[Insertion of TC motif into hepatitis B virus core protein c/e1 site does not affect the expression of S and e antigen]

OBJECTIVE

To investigate whether insertion of TC motif into hepatitis B virus (HBV) core protein c/e1 site affects the expression of S and e antigen.

METHODS

Different oligonucleotides encoding TC motif were inserted into the c/e1 site of the core gene of a 1.3 copy wild-type HBV genome vector. HepG2 cells were divided into several groups of cells to transiently transfect with the wild-type and mutant HBV vectors, respectively. In each group, the expression level of core protein inside cells was detected by western blotting, and the levels of S and e antigen in culture medium were analyzed by ELISA assay.

RESULTS

Western blotting showed that these TC-tagged core proteins were expressed at similar level of wild-type one. ELISA assay indicated that the level of S and e antigen in culture medium of different groups were not significantly different.

CONCLUSION

Insertion of TC motif into HBV core protein c/e1 site does not interference with the expression of viral protein encoded by HBV genome.

[Apigenin glycosides from Euphorbia humifusa wild]

The investigation on the herbal of Euphorbia humifusa Wild. was carried out in order to find its anti-HBV constituents. The isolation and purification were performed by chromatography such as Sephadex LH-20, MCI GEL CHP 20P, etc. Based on the spectral analysis, five apigenin glycosides were identified as apigenin-7-O-(6"-O-galloyl)-beta-D-glucopyranoside (1), apigenin-7-O-beta-D-apiofuranosyl (1-->2)-beta-D-glucopyranoside (2), apigenin-7-O-beta-D-lutinoside (3), apigenin-7-O-beta-D-glucopyranside (4) and apigenin (5). Among them, compound 1 is a new compound, compound 2 and 3 were isolated from this plant for the first time.

Inhibition of duck hepatitis B virus infection of liver cells by combined treatment with viral e antigen and carbohydrates

The e antigen (eAg) of duck hepatitis B virus (DHBV) is a glycosylated secretory protein with a currently unknown function. We concentrated this antigen from the supernatants of persistently infected primary duck liver cell cultures by ammonium sulphate precipitation, adsorption chromatography over concanavalin A Sepharose, preparative isoelectric focusing and molecular sieve chromatography. The combined treatment of duck liver cells with DHBV eAg (DHBe) concentrate and alpha-methyl-d-mannopyranoside strongly inhibited DHBV replication at de novo infection. When DHBe was added to non-infected primary duck liver cells, it was found to be associated with liver sinusoidal endothelial cells. This binding could be inhibited by the addition of alpha-methyl-d-mannopyranoside and other sugar molecules. The inhibitory effect of DHBe on infection could play a role in maintaining viral persistence.

Optimal design and validation of antiviral siRNA for targeting hepatitis B virus

AIM

Optimal design of antiviral short-interfering RNA (siRNA) targeting highly divergent hepatitis B virus (HBV) was validated by quantitative structure activity relationship (QSAR) analysis.

METHODS

The potency of 23 synthetic siRNAs targeting 23 sites throughout HBV pregenomic RNA were evaluated at 10 nmol/L by determining the inhibition on the expression of S/P/pregenomic mRNA and hepatitis B surface antigen (HBsAg) quantitatively in HepG2.2.15 cells. Genotype homology within HBV genomes was identified through plentiful computational analysis and the multiple linear regression analysis was made to validate the relationship between the functional siRNAs and primary characteristics. Based on the preliminary results, relationships between different determined endpoints [S/P mRNA, HBsAg, C/P mRNA, hepatitis B e antigen (HBeAg) and viral DNA load] and siRNA efficacy evaluation were investigated.

RESULTS

Genotype homology, open reading frame (ORF) S/P, X and C had tight correlation with the ability of siRNAs on inhibiting the expression of S/P/Pregenomic mRNA and HBsAg (P<0.01), of which, ORF C was negatively correlated with the siRNA potency (P<0.05). Further study showed that siRNA potency evaluation was influenced by different determined endpoints. P-target siRNAs showed significant inhibition on the S mRNA and HBsAg expression. S-target siRNAs inhibited the expression of S mRNA and HBsAg strongly. X-target siRNAs played active roles in inhibiting all 5 determined endpoints. C-target siRNAs blocked the expression of C mRNA, HBeAg and viral DNA load significantly.

