Anti-HBV effect of TAT- HBV targeted ribonuclease

Inhibition of hepatitis B virus gene expression & replication by crude destruxins from Metarhizium anisopliae var. dcjhyium

BACKGROUND & OBJECTIVES

Destruxin A, destruxin B and destruxin E isolated from entomopathogenic fungus Metarhizium anisopliae showed a strong suppressive effect on the replication of hepatitis B virus (HBV) in human hepatoma cells. In this study, the anti-HBV effects of the crude destruxins extracted from M. anisopliae var. dcjhyium were detected both in vitro and in vivo.

METHODS

HepG2.2.15 cells were cultured to observe the inhibitory effects of the crude destruxins on the gene expression and replication of HBV by radioimmunoassay detection and real-time quantitative PCR. In vivo, duck HBV (DHBV)-infected ducks were treated with the crude destruxins at 2.0, 4.0, 6.0 μg/kg once a day for 15 days, DHBV DNA was examined by real-time quantitative PCR.

RESULTS

The crude destruxins suppressed the replication of HBV-DNA and the production of HBsAg and HBeAg with IC 50 of about 1.2 and 1.4 μg/ml. Transcript of viral mRNA was significantly suppressed by the crude destruxins in HepG2.2.15 cells. In vivo, the duck serum DHBV-DNA levels were markedly reduced in the group of the crude destruxins.

INTERPRETATION & CONCLUSIONS

The crude destruxins inhibited the gene expression and replication of HBV both in vitro and in vivo, and their anti-HBV effect was stronger than that with destruxin B. Our results indicate that the crude destruxins from M.anisopliae var. dcjhyium may be potential antivirus agents. Further studies need to be done to confirm these findings.

Adenoviral-vector mediated transfer of HBV-targeted ribonuclease can inhibit HBV replication in vivo. Biochem Biophys Res Commun. 2008;371:541-545. [PMID: 18455508 DOI: 10.1016/j.bbrc.2008.04.121]

Hepatitis B virus (HBV)-targeted ribonuclease (HBV-TR) is a fused protein of HBV core protein and a ribonuclease, human eosinophil-derived neurotoxin (hEDN). Our previous results showed that HBV-TR could effectively inhibit HBV replication in vitro. To test whether HBV-TR can inhibit HBV replication in vivo, we constructed a recombinant adenoviral vector expressing HBV-TR (Ad-TR) and used it to treat HBV-transgenic mice. Immunohistochemical staining showed that TR was expressed at varied levels in different tissues of Ad-TR-treated mice. Serum HBsAg concentration was decreased by 64.8% for the Ad-TR-treated mice compared with empty adenoviral vector-treated control mice. The amount of HBV-DNA in the livers of the Ad-TR-treated mice was 0.74 x 10(7) copies/mug of genomic DNA while the amount of HBV-DNA in the livers of the empty adenoviral vector-treated control mice was 2.86 x 10(7) copies/mug of genomic DNA. Serum HBV-DNA of Ad-TR-treated mice was also decreased by 71.4% compared with empty adenoviral vector-treated control mice. In addition, for some Ad-TR-treated mice, the expression of HBsAg in the liver cells turned negative. No discernible adverse effects were observed for Ad-TR-treated mice. Taken together, our results indicated that adenovirus mediated transfer of HBV-TR can inhibit HBV replication in vivo.

Downregulation of HBx mRNA in HepG2.2.15 cells by small interfering RNA

OBJECTIVE

Hepatitis B virus (HBV) infection is one of the most prevalent viral infectious diseases in humans. And it is still a challenge for the development of an effective therapy for HBV infection. Recently, the progress in RNA interference (RNAi) has shed some light on the inhibition of HBV expression and replication by RNAi specific for the various genes of the HBV genome. Some prior researches suggests that the HBV x protein (HBx) plays an important role in viral transcription, cell growth, and apoptotic cell death.

METHODS

In the present study, we designed three siRNAs based on the X-protein of HBV sequences and tested their effects on the expression of HBx gene following sorting of siRNA-positive cells. The interference effect was tested in 24, 48, and 72 h. HBsAg in cultured media was assayed using western blot at various days post-transfection. The amount of HBx mRNA was quantitated by Real-time reverse-transcript PCR (RT-PCR).

RESULTS

There was a decrease in the levels of HBV mRNA and HBsAg from the the transfected cells. Among these three siRNAs, siRNA-2 was found to be the most effective at suppressing HBV gene expression.

LC-MS characterization of efficacy substances in serum of experimental animals treated with Sophora flavescens extracts

Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait.

