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Genomic analysis of anti-hepatitis B virus (HBV) activity by small interfering RNA and lamivudine in stable HBV-producing cells.

ABSTRACT: Hepatitis B virus (HBV) causes acute and chronic hepatitis and hepatocellular carcinoma. Small interfering RNA (siRNA) and lamivudine have been shown to have anti-HBV effects through different mechanisms. However, assessment of the genome-wide effects of siRNA and lamivudine on HBV-producing cell lines has not been reported, which may provide a clue to interrogate the HBV-cell interaction and to evaluate the siRNA's side effect as a potential drug. In the present study, we designed seven siRNAs based on the conserved HBV sequences and tested their effects on the expression of HBV genes following sorting of siRNA-positive cells. Among these seven siRNAs, siRNA-1 and siRNA-7 were found to effectively suppress HBV gene expression. We further addressed the global gene expression changes in stable HBV-producing cells induced by siRNA-1 and siRNA-7 by use of human genome-wide oligonucleotide microarrays. Data from the gene expression profiling indicated that siRNA-1 and siRNA-7 altered the expression of 54 and 499 genes, respectively, in HepG2.2.15 cells, which revealed that different siRNAs had various patterns of gene expression profiles and suggested a complicated influence of siRNAs on host cells. We further observed that 18 of these genes were suppressed by both siRNA-1 and siRNA-7. Interestingly, seven of these genes were originally activated by HBV, which suggested that these seven genes might be involved in the HBV-host cell interaction. Finally, we have compared the effects of siRNA and lamivudine on HBV and host cells, which revealed that siRNA is more effective at inhibiting HBV expression at the mRNA and protein level in vitro, and the gene expression profile of HepG2.2.15 cells treated by lamivudine is totally different from that seen with siRNA.

SUBMITTER: Guo Y

PROVIDER: S-EPMC1280207 | biostudies-literature | 2005 Nov

REPOSITORIES: biostudies-literature

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Genomic analysis of anti-hepatitis B virus (HBV) activity by small interfering RNA and lamivudine in stable HBV-producing cells.

Guo Yong Y Guo Hongyan H Zhang Liang L Xie Hongying H Zhao Xin X Wang Fangxun F Li Ze Z Wang Yahui Y Ma Shiliang S Tao Jiaping J Wang Weixing W Zhou Yuxiang Y Yang Weiping W Cheng Jing J

Journal of virology 20051101 22

Hepatitis B virus (HBV) causes acute and chronic hepatitis and hepatocellular carcinoma. Small interfering RNA (siRNA) and lamivudine have been shown to have anti-HBV effects through different mechanisms. However, assessment of the genome-wide effects of siRNA and lamivudine on HBV-producing cell lines has not been reported, which may provide a clue to interrogate the HBV-cell interaction and to evaluate the siRNA's side effect as a potential drug. In the present study, we designed seven siRNAs ...[more]

PMID: 16254373

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Project description:BackgroundApproximately 4 million of people are co-infected with HIV and Hepatitis B virus (HBV). In resource-limited settings, the majority of HIV-infected patients initiate first-line highly active antiretroviral therapy containing lamivudine (3TC-containing-HAART) and long-term virological response of HBV to lamivudine-containing HAART in co-infected patients is not well known.Methodology/principal findingHIV-HBV co-infected patients enrolled in the PHPT cohort (ClinicalTrials.gov NCT00433030) and initiating a 3TC-containing-HAART regimen were included. HBV-DNA, HIV-RNA, CD4+ T-cell counts and alanine transaminase were measured at baseline, 3 months, 12 months and then every 6 months up to 5 years. Kaplan-Meier analysis was used to estimate the cumulative rates of patients who achieved and maintained HBV-DNA suppression. Of 30 co-infected patients, 19 were positive for HBe antigen (HBeAg). At initiation of 3TC-containing-HAART, median HBV DNA and HIV RNA levels were 7.35 log(10) IU/mL and 4.47 log(10) copies/mL, respectively. At 12 months, 67% of patients achieved HBV DNA suppression: 100% of HBeAg-negative patients and 47% of HBeAg-positive. Seventy-three percent of patients had HIV RNA below 50 copies/mL. The cumulative rates of maintained HBV-DNA suppression among the 23 patients who achieved HBV-DNA suppression were 91%, 87%, and 80% at 1, 2, and 4 years respectively. Of 17 patients who maintained HBV-DNA suppression while still on 3TC, 4 (24%) lost HBsAg and 7 of 8 (88%) HBeAg-positive patients lost HBeAg at their last visit (median duration, 59 months). HBV breakthrough was observed only in HBeAg-positive patients and 6 of 7 patients presenting HBV breakthrough had the rtM204I/V mutations associated with 3TC resistance along with rtL180M and/or rtV173L.ConclusionsAll HBeAg-negative patients and 63% of HBeAg-positive HIV-HBV co-infected patients achieved long-term HBV DNA suppression while on 3TC-containing-HAART. This study provides information useful for the management of co-infected patients in resource-limited countries where the vast majority of co-infected patients are currently receiving 3TC.

Project description:Viruses are considered to use vesicular trafficking in infected cells, but the details of assembly/release pathways of hepatitis B virus (HBV) are still unknown. To identify key regulators of HBV production, we performed short interfering RNA (siRNA) screening for Rab proteins, which are considered to act as molecular switches in vesicular trafficking using HepG2.2.15 cells. Among 62 Rab proteins, the suppression of Rab5B most significantly increased HBV DNA in the culture supernatant. Surprisingly, 5 days after the transfection of Rab5B siRNA, HBV DNA in the supernatant was increased more than 30-fold, reflecting the increase of infectious HBV particles. Northern blotting showed that transcription of 2.4/2.1-kb mRNA coding envelope proteins containing large hepatitis B surface protein (LHBs) was increased. Analysis of hepatocyte nuclear factors (HNFs) showed that transcription of HNF4α, which is known to enhance 2.4-kb mRNA transcription, was regulated by Rab5B. Also, it was revealed that LHBs had accumulated in the endoplasmic reticulum (ER) after Rab5B depletion but not in the multivesicular body (MVB), which is thought to be an organelle utilized for HBV envelope formation. Therefore, it was considered that Rab5B is required for the transport of LHBs from the ER to MVB. Immunofluorescent microscopy showed that HBs proteins, including LHBs, colocalized with HBc in the ER of Rab5B-depleted cells, suggesting that HBV envelopment occurs not only in the MVB but also in the ER. In conclusion, Rab5B is a key regulator of HBV production and could be a target of antiviral therapy.IMPORTANCE HBV infection is a worldwide health problem, but the mechanisms of how HBV utilizes cellular machinery for its life cycle are poorly understood. In particular, it has been unclear how the viral components and virions are transported among the organelles. The HBV budding site has been reported to be the ER or MVB, but it has not been clearly determined. In this study, siRNA-based screening of Rab proteins using HBV-expressing cells showed that Rab5B, one of the Rab5 isoforms, has important roles in late steps of the HBV life cycle. Although Rab5 is known to work on early endosomes, this study showed that Rab5B plays a role in the transport of LHBs between the ER and MVB. Furthermore, it affects the transcription of LHBs. This is the first report on the mechanisms of HBV envelope protein transport among the organelles, and the results provide important insights into the therapeutic control of HBV infection.

Dataset Information

Genomic analysis of anti-hepatitis B virus (HBV) activity by small interfering RNA and lamivudine in stable HBV-producing cells.

Publications

Genomic analysis of anti-hepatitis B virus (HBV) activity by small interfering RNA and lamivudine in stable HBV-producing cells.

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