CONCLUSION

The antiviral potency of siRNA was relevant to its primary characteristics and determined endpoints were important for siRNA efficacy evaluation for complex genome with overlapping ORF, which was helpful for siRNA optimal design.

[Relationships between liver function test, serum HBeAg or HBV DNA level and liver pathological changes in patients with chronic hepatitis B]

OBJECTIVE

The aim of this study was to investigate the relationship between liver function test, serum HBeAg, HBV DNA level and liver pathological changes in patients with chronic hepatitis B.

METHODS

233 patients with chronic hepatitis B accept liver puncture biopsy, liver function test, HBeAg detection and HBV DNA fluorescent quantitation PCR detection. Comparisons of liver function test, HBeAg and HBV DNA level were conducted among different liver pathological changes including inflammation grading and fibrosis staging.

RESULTS

In different inflammation grading groups, ALT was highest in group G3 and lowest in group G(0-1)(P = 0.016); TBil was highest in group G4 and lowest in group G(0-1) (P = 0.000); HBV DNA level was highest in group G4 and lowest in group G(0-1), but not statistically significant among groups (P = 0.463). In different fibrosis staging groups, ALT was highest in group S3 and lowest in group S(0-1), but not statistically significant among groups (P = 0.562); TBil was highest in group S4 and lowest in group S2 (P = 0.039); HBV DNA level was highest in group S3 and lowest in group S(0-1), but not statistically significant among groups (P = 0.395). In HBeAg positive group,the proportion of G(3-4) in inflammation grading or S(3-4) in fibrosis staging was lower than that in HBeAg negative group (46% vs. 52%, P = 0.438; 38% vs. 53%, P = 0.025; respectively).

CONCLUSION

HBV DNA level can not indicate the severity of liver inflammation or fibrosis in chronic HBV infection. Patients with HBeAg negative often are complicated with more severity of liver fibrosis. In routine liver function test, TBil level correlates with liver inflammation grading or fibrosis staging; ALT level also correlates with liver inflammation grading but not with fibrosis staging.

Role of ISGF3 in modulating the anti-hepatitis B virus activity of interferon-alpha in vitro

BACKGROUND AND AIM

Although interferon-alpha (IFN-alpha) is an effective treatment for hepatitis B virus (HBV) infection, its precise mechanism of action has not been identified. In this study, we investigated the role of signal transduction pathways in the activation of anti-HBV responses mediated by IFN-alpha.

METHODS

Using an oligo microarray, we found that four genes in the IFN-alpha signal pathway were markedly upregulated by IFN-alpha in human hepatoma cells regardless of whether they had been transfected with a plasmid containing the HBV genome: signal transducers and activators of transcription 1 (STAT1), interferon regulatory factor-9 (IRF-9, also called ISGF3gamma or P48), IFN-alpha-inducible protein 15 (IFI-15) and IFN-alpha-inducible protein 6-16 (IFI-6-16). We also investigated the role of IFN-stimulated gene factor3 (ISGF3) complex in IFN-alpha-mediated anti-HBV responses in human hepatoma cells by measuring the mRNA of the three genes within ISGF3 (STAT1, STAT2 and IRF-9) using semiquantitative reverse-transcription PCR (RT-PCR), and expression of the three proteins by western blot, and the mRNA and protein of dsRNA-dependent protein kinase (PKR).

RESULTS

STAT1, STAT2, IRF-9 and PKR mRNA as well as protein levels were upregulated by IFN-alpha treatment. When cells were pretreated with genistein, STAT1, STAT2 and IRF-9 mRNA levels remained unchanged after IFN-alpha stimulation, but PKR mRNA levels decreased, and the expression of the STAT1, P-STAT2, IRF-9 and PKR proteins decreased. Levels of HBV DNA decreased in the supernatants of cells treated with IFN-alpha, while ISGF3 levels increased. The quantity of HBV DNA remained unchanged by pretreating with genistein.

