive modulation of CCK action. Receptor structure-activity relationship studies demonstrated that the mode of docking these derivatives was distinct from that of the parent compound, perhaps explaining their action as negative allosteric modulators. We conclude that this outcome is likely characteristic of the parental agonist, and that this strategy may be more successfully utilized with a parental ago-PAM, possessing intrinsic positive modulatory activity.
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Affiliation(s)
- Aditya J Desai
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 13400 East Shea Blvd, Scottsdale, AZ 85259, United States
| | - Brad R Henke
- Metabolic Pathways and Cardiovascular Therapy Area Unit, GlaxoSmithKline Inc., Research Triangle Park, NC 27709, United States
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 13400 East Shea Blvd, Scottsdale, AZ 85259, United States.
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7
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Fülöpová V, Krchňák V. Solid-phase synthesis of trisubstituted 2,5-dihydrobenzo[f][1,2,5]thiadiazepine 1,1-dioxide derivatives. ACS COMBINATORIAL SCIENCE 2014; 16:412-20. [PMID: 24884092 DOI: 10.1021/co500084k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The solid-phase synthesis of trisubstituted 2,5-dihydrobenzo[f][1,2,5]thiadiazepine 1,1-dioxides is reported. Acyclic polymer-supported intermediates were prepared using commercially available building blocks: Fmoc-protected amino acids, 2-nitrobenzenesulfonyl chlorides, and bromoketones. The acyclic precursors underwent acid-mediated release from the resin and the cyclization was completed in solution.
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Affiliation(s)
- Veronika Fülöpová
- Department
of Organic Chemistry, Institute of Molecular and Translational Medicine,
Faculty of Science, Palacky University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
| | - Viktor Krchňák
- Department
of Organic Chemistry, Institute of Molecular and Translational Medicine,
Faculty of Science, Palacky University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
- Department
of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland
Science Center, Notre Dame, Indiana 46556, United States
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8
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Desai AJ, Harikumar KG, Miller LJ. A type 1 cholecystokinin receptor mutant that mimics the dysfunction observed for wild type receptor in a high cholesterol environment. J Biol Chem 2014; 289:18314-26. [PMID: 24825903 DOI: 10.1074/jbc.m114.570200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cholecystokinin (CCK) stimulates the type 1 CCK receptor (CCK1R) to elicit satiety after a meal. Agonists with this activity, although potentially useful for treatment of obesity, can also have side effects and toxicities of concern, making the development of an intrinsically inactive positive allosteric modulator quite attractive. Positive allosteric modulators also have the potential to correct the defective receptor-G protein coupling observed in the high membrane cholesterol environment described in metabolic syndrome. Current model systems to study CCK1R in such an environment are unstable and expensive to maintain. We now report that the Y140A mutation within a cholesterol-binding motif and the conserved, class A G protein-coupled receptor-specific (E/D)RY signature sequence results in ligand binding and activity characteristics similar to wild type CCK1R in a high cholesterol environment. This is true for natural CCK, as well as ligands with distinct chemistries and activity profiles. Additionally, the Y140A construct also behaved like CCK1R in high cholesterol in regard to its internalization, sensitivity to a nonhydrolyzable GTP analog, and anisotropy of a bound fluorescent CCK analog. Chimeric CCK1R/CCK2R constructs that systematically changed the residues in the allosteric ligand-binding pocket were studied in the presence of Y140A. This established increased importance of unique residues within TM3 and reduced the importance of TM2 for binding in the presence of this mutation, with the agonist trigger likely pulled away from its Leu(356) target on TM7. The distinct conformation of this intramembranous pocket within Y140A CCK1R provides an opportunity to normalize this by using a small molecule allosteric ligand, thereby providing safe and effective correction of the coupling defect in metabolic syndrome.
