Variable influence of mutational patterns in reverse-transcriptase domain on replication capacity of hepatitis B virus isolates from antiviral-experienced patients. Clin Chim Acta. 2011;412:305-313. [PMID: 21056552 DOI: 10.1016/j.cca.2010.10.028]

Inhibition of hepatitis B virus via selective apoptosis modulation by Chinese patent medicine Liuweiwuling Tablet

BACKGROUND

Liuweiwuling Tablet (LWWL) is a Chinese patent medicine approved for the treatment of chronic inflammation caused by hepatitis B virus (HBV) infection. Previous studies have indicated an anti-HBV effect of LWWL, specifically in terms of antigen inhibition, but the underlying mechanism remains unclear.

AIM

To investigate the potential mechanism of action of LWWL against HBV.

METHODS

In vitro experiments utilized three HBV-replicating and three non-HBV-replicating cell lines. The in vivo experiment involved a hydrodynamic injection-mediated mouse model with HBV replication. Transcriptomics and metabolomics were used to investigate the underlying mechanisms of action of LWWL.

RESULTS

In HepG2.1403F cells, LWWL (0.8 mg/mL) exhibited inhibitory effects on HBV DNA, hepatitis B surface antigen and pregenomic RNA (pgRNA) at rates of 51.36%, 24.74% and 50.74%, respectively. The inhibition rates of LWWL (0.8 mg/mL) on pgRNA/covalently closed circular DNA in HepG2.1403F, HepG2.2.15 and HepG2.A64 cells were 47.78%, 39.51% and 46.74%, respectively. Integration of transcriptomics and metabolomics showed that the anti-HBV effect of LWWL was primarily linked to pathways related to apoptosis (PI3K-AKT, CASP8-CASP3 and P53 pathways). Apoptosis flow analysis revealed that the apoptosis rate in the LWWL-treated group was significantly higher than in the control group (CG) among HBV-replicating cell lines, including HepG2.2.15 (2.92% ± 1.01% vs 6.68% ± 2.04%, P < 0.05), HepG2.A64 (4.89% ± 1.28% vs 8.52% ± 0.50%, P < 0.05) and HepG2.1403F (3.76% ± 1.40% vs 7.57% ± 1.35%, P < 0.05) (CG vs LWWL-treated group). However, there were no significant differences in apoptosis rates between the non-HBV-replicating HepG2 cells (5.04% ± 0.74% vs 5.51% ± 1.57%, P > 0.05), L02 cells (5.49% ± 0.80% vs 5.48% ± 1.01%, P > 0.05) and LX2 cells (6.29% ± 1.54% vs 6.29% ± 0.88%, P > 0.05). TUNEL staining revealed a significantly higher apoptosis rate in the LWWL-treated group than in the CG in the HBV-replicating mouse model, while no noticeable difference in apoptosis rates between the two groups was observed in the non-HBV-replicating mouse model.

CONCLUSION

Preliminary results suggest that LWWL exerts a potent inhibitory effect on wild-type and drug-resistant HBV, potentially involving selective regulation of apoptosis. These findings offer novel insights into the anti-HBV activities of LWWL and present a novel mechanism for the development of anti-HBV medications.

Chinese Patent Medicine Liuweiwuling Tablet had Potent Inhibitory Effects on Both Wild-Type and Entecavir-Resistant Hepatitis B Virus (HBV) in vitro and Effectively Suppressed HBV Replication in Mouse Model