CONCLUSIONS

These observations suggested that the Janus tyrosine kinase-STAT (JAK-STAT) pathway may play a major role in mediating the effects of IFN-alpha against HBV, and that ISGF3 might be a key factor.

[Development of clevudine resistance after switching from lamivudine in a patient with chronic hepatitis B]

Clevudine is a nucleoside analog of the unnatural beta-L configuration which has potent antiviral activity against hepatitis B virus (HBV). Clevudine is expected to have similar pattern of resistance profile as lamivudine. However, there was no report on the mutation associated with clevudine resistance in patients with chronic hepatitis B. We report a case of young male patient with chronic hepatitis B who presented with clevudine resistance. The patient had received lamivudine therapy for 5 months with reduced serum HBV DNA levels. Then, lamivudine was switched to clevudine monotherapy. After the 6 months of clevudine therapy, the patient developed virologic breakthrough (>1.0chi10(8) copies/mL) as well as biochemical breakthrough, which was associated with the presence of rtM204I plus rtL80I mutant. After switching from clevudine to adefovir, the viral load decreased with biochemical improvement.

Combination therapy of siRNAs mediates greater suppression on hepatitis B virus cccDNA in HepG2.2.15 cell

BACKGROUND/AIMS

Hepatitis B virus (HBV) infection is a world-wide health problem. The major obstacles for current anti-HBV therapy are the low efficacy and the occurrence of drug resistant HBV mutations. Recent studies have demonstrated that combination therapy can enhance antiviral efficacy and overcome the shortcomings. Here, the inhibitory effect mediated by combination of small interfering RNAs (siRNAs) targeting different sites of HBV nuclear localization signal (NLS) was monitored in HepG2.2.15 cells.

METHODOLOGY

Recombinant plasmid psil-HBV was constructed and transfected into HepG2.2.15 cells. At 48, 72 and 96 h after transfection, culture media were collected and cells were harvested for HBV replication assay. HBsAg and HBeAg in the cell culture medium were detected by enzyme-linked immunoadsorbent assay. Intracellular viral DNA and covalently closed circular DNA (cccDNA) was quantified by real-time PCR. HBV viral mRNA was reverse transcribed and quantified by reverse-transcript PCR.

RESULTS

Our data demonstrated that three used siRNAs showed marked anti-HBV effects. The expression of HBsAg and the replication of HBV DNA could be specifically inhibited in a dose-dependent manner by siRNAs. Furthermore, combination of siRNAs, compared with individual use of each siRNA, exerted a stronger inhibition on antigen expression and viral replication, even though the final concentration of siRNA in the therapy was the same. More importantly, we showed that combination therapy significantly suppressed HBV cccDNA amplification.

CONCLUSION

Our results revealed that combination of siRNAs mediated a stronger inhibition on viral replication and antigen expression in HepG2.2.15 cells, especially, the amplification of cccDNA.

[The effects of extracts from Arenaria kansuensis on the levels of HBsAG and HBeAg in HepG2.2.15 cells]

OBJECTIVE

To investigate the anti-HBV effects of the extracts with alcohol and water from Arenaria kansuensis in vitro.

METHODS

HepG2.2.15 cells were used to estimate the effects of the extracts with alcohol and water from Arenaria kansuensis on the levels of HBsAg and HBeAg in medium by ELISA.

RESULTS

Incubation of HepG2.2.15 cells with both the extracts with alcohol and water from Arenaria kansuensis (50-400 mg/L) for 72 and 96h significantly inhibited the levels of HBsAg and HBeAg. The maximum inhibiting rate of HBeAg from the Arenaria kansuensis extracts with alcohol was 63.2% and 90. 8% at 72h and 96h, respectively. Meanwhile, the Arenaria kansuensis extracts with water had obvious inhibitory effects on the levels of HBsAg and HBeAg in HepG2.2.15 cells at 96 h, compared with that of the control group (P < 0.01). The maximum inhibiting rates were 52.5% and 72.8%, respectively.

