Small molecule SPB07257 inhibits JEV by blocking capsid-ANXA2 interaction, reducing viral growth

Despite causing fatal encephalitis and long-term neurological impairments, no antiviral drugs are currently available to treat Japanese encephalitis virus (JEV) infections, highlighting an urgent need for effective therapies. Viral replication relies on crucial virus-host protein interactions. The JEV capsid protein, lacking enzymatic functions, mediates all its roles via protein-protein interactions, making these specific interactions attractive and novel drug targets for therapeutic development.

Researchers identified two functional domains (P2 and P7) of the JEV capsid protein, crucial for viral replication, using competitive peptide binding assays. They then employed pull-down and MALDI-TOF-TOF techniques to demonstrate that the JEV capsid protein interacts with the host protein ANXA2 via these identified peptide domains. Subsequently, they computationally docked ~55,000 molecules from the Maybridge library against the P7 domain. From this screen, SPB07257 was identified and tested for its ability to inhibit Capsid-ANXA2 interaction and prevent JEV infection in vitro.

The study found that in the presence of P2 and P7 peptides, the ANXA2-capsid interaction in infected cells was significantly inhibited. Concomitantly, JEV growth was reduced when both P2 and P7 were present. From a screen of ~55,000 molecules, 10 compounds showed favorable binding to the P7 domain. Among these, SPB07257 emerged as a potent inhibitor.

SPB07257 inhibited Capsid-ANXA2 interaction and effectively prevented JEV infection with an IC50 of 10 μM and a CC50 (cytotoxic concentration) of >50 μM, indicating a favorable therapeutic index. This work successfully demonstrates a novel antiviral strategy by targeting specific virus-host protein interactions.