Transferrin receptor 1 is an entry factor for Japanese encephalitis virus

Japanese encephalitis virus (JEV) is a zoonotic pathogen that can be transmitted to humans and animals via arthropods, causing viral encephalitis. In this study, we investigated the role of transferrin receptor 1 (TfR1) in JEV infection. We found that knocking down TfR1 expression in A549 and HeLa cells significantly inhibited JEV entry, while overexpression of TfR1 in 293 T cells enhanced viral entry. The JEV E protein interacts with TfR1, specifically via the protease-like domain (residues 384–606). Additionally, the hTfR1 soluble ectodomain protein significantly blocked JEV infection in HeLa cells, and ferric ammonium citrate (FAC), an iron supplement, downregulated TfR1 expression and effectively inhibited JEV entry and infection. These findings identify TfR1 as an entry factor for JEV and a potential antiviral target, suggesting that small molecule inhibitors like FAC could offer a promising antiviral strategy.