CONCLUSION

The extracts with water from Arenaria kansuensis has obvious anti-HBV effects in vitro.

In vivo and in vitro anti-hepatitis B virus activity of total phenolics from Oenanthe javanica

The traditional Chinese medicine Oenanthe javanica (OJ) has been used for many years, mainly for the treatment of inflammatory conditions including hepatitis. In this study, human hepatoma Hep G2.2.15 cells culture system and duck hepatitis B virus (DHBV) infection model were used as in vivo and in vitro models to evaluate the anti-HBV effects of total phenolics from Oenanthe javanica (OJTP). The HBeAg and HBsAg concentrations in cell culture medium were determined by using the enzyme immunoassay kit after Hep G2.2.15 cells were treated with OJTP for 9 d. DHBV-DNA in duck serum was analyzed by dot blot hybridization assay. In the cell model, OJTP could dose-dependently inhibit the production of the HBeAg and HBsAg, and the inhibition rates of OJTP on HBeAg and HBsAg in the Hep G2.2.15 cells were 70.12% and 72.61% on day 9, respectively. In the DHBV infection model, OJTP also reduced HBV DNA level in a dose-dependent manner. The DHBV-DNA levels decreased significantly after the treatment with 0.10 g kg(-1)d(-1) and 0.20 g kg(-1)d(-1) OJTP. The inhibition of the peak of viremia was at the maximum at the dose of 0.20 g kg(-1)d(-1) and reached 64.10% on day 5 and 66.48% on day 10, respectively. Histopathological evaluation of the liver revealed significant improvement by OJTP. In conclusion, our results demonstrate that OJTP can efficiently inhibit HBV replication in Hep G2.2.15 cells line in vitro and inhibit DHBV replication in ducks in vivo. OJTP therefore warrants further investigation as a potential therapeutic agent for HBV infections.

[Effects of glycyrrhizin on the expression of hepatitis B virus and Toll like receptors 2,4 in HepG2.2.15 cells expressing low HBsAg]

OBJECTIVE

To investigate the effects of glycyrrhizin (GL) on the expression of hepatitis B virus e antigen (HBeAg), HBV DNA, Toll-like receptors 2,4 (TLR2,4) and proliferation of cells in HepG2.2.15 cell line.

METHODS

Real-time PCR examined HBV DNA, ELISA examined HBsAg, HBeAg and MTT examined the proliferation of cells. FCM examined the positive percent of cells expressing TLR2,4 before and after stimulated with GL, in contrast to the blank group.

RESULTS

The expression of HBsAg was low in the cell line, so e antigen was studied. The total HBeAg mean was significantly difference on the second day after stimulated (P<0.01), but only in the group with 400 microg/ml HBeAg decreased significantly in contrast to the blank group (P<0.05), the group with 800 microg/ml increased significantly in contrast to the other groups (P<0.01). The total HBV DNA mean on the third day after stimulated was significant, only the group with 50 microg/ml decreased in contrast to the blank group, but P>0.05, the other four groups increased. The intensity of TLR4 expression in the cells was significantly higher than that of the control group (P<0.05), both of total mean TLR2,4 increased significantly (P<0.01). The four groups except the group with 200 microg/ml increased significantly in no dose-dependent manner (P<0.05). GL in three goups under 200 microg/ml all could make cells proliferate, but only 200 microg/ml group had significant difference compared to the blank group (P<0.05). Both 400 and 800 microg/ml groups inhibited the growth of cells (P<0.01). The proliferation of cells were notably negative correlated with the expression of HBeAg, HBV DNA (P<0.05).

CONCLUSION

The study suggestes GL could inhibit or promote HBV DNA replicating and e antigen secreting in mutative HepG2.2.15 cell line, the correlation between the proliferation of cells and the both are negative. GL could upregulate TLR2,4 in no dose-dependent manner. Influencing HBV maybe have no correlation to up regulating TLR2,4 by GL at least in vitro.

