title: Novel Electrophilic and Photoaffinity Covalent Probes for Mapping the Cannabinoid 1 Receptor Allosteric Site(s).
abstract: Undesirable side effects associated with orthosteric agonists/antagonists of cannabinoid 1 receptor (CB1R), a tractable target for treating several pathologies affecting humans, have greatly limited their translational potential. Recent discovery of CB1R negative allosteric modulators (NAMs) has renewed interest in CB1R by offering a potentially safer therapeutic avenue. To elucidate the CB1R allosteric binding motif and thereby facilitate rational drug discovery, we report the synthesis and biochemical characterization of first covalent ligands designed to bind irreversibly to the CB1R allosteric site. Either an electrophilic or a photoactivatable group was introduced at key positions of two classical CB1R NAMs: Org27569 (1) and PSNCBAM-1 (2). Among these, 20 (GAT100) emerged as the most potent NAM in functional assays, did not exhibit inverse agonism, and behaved as a robust positive allosteric modulator of binding of orthosteric agonist CP55,940. This novel covalent probe can serve as a useful tool for characterizing CB1R allosteric ligand-binding motifs.
authors.forename: Pushkar M
authors.initials: PM
authors.lastname: Kulkarni
authors.forename: Abhijit R
authors.initials: AR
authors.lastname: Kulkarni
authors.forename: Anisha
authors.initials: A
authors.lastname: Korde
authors.forename: Ritesh B
authors.initials: RB
authors.lastname: Tichkule
authors.affiliation: Department of Pharmacology, Dalhousie University , Halifax NS Canada B3H 4R2.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Laprairie
authors.affiliation: Department of Pharmacology, Dalhousie University , Halifax NS Canada B3H 4R2.
authors.forename: Eileen M
authors.initials: EM
authors.lastname: Denovan-Wright
authors.forename: Han
authors.initials: H
authors.lastname: Zhou
authors.forename: David R
authors.initials: DR
authors.lastname: Janero
authors.forename: Nikolai
authors.initials: N
authors.lastname: Zvonok
authors.forename: Alexandros
authors.initials: A
authors.lastname: Makriyannis
authors.affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen , Foresterhill, Aberdeen, AB25 2ZD, Scotland.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Cascio
authors.affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen , Foresterhill, Aberdeen, AB25 2ZD, Scotland.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Pertwee
authors.forename: Ganesh A
authors.initials: GA
authors.lastname: Thakur
mesh_terms: D000345:Affinity Labels; D000495:Allosteric Site; D000818:Animals; D019390:Arrestins / Q000187:drug effects / Q000378:metabolism; D001665:Binding Sites / Q000187:drug effects; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000037:antagonists & inhibitors; D003511:Cyclohexanols / Q000494:pharmacology; D055808:Drug Discovery / Q000379:methods; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008024:Ligands; D008958:Models, Molecular; D010671:Phenylurea Compounds / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D043884:Receptor, Cannabinoid, CB1 / Q000737:chemistry* / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: C526691:1-(4-chlorophenyl)-3-(3-(6-pyrrolidin-1-ylpyridin-2-yl)phenyl)urea; C572504:5-chloro-3-ethyl-1H-indole-2-carboxylic acid (2-(4-piperidin-1-yl-phenyl)ethyl)amide; D000345:Affinity Labels; D019390:Arrestins; D003511:Cyclohexanols; D007211:Indoles; D008024:Ligands; D010671:Phenylurea Compounds; D010880:Piperidines; D011725:Pyridines; D043884:Receptor, Cannabinoid, CB1; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C054649:3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol; D000242:Cyclic AMP