Human tryptophanyl-tRNA synthetase is an IFN-γ–inducible entry factor for Enterovirus
Man Lung Yeung, Lilong Jia, Cyril C. Y. Yip, Jasper F. W. Chan, Jade L. L. Teng, Kwok-Hung Chan, Jian-Piao Cai, Chaoyu Zhang, Anna J. Zhang, Wan-Man Wong, Kin-Hang Kok, Susanna K. P. Lau, Patrick C. Y. Woo, Janice Y. C. Lo, Dong-Yan Jin, Shin-Ru Shih, Kwok-Yung Yuen
Man Lung Yeung, Lilong Jia, Cyril C. Y. Yip, Jasper F. W. Chan, Jade L. L. Teng, Kwok-Hung Chan, Jian-Piao Cai, Chaoyu Zhang, Anna J. Zhang, Wan-Man Wong, Kin-Hang Kok, Susanna K. P. Lau, Patrick C. Y. Woo, Janice Y. C. Lo, Dong-Yan Jin, Shin-Ru Shih, Kwok-Yung Yuen
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Research Article Infectious disease Microbiology

Human tryptophanyl-tRNA synthetase is an IFN-γ–inducible entry factor for Enterovirus

Abstract

Enterovirus A71 (EV-A71) receptors that have been identified to date cannot fully explain the pathogenesis of EV-A71, which is an important global cause of hand, foot, and mouth disease and life-threatening encephalitis. We identified an IFN-γ–inducible EV-A71 cellular entry factor, human tryptophanyl-tRNA synthetase (hWARS), using genome-wide RNAi library screening. The importance of hWARS in mediating virus entry and infectivity was confirmed by virus attachment, in vitro pulldown, antibody/antigen blocking, and CRISPR/Cas9-mediated deletion. Hyperexpression and plasma membrane translocation of hWARS were observed in IFN-γ–treated semipermissive (human neuronal NT2) and cDNA-transfected nonpermissive (mouse fibroblast L929) cells, resulting in their sensitization to EV-A71 infection. Our hWARS-transduced mouse infection model showed pathological changes similar to those seen in patients with severe EV-A71 infection. Expression of hWARS is also required for productive infection by other human enteroviruses, including the clinically important coxsackievirus A16 (CV-A16) and EV-D68. This is the first report to our knowledge on the discovery of an entry factor, hWARS, that can be induced by IFN-γ for EV-A71 infection. Given that we detected high levels of IFN-γ in patients with severe EV-A71 infection, our findings extend the knowledge of the pathogenicity of EV-A71 in relation to entry factor expression upon IFN-γ stimulation and the therapeutic options for treating severe EV-A71–associated complications.

Authors

Man Lung Yeung, Lilong Jia, Cyril C. Y. Yip, Jasper F. W. Chan, Jade L. L. Teng, Kwok-Hung Chan, Jian-Piao Cai, Chaoyu Zhang, Anna J. Zhang, Wan-Man Wong, Kin-Hang Kok, Susanna K. P. Lau, Patrick C. Y. Woo, Janice Y. C. Lo, Dong-Yan Jin, Shin-Ru Shih, Kwok-Yung Yuen

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Figure 5

EV-A71 infection in mouse cells overexpressing hWARS.

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EV-A71 infection in mouse cells overexpressing hWARS. (A) Western blot a...
(A) Western blot analyses of EV-A71 protein in the skeletal muscles of EV-A71–challenged neonatal BALB/c mice pretransduced with empty lentiviral vectors (lanes 2 and 3) or a lentiviral vector expressing hWARS (lanes 4 and 5). Two representative samples were included in each category. A noninfected empty lentiviral vector (lane 1) was included as a control. Representative images of muscle (B) and brain (C) tissues from hWARS-transduced mice. Tissues from EV-A71–infected mice were immunostained with anti–EV-A71 (green) and anti-hWARS antibodies (red), respectively. The tissues from empty lentiviral vector–transduced mice inoculated with EV-A71 served as negative controls. DAPI-stained nuclei (blue) are also shown in the merged images. (D) Histopathology of the EV-A71–inoculated hWARS-transduced mice on day 5 after infection. Interstitial infiltrations of lymphocytes in various organs were detected using anti-CD19 antibodies (green). The nuclei were stained with DAPI (blue). H&E staining showed the inflammatory infiltrates of mononuclear cells (arrowheads) and degenerated neuronal cells (arrows). (E) Schematic representation of an IFN-γ–inducible cell entry model for EV-A71 infection. EV-A71 semi- or nonpermissive cells show low or no surface expression of hWARS in a quiescent state (left). The proinflammatory response leading to the production of IFN-γ can induce the expression and membrane translocation of hWARS. This in turn sensitizes poorly susceptible cells to EV-A71 infection by facilitating hWARS–EV-A71 interaction (middle). As a result, EV-A71 can be internalized into the cells, and infection occurs. The images shown in B–D are representative of 3 independent experiments. Scale bars: 30 μm.