[Efficacy of antiviral treatment on intrahepatic HBV DNA and histology in HBeAg -positive chronic hepatitis B patients]

OBJECTIVE

To evaluate the effect of antiviral agents on intrahepatic HBV DNA and histology in HBeAg-positive chronic hepatitis B patients.

METHODS

Thirty-five patients were treated with lamivudine, 16 with interferon alfa (INF-alpha), 24 with sequential Lamivudine and INF-alpha. The total duration of therapy was 12 months. Intrahepatic HBV DNA was measured quantitatively by real-time polymerase chain reaction.

RESULTS

There was significant change in all parameters of the groups of patients at the end of treatment (P < 0.05). The patients treated with sequential treatment had slightly higher HBeAg seroconversion rate (38.1%) than that of the other patients (P=0.1352). The baseline levels of intrahepatic HBV DNA in the patients with HBeAg seroconversion or undetectable serum HBV DNA were significantly lower than that of the other patients (P < 0.05).

CONCLUSION

Antiviral agents could effectively inhibit intrahepatic HBV DNA and improve hepatic histology. The patients with low baseline intrahepatic HBV DNA level may achieve better antiviral efficacy. Sequential treatment might produce high HBeAg seroconversion rate.

[The influence of HBV/P22 protein on the apoptosis of HepG2 cells: an experimental study]

OBJECTIVE

To study the influence of HBV/P22 protein on the induced apoptosis of HepG2 cells.

METHODS

In vitro, two HepG2 strains were transfected with pcDNA3.1+ and pcDNA3.1+HBV/P22 respectively and the cells were exposed to Act D and TNF alpha for 6h and then the induced apoptosis was detected by flow cytometry (FCM) and TUNEL technique. Supernatant HBeAg was detected by Abbott reagent. The intracellular expression of HBV/P22 protein was measured by Western blot and immunochemistry. In vivo, three cell groups were inoculated into nude mice by subcutaneous injections. After two weeks, Act D and TNF alpha were injected into the tumors and then the induced apoptosis in the tissues was detected by TUNEL technique. The expression of HBV/P22 protein in the tumor tissues was detected by immunochemistry.

RESULTS

In vitro, in HepG2- pcDNA3.1+HBV/P22 cells, supernatant HBeAg was positive and intracellular HBV/P22 protein was positively expressed. The apoptosis proportion of HepG2-pCDNA3.1+HBV/P22 cells was markedly lower than HepG2 and HepG2-pcDNA3.1+ cells (P < 0.05). In vivo, HBV/P22 protein was expressed in the tumor tissues, and the apoptosis proportion in the group injected with HepG2-pcDNA3.1+HBV/P22 cells was markedly lower than those injected with HepG2 and HepG2-pcDNA3.1+cells (P < 0.05).

CONCLUSION

HBV/P22 protein could inhibit the induced apoptosis of HepG2 cells both in vitro and in vivo.

[Dynamic analysis of HBV cccDNA in HepG2 cells infected with Ad-1.2 HBV]

OBJECTIVE

o study the replication of hepatitis B virus (HBV) in HepG2 cells infected with Ad-1.2 HBV.

METHODS

HepG2 cells were transfected with adenovirus containing 1.2 copies of HBV DNA. The expression of HBV antigens were detected in the culture medium by means of enzyme-linked immunosorbent assay (ELISA), and the covalently closed circular DNA (cccDNA) in the cells was extracted with plasmid extraction kit and detected by real-time PCR with selective primer after treatment with mung bean nuclease.

RESULTS

HBsAg, HBeAg and HBV cccDNA were all detected in HepG2 cells after tranfection with Ad-1.2 HBV. HBV cccDNA was detected 1 day after the infection, reaching the peak level 4 days after infection.

CONCLUSION

Ad-1.2 HBV-infected cells can serve as the model for screening and evaluation of antiviral agents.

