Short interfering RNA‐directed inhibition of hepatitis B virus replication

Hamasaki, Koji; Nakao, Kazuwa; Matsumoto, Kojiro; Ichikawa, Tatsuki; Ishikawa, Hiroki; Eguchi, Katsumi

doi:10.1016/s0014-5793(03)00400-9

Cited by 134 publications

(82 citation statements)

References 21 publications

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“…ported. [35][36][37] We have shown here that siRNA targeted against a specific sequence in the HBV genome can inhibit HBV replication, resulting in decreased amounts of HBV protein in cells and medium using a stable HBV-producing cell line. The HepG2 2.2.15 system was selected as a model because the production of virus is constitutive, and levels of RNA and antigens are stable.…”

Section: Discussionmentioning

confidence: 91%

Inhibition of HBV replication by siRNA in a stable HBV-producing cell line

Konishi

2003

Hepatology

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Potent inhibition of endogenous gene expression by RNA interference has been achieved by using sequence-specific posttranscriptional gene silencing through the action of small interfering RNA molecules (siRNA). In these reports, the natural function of genes could be deduced through the ensuing loss of function. Based on the extraordinary effectiveness in silencing endogenous genes, we wondered whether siRNA could be applied against viral replication in a hepatitis B virus (HBV) model using HBV-specific siRNA. To test this idea, HepG2 2.2.15, a human hepatoblastoma cell line that constitutively produces infectious HBV particles, was transfected with HBV-specific siRNh and controls. HBV surface antigen (HBsAg) secretion into culture media was inhibited by 78%, 67%, and 42% with siRNA against the polyadenylation (PA), precore (PreC), and surface (S) regions, respectively, compared with controls as detected by enzyme-linked immunosorbent assay. After exposure to HBVPA siRNA, Northern blot analysis showed that HBV pregenomic RNA levels were decreased by 72%, and levels of HBV RNA containing the polyadenylation signal sequence were suppressed by 86%, as detected by RNase protection assay. Levels of HBV coreassociated DNA, a replication intermediate, also decreased by 71 %. Immunocytochemistry revealed that 30% to 40% of the cells transfected with HBVPA siRNA were completely negative for detectable HBsAg levels. Controls consisting of treatment with HBV-specific siRNA alone, lipofection reagent alone, or random double-stranded RNA (dsRNA) lipofection complex failed to decrease HBV surface antigen, HBV messenger RNA (mRNA), or core-associated HBV-DNA levels. In conclusion, siRNA inhibits hepatitis B viral replication in a cell culture system. Future studies are needed to explore the specific delivery of siRNA to liver cells in vivo and the applicability of this approach. ( Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030-1845. E-mail: wu@nso.uchc.edu; f u : 860-679-3159

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Section: Discussionmentioning

confidence: 91%

Inhibition of HBV replication by siRNA in a stable HBV-producing cell line

Konishi

2003

Hepatology

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“…Knock-down of HBx expression by si-or sh-RNA methods has been reported to down-regulate HBV transcription and replication. (67)(68)(69) Down-regulation of HBx might reduce HBV gene expression and replication and might also reduce the ability to overcome OIS. It is natural to expect that HBV replication and tumorigenic incidence would be reduced or prevented by the knock-down of HBx or by specific inhibitors of HBx.…”

Section: Resultsmentioning

confidence: 99%

Molecular functions and biological roles of hepatitis B virus x protein

Tang¹,

Oishi²,

Kaneko³

et al. 2006

Cancer Science

266

244

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Chronic infection of hepatitis B virus (HBV) isH epatitis B virus (HBV) infection is a worldwide health problem and is one of the major causes of hepatocellular carcinoma (HCC) in the world. However, new incidences of HBV infection have been dramatically reduced by several prevention programs. The crucial role of HBV in hepatocarcinogenesis is beyond doubt, however, the mechanism by which HBV causes transformation of hepatocytes remains uncertain.(1-3) Hepatitis B virus X protein (HBx) has long been suspected to play a positive role in hepatocarcinogenesis because HCC incidence has been reported in animals infected with mammalian hepadnaviruses. Among these hepadnaviruses, open reading frame-X (X-ORF) is conserved in the genomes. However, hepatocarcinogenesis has not been found in avian infected with avian hepadnaviruses where X-ORF is absent. In addition to the putative contribution of HBx, other oncogenic mechanisms of the HBV-related hepatocarcinogenesis have also been proposed, such as the integration-dependent scenario of HBV DNA in host genomes, (4) and the inflammation-dependent scenario.(5) Since no higher incidence of HCC has been reported in HBV-expressing transgenic mice, (6) host immunological responses to HBV infection (but not HBV proliferation by itself ) might be primarily contributing to the HBV-related hepatocarcinogenesis. HBx, a small protein of 154 amino acids, is a multifunctional regulator that modulates a variety of host processes through directly or indirectly interacting with virus and host factors. (2,3) In this short review, we briefly summarize the life cycle of HBV, expression of HBx, and the molecular functions of HBx. We then focus on the recent progress on the biological roles of HBx in HBV replication and cellular transformation. Expression and functions of HBx. HBV is a prototype of Hepadnaviridae, hepatotropic small DNA viruses, of which hosts are among limited species of water birds, squirrels and primates. The HBV genome is a 3.2-kb circular, partially double-stranded DNA molecule with four overlapping ORFs, PC-C, PS-S, P, and X-ORFs (Fig. 1). (7) Once HBV infection of hepatocytes occurs, its genome is converted to covalently closed circular (CCC) DNA, which serves as the template for transcription by the host RNA polymerase II, generating the 3.5-, 2.4-, 2.1-, and 0.7-kb transcripts under control of four HBV promoters (Cp, PS1p, Sp, and Xp), respectively (Fig. 1). Two HBV enhancers (Enh I and Enh II) positively regulate transcription of the HBV promoters in combination with the transcription factors that bind these promoters.(7-9) HBV replicates by reverse transcription of the viral pregenomic 3.5-kb RNA (pgRNA) using the HBV polymerase that catalyzes RNA-dependent DNA synthesis and DNA-dependent DNA synthesis. (7,10) The reverse transcription of hepadnaviruses is unique among DNA viruses, and the primer of the reverse transcription is a tyrosine residue of an N-terminal domain of Pol that is distinct from reverse transcription of retroviruses. (10)

