Clinical management of chronic hepatitis B (CHB) virus infection remains a big challenge and urges the development of novel therapeutics to achieve long-term virological control and seroconversion. In this study, we report on the development and evaluation of a highly efficacious therapeutic mRNA vaccine encoding the full-length hepatitis B virus (HBV) surface antigen (HBsAg). In pAAV-HBV1.2 and rAAV8-HBV1.3-transduced CHB mouse models, the HBV mRNA vaccine demonstrated potent therapeutic efficacy indicated by a complete serum viral clearance, a remarkable decline in intrahepatic HBcAg, viral DNA and RNA copies, as well as the induction of robust levels of anti-HBs antibodies, virus-specific T cells and memory B cells. In addition, the HBV mRNA vaccine induced strong innate immune activation, represented by the maturation of CD8α+ and CD103+ cDC1, CD11b+ cDC2, monocytes and neutrophils. Taken together, the HBV mRNA vaccine is a promising therapeutic candidate holding prospect for further development and clinical investigation.
Autophagy, a cellular surveillance mechanism, plays an important role in combating invading pathogens. However, viruses have evolved various strategies to disrupt autophagy and even hijack it for replication and release. Here, we demonstrated that Middle East respiratory syndrome coronavirus (MERS-CoV) non-structural protein 1(nsp1) induces autophagy but inhibits autophagic activity. MERS-CoV nsp1 expression increased ROS and reduced ATP levels in cells, which activated AMPK and inhibited the mTOR signalling pathway, resulting in autophagy induction. Meanwhile, as an endonuclease, MERS-CoV nsp1 downregulated the mRNA of lysosome-related genes that were enriched in nsp1-located granules, which diminished lysosomal biogenesis and acidification, and inhibited autophagic flux. Importantly, MERS-CoV nsp1-induced autophagy can lead to cell death
in vitro
and
in vivo
. These findings clarify the mechanism by which MERS-CoV nsp1-mediated autophagy regulation, providing new insights for the prevention and treatment of the coronavirus.
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