Design, synthesis, and biological evaluation of novel pyrimidine/pyridine derivatives for Vesicular Stomatitis Virus (VSV) infection.

Restricting the transmission of Vesicular Stomatitis Virus (VSV) holds significant economic implications for the livestock industry. Few regulators targeting VSV and rising drug resistance highlight the urgent need for develop new and efficient anti-VSV agents to improve animal welfare. In this study, we employed recombinant VSV expressing green fluorescent protein (VSV-GFP) to evaluate 1,500 compounds from commercial and self-built compound libraries, leading to the identification of SMU-T2d as a lead compound with preliminary anti-VSV activity. Subsequent structural optimization yielded the preferred compound SMU-V18. It significantly inhibited the fluorescence intensity of VSV-GFP, viral mRNA and protein expression levels in a concentration-dependent manner, and demonstrated stable antiviral activity at different virus concentrations and administration time points. The EC50 of SMU-V18 against VSV was determined to be 6.2 ± 0.9 μM, with minimal cytotoxicity observed in cultured cells, resulting in a favorable selectivity index (SI > 170). Mechanistic studies revealed that SMU-V18 interferes the early stages of viral infection, effectively suppressing progeny virus replication, and it also showed efficacy against wild-type VSV (VSV-WT). Furthermore, SMU-V18 significantly inhibited VSV-GFP infection in various tissues of mice, protected the tissue from VSV-associated pathological injury, and prolonged the survival time of mice, with a strong inhibitory effect and good biological safety. Here, we successfully identified a novel, highly efficient, and safe anti-VSV small molecule, providing a candidate agent with significant application potential for the antiviral prevention and control of animals.