Liuweiwuling Tablet (LWWL) is a licensed Chinese patent medicine (approval number: Z20060238) included in the national health insurance for anti-inflammation of chronic HBV infection, whereas its anti-HBV effect remains clarification. The study aimed to clarify its antiviral effect and related mechanisms. HepG2.2.15 cells (wild-type HBV-replicating cells) and HepG2. A64 cells (entecavir-resistant HBV-replicating cells) were used for in vitro test. Hydrodynamic injection-mediated HBV-replicating mouse model was used for in vivo test. Active compounds and related mechanisms for antiviral effect of LWWL were analyzed using network pharmacology and transcriptomics. The inhibition rates of LWWL (0.8 mg/ml) on HBV DNA, HBsAg, and pgRNA were 57.06, 38.55, and 62.49% in HepG2.2.15 cells, and 51.57, 17.57, and 53.88% in HepG2. A64 cells, respectively. LWWL (2 g kg^-1 d^-1 for 4 weeks)-treated mice had 1.16 log₁₀ IU/mL decrease of serum HBV DNA, and more than 50% decrease of serum HBsAg/HBeAg and hepatic HBsAg/HBcAg. Compared to tenofovir control, LWWL was less effective in suppressing HBV DNA but more effective in suppressing HBV antigens. Thirteen differentially-expressed genes were found in relation to HBV-host interaction and some of them were enriched in interferon (IFN)-β pathway in LWWL-treated HepG2.2.15 cells. CD3⁺CD4⁺ T-cell frequency and serum IFN-γ were significantly increased in LWWL-treated mice compared to LWWL-untreated mice. Among 26 compounds with potential anti-HBV effects that were predicted by network pharmacology, four compounds (quercetin, luteolin, wogonin, and kaempferol) were experimentally confirmed to have antiviral potency. In conclusion, LWWL had potent inhibitory effect on both wild-type and entecavir-resistant HBV, which might be associated with increasing IFN-β and IFN-γ production.

Patterns of hepatitis B virus S gene escape mutants and reverse transcriptase mutations among genotype D isolates in Jordan

Background

Hepatitis B virus (HBV) is an important infectious cause of morbidity and mortality in Jordan. HBV genotype D is the most prevalent in the country. Virus escape mutants in the HBV S region is an important public health problem halting preventive efforts. The aim of the current study was to investigate patterns of HBV escape and resistance mutations and to assess domestic transmission of the virus.

Methods

Patients infected with HBV were recruited at Jordan University Hospital (n = 56) and were diagnosed during (1984-2012). A total of 37 partial HBV S sequences were generated using Sanger's method. Mutation analysis was done using the HIV grade HBV drug resistance interpretation online tool and Geno2pheno (HBV) online tools. Domestic transmission of HBV was assessed using maximum likelihood phylogenetic inference with similar GenBank sequences.

Results

Genotyping revealed an exclusive presence of sub-genotype D1. Typical HBV escape mutants were identified in seven patients. These mutations included: L109R, Q129R, M133L, S143L and D144E with overall prevalence of 18.9% (95% CI [9.5-34.2]). Reverse transcriptase (RT) sequence analysis showed mutations in three patients with overall prevalence of 8.1% (95% CI [2.8-21.3]). RT mutations included: V173L, S202I, L180M, M204V and T184A. Transmission cluster analysis revealed a relatively high proportion of infections taking place as a result of domestic spread (29.7%).

Conclusions

Based on our findings, RT mutation analysis appears to be of high value before the initiation of therapy in patients with chronic HBV infection in Jordan. Phylogenetic analyses revealed a considerable proportion of local spread in the country which should be considered in the preventive infection control efforts.

Chinese herbal extract Su-duxing had potent inhibitory effects on both wild-type and entecavir-resistant hepatitis B virus (HBV) in vitro and effectively suppressed HBV replication in mouse model

This study aimed to investigate anti-HBV effect and major active compounds of Su-duxing, a medicine extracted from Chinese herbs. HBV-replicating cell lines HepG2.2.15 (wild-type) and HepG2.A64 (entecavir-resistant) were used for in vitro test. C57BL/6 mice infected by adeno-associated virus carrying 1.3 mer wild-type HBV genome were used for in vivo test. Inhibitory rates of Su-duxing (10 μg/mL) on HBV replicative intermediate and HBsAg levels were 75.1%, 51.0% in HepG2.2.15 cells and 65.2%, 42.9% in HepG2.A64 cells. The 50% inhibitory concentration of Su-duxing and entecavir on HBV replicative intermediates had 0.2-fold and 712.5-fold increase respectively for entecavir-resistant HBV compared to wild-type HBV. Su-duxing and entecavir combination showed a better anti-HBV effect than each single of agents. Mice treated with Su-duxing (45.0 mg kg^-1 d^-1 for 2 weeks) had 1.39 log₁₀ IU/mL decrease of serum HBV DNA, and 48.9% and 51.7% decrease of serum HBsAg and HBeAg levels. GeneChip and KEGG analysis proposed that anti-HBV mechanisms included relief of HBx stability and viral replication, deregulation of early cell cycle checkpoints, and induction of type I interferon. Quantitative RT-PCR verified that CCNA2, ATF4, FAS and CDKN1A expression levels had significant difference between Su-duxing-treated and control groups. Six active compounds (Matrine, Oxymatrine, Chlorogenic acid, Sophocarpine, Baicalein, and Wogonin) against HBV were identified in Su-duxing. Greater anti-HBV effects were observed in some compound pairs compared to each single compound. In conclusion, Su-duxing had potent inhibitory effects on both wild-type and entecavir-resistant HBV. Its effects were associated with coordinated roles of active compounds in its composition.

