title: Synthesis and characterization of high-affinity 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene-labeled fluorescent ligands for human β-adrenoceptors.
abstract: The growing practice of exploiting noninvasive fluorescence-based techniques to study G protein-coupled receptor pharmacology at the single cell and single molecule level demands the availability of high-quality fluorescent ligands. To this end, this study evaluated a new series of red-emitting ligands for the human β-adrenoceptor family. Upon the basis of the orthosteric ligands propranolol, alprenolol, and pindolol, the synthesized linker-modified congeners were coupled to the commercially available fluorophore BODIPY 630/650-X. This yielded high-affinity β-adrenoceptor fluorescent ligands for both the propranolol and alprenolol derivatives; however, the pindolol-based products displayed lower affinity. A fluorescent diethylene glycol linked propranolol derivative (18a) had the highest affinity (log K(D) of -9.53 and -8.46 as an antagonist of functional β2- and β1-mediated responses, respectively). Imaging studies with this compound further confirmed that it can be employed to selectively label the human β2-adrenoceptor in single living cells, with receptor-associated binding prevented by preincubation with the nonfluorescent β2-selective antagonist 3-(isopropylamino)-1-[(7-methyl-4-indanyl)oxy]butan-2-ol (ICI 118551) ( J. Cardiovasc. Pharmacol.1983, 5, 430-437. ).
authors.affiliation: School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
authors.forename: Jillian G
authors.initials: JG
authors.lastname: Baker
authors.forename: Luke A
authors.initials: LA
authors.lastname: Adams
authors.forename: Karolina
authors.initials: K
authors.lastname: Salchow
authors.forename: Shailesh N
authors.initials: SN
authors.lastname: Mistry
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Middleton
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Hill
authors.forename: Barrie
authors.initials: B
authors.lastname: Kellam
mesh_terms: D000318:Adrenergic beta-Agonists / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000526:Alprenolol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D054333:Drug Partial Agonism; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D008024:Ligands; D018613:Microscopy, Confocal; D010869:Pindolol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D011433:Propranolol / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D011869:Radioligand Assay; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism*; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D022702:Receptors, Adrenergic, beta-3 / Q000378:metabolism*; D059010:Single-Cell Analysis; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D001896:Boron Compounds; D005456:Fluorescent Dyes; D008024:Ligands; C568515:N-(3-hydroxy-1-(naphthalen-1-yl)-1,8,11-trioxa-5-azatridecan-13-yl)-6-(2-(2-(4,4-difluoro-4,4a-dihydro-5-(thiophen-2-yl)-4-bora-3a,4a-diaza-s-indacene-3-yl)vinyl)phenoxyacetamido)hexanamide; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D022702:Receptors, Adrenergic, beta-3; D000526:Alprenolol; D011433:Propranolol; D010869:Pindolol