Correlation study between A3 adenosine receptor binding affinity and anti-renal interstitial fibrosis activity of truncated adenosine derivatives

Truncated 4′-thionucleosides 1–4 and 4′-oxonucleosides 5–8 as potent and selective A3AR antagonists were synthesized from d-mannose and d-erythronic acid γ-lactone, respectively. These nucleosides were evaluated for their anti-fibrotic renoprotective activity in TGF-β1-treated murine proximal tubular (mProx) cells. Their antagonistic activities for A3AR were proportional to their inhibitory activities against TGF-β1-induced collagen I upregulation in mProx cells. This result suggests that the binding affinity of A3AR antagonists is closely correlated with their anti-fibrotic activity. Thus, A3AR antagonists might be novel therapeutic candidates for treating chronic kidney disease.