J Virol. 2018 Feb 28. pii: JVI.02221-17. doi: 10.1128/JVI.02221-17. [Epub ahead of print]
Relative abundance of the integrant-derived viral RNAs in infected tissues harvested from chronic HBV carriers.Freitas N1, Lukash T1, Gunewardena S2, Chappell B1, Slagle BL3, Gudima SO4. Author information1Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA.2Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA.3Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA.4Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA [email protected].
AbstractFive matching sets of non-malignant liver tissues and HCCs from individuals chronically infected with hepatitis B virus (HBV) were examined. The HBV genomic sequences were determined using overlapping PCR amplicons covering the entire viral genome. Four pairs of tissues were infected with HBV of genotype C, while one pair - with genotype B. HBV replication markers were found in all tissues. In majority of HCC samples, the levels of pre-genomic/pre-core RNA (pgRNA) and covalently closed circular DNA (cccDNA) were lower than those of liver tissue counterparts. Regardless of the presence of HBV replication markers, (i) integrant-derived HBV RNAs (id-RNAs) were found using RT-PCR analysis in all tissues, and were considerably abundant or predominant in 6/10 tissue samples (2 livers and 4 HCCs); (ii) the RNAs that were polyadenylated using cryptic HBV polyadenylation signal and therefore could be produced by HBV replication or derived from integrated HBV DNA were found in 5/10 samples (3 livers and 2 HCCs), and were considerably abundant species in 3/10 tissues (2 livers and 1 HCC); and (iii) cccDNA-transcribed RNAs polyadenylated near position 1931 were not abundant in 7/10 tissues (2 livers and 5 HCCs), and were predominant only in two livers. Subsequent RNA sequencing analysis of selected liver/HCC samples also showed relative abundance of id-RNAs in most of examined tissues. Our findings suggesting that id-RNAs could represent a significant source of HBV envelope proteins, which is independent of viral replication, are discussed in the context of possible contribution of id-RNAs to the HBV life cycle.IMPORTANCE The relative abundance of integrant-derived HBV RNAs (id-RNAs) in chronically infected tissues suggests that id-RNAs coding for the envelope proteins may facilitate production of considerable fraction of surface antigens (HBsAg) in infected cells bearing HBV integrants. If the same cells support HBV replication, then a significant fraction of assembled HBV virions could bear id-RNA-derived HBsAg as a major component of their envelopes. Therefore, infectivity of these HBV virions, and their ability to facilitate virus cell-to-cell spread could be determined mainly by the properties of id-RNA-derived envelope proteins, and not by the properties of replication-derived HBsAg. These interpretations suggest that id-RNAs may play a role in maintenance of chronic HBV infection, and therefore contribute to HBV life cycle. Furthermore, the production of HBsAg from id-RNAs independently of viral replication may at least in part explain why treatment with interferon or nucleos(t)ides in most cases failed to achieve loss of serum HBsAg.
PMID:29491161DOI:10.1128/JVI.02221-17