Cholesterol Conjugation Strategies to Enhance In Vivo Antisense Oligonucleotide-Mediated Exon Skipping in the Mouse Retina.

PURPOSE: Antisense oligonucleotide (AON)-mediated exon skipping is a potential therapeutic approach to certain inherited retinal diseases, including Usher's Syndrome Type 2 A. Heteroduplex AONs (HAONs) have been reported to enhance RNA-modulating activity in vivo; this study evaluated whether the HAON strategy improves Ush2a exon skipping activity in the mouse retina.

METHODS

AONs of different chemical makeup targeting Ush2a exon 12 were formulated as HAONs with and without lipid conjugation. Activity was evaluated in 2D and 3D cell models and in the mouse eye following intravitreal administration.

RESULTS

Lipid conjugation was required to increase activity in the mouse retina. However, exon-skipping effects observed for cholesterol (Chol)-conjugated HAONs in vivo were not reflected in cell models. A single dose of HAONs bearing a Chol on either strand or the Chol-AON conjugate produced up to a 4.6-fold increase in Ush2a exon 12 skipping in mouse retina over AON alone, with effects lasting at least 28 days without major tolerability findings.

CONCLUSION

Chol conjugation-either to a HAON construct or directly to the AON-can substantially enhance the potency of retina-targeted exon-skipping AON therapies in vivo.