Antiviral activity of chemical compound isolated from Artemisia morrisonensis against hepatitis B virus in vitro. Antiviral Res. 2014;101:97-104. [PMID: 24269476 DOI: 10.1016/j.antiviral.2013.11.007]

The compound p-hydroxyacetophenone (PHAP) isolated from Artemisia morrisonensis was found to have potential anti-HBV effects in HepG2 2.2.15 cells. We clarified its antiviral mode further and HBV-transfected Huh7 cells were used as the platform. During viral gene expression, treatment with PHAP had no apparent effects on the viral precore/pregenomic RNA. However, the 2.4-kb preS RNA of viral surface gene increased significantly relative to the 2.1-kb S RNA with PHAP. Promoter activity analysis demonstrated that PHAP had a potent effect on augmenting the viral preS promoter activity. The subsequent increase in the large surface protein and induce endoplasmic reticular (ER) stress has been reported previously. Interestingly, PHAP specifically reduced ER stress related GRP78 RNA/protein levels, but not those of GRP94, in treated Huh7 cells while PHAP also led to the significant intracellular accumulation of virus. Moreover, treatment with the ER chaperone inducer thapsigargin relieved the inhibitory effect of PHAP based on the supernatant HBV DNA levels of HBV-expressed cells. In conclusion, this study suggests that the mechanism of HBV inhibition by PHAP might involve the regulation of viral surface gene expression and block virion secretion by interference with the ER stress signaling pathway.

Antiviral effects of locked nucleic acid antisense oligonucleotides targeting HBV S gene mRNA in HepG2 2.2.15 cells

AIM: To investigate the inhibitory effects of locked nucleic acid (LNA) antisense oligonucleotides targeting hepatitis B virus (HBV) S gene in HepG2 2.2.15 cells, and screen effective LNA antisense oligonucleotides.

METHODS: Four LNA antisense oligonucleotides of different lengths that are complementary to the translation initiation region of HBV S gene were designed, synthesized, and introduced into HepG2 2.2.15 cells by cationic liposome-mediated transfection. Hepatitis B surface antigen (HBsAg) and HBV DNA levels in cell supernatant were tested by enzyme-linked immunosorbent assay (ELISA) and fluorescent quantitative-polymerase chain reaction (FQ-PCR) 24, 48 and 72 h after transfection. The cell toxicity of LNA antisense oligonucleotides was detected by methyl thiazolyl tetrazolium (MTT) assay.

RESULTS: All four LNA antisense oligonucleotides (10, 15, 20 and 25 base, respectively) could inhibit the expression of HBsAg and the replication of HBV DNA. Seventy-two hours after transfection, the reduced rates of HBsAg and HBV DNA levels were 46.58%, 54.38%, 72.43% and 69.92% as well as 27.09%, 28.77%, 34.71% and 32.68%, respectively. No obvious cell toxicity of LNA antisense oligonucleotides was noted.

CONCLUSION: LNA antisense oligonucleotides targeting HBV S gene show strong inhibitory effects on HBV replication in vitro. The optimal length of LNA antisense oligonucleotides ranges from 15 to 25 base. LNA antisense oligonucleotides targeting HBV S gene have a therapeutic potential in patients infected with HBV.