Clinical and virological implications of A1846T and C1913A/G mutations of hepatitis B virus genome in severe liver diseases

OBJECTIVE

Mutations occurring within different genes of hepatitis B virus (HBV) genome may have different clinical implications. This study aimed to observe the clinical and virological implications of the A1846T and C1913A/G mutations of HBV genome in the development and treatment outcome of severe liver diseases, which has not been previously determined.

MATERIALS AND METHODS

A total of 438 cases of patients with liver diseases were retrospectively reviewed, including 146 with mild chronic hepatitis B infection (CHB-M), 146 with severe chronic hepatitis B infection (CHB-S), and 146 with acute-on-chronic liver failure (ACLF). Partial or full-length HBV genome was directly sequenced. Replicons containing A1846T, C1913A or other mutant sequences, or the wild-type counterparts were constructed respectively, and then transfected into HepG2 cells for phenotype analysis.

RESULTS

There was significant difference in the detection rates of A1846T (30.82%, 40.41% and 55.48%, respectively) and C1913A/G (15.52%, 28.77%, and 35.62%, respectively) among patients with CHB-M, those with CHB-S, and those with ACLF (p < .01). A1846T was significantly associated with the mortality of ACLF patients within six months after the disease onset (OR 1.704, p = .041). In vitro experiment revealed that A1846T mutant resulted in 3.20-fold and 1.85-fold increase of replication capacity and promoter activity, respectively compared with wild type counterpart (p < .001), while C1913A led to a significant decrease of core protein expression (p < .05).

CONCLUSION

Occurrence of A1846T and C1913A is positively associated with clinical presentations of severe liver disease. A1846T mutation is significantly associated with poor prognosis of ACLF.

Antigenicity reduction contributes mostly to poor detectability of HBsAg by hepatitis B virus (HBV) S-gene mutants isolated from individuals with occult HBV infection

Mutations in hepatitis B virus (HBV) S gene are one of factors contributing to occult HBV infection (OBI). The study aimed to uncover the impact of OBI-related S-gene mutations on the detectability of hepatitis B surface antigen (HBsAg). Nine representative mutations within the major hydrophilic region of the S region were investigated. These included six (M1-M6) from an OBI patient with HBV-related hepatocellular carcinoma, and three (M7-M9) from three OBI blood donors. Recombinant plasmids on the basis of pTriEx-mod-1.1 HBV and pcDNA3.1(-)/myc-His A vectors were constructed for each and transfected into HepG2 or Huh7 cells, respectively. Electrochemical luminescence, ELISA, Western blotting, and confocal immunofluorescence were used to examine HBsAg expression and antigenicity. In comparison to wild-type strain, supernatant and intracellular HBsAg levels of the nine mutants were reduced by 56.39-99.09% and 42.76-99.77% upon Roche quantitative Elecsys assay, respectively. Confocal immunofluorescence showed that relative intensity ratios of HBsAg-myc-His fusion protein detected by anti-HBs and anti-His-tag were lower by 11.87-76.27% for the nine mutants compared to the wild-type strain. Specifically, M1-M5 mutants that we firstly found recently were 33.14%, 76.27%, 57.93%, 53.37%, and 40.88% lower, respectively. Consistent results were obtained using double-antibody sandwich ELISA assays (anti-myc + anti-HBs vs anti-myc + anti-His). Antigenicity reduction played a major role for the poor detectability of HBsAg caused by the OBI-related mutations, although decreased HBsAg expression of some mutants and anti-HBs in samples might play coordinated roles. Taken together, antigenicity reduction contributes mostly to poor detectability of HBsAg caused by these OBI-related mutations.

