Rab4b is associated with inflammatory responses and TLR3-related signaling during Japanese encephalitis virus infection.

Japanese Encephalitis Virus (JEV) is a mosquito-borne zoonotic pathogen that triggers severe inflammatory responses upon infection. Previous research has demonstrated that the interaction between Ras-associated GTP-binding protein 4B (Rab4b) and the JEV E protein is essential for the virus's entry into early endosomes. However, the precise mechanism by which Rab4b contributes to JEV-induced inflammatory responses remains inadequately understood. In this study, we developed a Rab4b-knockout U251 cell model and found that Rab4b deficiency markedly inhibited viral replication and concurrently reduced levels of key inflammatory mediators, including IL-1β, IL-6, TNF-α, and IFN-β. Transcriptomic analysis further indicated that the loss of Rab4b disrupted the Toll-like receptor 3 (TLR3)-related gene network. Subsequent co-immunoprecipitation experiments confirmed an interaction between Rab4b and TLR3, and treatment with a TLR3 inhibitor recapitulated the anti-inflammatory phenotype observed in Rab4b-deficient cells, suggesting the involvement of Rab4b in TLR3-related signaling. In conclusion, these findings support an association between Rab4b and a TLR3-related inflammatory signaling axis during JEV infection, although the precise mechanistic relationship requires further investigation.