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Affiliation(s)
- Aditya J Desai
- From the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259
| | - Kaleeckal G Harikumar
- From the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259
| | - Laurence J Miller
- From the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259
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9
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Figueredo YN, Rodríguez EO, Reyes YV, Domínguez CC, Parra AL, Sánchez JR, Hernández RD, Verdecia MP, Pardo Andreu GL. Characterization of the anxiolytic and sedative profile of JM-20: a novel benzodiazepine–dihydropyridine hybrid molecule. Neurol Res 2013; 35:804-12. [DOI: 10.1179/1743132813y.0000000216] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - Estael Ochoa Rodríguez
- Laboratorio de Síntesis Orgánica de La Facultad de Química de La Universidad de La Habana Ciudad de la Habana, Cuba
| | - Yamila Verdecia Reyes
- Centro de Estudio para las Investigaciones y Evaluaciones Biológicas, Instituto de Farmacia y Alimentos, Universidad de La Habana, Ciudad Habana, Cuba
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10
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Wu F, Dong M, Fang F, Sang Y, Li Y, Cheng B, Zhang L, Zhai H. Direct access to tetrahydro[1,2]diazepinones from α,β-epoxy-N-aziridinylimines via anionic rearrangement. Org Lett 2013; 15:914-6. [PMID: 23379787 DOI: 10.1021/ol400070j] [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
A novel one-step synthetic approach to tetrahydro[1,2]diazepinones via base-promoted rearrangement of α,β-epoxy-N-aziridinylimines, derived from α,β-epoxyketones and N-aminoaziridines, has been developed.
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Affiliation(s)
- Fufang Wu
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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11
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Panini P, Chopra D. Quantitative insights into energy contributions of intermolecular interactions in fluorine and trifluoromethyl substituted isomeric N-phenylacetamides and N-methylbenzamides. CrystEngComm 2013. [DOI: 10.1039/c3ce40111a] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Mwande-Maguene G, Jakhlal J, Lekana-Douki JB, Mouray E, Bousquet T, Pellegrini S, Grellier P, Ndouo FST, Lebibi J, Pelinski L. One-pot microwave-assisted synthesis and antimalarial activity of ferrocenyl benzodiazepines. NEW J CHEM 2011. [DOI: 10.1039/c1nj20551j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Synthesis of pseudopeptidic (S)-6-amino-5-oxo-1,4-diazepines and (S)-3-benzyl-2-oxo-1,4-benzodiazepines by an Ugi 4CC Staudinger/aza-Wittig sequence. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.06.062] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Synthesis of 3-aryl substituted benzo[1,2,5]triazepin-4-ones via intramolecular imine formation. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.01.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Araújo AC, Nicotra F, Airoldi C, Costa B, Giagnoni G, Fumagalli P, Cipolla L. Synthesis and Biological Evaluation of Novel Rigid 1,4-Benzodiazepine-2,5-dione Chimeric Scaffolds. European J Org Chem 2008. [DOI: 10.1002/ejoc.200700952] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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16
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Ho J, Cox JM, Wagner EJ. Cannabinoid-induced hyperphagia: correlation with inhibition of proopiomelanocortin neurons? Physiol Behav 2007; 92:507-19. [PMID: 17532014 PMCID: PMC2720321 DOI: 10.1016/j.physbeh.2007.04.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/17/2007] [Accepted: 04/18/2007] [Indexed: 11/17/2022]
Abstract
We tested the hypothesis that cannabinoids modulate feeding in male guinea pigs, and correlated cannabinoid-induced changes in feeding behavior with alterations in glutamatergic synaptic currents impinging upon proopiomelanocortin (POMC) neurons of the hypothalamic arcuate nucleus. Feeding experiments were performed as follows: after a three-day acclimation period, animals were weighed and injected with either the CB1 receptor agonist WIN 55,212-2 (1 mg/kg, s.c.), antagonist AM251 (3 mg/kg, s.c.) or their cremophore/ethanol/saline vehicle (1:1:18; 1 ml/kg, s.c.) each day for seven days. WIN 55,212-2 increased, whereas AM251 decreased, the rate of cumulative food intake. The agonist effect was manifest primarily by increases in meal frequency and the amount of food eaten per meal. By contrast, the antagonist effect was associated with decreases in meal frequency, duration and weight loss. For the electrophysiological experiments, we performed whole-cell patch-clamp recordings from POMC neurons in hypothalamic slices. WIN 55,212-2 decreased the amplitude of evoked, glutamatergic excitatory postsynaptic currents (eEPSCs) and increased the S2:S1 ratio. Conversely, AM251 increased eEPSC amplitude per se, and blocked the inhibitory effects of the agonist. WIN 55,212-2 also decreased miniature EPSC (mEPSC) frequency; whereas AM251 increased mEPSC frequency per se, and again blocked the inhibitory effect of the agonist. A subpopulation of cells exhibited an agonist-induced outward current, which was blocked by AM251, associated with increased conductance and reversed polarity near the Nernst equilibrium potential for K(+). These data demonstrate that cannabinoids regulate appetite in the guinea pig in part through both presynaptic and postsynaptic actions on anorexigenic POMC neurons.
