Characterization of IL-21-expressing recombinant hepatitis B virus (HBV) as a therapeutic agent targeting persisting HBV infection

• Published in: Theranostics 2020-01, Vol.10 (12), p.5600-5612
• Main Authors: Shen, Zhongliang, Wu, Jingwen, Gao, Zixiang, Wang, Jingyu, Zhu, Haoxiang, Mao, Richen, Wang, Xuanyi, Zhang, Jiming, Xie, Youhua, Liu, Jing
• Format: Article
• Language: English
• Subjects: Animals; Disease Models, Animal; DNA, Viral - genetics; Gene expression; Genetic Vectors - administration & dosage; Genomes; Hepatitis - genetics; Hepatitis - pathology; Hepatitis - therapy; Hepatitis - virology; Hepatitis B; Hepatitis B virus - genetics; Hepatitis B virus - isolation & purification; Humans; Infections; Interleukins - administration & dosage; Interleukins - genetics; Interleukins - metabolism; Liver; Liver cancer; Liver cirrhosis; Male; Mice; Mice, Inbred BALB C; Plasmids; Proteins; Research Paper; Veins & arteries
• ISSN: 1838-7640; 1838-7640
• DOI: 10.7150/thno.44715

Chronic infection by hepatitis B virus (HBV) is associated with high risks of liver fibrosis, cirrhosis and hepatocellular carcinoma. In mouse models of HBV persistence, interleukin 21 (IL-21) has been identified as a potent inducer of viral clearance. Strict hepatotropism makes recombinant HBV (rHBV) vectors ideal for liver-targeting gene delivery. Previously, we established an rHBV vector termed 5c3c, which is highly replicative by itself, but requires HBV envelope proteins provided to produce virions. 5c3c-based rHBV virions are capable of delivering cargo gene expression driven by HBV Sp1 promoter into infected hepatocytes. In this work, we explore the feasibility of using 5c3c-derived rHBV for liver-specific delivery of IL-21 as treatment of chronic HBV infection. 5c3c-derived rHBV replicons harboring mouse or human IL-21 genes (termed 5c3c-mIL-21 and 5c3c-hIL-21 respectively) were constructed and then tested for the production of rHBV virions and . 5c3c-mIL-21's anti-HBV effects were determined in chronic HBV mouse model. Furthermore, superinfection by rHBV virions was analysed using HBV-infected HepG2/NTCP cells and human liver chimeric mice. 5c3c-mIL-21 and 5c3c-hIL-21 were efficiently replicative and produced enveloped virions when provided with envelope proteins, both and . In mouse model of HBV persistence, IL-21 expressed from injected 5c3c-mIL-21 replicon induced complete viral clearance. 5c3c-mIL-21 and 5c3c-hIL-21 virions could infect HepG2/NTCP cells and engender sustained IL-21 expression. Most importantly, IL-21-expressing rHBV virions could superinfect HBV-infected HepG2/NTCP cells and human hepatocytes in human liver chimeric mice, and engender sustained IL-21 expression and rHBV production. These data suggest the high potential of 5c3c-derived IL-21-expressing rHBV as a novel therapeutic against chronic HBV infection.