RNAi as a new therapeutic strategy against HCV

Khaliq, Saba; Khaliq, Sadaf A.; Zahur, Muzna; Ijaz, Bushra; Saleem, Sidrah; Ansar, Muhammad; Riazuddin, Sheikh; Hassan, Sajida

doi:10.1016/j.biotechadv.2009.08.004

Cited by 33 publications

(27 citation statements)

References 104 publications

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“…This has prompted international efforts to develop A number of direct-acting antivirals (DAA) targeting HCVencoding regulatory proteins show the rapid appearance of drugresistant viruses (6). Since the HCV genome is present exclusively in RNA form during replication, various RNA-based therapeutics targeting the HCV genome have been suggested as tools against HCV (37,38). However, the rapid emergence of HCV escape variants also could limit such HCV genome-targeting RNA approaches.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Hepatitis C Virus (HCV) Replication by Specific RNA Aptamers against HCV NS5B RNA Replicase

Lee

Kim

et al. 2013

J Virol

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This study identified specific and avid RNA aptamers consisting of 2=-hydroxyl-or 2=-fluoropyrimidines against hepatitis C virus (HCV) NS5B replicase, an enzyme that is essential for HCV replication. These aptamers acted as potent decoys to competitively impede replicase-catalyzed RNA synthesis activity. Cytoplasmic expression of the 2=-hydroxyl aptamer efficiently inhibited HCV replicon replication in human liver cells through specific interaction with, and sequestration of, the target protein without either off-target effects or escape mutant generation. A selected 2=-fluoro aptamer could be truncated to a chemically manufacturable length of 29 nucleotides (nt), with increase in the affinity to HCV NS5B. Noticeably, transfection of the truncated aptamer efficiently suppressed HCV replication in cells without escape mutant appearance. The aptamer was further modified through conjugation of a cholesterol or galactose-polyethylene glycol ligand for in vivo availability and liver-specific delivery. The conjugated aptamer efficiently entered cells and inhibited genotype 1b subgenomic and genotype 2a full-length HCV JFH-1 RNA replication without toxicity and innate immunity induction. Importantly, a therapeutically feasible amount of the conjugated aptamer was delivered in vivo to liver tissue in mice. Therefore, cytoplasmic expression of 2=-hydroxyl aptamer or direct administration of chemically synthesized and ligand-conjugated 2=-fluoro aptamer against HCV NS5B could be a potent anti-HCV approach. Hepatitis C virus (HCV) is the main causative agent of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (1, 2). Although HCV infection causes worldwide health problems, efficient and specific antiviral therapy has not yet been developed.HCV belongs to the genus Hepacivirus in the family Flaviviridae. The enveloped virus contains a single, positive-stranded RNA genome about 9.6 kb in length encoding a single polyprotein of about 3,010 amino acids (3). This polyprotein precursor is co-or posttranslationally processed by cellular and viral proteases to yield functional structural and nonstructural proteins (4). The structural proteins include the core protein, C, and the envelope glycoproteins E1 and E2. The nonstructural (NS) proteins comprise the protease NS2, the multifunctional protein NS3 consisting of serine protease and helicase, the serine protease cofactor NS4A, the proteins NS4B and NS5A, and the RNA-dependent RNA polymerase NS5B, which are components of a complex responsible for HCV replication (5). NS5B is the central catalytic enzyme in HCV RNA replication. A number of drugs targeting HCV NS5B replicase are under development. However, the rapid appearance of drug-resistant escape mutant viruses has been reported (6).RNA aptamers are small structured single-stranded RNAs which have emerged as attractive and feasible alternatives to small-molecule and antibody-based therapy. Aptamers can be evolved by systematic evolution of ligands by exponential enrichment (SELEX), an iterative selection method...

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Section: Discussionmentioning

confidence: 99%

Inhibition of Hepatitis C Virus (HCV) Replication by Specific RNA Aptamers against HCV NS5B RNA Replicase

Lee

Kim

et al. 2013

J Virol

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“…Many other groups also reported that siRNAs or small hairpin RNAs (shRNAs) targeting against HCV protein-coding regions including NS3 or NS5B as well as conserved HCV 5 0 -NCR can specifically inhibit replication of the HCV replicon and gene expression (reviewed in Khaliq et al 2010). However, most of studies did not perform 5 0 -RACE PCR analysis to verify specific intracellular RNAi activity by the siRNAs.…”

Section: Specific Cleavage Of Hcv Genomic Rna By Synthetic Sirnasmentioning

confidence: 95%

“…Therefore, RNA-based antiviral therapeutic strategies including trans-cleavage ribozyme, trans-splicing ribozyme, antisense RNA, or small interfering RNA (siRNA) have been recently proposed against HCV replication (Hugle and Cerny 2003;Ryu et al 2003;Khaliq et al 2010). Among the possible therapeutic strategies, RNA interference (RNAi) is an attractive antiviral method due to its highly specific and efficient gene silencing activity.…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of intracellular inhibition of hepatitis C virus replication by small interfering RNAs

Chang

Lee

et al. 2010

Biotechnol Lett

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Several synthetic siRNAs were designed to target various regions of hepatitis C virus (HCV) replicon RNA. The antiviral efficacies of the siRNAs were compared using real time PCR and western blot assessment. siRNAs targeting either specific coding region of HCV NS3 or NS5B were the most efficacious in terms of gene silencing and inhibitory activity of the HCV replicon replication. There was no activation of genes involved in innate immune response by the HCV-specific siRNA, indicating that HCV replication inhibition was not due to non-specific antiviral response. Moreover, 5'-RACE PCR analysis showed that the silencing effect by the siRNAs was mainly caused by specific cleavage of targeted HCV genomic RNA. These findings suggest that RNAi targeting HCV coding regions could provide a useful approach to anti-HCV treatment.

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“…However, design and selection of siRNAs targeting conserved regions of virus and combination of siRNAs targeting multiple genes or regions in viral genome can help avoid problem of resistance to siRNA therapy (Khaliq et al 2010). In a study using a T cell line expressing three potent shRNAs against HIV-1, it was found that even after an extended culturing for more than 100 days there was no viral replication (von Eije et al 2009).…”

Section: Viral Escapementioning

confidence: 99%

Rna Interference as Antiviral Therapy: Dream or Reality?

Nizamani¹,

Holz²,

Keita³

et al. 2013

VR&R

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Soon aft er discovery of RNA interference (RNAi), its potential as eff ective antiviral therapy was recognized. Since then RNAi has been variously exploited for antiviral purposes which could eff ectively block viral replication in vitro. For in vivo use, however, delivery issue, toxicity, RNAi suppression and viral escape are still major hurdles. Here, we provide an overview of the RNAi strategy and review the approaches that have been developed to surpass the obstacles and to achieve targeted gene silencing for antiviral and other therapies.

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RNAi as a new therapeutic strategy against HCV

Cited by 33 publications

References 104 publications

Inhibition of Hepatitis C Virus (HCV) Replication by Specific RNA Aptamers against HCV NS5B RNA Replicase

Inhibition of Hepatitis C Virus (HCV) Replication by Specific RNA Aptamers against HCV NS5B RNA Replicase

Comparative analysis of intracellular inhibition of hepatitis C virus replication by small interfering RNAs

Rna Interference as Antiviral Therapy: Dream or Reality?

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