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Affiliation(s)
- Jennie Ho
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, Ca 91766, United States
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17
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Affiliation(s)
- Gerard P Smith
- New York-Presbyterian Hospital, 21 Bloomingdale Road, White Plains, NY 10605, USA.
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18
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Narayana B, Vijaya Raj KK, Ashalatha BV, Kumari NS. Synthesis of some new substituted triazolo [4,3-a][1,4] benzodiazepine derivatives as potent anticonvulsants. Eur J Med Chem 2006; 41:417-22. [PMID: 16472891 DOI: 10.1016/j.ejmech.2005.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2005] [Revised: 12/10/2005] [Accepted: 12/27/2005] [Indexed: 10/25/2022]
Abstract
Novel 8-chloro-6-(2-fluorophenyl)-1-(aryl)-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepines (5a-f) were prepared by treating 7-chloro-5-(2-fluorophenyl)-1,3-dihydro-2H-1,4-benzodiazepine-2-thione with various aromatic acid hydrazides. The newly prepared compounds were characterized by spectral analysis. Compounds were tested for anticonvulsant activity. Four of the tested compounds such as 5a, 5d, 5e and 5f exhibited excellent anticonvulsant activity in comparison with standard drug, diazepam.
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Affiliation(s)
- B Narayana
- Department of Post-Graduate Studies and Research in Chemistry, Mangalore University, Mangalagangotri, India.
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19
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Giragossian C, Sugg EE, Szewczyk JR, Mierke DF. Intermolecular interactions between peptidic and nonpeptidic agonists and the third extracellular loop of the cholecystokinin 1 receptor. J Med Chem 2003; 46:3476-82. [PMID: 12877585 DOI: 10.1021/jm030144z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intermolecular interactions were determined between a synthetic peptide corresponding to the third extracellular loop and several residues from the adjoining sixth and seventh transmembrane domains of the human cholecystokinin-1 receptor, CCK(1)-R(329-357), and the synthetic agonists Ace-Trp-Lys[NH(epsilon)CONH-o-(MePh)]-Asp-MePhe-NH(2) (GI5269) and the C1 N-isopropyl-N-(4-methoxyphenyl)acetamide derivative of 3-(1H-Indazol-3ylmethyl)-3-methyl-5-pyridin-3-yl-1,5-benzodiazepine (GI0122), using high-resolution nuclear magnetic resonance spectroscopy and computer simulations. Addition of the ligands to CCK(1)-R(329-357) in an aqueous solution of DPC micelles produced a number of intermolecular nuclear Overhauser enhancements (NOEs) to residues in TMs 6 and 7 of the receptor fragment. NOE-restrained molecular models of the GI5269 and GI0122/CCK(1)-R complexes provide evidence for overlapping ligand-binding sites for peptidic and nonpeptidic agonists. The proposed binding modes of GI5269 and GI0122 are supported by the structure-activity relationship of analogues and mutagenesis data for the CCK(1)-R selective antagonist L-364,718.
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Affiliation(s)
- Craig Giragossian
- Department of Chemistry, Division of Biology & Medicine, Brown University, Providence, RI 02912, USA
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Martín-Martínez M, Latorre M, García-López MT, Cenarruzabeitia E, Del Río J, González-Muñiz R. Effects of the incorporation of IBTM beta-turn mimetics into the dipeptoid CCK(1) receptor agonist PD 170292. Bioorg Med Chem Lett 2002; 12:109-12. [PMID: 11755332 DOI: 10.1016/s0960-894x(01)00630-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Replacement of the 2-Adoc-D-alphaMeTrp residue in the non-selective CCK(1) receptor agonist PD 170292 by the Z-(2R,5R,11bS)-IBTM skeleton, able to fix a type II beta-turn-like conformation, led to a conformationally restricted dipeptoid analogue, namely 3a, which exhibited a notable increase in the CCK(1) selectivity and antagonist properties.
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