HBV Drug Resistance Substitutions Existed before the Clinical Approval of Nucleos(t)ide Analogues: A Bioinformatic Analysis by GenBank Data Mining

Naturally occurring nucleos(t)ide analogue resistance (NUCr) substitution frequencies in the reverse transcriptase (RT) of the hepatitis B virus (HBV) were studied extensively after the clinical approval of nucleos(t)ide analogues (NUCs; year of approval 1998). We aimed to study NUCr substitutions in HBV RT sequences obtained before 1998 and better understand the evolution of RT sequences without NUC pressures. Our strategy was to retrieve HBV sequences from GenBank deposited before 1998. The initial search used the keywords "hepatitis B virus" or "HBV" and 1139 sequences were found. Data analyses included information extraction: sequence quality control and amino acid substitution analysis on 8 primary NUCr and 3 secondary substitution codons. Three hundred and ninety-four RT-containing sequences of 8 genotypes from 25 countries in 4 continents were selected. Twenty-seven (6.9%) sequences were found to harbor substitutions at NUCr-related codons. Secondary substitutions (rtL80V and rtV173G/A/L) occurred more frequently than primary NUCr substitutions (rtI169L; rtA181G; T184A/S; rtS202T/R; rtM204L and rtM250K). Typical amino acid substitutions associated with NUCr were of rtL80V, rtV173L and rtT184A/S. We confirm the presence of naturally occurring typical HBV NUCr substitutions with very low frequencies, and secondary substitutions are more likely to occur than primary NUCr substitutions without the selective pressure of NUCs.

Intergenotype recombinant analysis of full-length hepatitis B virus genomes from 516 Chinese patients with different illness categories

This study aimed to reveal characteristics and clinical relevance of HBV intergenotypic recombinants. Serum samples of 516 patients from Northern China were collected, including 131 with acute hepatitis B (AHB), 239 with chronic hepatitis B (CHB), and 146 with acute-on-chronic liver failure (ACLF). Full-length HBV genomes were sequenced and HBV genotypes were analyzed. Genotypes C, B, D, and intergenotypic recombinants were detected in 71.12% (367/516), 19.96% (103/516), 0.78% (4/516), and 8.14% (42/516) of the patients. The latter comprised 21 with AHB, 10 with CHB, and 11 with ACLF; and the occupations of intergenotypic recombinants in AHB, CHB, and ACLF groups were 16.03%, 4.18%, and 7.53% (P < 0.01), respectively. HBV B/C and C/D hybrids accounted for 85.71% (36/42) and 14.29% (6/42) of the intergenotypic recombinants. In AHB and CHB groups, serum HBV DNA levels were significantly lower in patients with intergenotypic recombinants than those without intergenotypic recombinants. Difference in basal core promoter A1762T/G1764A mutations and precore G1896A mutation incidences was not significant between B/C recombinant and genotypes B or C virus, although the significance was there between genotypes B and C viruses. Clonal sequence analysis showed that intergenotypic recombinant viral strains existed in single or in concomitance with other genotype virus. Phenotypic analysis showed that viral replication capacity was similar between recombinant and non-recombinant strains in tested samples. Taken together, the occurrence of intergenotypic recombinant HBV is relatively low in HBV-infected patients in Northern China, and intergenotypic recombinant HBV infection is likely favorable to induce an acute course of disease. J. Med. Virol. 89:139-145, 2017. © 2016 Wiley Periodicals, Inc.

PreS deletion profiles of hepatitis B virus (HBV) are associated with clinical presentations of chronic HBV infection

BACKGROUND

The association of hepatitis B virus (HBV) preS1 and preS2 deletions with progressive liver diseases are not fully understood.

