Lycorine Inhibits Influenza Virus Replication by Affecting Nascent Nucleoporin Nup93 Synthesis.

The influenza A virus (IAV) is a major cause of recurrent seasonal epidemics and global pandemics, posing a significant threat to public health. Although lycorine has demonstrated broad-spectrum antiviral activity, its specific mechanisms of action against IAV remain incompletely understood. In this study, we characterized the potent inhibitory effects of lycorine on seasonal and drug-resistant IAV subtypes (H1N1/H3N2) as well as the influenza B virus, showing its ability to suppress viral mRNA, viral titers, and M2 protein expression across multiple cell lines. Time-of-addition and time-course assays revealed that lycorine exerts multiphasic interference, and the critical late stage of the IAV life cycle aroused our interest to study this further. Mechanistically, we discovered that lycorine specifically interferes with the de novo synthesis of nucleoporin Nup93, thereby disrupting the nuclear export of viral nucleoprotein (NP). These findings not only establish lycorine as a promising broad-spectrum anti-influenza candidate but also provide new insights for developing host-targeted antiviral strategies.