Curcumin inhibits hepatitis B virus infection by downregulating ccc DNA-bound histone acetylation

AIM To investigate the potential effect of curcumin on hepatitis B virus(HBV) covalently closed circular DNA(ccc DNA) and the underlying mechanism.METHODS A Hep G2.2.15 cell line stably transfected with HBV was treated with curcumin, and HBV surface antigen(HBs Ag) and e antigen(HBe Ag) expression levels were assessed by ELISA. Intracellular HBV DNA replication intermediates and ccc DNA were detected by Southern blot and real-time PCR, respectively. The acetylation levels of histones H3 and H4 were measured by Western blot. H3/H4-bound ccc DNA was detected by chromatin immunoprecipitation(Ch IP) assays. The deacetylase inhibitors trichostatin A and sodium butyrate were used to study the mechanism of action for curcumin. Additionally, short interfering RNAs(si RNAs) targeting HBV were tested along with curcumin.RESULTS Curcumin treatment led to time-and dose-dependent reductions in HBs Ag and HBe Ag expression and significant reductions in intracellular HBV DNA replication intermediates and HBV ccc DNA. After treatment with 20 μmol/L curcumin for 2 d, HBs Ag and ccc DNA levels in Hep G2.2.15 cells were reduced by up to 57.7%(P < 0.01) and 75.5%(P < 0.01), respectively, compared with levels in non-treated cells. Meanwhile, time-and dose-dependent reductions in the histone H3 acetylation levels were also detected upon treatment with curcumin, accompanied by reductions in H3-and H4-bound ccc DNA. Furthermore, the deacetylase inhibitors trichostatin A and sodium butyrate could block the effects of curcumin. Additionally, transfection of si RNAs targeting HBV enhanced the inhibitory effects of curcumin.CONCLUSION Curcumin inhibits HBV gene replication via downregulation of ccc DNA-bound histone acetylation and has the potential to be developed as a ccc DNA-targeting antiviral agent for hepatitis B.

Dynamic changes of HBV DNA in serum and peripheral blood mononuclear cells of chronic hepatitis patients after lamivudine treatment

AIM： To study the dynamic changes of hepatits B virus （HBV） DNA in serum and peripheral blood mononuclear cells （PBMCs） of patients after lamivudine therapy. METHODS： A total of 72 patients with chronic HBV infection were included in this study. All patients were confirmed to have the following conditions： above 16 years of age, elevated serum alanine amonotransferase （ALT）, positive hepatitis B e antigen （HBeAg）, positive HBV DNA in serum and PBMCs, negative antibodies against HAV, HCV, HDV, HEV. Other possible causes of chronic liver damages, such as drugs, alcohol and autoimmune diseases were excluded. Seventy-two cases were randomly divided into lamivudine treatment group （n = 42） and control group （n = 30）. HBV DNA was detected both in serum and in PBMCs by fluorescence quantitative polymerase chain reaction （PCR）, during and after lamivudine treatment. RESULTS： In the treatment group, HBV DNA became negative both in serum and in PBMC, of, 38 and 25 out of 42 cases respectively during the 48 wk oflamivudine treatment, the negative rate was 90.5% and 59.5% respectively. In the control group, the negative rate was 23.3% and 16.7% respectively. It was statistically significant at 12, 24 and 48 wk as compared with the control group （P 〈 0.005）. The average conversion period of HBV DNA was 6 wk （2-8 wk） in serum and 16 wk （8-24 wk） in PBMC.CONCLUSION： Lamivudine has remarkable effects on HBV replication both in serum and The inhibitory effect on HBV DNA in PBMCs than that in serum inhibitory in PBMCs. is weaker