Multi-stage Virtual Screening Of Adenosine A₁ Receptor Antagonists

Selective antagonists towards each adenosine receptor?AR?subtype as potent clinical candidates is of growing interest due to their involvement in the treatment of various diseases.The recent resolution of several A₁ and A_2AARs X-ray structures provides opportunities for structure-based drug design.In this study,we describe the discovery of novel A₁ adenosine receptor antagonists by applying a multistage virtual screening approach,which is based on random forest,e-Pharmacophore modeling and docking methods.Multistage virtual screening approach was applied to screen the Chem Div library?1,492,362 compounds?.From the final hits,22 compounds were selected for further radioligand binding assay analysis on human A₁ adenosine receptor,and 18 compounds?81.82%success?exhibited nanomolar or low micromolar binding potency?K_i?.Then,we selected six compounds?p K_i>6?for further evaluating their antagonist profile in a c AMP functional assay,and found that they had low micromolar antagonistic activity(IC₅₀=0.42–3.12?M)on the A₁ adenosine receptor.Particularly,three out of six compounds?p K_i>6?showed a very good affinity?p K_i=6.11–7.13?and selectively?>100-fold?against A₁ over A_2A adenosine receptors.Moreover,novelty analysis suggests that four out of six compounds?p K_i>6?are dissimilar to the existing A₁AR antagonists,hence are novel A₁AR antagonists.We hope that these findings could provide new insights into the drug discovery against A₁AR,and facilitate research into new drugs and treatments for A₁AR-related human pathologies.