Репозиторий Университета

© 2019 National Academy of Sciences. All rights reserved. Shrews, insectivorous small mammals, pertain to an ancient mammalian order. We screened 693 European and African shrews for hepatitis B virus (HBV) homologs to elucidate the enigmatic genealogy of HBV. Shrews host HBVs at low prevalence (2.5%) across a broad geographic and host range. The phylogenetically divergent shrew HBVs comprise separate species termed crowned shrew HBV (CSHBV) and musk shrew HBV (MSHBV), each containing distinct genotypes. Recombination events across host orders, evolutionary reconstructions, and antigenic divergence of shrew HBVs corroborated ancient origins of mammalian HBVs dating back about 80 million years. Resurrected CSHBV replicated in human hepatoma cells, but human- and tupaia-derived primary hepatocytes were resistant to hepatitis D viruses pseudotyped with CSHBV surface proteins. Functional characterization of the shrew sodium taurocholate cotransporting polypeptide (Ntcp), CSHBV/MSHBV surface peptide binding patterns, and infection experiments revealed lack of Ntcp-mediated entry of shrew HBV. Contrastingly, HBV entry was enabled by the shrew Ntcp. Shrew HBVs universally showed mutations in their genomic preCore domains impeding hepatitis B e antigen (HBeAg) production and resembling those observed in HBeAg-negative human HBV. Deep sequencing and in situ hybridization suggest that HBeAg-negative shrew HBVs cause intense hepatotropic monoinfections and low within-host genomic heterogeneity. Geographical clustering and low MSHBV/CSHBV-specific seroprevalence suggest focal transmission and high virulence of shrew HBVs. HBeAg negativity is thus an ancient HBV infection pattern, whereas Ntcp usage for entry is not evolutionarily conserved. Shrew infection models relying on CSHBV/MSHBV revertants and human HBV will allow comparative assessments of HBeAg-mediated HBV pathogenesis, entry, and species barriers.

© 2018, MDPI AG. All rights reserved. Chronic hepatitis B virus (HBV) infection has long remained a critical global health issue. Covalently closed circular DNA (cccDNA) is a persistent form of the HBV genome that maintains HBV chronicity. Decades of extensive research resulted in the two therapeutic options currently available: nucleot(s)ide analogs and interferon (IFN) therapy. A plethora of reliable markers to monitor HBV patients has been established, including the recently discovered encapsidated pregenomic RNA in serum, which can be used to determine treatment end-points and to predict the susceptibility of patients to IFN. Additionally, HBV RNA splice variants and cccDNA and its epigenetic modifications are associated with the clinical course and risks of hepatocellular carcinoma (HCC) and liver fibrosis. However, new antivirals, including CRISPR/Cas9, APOBEC-mediated degradation of cccDNA, and T-cell therapies aim at completely eliminating HBV, and it is clear that the diagnostic arsenal for defining the long-awaited sterilizing cure is missing. In this review, we discuss the currently available tools for detecting and measuring HBV RNAs and cccDNA, as well as the state-of-the-art in clinical implications of these markers, and debate needs and goals within the context of the sterilizing cure that is soon to come.

© 2017 Izdatel'stvo Meditsina. All rights reserved. Chronic hepatitis B is caused by a persistent form of hepatitis B virus, covalentiy closed circular DNA (cccDNA). Stability of cccDNA is associated with intracellular localization of cccDNA and formation of minichromosome, regu-lated by epigenetic mechanisms. One of the key mechanisms in epigenetics is methylation of DNA on CpG islands. Expression levels of DNA-methyltransferases (DNMTs) in chronic hepatitis B patients were shown to be upregu-lated. Nevertheless, the role of DNMTs in the life cycle of HBV and their effects on the cell remain elusive. In this review, we discuss latest achievements on the role of DNMTs in chronic hepatitis B and HBV in vitro models.

© 2018 Ruslania. All rights reserved. Liver cirrhosis and hepatocellular carcinoma are the most common outcomes of chronic hepatitis B. Hepatitis B virus (HBV) induces transformation and cell death in chronic hepatitis B (CHB). DNA double strand breaks (DSBs) represent the most dangerous type of genome damage. It was shown previously that generation of phosphorylated histone H2AX foci is a reliable marker of DSBs. The aim of this study was to analyse generation of yH2AX foci in HBV and hepatitis D virus (HDV) infection in vitro and in liver biopsies of patients with CHB and CHB with delta-agent (CHD). Human hepatoma cell line HepG2-1.1merHBV with activated HBV life cycle was used to perform real-time PCR for analysis of pregenomic RNA, HBV DNA, HBV cccDNA and for immunocytochemical analysis of yH2AX. Liver biopsies from CHB and CHD patients were analyzed to confirm the results. HBV induces multiple discrete yH2AX foci in HepG2-1.1merHBV cells in vitro and in biopsies of CHB and CHB+D patients. The ratio of hepatocytes w/o yH2AX foci is significantly lower (49,9+7-12,3% vs. 85,5+/-0,9%, p<0,05), while the proportion of cells with 1-10 yH2AX foci is higher (49,3+7-12,6% vs. 14,5+/-0,9%, p<0,05) compared to healthy control. There is a significant increase In the mean number of yH2AX foci in biopsies from CHB+D patients (3,5+7-1,1 and 5,5+/-1,5 vs. 0,5+/-0,16 in control hepatocytes, p<0.05). The ratio of hepatocytes w/o yH2AX foci is significantly lower in CHB and CHB+D patients, while percentage of cells with 1-10 yH2AX foci is higher. Rare hepatocytes with multiple (11-30 yH2AX foci per cell) foci appear in CHB and CHB+D patients. In conclusion, yH2AX foci are generated in hepatocytes of CHB and CHB+D patients and can be utilized to assess genome damage, associated with HBV and HDV viral infection.