OBJECTIVE

The study aimed to investigate characteristics of HBV preS deletion in HBV-infected patients with different illness categories.

STUDY DESIGN

Total of 539 HBV-infected patients were enrolled in the study, including 146 with chronic hepatitis B (CHB), 111 with HBV-related liver cirrhosis (LC), 146 with HBV-related acute-on-chronic liver failure (ACLF), and 136 with HBV-related hepatocellular carcinoma (HCC). PreS deletion was determined by sequencing. Replicons containing representative preS1 and preS2 deletion mutants and wild-type were respectively constructed and transfected into HepG2 cells for phenotypic analysis.

RESULTS

The detection rates of overall preS deletion were 15.8%, 26.1%, 24.0%, and 34.6% in CHB, LC, ACLF, and HCC patients, respectively. PreS1 deletion was most frequently detected in LC patients while preS2 deletion was most frequently detected in HCC patients, both frequencies were significantly higher than that in CHB patients (17.1% vs. 4.8%, P<0.01; 19.1% vs. 4.8%, P<0.01). The deletion patterns across preS gene were different among the 4 illness categories. Compared with wild-type strain, the preS1 deletion mutant had defected preS1 expression, significantly decreased viral mRNA level and SP II promoter activity; while preS2 deletion mutant had defected preS2 expression, and significantly decreased viral mRNA level.

CONCLUSIONS

HBV preS deletion was associated with advancement of liver diseases not only presented in preS deletion incidence, but also in the deletion pattern. Patients with preS2 deletion might have a higher risk to develop HCC.

Overview of hepatitis B virus mutations and their implications in the management of infection

Hepatitis B virus (HBV) affects approximately two billion people worldwide and more than 240 million people in the world are currently chronic carrier that could develop serious complications in the future, like liver cirrhosis and hepatocellular carcinoma. Although an extended HBV immunization program is being carried out since the early ‘80s, representing effective preventive measure, leading to a dramatic reduction of HBV hepatitis incidence, globally HBV infection still represents a major public health problem. The HBV virus is a DNA virus belongs to the Hepadnaviridae family. The HBV-DNA is a circular, partial double strand genome. All coding information is on the minus DNA strand and it is organized into four open reading frames. Despite hepatitis B virus is a DNA virus, it has a high mutation rate due to its replicative strategy, that leads to the production of many non-identical variants at each cycle of replication. In fact, it contains a polymerase without the proofreading activity, and uses an RNA intermediate (pgRNA) during its replication, so error frequencies are comparable to those seen in retroviruses and other RNA viruses rather than in more stable DNA viruses. Due to the low fidelity of the polymerase, the high replication rate and the overlapping reading frames, mutations occur throughout the genome and they have been identified both in the structural and not structural gene. The arise of mutations being to develop of a whole of viral variants called “quasi-species” and the prevalent population, which favors virus replication, was selected by viral fitness, host’s immune pressure and external pressure, i.e., vaccination or antiviral therapy. Naturally occurring mutations were found both in acute and chronic subjects. In the present review we examine and discuss the most recent available data about HBV genetic variability and its significance.

A novel complex A/C/G intergenotypic recombinant of hepatitis B virus isolated in southern China

Hepatitis B virus (HBV) genotypes and subgenotypes may vary in geographical distribution and virological features. Previous investigations, including ours, showed that HBV genotypes B and C were respectively predominant in South and North China, while genotypes A and D were infrequently detected and genotype G was not found. In this study, a novel A/C/G intergenotype was identified in patients with chronic HBV infection in Guilin, a city in southern China. Initial phylogenetic analysis based on the S gene suggested the HBV recombinant to be genotype G. However, extended genotyping based on the entire HBV genome indicated it to be an A/C/G intergenotype with a closer relation to genotype C. Breakpoint analysis using the SIMPLOT program revealed that the recombinant had a recombination with a arrangement of genotypes A, G, A and C fragments. Compared with the HBV recombinants harboring one or two genotype G fragments found in Asian countries, this Guilin recombinant was highly similar to the Vietnam (98-99%) and Long An recombinants (96-99%), but had a relatively low similarity to the Thailand one (89%). Unlike those with the typical genotype G of HBV, the patients with the Guilin recombinant were seropositive for HBeAg. Moreover, a relatively high HBV DNA viral load (>2 × 10(6) IU/ml) was detected in the patients, and the analysis of viral replication capacity showed that the Guilin recombinant strains had a competent replication capacity similar to genotypes B and C strains. These findings can aid in not only the clarification of the phylogenetic origin of the HBV recombinants with the genotype G fragment found in Asian countries, but also the understanding of the virological properties of these complicated HBV recombinants.

