title: 5'-Substituted Amiloride Derivatives as Allosteric Modulators Binding in the Sodium Ion Pocket of the Adenosine A2A Receptor.
abstract: The sodium ion site is an allosteric site conserved among many G protein-coupled receptors (GPCRs). Amiloride 1 and 5-(N,N-hexamethylene)amiloride 2 (HMA) supposedly bind in this sodium ion site and can influence orthosteric ligand binding. The availability of a high-resolution X-ray crystal structure of the human adenosine A2A receptor (hA2AAR), in which the allosteric sodium ion site was elucidated, makes it an appropriate model receptor for investigating the allosteric site. In this study, we report the synthesis and evaluation of novel 5'-substituted amiloride derivatives as hA2AAR allosteric antagonists. The potency of the amiloride derivatives was assessed by their ability to displace orthosteric radioligand [(3)H]4-(2-((7-amino-2-(furan-2-yl)-[1,2,4]triazolo[1,5-a]-[1,3,5]triazin-5-yl)amino)ethyl)phenol ([(3)H]ZM-241,385) from both the wild-type and sodium ion site W246A mutant hA2AAR. 4-Ethoxyphenethyl-substituted amiloride 12l was found to be more potent than both amiloride and HMA, and the shift in potency between the wild-type and mutated receptor confirmed its likely binding to the sodium ion site.
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Arnault
authors.initials: A
authors.lastname: Massink
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Julien
authors.initials: J
authors.lastname: Louvel
authors.affiliation: Latvian Institute of Organic Synthesis , Riga LV-1006, Latvia.
authors.forename: Ilze
authors.initials: I
authors.lastname: Adlere
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Corine
authors.initials: C
authors.lastname: van Veen
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Berend J H
authors.initials: BJ
authors.lastname: Huisman
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Gabrielle S
authors.initials: GS
authors.lastname: Dijksteel
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Dong
authors.initials: D
authors.lastname: Guo
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Eelke B
authors.initials: EB
authors.lastname: Lenselink
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Buckley
authors.forename: Hayden
authors.initials: H
authors.lastname: Matthews
authors.forename: Marie
authors.initials: M
authors.lastname: Ranson
authors.forename: Michael
authors.initials: M
authors.lastname: Kelso
authors.affiliation: Division of Medicinal Chemistry, LACDR, Leiden University , 2300 RA Leiden, The Netherlands.
authors.forename: Adriaan P
authors.initials: AP
authors.lastname: IJzerman
mesh_terms: D058917:Adenosine A2 Receptor Antagonists / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D000494:Allosteric Regulation / Q000187:drug effects*; D000495:Allosteric Site / Q000187:drug effects; D000584:Amiloride / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D062105:Molecular Docking Simulation; D015394:Molecular Structure; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D043705:Receptor, Adenosine A2A; D000584:Amiloride