Minimal-length Synthetic shRNAs Formulated with Lipid Nanoparticles are Potent Inhibitors of Hepatitis C Virus IRES-linked Gene Expression in Mice

• Main Authors: Anne Dallas (Author), Heini Ilves (Author), Joshua Shorenstein (Author), Adam Judge (Author), Ryan Spitler (Author), Christopher Contag (Author), Suet Ping Wong (Author), Richard P Harbottle (Author), Ian MacLachlan (Author), Brian H Johnston (Author)
• Format: Book
• Published: Elsevier, 2013-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 2162-2531; 10.1038/mtna.2013.50
• Keywords: HCV; lipid nanoparticles; PK; RNAi; shRNA; sshRNA; Therapeutics. Pharmacology; RM1-950
• Source: Molecular Therapy: Nucleic Acids, Vol 2, Iss C (2013)

We previously identified short synthetic shRNAs (sshRNAs) that target a conserved hepatitis C virus (HCV) sequence within the internal ribosome entry site (IRES) of HCV and potently inhibit HCV IRES-linked gene expression. To assess in vivo liver delivery and activity, the HCV-directed sshRNA, SG220 was formulated into lipid nanoparticles (LNP) and injected i.v. into mice whose livers supported stable HCV IRES-luciferase expression from a liver-specific promoter. After a single injection, RNase protection assays for the sshRNA and 3H labeling of a lipid component of the nanoparticles showed efficient liver uptake of both components and long-lasting survival of a significant fraction of the sshRNA in the liver. In vivo imaging showed a dose-dependent inhibition of luciferase expression (>90% 1 day after injection of 2.5 mg/kg sshRNA) with t1/2 for recovery of about 3 weeks. These results demonstrate the ability of moderate levels of i.v.-injected, LNP-formulated sshRNAs to be taken up by liver hepatocytes at a level sufficient to substantially suppress gene expression. Suppression is rapid and durable, suggesting that sshRNAs may have promise as therapeutic agents for liver indications.