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Finneran D, Li Q, Subbarayan MS, Joly-Amado A, Kamath S, Dengler DG, Gordon MN, Jackson MR, Morgan D, Bickford PC, Smith LH, Nash KR. Concentration and proteolysis of CX3CL1 may regulate the microglial response to CX3CL1. Glia 2023; 71:245-258. [PMID: 36106533 PMCID: PMC9772123 DOI: 10.1002/glia.24269] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 12/24/2022]
Abstract
Fractalkine (FKN) is a membrane-bound chemokine that can be cleaved by proteases such as ADAM 10, ADAM 17, and cathepsin S to generate soluble fragments. Studies using different forms of the soluble FKN yield conflicting results in vivo. These observations prompted us to investigate the function and pharmacology of two commonly used isoforms of FKN, a human full-length soluble FKN (sFKN), and a human chemokine domain only FKN (cdFKN). Both are prevalent in the literature and are often assumed to be functionally equivalent. We observed that recombinant sFKN and cdFKN exhibit similar potencies in a cell-based cAMP assay, but binding affinity for CX3CR1 was modestly different. There was a 10-fold difference in potency between sFKN and cdFKN when assessing their ability to stimulate β-arrestin recruitment. Interestingly, high concentrations of FKN, regardless of cleavage variant, were ineffective at reducing pro-inflammatory microglial activation and may induce a pro-inflammatory response. This effect was observed in mouse and rat primary microglial cells as well as microglial cell lines. The inflammatory response was exacerbated in aged microglia, which is known to exhibit age-related inflammatory phenotypes. We observed the same effects in Cx3cr1-/- primary microglia and therefore speculate that an alternative FKN receptor may exist. Collectively, these data provide greater insights into the function and pharmacology of these common FKN reagents, which may clarify conflicting reports and urge greater caution in the selection of FKN peptides for use in in vitro and in vivo studies and the interpretation of results obtained using these differing peptides.
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Affiliation(s)
- Dylan Finneran
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
- Michigan State University, Department of Translational Neuroscience, 400 Monroe Ave. NW, Grand Rapids, MI, United States
| | - Qingyou Li
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
| | - Meena S. Subbarayan
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
- Center for Excellence in Aging and Brain Repair, Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
- Gladstone Institute of Neurological Disease, Gladstone Institutes, 1650 Owens St, San Francisco, CA 94158
| | - Aurelie Joly-Amado
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
| | - Siddharth Kamath
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
| | - Daniela G. Dengler
- Conrad Prebys Center for Chemical Genomics, Sandford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Marcia N. Gordon
- Michigan State University, Department of Translational Neuroscience, 400 Monroe Ave. NW, Grand Rapids, MI, United States
| | - Michael R. Jackson
- Conrad Prebys Center for Chemical Genomics, Sandford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Dave Morgan
- Michigan State University, Department of Translational Neuroscience, 400 Monroe Ave. NW, Grand Rapids, MI, United States
| | - Paula C. Bickford
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
- Center for Excellence in Aging and Brain Repair, Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
- Research Service, James A Haley Veterans Hospital, 13000 Bruce B Downs Blvd, Tampa FL-33612, USA
| | - Layton H. Smith
- Conrad Prebys Center for Chemical Genomics, Sandford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Kevin R. Nash
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa FL-33612, USA
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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 (Basel) 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] [What about the content of this article? (0)] [Affiliation(s)] [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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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 Discov 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Harikumar KG, Coudrat T, Desai AJ, Dong M, Dengler DG, Furness SGB, Christopoulos A, Wootten D, Sergienko EA, Sexton PM, Miller LJ. Discovery of a Positive Allosteric Modulator of Cholecystokinin Action at CCK1R in Normal and Elevated Cholesterol. Front Endocrinol (Lausanne) 2021; 12:789957. [PMID: 34950108 PMCID: PMC8689142 DOI: 10.3389/fendo.2021.789957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/11/2021] [Indexed: 11/13/2022] Open
Abstract
Drugs useful in prevention/treatment of obesity could improve health. Cholecystokinin (CCK) is a key regulator of appetite, working through the type 1 CCK receptor (CCK1R); however, full agonists have not stimulated more weight loss than dieting. We proposed an alternate strategy to target this receptor, while reducing likelihood of side effects and/or toxicity. Positive allosteric modulators (PAMs) with minimal intrinsic agonist activity would enhance CCK action, while maintaining spatial and temporal characteristics of physiologic signaling. This could correct abnormal stimulus-activity coupling observed in a high-cholesterol environment observed in obesity. We utilized high-throughput screening to identify a molecule with this pharmacological profile and studied its basis of action. Compound 1 was a weak partial agonist, with PAM activity to enhance CCK action at CCK1R, but not CCK2R, maintained in both normal and high cholesterol. Compound 1 (10 µM) did not exhibit agonist activity or stimulate internalization of CCK1R. It enhanced CCK activity by slowing the off-rate of bound hormone, increasing its binding affinity. Computational docking of Compound 1 to CCK1R yielded plausible poses. A radioiodinatable photolabile analogue retained Compound 1 pharmacology and covalently labeled CCK1R Thr211, consistent with one proposed pose. Our study identifies a novel, selective, CCK1R PAM that binds to the receptor to enhance action of CCK-8 and CCK-58 in both normal and disease-mimicking high-cholesterol environments. This facilitates the development of compounds that target the physiologic spatial and temporal engagement of CCK1R by CCK that underpins its critical role in metabolic regulation.