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“…Hence, there is a need for alternative ways to treat this persistent infection. RNA interference (RNAi) has rapidly emerged as a technology for regulating mammalian gene expression because it provides a means of sequence-directed degradation of specific RNAs (1)(2)(3)(4)(5)(6)(7)(8). In the case of HBV, published in vivo hydrodynamic transfection studies have shown that simultaneous delivery of HBV expression plasmids and HBV-specific small interfering RNAs (siRNAs) (or siRNA-expressing constructs) to the mouse liver can prevent the induction of HBV gene expression and replication (9)(10)(11).…”

mentioning

confidence: 99%

Clearance of hepatitis B virus from the liver of transgenic mice by short hairpin RNAs

Uprichard

Boyd

Althage

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

185

135

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Hepatitis B virus (HBV) causes acute and chronic hepatitis and hepatocellular carcinoma. Although a preventive vaccine is available, the therapeutic options for chronically infected patients are limited. It has been shown that RNA interference can prevent HBV gene expression and replication in vivo when HBV expression vectors are delivered simultaneously with small interfering RNA (siRNA) or siRNA expression constructs. However, the therapeutic potential of siRNAs to interrupt ongoing HBV replication in vivo has not been established. Here, we show that expression of HBVspecific siRNAs in the liver of HBV transgenic mice by recombinant adenoviruses can suppress preexisting HBV gene expression and replication to almost undetectable levels for at least 26 days. These results demonstrate that efficiently delivered siRNAs should be able to silence HBV in chronically infected patients.adenovirus vector ͉ RNA interference C hronic hepatitis B virus (HBV) infection causes Ͼ1 million deaths each year due to cirrhosis of the liver and hepatocellular carcinoma (www.cdc.gov͞hepatitis and www.who.int͞ mediacentre͞factsheets͞fs204͞en). Hence, there is a need for alternative ways to treat this persistent infection. RNA interference (RNAi) has rapidly emerged as a technology for regulating mammalian gene expression because it provides a means of sequence-directed degradation of specific RNAs (1-8). In the case of HBV, published in vivo hydrodynamic transfection studies have shown that simultaneous delivery of HBV expression plasmids and HBV-specific small interfering RNAs (siRNAs) (or siRNA-expressing constructs) to the mouse liver can prevent the induction of HBV gene expression and replication (9-11). To expand on those studies, we have examined the therapeutic potential of RNAi for the treatment of chronic HBV infection where ongoing viral gene expression and replication are established in the liver before siRNA delivery.Several variables that have not been previously addressed could affect the utility of RNAi for the treatment of an ongoing HBV infection. First, in the context of an established infection, viral RNAs may be protected within complexes or nucleocapsid structures as has been reported for hepatitis D virus (1), Rous sarcoma virus (12), and respiratory syncytial virus (RSV) (13). This is particularly relevant to HBV, which replicates in capsids after encapsidation of the viral pregenomic RNA. A second variable is how efficiently preexisting viral RNA can be reduced and to what extent RNA suppression can block viral DNA replication. Finally, established viral gene expression may allow for the induction of viral RNAi-defense mechanisms as reported for plant viruses (14) and flockhouse nodavirus (15).It has been shown that RNAi is capable of reducing mammalian gene expression in vivo. Genes such as fas (16), caspase-8 (17), agouti-related peptide (18), tyrosine hydroxylase (19), and ras (20, 21) have been targeted for degradation in mice, and corresponding changes in phenotype were observed. Yet, the actual degree o...

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Short interfering RNA‐directed inhibition of hepatitis B virus replication

Cited by 134 publications

References 21 publications

Inhibition of HBV replication by siRNA in a stable HBV-producing cell line

Inhibition of HBV replication by siRNA in a stable HBV-producing cell line

Molecular functions and biological roles of hepatitis B virus x protein

Clearance of hepatitis B virus from the liver of transgenic mice by short hairpin RNAs

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