Targeted correction of point mutations in the low density lipoprotein receptor gene mediated by single-stranded oligonucleotides in vivo

This study was designed to investigate the repair of point mutations in the low density lipoprotein receptor (LDLR) gene mediated by single-stranded oligonucleotides (SSOs) in vivo. Mutations in the LDLR gene are known to be the prime cause of familial hypercholesterolemia (FH). SSOs result in sequence-specific alterations leading to the correction of mutations. In the present study, the LDLR gene with a nonsense mutation (c660x) was fused to a luciferase reporter gene (p660-LDLR-luc) and introduced into mouse liver by hydrodynamic gene transfer. These mice were then injected via the tail vein with different SSOs complexed with polyethylenimine. Firefly luciferase activity present in hepatic cell lysate was measured to analyze repair efficiency. Restriction fragment length polymorphism analysis and direct sequencing were performed to affirm that the LDLR mutation was corrected. The results indicate that the LDLR mutation was corrected in the liver in vivo only in the presence of antisense SSOs (anti-SSOs). Our findings provide initial evidence that the point mutation in p660-LDLR-luc can be corrected by anti-SSO targeted repair in vivo. This may be a potential strategy for the treatment of FH.