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Affiliation(s)
- Kaleeckal G. Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States
| | - Thomas Coudrat
- Drug Discovery Biology Theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC (Australian Research Council) Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Aditya J. Desai
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States
| | - Maoqing Dong
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States
| | - Daniela G. Dengler
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Sebastian G. B. Furness
- Drug Discovery Biology Theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology Theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC (Australian Research Council) Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Denise Wootten
- Drug Discovery Biology Theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC (Australian Research Council) Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Eduard A. Sergienko
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Patrick M. Sexton
- Drug Discovery Biology Theme, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC (Australian Research Council) Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute for Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Laurence J. Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, United States
- *Correspondence: Laurence J. Miller,
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Dengler DG, Sun Q, Holleran J, Pollari S, Beutel J, Brown BT, Shinoki Iwaya A, Ardecky R, Harikumar KG, Miller LJ, Sergienko EA. Development of a Testing Funnel for Identification of Small-Molecule Modulators Targeting Secretin Receptors. SLAS Discov 2021; 26:1-16. [PMID: 32749201 PMCID: PMC8278649 DOI: 10.1177/2472555220945284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The secretin receptor (SCTR), a prototypical class B G protein-coupled receptor (GPCR), exerts its effects mainly by activating Gαs proteins upon binding of its endogenous peptide ligand secretin. SCTRs can be found in a variety of tissues and organs across species, including the pancreas, stomach, liver, heart, lung, colon, kidney, and brain. Beyond that, modulation of SCTR-mediated signaling has therapeutic potential for the treatment of multiple diseases, such as heart failure, obesity, and diabetes. However, no ligands other than secretin and its peptide analogs have been described to regulate SCTRs, probably due to inherent challenges in family B GPCR drug discovery. Here we report creation of a testing funnel that allowed targeted detection of SCTR small-molecule activators. Pursuing the strategy to identify positive allosteric modulators (PAMs), we established a unique primary screening assay employing a mixture of three orthosteric stimulators that was compared in a screening campaign testing 12,000 small-molecule compounds. Beyond that, we developed a comprehensive set of secondary assays, such as a radiolabel-free target engagement assay and a NanoBiT (NanoLuc Binary Technology)-based approach to detect β-arrestin-2 recruitment, all feasible in a high-throughput environment as well as capable of profiling ligands and hits regarding their effect on binding and receptor function. This combination of methods enabled the discovery of five promising scaffolds, four of which have been validated and further characterized with respect to their allosteric activities. We propose that our results may serve as starting points for developing the first in vivo active small molecules targeting SCTRs.
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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
| | - John Holleran
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Sirkku Pollari
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Jannis Beutel
- Department of Chemistry and Pharmacy, Chemikum, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Brock T. Brown
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Aki Shinoki Iwaya
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Robert Ardecky
- 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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Dengler DG, Sun Q, Kaleeckal HG, Beutel J, Holleran J, Pollari S, Ma CT, Miller LJ, Sergienko E. Identification and Characterization of Dual‐Acting Small Molecule Modulators targeting Secretin Receptors. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.07363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Qing Sun
- Sanford Burnham Prebys Medical Discovery Institute
| | | | | | | | | | - Chen-Ting Ma
- Sanford Burnham Prebys Medical Discovery Institute
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