A Potent and Specific Morpholino Antisense Inhibitor of Hepatitis C Translation in Mice

Abstract

C ap-independent translation of the hepatitis C virus (HCV) polyprotein initiates at a highly structured internal ribosome entry site (IRES) at the 5Ј end of the genomic RNA. The conserved HCV IRES is a likely target for effective therapeutic intervention. Extensive effort has been devoted to the development of antisense oligonucleotide, 1-7 ribozyme, [8][9][10] and DNA ribonuclease 11 inhibitors targeting HCV IRES sequences that are accessible for nucleic acid hybridization.Although in vitro assays have been invaluable in the early evaluation of inhibitors, work by our group 12 and that of others 13,14 suggests that cell-free systems may not faithfully recapitulate translation from the HCV IRES. A recent report that HCV IRES translation varies with cell cycling 15 also raises concern that rapidly dividing cells in tissue culture may not accurately model the normally quiescent human liver. Therefore, model systems that allow evaluation of pharmacokinetic parameters such as inhibitor bioavailability, toxicity, and systemic clearance in the complex milieu of a mammalian organism would be useful. Preclinical small animal models for testing nucleic acid inhibitors of HCV will help move candidate inhibitors into the clinic. Recently, a mouse xenotransplantation model was reported that supports HCV viral replication in transplanted human liver cells. 16 Although very exciting, this system requires access to fresh human liver tissue. A vaccinia virus expressing a HCV IRES luciferase fusion also has been used as a model system for evaluating antisense inhibitors in vivo. 4 In this model, a phosphorothioate and a 5-methylcytidine antisense oligonucleotide moderately reduced expression from the HCV IRES (ϳ50% and 80%). However, nonspecific effects

Inhibitory Effect of Antisense Oligonucleotide Targeting TIMP-2 on Immune-Induced Liver Fibrosis

“…Antisense DNA acts at a different step in gene expression by blocking translational initiation. Therefore, it has been described that if a sufficient amount of ASON can be delivered to the appropriate subcellular compartment, antisense inhibition of gene expression can be as potent as RNAi [28][29][30]. In addition, in the current study, we used HSA to induce liver fibrosis, the mechanism of which is similar to liver fibrosis caused by HBV or HCV.…”

A chimeric GB virus B with 5′ nontranslated RNA sequence from hepatitis C virus causes hepatitis in tamarins†

“…This HCV sequence is highly conserved among different HCV strains, and has been a favorite target for development of candidate antisense oligonucleotide or small interfering RNA (siRNA) therapeutics. 39,40 This chimeric virus makes possible the evaluation of such candidate therapeutics in cultured hepatocytes supporting a complete viral life cycle, and in a primate model of hepatitis C that does not involve use of an endangered animal species. The viability of this chimera also suggests the feasibility of constructing additional chimeric viruses involving exchanges of other regions of the genomes of GBV-B and HCV.…”

Transient Expression of Proteins by Hydrodynamic Gene Delivery in Mice

“…In addition, since the DNA molecules delivered by HGD do not need packaging, this method is suitable for the delivery of bacterial artificial chromosomes (BAC) as large as 150 kb 4 . Other types of molecules that have been delivered by a hydrodynamic method include RNA [5][6][7][8][9][10] , morpholinos 11 , proteins 12,13 and other small molecules 12,14 . The advantages and disadvantages of HGD over other delivery methods have been discussed in excellent reviews in the literature [15][16][17][18][19][20] and a number of authors have provided a detailed description of the procedure [21][22][23] .…”