Viperin restricts chikungunya virus replication and pathology
Terk-Shin Teng, Suan-Sin Foo, Diane Simamarta, Fok-Moon Lum, Teck-Hui Teo, Aleksei Lulla, Nicholas K.W. Yeo, Esther G.L. Koh, Angela Chow, Yee-Sin Leo, Andres Merits, Keh-Chuang Chin, Lisa F.P. Ng
Terk-Shin Teng, Suan-Sin Foo, Diane Simamarta, Fok-Moon Lum, Teck-Hui Teo, Aleksei Lulla, Nicholas K.W. Yeo, Esther G.L. Koh, Angela Chow, Yee-Sin Leo, Andres Merits, Keh-Chuang Chin, Lisa F.P. Ng
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Research Article Virology

Viperin restricts chikungunya virus replication and pathology

Abstract

Chikungunya virus (CHIKV) is a mosquito-borne arthralgia arbovirus that is reemergent in sub-Saharan Africa and Southeast Asia. CHIKV infection has been shown to be self-limiting, but the molecular mechanisms of the innate immune response that control CHIKV replication remain undefined. Here, longitudinal transcriptional analyses of PBMCs from a cohort of CHIKV-infected patients revealed that type I IFNs controlled CHIKV infection via RSAD2 (which encodes viperin), an enigmatic multifunctional IFN-stimulated gene (ISG). Viperin was highly induced in monocytes, the major target cell of CHIKV in blood. Anti-CHIKV functions of viperin were dependent on its localization in the ER, and the N-terminal amphipathic α-helical domain was crucial for its antiviral activity in controlling CHIKV replication. Furthermore, mice lacking Rsad2 had higher viremia and severe joint inflammation compared with wild-type mice. Our data demonstrate that viperin is a critical antiviral host protein that controls CHIKV infection and provide a preclinical basis for the design of effective control strategies against CHIKV and other reemerging arthrogenic alphaviruses.

Authors

Terk-Shin Teng, Suan-Sin Foo, Diane Simamarta, Fok-Moon Lum, Teck-Hui Teo, Aleksei Lulla, Nicholas K.W. Yeo, Esther G.L. Koh, Angela Chow, Yee-Sin Leo, Andres Merits, Keh-Chuang Chin, Lisa F.P. Ng

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Figure 4

The N-terminal amphipathic α-helical domain of viperin controls CHIKV replication.

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The N-terminal amphipathic α-helical domain of viperin controls CHIKV re...
(A) Schematic representation of the domain organization of GFP–WT viperin (GFP-WT), the GFP–N-terminal α-helical domain of viperin (GFP-1-42), and another GFP-tagged viperin mutant with both the N-terminal amphipathic α-helical and radical SAM domains (GFP-1-220). (B) HEK 293T cells were transfected with the various plasmids for 24 hours before infection with either HI CHIKV (control) or CHIKV at MOI 2.5. Cells were analyzed for CHIKV infectivity as described in Figure 3B. Histogram plots of percent CHIKV Ag+ cells in the indicated cell populations are representative of 3 independent experiments. (C) Graphical presentation of histogram plots in B. Data are mean ± SD of percent CHIKV Ag+ cells relative to vector-transfected cells infected with CHIKV (n = 3). ***P < 0.001, 1-way ANOVA with Tukey’s post-test. Horizontal dotted line represents the mean percent CHIKV Ag+ cells in controls. (D) Viral load was determined by qRT-PCR as described in Figure 3D. Data are mean ± SD (n = 3). **P < 0.01, 1-way ANOVA with Tukey’s post-test. Horizontal dotted line represents the mean amount of RNA detected in controls. (E) Viperin expression was detected with anti-GFP antibody. CHIKV nsP2 expression in the infected cells was detected with anti-nsP2 antibody. Detection of α-actin expression served as a loading control. Immunoblots are representative of 2 independent experiments. (F) Densitometric analysis of the nsP2 band in E was performed with NIH ImageJ software and normalized against actin band before being expressed relative to GFP-transfected cells.