Bitopic fluorescent antagonists of the A2A adenosine receptor based on pyrazolo[4,3-: E] [1,2,4]triazolo[1,5- c] pyrimidin-5-amine functionalized congeners

Romain Duroux, Antonella Ciancetta, Philip Mannes, Jinha Yu, Shireesha Boyapati, Elizabeth Gizewski, Said Yous, Francisco Ciruela, John A. Auchampach, Zhan Guo Gao, Kenneth A. Jacobson

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

A pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine antagonist of the A2A adenosine receptor (AR) was functionalized as amine congeners, fluorescent conjugates and a sulfonate, and the A2AAR binding modes were predicted computationally. The optimal n-butyl spacer was incorporated into the following A2AAR-selective (Ki, nM) conjugates: BODIPY630/650 derivative 11 (MRS7396, 24.6) and AlexaFluor488 derivative 12 (MRS7416, 30.3). Flow cytometry of 12 in hA2AAR-expressing HEK-293 cells displayed saturable binding (low nonspecific) and inhibition by known A2AAR antagonists. Water-soluble sulfonate 13 was a highly potent (Ki = 6.2 nM) and selective A2AAR antagonist based on binding and functional assays. Docking and molecular dynamics simulations predicted the regions of interaction of the distal portions of these chain-extended ligands with the A2AAR. The BODIPY630/650 fluorophore of 11 was buried in a hydrophobic interhelical (TM1/TM7) region, while AlexaFluor488 of 12 associated with the hydrophilic extracellular loops. In conclusion, we have identified novel high affinity antagonist probes for A2AAR drug discovery and characterization.

Original languageEnglish
Pages (from-to)1659-1667
Number of pages9
JournalMedChemComm
Volume8
Issue number8
DOIs
StatePublished - 2017

Bibliographical note

Funding Information:
This research was supported in part by the Intramural Research Program of the NIH, National Institute of Diabetes and Digestive and Kidney Diseases. RD was supported by Inserm, Univ. Lille, France. We thank Dr. John Lloyd (NIDDK) for mass spectroscopy. SB was supported by UGC, India. JA acknowledges support from the National Heart, Lung, and Blood Institute (R01HL133589).

Publisher Copyright:
© 2017 The Royal Society of Chemistry.

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