The rtL229 substitutions in the reverse transcriptase region of hepatitis B virus (HBV) polymerase are potentially associated with lamivudine resistance as a compensatory mutation

BACKGROUND

It remains unclear whether hepatitis B virus (HBV) reverse-transcriptase (RT) rtL229 substitutions influence HBV drug resistance.

OBJECTIVE

The study was to investigate the association of HBV rtL229 substitutions with viral resistance to lamivudine (LAM).

STUDY DESIGN

Entire HBV RT genes were amplified by nested PCR and sequenced from sera of 6000 nucleos(t)ide analog-experienced patients with chronic HBV infection. The incidence and clinic relevance of rtL229 substitutions were analyzed. Replication-competent viral amplicons which harbored HBV genomes of wild-type, rtM204I, or rtM204I in conjunction with various rtL229 substitutions (rtL229F/W/M/V) were constructed. The amplicons were transfected into HepG2 cells for phenotyping of replication capacity and susceptibility to nucleos(t)ide analogs.

RESULTS

The rtL229 substitutions were detected in 6.57% (394/6000) of patients. Individual substitution incidences were 2.77%, 0.97%, 0.83% and 0.55% for rtL229V, rtL229F, rtL229M and rtL229W, respectively. The incidence of rtL229 substitutions was significantly higher in LAM-experienced patients (341/4220, 8.1%) than in LAM-naïve patients (53/1780, 3.0%), and were independently associated with genotypic LAM resistance (77.9% vs. 21.2%, OR 8.806, 95%CI 6.345-12.223) and low viral replication (HBV DNA <1000IU/mL) (4.60% vs. 24.2%, OR 0.478, 95%CI 0.254-0.898). Representative cases follow-up showed that rtL229F developed subsequent to rtM204I emergence during LAM treatment and regressed with rtM204I after LAM withdrawal. Functionally, rtL229F did not confer reduced susceptibility to LAM, but could restore replication capacity of rtM204I strain.

CONCLUSION

The rtL229 substitutions were potentially associated with LAM resistance in Chinese patients and rtL229F had characteristics of a compensatory mutation of rtM204I mutant.

Quantitation of HBV covalently closed circular DNA in micro formalin fixed paraffin-embedded liver tissue using rolling circle amplification in combination with real-time PCR

BACKGROUND

The study aimed to develop an effective method to quantitate HBV covalently closed circular DNA (cccDNA) using small section of formalin fixed paraffin-embedded (FFPE) liver biopsy.

METHODS

Plasmid-safe ATP-dependent DNase (PSAD)-treated samples were subjected to rolling circle amplification (RCA) prior to real-time PCR mediated by cccDNA-selective primers. Human beta-actin gene was used as a reference control.

RESULTS

Compared to the classical method, i.e., PSAD digestion+real-time PCR, introduction of RCA increased the lower limit of detection for about 2 logs with good inter- and intra-assay reproducibility. HBV cccDNA was detected in 91.5% (119/130) of the FFPE samples. The cccDNA levels (copy/cell) between FFPE liver tissues and fresh frozen counterpart tissues were comparable. The median of cccDNA level in HBeAg-positive patients was higher than that in HBeAg-negative ones (52.60 vs. 31.25copies/cell, P<0.01). Intrahepatic cccDNA level was positively correlated with intrahepatic HBV total DNA level, but not obviously correlated with serum HBV DNA or alanine aminotransferase levels.

CONCLUSIONS

The method could sensitively and specifically quantitate intrahepatic HBV cccDNA in micro FFPE liver biopsy tissue for evaluation of HBV replication status in the liver.