Transforming growth factor-beta1 suppresses hepatitis B virus replication primarily through transcriptional inhibition of pregenomic RNA

Transforming growth factor-beta1 (TGF-beta1) is a pleiotropic cytokine with pivotal roles in the regulation of cellular functions and immune responses. In this study, we found that TGF-beta1 was able to effectively suppress hepatitis B virus (HBV) replication. In the presence of TGF-beta1, the level of viral replicative intermediates was dramatically decreased, both in actively dividing cells and in confluent cells. At the same time, the levels of viral transcripts, core protein, and nucleocapsid were significantly diminished by TGF-beta1 treatment. Interestingly, the inhibitory activity of TGF-beta1 was associated with preferential reduction of the level of pregenomic RNA compared with pre-C mRNA. Further analysis indicated that TGF-beta1 might exert its antiviral effect primarily through reducing expression of the HBV core protein by transcriptional regulation instead of posttranscriptional modification.

CONCLUSION

TGF-beta1 may play a dual role in HBV infection, in the suppression of immune responses against viral infection and in the direct inhibition of viral replication, resulting in minimization of liver damage in patients with chronic hepatitis.

Viral quasi-species evolution during hepatitis Be antigen seroconversion

BACKGROUND & AIMS

Although viral quasi-species evolution may be related to pathogenesis of disease, little is known about this in hepatitis B virus (HBV); consequently, we aimed to evaluate the evolution of HBV quasi-species in patients with well-characterized clinical phenotypes of chronic hepatitis B.

METHODS

Four cohorts of well-defined clinical phenotypes of chronic hepatitis B, hepatitis Be antigen (HBeAg) seroconverters (spontaneous seroconverters and interferon-induced seroconverters) and nonseroconverters (controls and interferon nonresponders) were followed during 60 months on average. Serum from 4 to 5 time points was used for nested polymerase chain reaction, cloning, and sequencing of the precore/core gene (20 clones/sample). Only patients with genotype B were used. Sequences were aligned using Clustal X, then serial-sample unweighted pair grouping method with arithmetic means phylogenetic trees were constructed using Pebble 1.0 after which maximum likelihood estimates of pairwise distances under a GTR + I + G model was assessed. Viral diversity and substitution rates were then estimated.

RESULTS

Analysis of 3386 sequences showed that HBeAg seroconverters had 2.4-fold higher preseroconversion viral sequence diversity (P = .0183), and 10-fold higher substitution rate (P < .0001) than did nonseroconverters, who had persistently low viral diversity (3.6 x 10(-3) substitutions/site) and substitution rate (2.2 x 10(-5) substitutions x site(-1) x month(-1)). After seroconversion, there was a striking increase in viral diversity. Most seroconverters had viral variants that showed evidence of positive selection, which was seen mainly after seroconversion.

CONCLUSIONS

The high viral diversity before a reduction in HBV DNA and before HBeAg seroconversion could either be related to occurrence of stochastic mutations that lead to a break in immune tolerance or to increased immune reactivity that drives escape mutations.

Two new alkaloids and active anti-hepatitis B virus constituents from Hypserpa nitida

Two new alkaloids, hypserpanines A and B (1, 11), together with eleven known compounds, phenolbetain (2), acutumine (3), acutumidine (4), dechloroacutumine (5), dauricumine (6), dauricumidine (7), pronuciferine (8), glaziovine (9), S-reticuline (10), magnoflorine (12) and laurifoline(13), were isolated from Hypserpa nitida Miers. (Menispermaceae) and chemically elucidated through spectral analyses. All the isolated alkaloids were evaluated for their anti-HBV activities in vitro using the HBV transfected Hep G2.2.15 cell line. The most active compound, dauricumidine (7), exhibited an IC(50) value of 0.450 mM (SI=4.13) on hepatitis B virus (HBV) surface antigen (HBsAg) secretion of the Hep G2.2.15 cell line.

Pyrrolidine-carboxamides and oxadiazoles as potent hNK1 antagonists

The preparation and structure-activity-relationships of novel pyrrolidine-carboxamides and oxadiazoles are described. Compounds in this series were found to be potent hNK(1) antagonists in vitro and efficacious in vivo with minimal interactions with P(450) liver enzymes. Oxadiazole analog 22 was determined to have excellent hNK(1) binding affinity, functional activity, and a good PD response in vivo.

