De novo synthesis of hepatitis B virus nucleocapsids is dispensable for the maintenance and transcriptional regulation of cccDNA
Thomas Tu, Benno Zehnder, Bingqian Qu, Stephan Urban
Abstract
BACKGROUND & AIMS: nucleocapsid-mediated replenishment (reimport) contributes to cccDNA levels in an infected hepatocyte. METHODS: HBV infection markers were followed for up for 9 weeks in HepG2-NTCP cells (A3 clone) and HBV DNA was quantified using a newly-developed, highly-precise PCR assay (cccDNA inversion quantitative PCR). RESULTS: infection via the receptor sodium taurocholate cotransporting polypeptide (NTCP). In primary human hepatocytes, Huh7-NTCP, HepG2-NTCP, and HepaRG-NTCP cells, comparable copy numbers of cccDNA were formed. cccDNA levels, transcription of viral RNA, and HBsAg secretion remained comparably stable in WT and ΔHBc HBV-infected cells for at least 9 weeks. CONCLUSIONS: DNA-containing nucleocapsids is not required. Thus, short-term therapeutic targeting of capsid-reimport is likely an inefficient strategy in eliminating cccDNA in chronically infected hepatocytes. LAY SUMMARY: The hepatitis B virus can maintain itself in the liver for a patient's lifetime, causing liver injury and cancer. We have clarified exactly how it maintains itself in an infected cell. This now means we have a better idea at how to target the virus and cure a chronic infection.