Reversal of hepatitis B virus-induced immune tolerance by an immunostimulatory 3p-HBx-siRNAs in a retinoic acid inducible gene I–dependent manner

Authors

  • Qiuju Han,

    1. Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, China
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  • Cai Zhang,

    Corresponding author
    1. Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, China
    • Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua West Road, Jinan 250012, China
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  • Jian Zhang,

    1. Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, China
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  • Zhigang Tian

    Corresponding author
    1. Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, China
    2. Institute of Immunology, School of Life Sciences, University of Science and Technology of China, Hefei, China
    • Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua West Road, Jinan 250012, China
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    • fax: 86-531-8838-3782


  • Potential conflict of interest: Nothing to report.

  • This work was supported by grants from the Natural Science Foundation of China (#90713033), the National 973 Basic Research Program of China (#2007CB815803), and the National 115 Key Project for HBV Research (#2008ZX10002-008).

Abstract

It is extensively accepted that hepatitis B virus (HBV) escapes from innate immunity by inhibiting type I interferon (IFN) production, but efficient intervention to reverse the immune tolerance is still not achieved. Here, we report that 5′-end triphosphate hepatitis B virus X gene (HBx)-RNAs (3p-HBx-short interfering [si]RNAs) exerted significantly stronger inhibitory effects on HBV replication than regular HBx-siRNAs in stably HBV-expressing hepatoplastoma HepG2.2.15 cells through extremely higher expression of type I IFNs, IFN-induced genes and proinflammatory cytokines, and retinoic acid inducible gene I (RIG-I) activation. Also, 3p-HBx-siRNA were more efficient to stimulate type I IFN response than HBx sequence-unrelated 3p-scramble-siRNA in HepG2.2.15 cells, indicating that a stronger immune-stimulating effect may partly result from the reversal of immune tolerance through decreasing HBV load. In RIG-I-overexpressed HepG2.2.15 cells, 3p-HBx-siRNAs exerted stronger inhibitory effects on HBV replication with greater production of type I IFNs; on the contrary, in RIG-I-silenced HepG2.2.15 cells or after blockade of IFN receptor by monoclocnal antibody, inhibitory effect of 3p-HBx-siRNAs on HBV replication was largely attenuated, indicating that immunostimulatory function of 3p-HBx-siRNAs was RIG-I and type I IFN dependent. Moreover, in HBV-carrier mice, 3p-HBx-siRNA more strongly inhibited HBV replication and promoted IFN production than HBx-siRNA in primary HBV+ hepatocytes and, therefore, significantly decreased serum hepatitis B surface antigen and increased serum IFN-β. Conclusion: 3p-HBx-siRNAs may not only directly inhibit HBV replication, but also stimulate innate immunity against HBV, which are both beneficial for the inversion of HBV-induced immune tolerance. (HEPATOLOGY 2011;)

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