Low-dose tenofovir is more potent than adefovir and is effective in controlling HBV viremia in chronic HBeAg-negative hepatitis B

AIM: To study the efficacy of tenofovir disoproxil fumarate (TDF) at low dose in a small open trial of chronic hepatitis B patients with advanced stage disease.

METHODS: Eleven patients were treated with TDF 75 mg for a median period of 80 (range, 24-576) wk and then 7 cases were shifted to an adefovir 10 mg treatment group. All patients had been pre-treated with lamivudine: 5 had YMDD resistant mutants and 6 wild-type virus. When TDF was started, 4 patients had low-level viremia and 6 were PCR-negative.

RESULTS: During TDF treatment, PCR remained negative in 10 patients, transaminase levels were normal and no significant viral breakthrough was observed. The drug was well tolerated in all cases. When TDF 75 mg was substituted with adefovir 10 mg, 3 out of 7 patients had a persistent viral rebound (2700-130 000 copies/mL), in whom lamivudine had to be reintroduced.

CONCLUSION: Low-dose TDF monotherapy can control HBV viremia for an extended period of time without the emergence of resistance and is more potent than adefovir at the standard dosage. The use of a reduced dose of TDF could diminish the cost of therapy in low-income countries, but further studies in a larger population and in HBeAg-positive subjects are needed.

Genetic characteristics of hepatitis B virus genotypes as a factor for interferon-induced HBeAg clearance

The factors determining the responsiveness of different hepatitis B virus (HBV) genotypes to interferon treatment are not fully understood. We investigated the relationship between HBV genetic characteristics and the outcome of short (16 weeks) or prolonged (32 weeks) treatment with standard interferon-alpha in a prospectively followed cohort of 103 patients across Europe with HBeAg positive chronic hepatitis B. INNO-LiPA assays and HBV DNA sequencing were used to determine HBV genotypes, mutations in the core promoter and precore/core regions. After 16-weeks interferon-alpha treatment, the rate of HBeAg clearance was higher in genotype A versus all other genotypes (P = 0.014), or genotype D alone (P = 0.05). The HBV genome analysis revealed that: (i) after 16-weeks treatment, an HBV subpopulation with core promoter mutations emerged or increased (P < 0.001) only in genotype A; (ii) the core gene of genotype A has the lowest number of amino acid variations in comparison with genotypes B, C, or D. Logistic regression analysis identified genotype A as a positive predictor of short (16 weeks) treatment response (P = 0.001; odds ratio 6.19, 95 confidence interval 1.94-19.8), having a greater impact than baseline HBV DNA or alanine aminotransferase (ALT) levels. In contrast, the response to prolonged interferon-alpha treatment was not different between HBV genotypes. These results suggest that HBV genotype A responds earlier to interferon treatment than other genotypes, which is associated with its molecular characteristics. The optimal duration of interferon-based therapies in chronic hepatitis B may vary between different HBV genotypes.

Evaluation of hepatitis B virus replication and proteomic analysis of HepG2.2.15 cell line after cyclosporine A treatment

AIM

The effect of cyclosporine A (CsA) on hepatitis B virus (HBV) replication was investigated, and proteomics expression differentiation after CsA treatment was studied in order to provide clues to explore the effect of CsA on HBV replication.

METHODS

Methyl thiazolyl tetrazolium (MTT) assay was used to evaluate the cytotoxicity of CsA. The HBV replication level in the HBV genomic DNA transfected HepG2.2.15 cell line was determined by an ELISA analysis of hepatitis B surface antigens (HBsAg) and Hepatitis B e antigens (HBeAg) in culture supernatant, while the intracellular HBV DNA replication level was analyzed by slot blot hybridization. Two-dimensional electrophoresis was used to investigate the alteration of protein expression in HepG2.2.15 after CsA treatment in vitro. The differentially-expressed proteins were identified by Matrix-assisted laser desorption/ionization-time of flight mass spectrometry combined with an online database search.

