Novel Disulfide-Bridged Bioresponsive Antisense Oligonucleotide Induces Efficient Splice Modulation in Muscle Myotubes in Vitro

Splice-modulating antisense therapy has shown tremendous potential in therapeutic development in recent years with four FDA-approved antisense drugs since 2016. However, an efficient and nontoxic antisense oligonucleotide (AO) delivery system still remains as a major obstacle in nucleic acid therapeutics field. Vitamin-E (alpha-tocopherol) is an essential dietary requirement for human body. This fat-soluble compound is one of the most important antioxidants which involves in numerous biological pathways. In this study, for the first time, we explored the scope of using alpha-tocopherol-conjugated bioresponsive AOs to induce splice modulation in mouse muscle myotubes in vitro. Our results showed that the bioresponsive construct efficiently internalized into the cell nucleus and induced exon 23 skipping in mdx mouse myotubes. Based on our exciting new results, we firmly believe that our findings could potentially benefit toward establishing a delivery approach to advance the field of splice-modulating AO therapy.