Faculty Collaboration Database

First Potent Macrocyclic A₃ Adenosine Receptor Agonists Reveal G-Protein and β-Arrestin2 Signaling Preferences. ACS Pharmacol Transl Sci 2023 Sep 08;6(9):1288-1305

Date

09/14/2023

Pubmed ID

37705595

Pubmed Central ID

PMC10496144

DOI

10.1021/acsptsci.3c00126

Scopus ID

2-s2.0-85168520378 (requires institutional sign-in at Scopus site)   1 Citation

Abstract

(N)-Methanocarba adenosine derivatives (A₃ adenosine receptor (AR) agonists containing bicyclo[3.1.0]hexane replacing furanose) were chain-extended at N⁶ and C2 positions with terminal alkenes for ring closure. The resulting macrocycles of 17-20 atoms retained affinity, indicating a spatially proximal orientation of these receptor-bound chains, consistent with molecular modeling of 12. C2-Arylethynyl-linked macrocycle 19 was more A₃AR-selective than 2-ether-linked macrocycle 12 (both 5'-methylamides, human (h) A₃AR affinities (K_i): 22.1 and 25.8 nM, respectively), with lower mouse A₃AR affinities. Functional hA₃AR comparison of two sets of open/closed analogues in β-arrestin2 and G_i/o protein assays showed certain signaling preferences divergent from reference agonist Cl-IB-MECA 1. The potencies of 1 at all three Gα_i isoforms were slightly less than its hA₃AR binding affinity (K_i: 1.4 nM), while the Gα_i1 and Gα_i2 potencies of macrocycle 12 were roughly an order of magnitude higher than its radioligand binding affinity. Gα_i2-coupling was enhanced in macrocycle 12 (EC₅₀ 2.56 nM, ∼40% greater maximal efficacy than 1). Di-O-allyl precursor 18 cyclized to form 19, increasing the Gα_i1 potency by 7.5-fold. The macrocycles 12 and 19 and their open precursors 11 and 18 potently stimulated β-arrestin2 recruitment, with EC₅₀ values (nM) of 5.17, 4.36, 1.30, and 4.35, respectively, and with nearly 50% greater efficacy compared to 1. This example of macrocyclization altering the coupling pathways of small-molecule (nonpeptide) GPCR agonists is the first for potent and selective macrocyclic AR agonists. These initial macrocyclic derivatives can serve as a guide for the future design of macrocyclic AR agonists displaying unanticipated pharmacology.

Author List

Tosh DK, Fisher CL, Salmaso V, Wan TC, Campbell RG, Chen E, Gao ZG, Auchampach JA, Jacobson KA

Authors

John A. Auchampach PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Tina C. Wan PhD Research Scientist II in the Pediatrics department at Medical College of Wisconsin