Capsid-targeted viral inactivation can destroy dengue 2 virus from within in vitro

Capsid-targeted viral inactivation (CTVI) has emerged as a conceptually powerful antiviral strategy that exploits viral structural proteins to target a destructive enzyme specifically into progeny virions. We have recently demonstrated the principle of CTVI against dengue virus infection and observed a modest therapeutic effect in vitro (Arch Virol 2005, 150: 659-669). Here we tested a prophylactic model of CTVI, in which mammalian cells stably expressing the dengue 2 virus capsid protein fused to a nuclease were infected with dengue virus and determined the effects on progeny virion infectivity. CTVI efficiently destroyed dengue 2 virus from within and decreased the infectious titers by 10(3)- to 10(4)-fold, suggesting that CTVI has potential in the prophylactic application for dengue virus infection.

Inhibition of hepatitis B virus replication in 2.2.15 cells by expressed shRNA

Hepatitis B virus (HBV) infection is a worldwide health problem. To determine whether RNA interference (RNAi) could inhibit ongoing HBV replication in 2.2.15 cells, we constructed shRNA-producing vector pU6P based on the mouse U6 RNA promoter and cloned 12 targeted sequences against HBV into the vector, resulting in a series of pU6-siHBV vectors. The recombinant vectors were transfected into 2.2.15 cells, HBsAg and HBeAg in cultured media were assayed using enzyme-linked immunosorbent assay at various days after transfection. The amount of HBV DNA in the culture medium was quantitated by real-time polymerase chain reaction. HBsAg and HBeAg expression were inhibited by 72.8 +/- 5.4% (P = 0.00003) and 55.8 +/- 6.2% (P = 0.000026), respectively, 4 days after transfection with pU6-siHBV5. The greatest inhibition of HBV DNA was decreased by approximately 1.9-fold (P = 0.013) on day 6 post transfection with pU6-siHBV11 compared with that of empty vector. No change was found for HBV protein expression and DNA replication on pU6-siGFP (negative control) transfected cells. Our data demonstrate that the transfection of HBV-targeted shRNA-producing vector in 2.2.15 cells could inhibit the HBV protein expression and HBV DNA replication specifically. RNAi may be considered as a potential antiviral approach for human HBV infection.

Anti-HBV effect of liposome-encapsulated matrine in vitro and in vivo

AIM

To study the anti-HBV effect of liposome-encapsulated matrine (Lip-M) in vitro and in vivo.

METHODS

2.2.15 cell line was cultured in vitro to observe the effect of Lip-M and matrine on the secretion of HBsAg and HBeAg. The toxicity of Lip-M and matrine to 2.2.15 cell line was also studied by MTT method. In in vivo study, drug treatment experiment was carried out on the 13th day after ducks were infected with duck hepatitis B virus (DHBV). The ducks were randomly divided into 4 groups with 5-6 ducks in each group. Lip-M and matrine were given to DHBV-infected ducks respectively by gastric perfusion. Four groups were observed: group of Lip-M (20 mg/kg), group of Lip-M (10 mg/kg), group of matrine (20 mg/kg) and group of blank model. The drug was given once daily for 20 d continuously, and normal saline was used as control. The blood was drawn from the posterior tibial vein of all ducks before treatment (T(0)), after the medication for 5 (T5), 10 (T10), 15 (T15), 20 (T20) d and withdrawl of the drug for 3 d (P3). The serum samples were separated and stored at -70 degrees, DHBV-DNA was detected by the dot-blot hybridization.

RESULTS

After addition of Lip-M and matrine to 2.2.15 cell line for eleven d, the median toxic concentration (TC50) of Lip-M and matrine was 7.29 mg/mL and 1.33 mg/mL respectively. The median concentration (IC50) of Lip-M to inhibit HBsAg and HBeAg expression was 0.078 mg/mL and 3.35 mg/mL respectively. The treatment index (TI) value of Lip-M for HBsAg and HBeAg was 93.46 and 2.17 respectively, better than that of matrine. The DHBV-infected duck model treatment test showed that the duck serum DHBV-DNA levels were markedly reduced in the group of Lip-M (20 mg/kg) after treated by gastric perfusion for 10, 15 and 20 d (0.43+/-0.22 vs 0.95+/-0.18, t = 4.70, P = 0.001<0.01.0.40+/-0.12 vs 0.95+/-0.18, t = 6.34, P = 0.000<0.01. 0.22+/-0.10 vs 0.95+/-0.18, t = 8.30, P = 0.000<0.01), compared to the group of matrine (20 mg/kg) (0.43+/-0.22 vs 0.79+/-0.19, t = 3.17, P = 0.01<0.05. 0.40+/-0.12 vs 0.73+/-0.24, t = 3.21, P = 0.009<0.05. 0.22+/-0.10 vs 0.55+/-0.32, t = 2.27, P = 0.046<0.05.), and the control(0.43+/-0.22 vs 0.98+/-0.29, t = 3.68, P = 0.005<0.01. 0.40+/-0.12 vs 0.97+/-0.30, t = 4.26, P = 0.002<0.01. 0.22+/-0.10 vs 0.95+/-0.27, t = 5.76, P = 0.000<0.01). After the treatment for 20 d and withdrawl of the drug for 3 d, duck serum DHBV-DNA level in the group of Lip-M (10 mg/kg) markedly reduced (0.56+/-0.26 vs 0.95+/-0.38, t = 5.26, P = 0.003<0.05. 0.55+/-0.25 vs 0.95+/-0.38, t = 5.52, P = 0.003<0.05), and the difference was significant as compared with the control (0.56+/-0.26 vs 0.95+/-0.27, t = 2.37, P = 0.042<0.05. 0.55+/-0.25 vs 0.89+/-0.18, t = 2.55, P = 0.031<0.05), but not significant as compared with the group of matrine (20 mg/kg). After withdrawl of the drug for 3 d, the levels of DHBV-DNA did not relapse in both groups of Lip-M.

