TIM-1 Promotes Japanese Encephalitis Virus Entry and Infection.

Jichen Niu,Puyan Chen,Guodong Zhou,Ya Jiang,Hao Xu,Changjing Zhao,Ruibing Cao

doi:10.3390/v10110630

Jichen Niu, Puyan Chen + Show 5 more

Open Access

https://doi.org/10.3390/v10110630

Copy DOI

Journal: Viruses	Publication Date: Nov 14, 2018
Citations: 31	License type: CC BY 4.0

Affiliation: Nanjing Agricultural University

Abstract

Japanese encephalitis virus (JEV) is a mosquito-borne Flavivirus, the leading cause of viral-induced encephalitis. Several host molecules have been identified as the JEV attachment factor; however, the molecules involved in JEV entry remain poorly understood. In the present study, we demonstrate that TIM-1 is important for efficient infection by JEV. Firstly, three TIM-1 variants (V1, V2, and V3) were cloned from A549 cells, and we revealed that only ectopically TIM-1 V2 expression in 293T cells significantly promotes JEV attachment, entry and infection. Point mutation of phosphatidylserine (Ptdser) binding pocket in the TIM-1 IgV domain dampened JEV entry, indicating that TIM-1-mediated JEV infection is Ptdser-dependent. Furthermore, we found the cytoplasmic domain of TIM-1 is also required for enhancing JEV entry. Additionally, knock down of TIM-1 expression in A549 cells impaired JEV entry and infection, but not attachment, suggesting that additional factors exist in A549 cells that allow the virus to bind. In conclusion, our findings demonstrate that TIM-1 promotes JEV infection as an entry cofactor, and the polymorphism of TIM-1 is associated with JEV susceptibility to host cells.

Highlights

Japanese encephalitis (JE) is a severe epidemic of viral encephalitis with a high fatality rate, and it is caused by the Japanese encephalitis virus (JEV) [1]
We examined whether 293T cell is comparatively poorly permissive to JEV, and we compared the susceptibility of three cell lines to JEV. 293T, A549, and BHK-21 cells were infected with
Western blot analysis revealed that the level of JEV NS5 protein in infected 293T cells was nearly undetectable at 12 h post-infection (h.p.i.), and it was low at 24 h.p.i

Summary

Introduction

Japanese encephalitis (JE) is a severe epidemic of viral encephalitis with a high fatality rate, and it is caused by the Japanese encephalitis virus (JEV) [1]. In eastern Asia, JEV infections cause about 30,000 to 50,000 cases of encephalitis that lead to 10,000 deaths annually. JEV is an enveloped virus containing a single strand of positive-sense RNA and it belongs to the Flavivirus genus. JEV is mosquito-borne, and it maintains a zoonotic cycle between wading birds or pigs and. Culex mosquitoes [1,3]. The genomic RNA of JEV is approximately 11 knt. It encodes a large precursor polyprotein, which is cleaved into three structural proteins and seven nonstructural proteins by host and virus-encoded proteases. The envelope E glycoprotein is considered a major antigenic determinant that mediates cellular attachment and membrane fusion [4]

Methods

Results

Conclusion