RESULTS

CsA was able to inhibit the expression of HBsAg, HBeAg, and HBV DNA replication in vitro in a dose-dependent manner. A proteomics analysis indicated that the expression of 17 proteins changed significantly in the CsA treatment group compared to the control group. Eleven of the 17 proteins were identified, including the overexpression of eukaryotic translation initiation factors (eIF) 3k, otubain 1, 14.3.3 protein, eIF2-1 alpha, eIF5A, and the tyrosine 3/tryptophan 5-mono-oxygenase activation protein in CsA-treated HepG2.2.15 cells. The downregulation of the ferritin light subunit, erythrocyte cytosolic protein of 51 kDa (ECP-51), stathmin 1/oncoprotein, adenine phosphoribosyl-transferase, and the position of a tumor protein, translationally controlled 1, was shifted, suggesting it had undergone posttranslational modifications.

CONCLUSION

Our study identified the inhibitory effect of CsA on HBV replication, and found that a group of proteins may be responsible for this inhibitory effect.

Combination of small interfering RNA and lamivudine on inhibition of human B virus replication in HepG2.2.15 cells

AIM: To observe the inhibition of hepatitis B virus (HBV) replication and expression by combination of siRNA and lamivudine in HepG2.2.15 cells.

METHODS: Recombinant plasmid psil-HBV was constructed and transfected into HepG2.2.15 cells. The transfected cells were cultured in lamivudine-containing medium (0.05 μmol/L) and harvested at 48, 72 and 96 h. The concentration of HBeAg and HBsAg was determined using ELISA. HBV DNA replication was examined by real-time PCR and the level of HBV mRNA was measured by RT-PCR.

RESULTS: In HepG2.2.15 cells treated with combination of siRNA and lamivudine, the secretion of HBeAg and HBsAg into the supernatant was found to be inhibited by 91.80% and 82.40% (2.89 ± 0.48 vs 11.73 ± 0.38, P < 0.05; 4.59 ± 0.57 vs 16.25 ± 0.48, P < 0.05) at 96 h, respectively; the number of HBV DNA copies within culture medium was also significantly decreased at 96 h (1.04 ± 0.26 vs 8.35 ± 0.33, P < 0.05). Moreover, mRNA concentration in HepG2.2.15 cells treated with combination of siRNA and lamivudine was obviously lower compared to those treated either with siRNA or lamivudine (19.44 ± 0.17 vs 33.27 ± 0.21 or 79.9 ± 0.13, P < 0.05).

CONCLUSION: Combination of siRNA and lamivudine is more effective in inhibiting HBV replication as compared to the single use of siRNA or lamivudine in HepG2.2.15 cells.

In vitro resistance to interferon-alpha of hepatitis B virus with basic core promoter double mutation

The hepatitis B virus (HBV) genome basic core promoter (BCP) modulates HBeAg secretion at the transcriptional level. In addition to pre-core mutations, variations in the BCP are related to hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. HBeAg-negative chronic hepatitis B patients show a lower sustained response to interferon (IFN). The aim of this study was to determine if there is a relationship between HBV BCP mutation and sensitivity of HBV to IFN-alpha in vitro. BCP mutations were introduced by site-directed mutagenesis and the entire genomes of wild-type and mutant HBV were transiently transferred into Huh7 cells by calcium phosphate transfection. With or without IFN-alpha, viral products in the culture medium and viral replication intermediates in the cytoplasm were detected 3 days after transfection. The amount of hepatitis B surface antigen (HBsAg) secreted by wild-type HBV and the BCP mutant was similar, while HBeAg secreted by the mutant was decreased by 35.4%. HBV particles and replication intermediates of the BCP mutant were increased. After IFN-alpha was added, HBeAg, HBV DNA and HBV replication intermediates decreased for both the wild-type HBV (by 25.7%, 31.8%, 29.8%, respectively) and the BCP mutant (by 8.4%, 27.4%, 10.1%, respectively). These data indicate that HBV harboring the BCP double mutation has stronger replication competence and lower sensitivity to IFN-alpha than wild-type.