CONCLUSION

Lip-M can evidently inhibit the replication of hepatitis B virus in vitro and in vivo; its anti-HBV effect is better than that of matrine.

Anti-hepatitis B virus effects of human peripheral blood mononuclear cells activated by CpG-ODN

AIM: To investigate the inhibitory effect of peripheral blood mononuclear cells (PBMCs) activated by synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG dinucleotides (CpG-ODN) on hepatitis B virus (HBV) in vitro.

METHODS: CpG-ODN was co-cultured with PBMCs. The IFN-α and IFN-γ in the supernatant were measured by ELISA. PBMCs activated by CpG-ODN were added to HBV transfected HepG2.2.15 cells After 1, 2 and 3 days, HBsAg and HBeAg in the supernatant were measured by ELISA; HBV DNA and HBV mRNA in HepG2.2.15 cells were detected by fluorogenic quantitative PCR method. MTT method and enzyme assays were used to detect PBMC-mediated lytic activity against HepG2.2.15 cells.

RESULTS: CpG-ODN induced high amounts of IFN-α as well as IFN-γ production (382.69±136.62, 37.42±6.55). Though CpG-ODN was unable to inhibit HBV replication directly, PMBC activated by CpG-ODN significantly reduced HBsAg and HBeAg secretion of HepG2.2.15 cells with rates of 82.6% and 52.4% at 72 h respectively (P < 0.05). The remarkable inhibitory effects of PMBC activated by CpG-ODN on HBV DNA (21.5%) and HBV mRNA (81.3%) in HepG2.2.15 cells were also observed (P < 0.05, P < 0.01).

CONCLUSION: PMBC activated by CpG-ODN can indirectly inhibit HBV replication and expression in vitro.

Anti-HBV effect of compound Ganaining in vitro

AIM: To study the anti-HBV effect of compound Ganaining in vitro.

METHODS: The 2.2.15 cell line was cultured in vitro to observe the inhibitory effect of compound Ganaining on secretion of HBsAg and HBeAg, and its toxicity on 2.2.15 cell line was also studied.

RESULTS: After the addition of compound Ganaining in 2.2.15 cell line for eight days, it showed that median toxic concentration (TC₅₀) of compound Ganaining was more than 10 g/L. IC₅₀ of compound Ganaining on HBsAg and HBeAg was 0.67g/L, and 0.13g/L, respectively; its treatment index (TI) value on HBsAg and HBeAg was 93.46 and 2.17, respectively.

CONCLUSION: Compound Ganaining has a strong inhibitory action on secretion of HBsAg and HBeAg, and shows good effect of anti-HBV in 2.2.15 cell line.

Effect of HBeAg on the hepatitis B virus vertical transmission in neonates

AIM: To investigate the effect of HBeAg on the hepatitis B virus vertical transmission in neonates.

METHODS: HBsAg positive pregnant women were enrolled,and ELISA or Abbott was employed to detect the HBeAg and HBsAg in the peripheral blood of neonates and their mothers.

RESULTS: Fifty-seven HBsAg positive pregnant women were reconfirmed as HBsAg positive. Fifteen of them were detected as HBeAg positive. Eleven of 16 neonates born to 15 HBeAg positive mother were detected as HBeAg positive. Three neonates diagnosed as HBsAg positive by ELISA or Abbott reagents were detected as HBeAg positive. Statistic analysis indicated that HBeAg in newborns was an important risk factor.

CONCLUSION: HBeAg in neonates played an important role during HBV vertical transmission.