Transcriptomic Analysis Suggests the M1 Polarization and Launch of Diverse Programmed Cell Death Pathways in Japanese Encephalitis Virus-Infected Macrophages.

Zhao-Yang Wang,Jing An,Zi-Da Zhen,Pei-Gang Wang,Dong-Ying Fan

doi:10.3390/v12030356

Abstract

The Japanese encephalitis virus (JEV) is a Culex mosquito-borne flavivirus and is the pathogenic agent of Japanese encephalitis, which is the most important type of viral encephalitis in the world. Macrophages are a type of pivotal innate immunocyte that serve as sentinels and respond quickly to pathogen invasions. However, some viruses like JEV can hijack macrophages as a refuge for viral replication and immune escape. Despite their crucial involvement in early JEV infection, the transcriptomic landscapes of JEV-infected macrophages are void. Here, by using an in situ JEV infection model, we investigate the transcriptomic alteration of JEV-infected peritoneal macrophages. We found that, upon JEV infection, the macrophages underwent M1 polarization and showed the drastic activation of innate immune and inflammatory pathways. Interestingly, almost all the programmed cell death (PCD) pathways were activated, especially the apoptosis, pyroptosis, and necroptosis pathways, which were verified by the immunofluorescent staining of specific markers. Further transcriptomic analysis and TUNEL staining revealed that JEV infection caused apparent DNA damage. The transcriptomic analysis also revealed that JEV infection promoted ROS and RNS generation and caused oxidative stress, which activated multiple cell death pathways. Our work uncovers the pivotal pathogenic roles of oxidative stress and multiple PCD pathways in JEV infection, providing a novel perspective on JEV–host interactions.

Highlights

Japanese encephalitis virus (JEV) taxonomically belongs to the family Flaviviridae and the genusFlavivirus
Mice were randomly divided into a mock-treated group and a JEV-infected group (n = 5 for each group), in which each mouse was i.p. injected with 200 μL phosphate-buffered saline (PBS) or 105 PFU of JEV in 200 μL
The infection rate of the JEV-infected macrophages was 50%, which was examined by the IF staining of JEV antigens (Figure 1C,D)

Summary

Introduction

Japanese encephalitis virus (JEV) taxonomically belongs to the family Flaviviridae and the genus. Compared with other flaviviruses, such as dengue virus (DENV) and Zika virus (ZIKV), JEV is much more neurotropic [1]. The infection of JEV in the brain causes severe encephalitis, named. JE is the top type of viral encephalitis in the world, posing a threat to the health of more than two billion people in twenty-four countries. 69,000, with a global incidence of 1.8/100,000, causing 10,000–15,000 mortalities [2]. The case fatality of JE is 20% and can be 30% in children. The disease burden of JE has exceeded dengue and ranks first among arboviral encephalitis in the world [1]. We have very limited knowledge about the pathogenesis and specific therapeutics of JE

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