Discovery of a Positive Allosteric Modulator of Cholecystokinin Action at CCK1R in Normal and Elevated Cholesterol.

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.

• Authors: Kaleeckal G Harikumar, Thomas Coudrat, Aditya J Desai, Maoqing Dong, Daniela G Dengler, Sebastian G B Furness, Arthur Christopoulos, Denise Wootten, Eduard A Sergienko, Patrick M Sexton, Laurence J Miller
• Journal: Frontiers in endocrinology (Front Endocrinol (Lausanne)) Vol. 12 Pg. 789957 ( 2021) ISSN: 1664-2392 [Print] Switzerland
• PMID: 34950108 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2021 Harikumar, Coudrat, Desai, Dong, Dengler, Furness, Christopoulos, Wootten, Sergienko, Sexton and Miller.

Chemical References

• CCL28 protein, human
• Chemokines, CC
• Cholecystokinin
• Cholesterol

Topics

• Allosteric Regulation (drug effects, physiology)
• Animals
• CHO Cells
• Chemokines, CC (agonists, metabolism)
• Cholecystokinin (chemistry, metabolism, pharmacology)
• Cholesterol (metabolism)
• Cricetinae
• Cricetulus
• Dose-Response Relationship, Drug
• Drug Discovery (methods)
• Humans
• Hypercholesterolemia (drug therapy, metabolism)
• Macaca fascicularis
• Mice
• Rats