Antisense oligonucleotide modified with serinol nucleic acid (SNA) induces exon skipping in mdx myotubes

Serinol nucleic acid (SNA) is a novel nucleic acid analogue that can form highly stable heteroduplexes with complementary DNA and RNA sequences. Structurally, SNA is a close mimic to peptide nucleic acid (PNA) which is widely used in diagnostic and therapeutic applications. SNA chemistry is relatively new, and so far the scope of SNA has only been explored in improving the efficacy of small interfering RNA and for developing a highly sensitive molecular beacon for diagnostic applications. In this study, we investigated the potential of SNA-modified antisense oligonucleotide (AO) in parallel to PNA-oligo for splice-modulation in an in vitro cellular model of Duchenne muscular dystrophy (DMD). We synthesized a 20-mer SNA and PNA antisense oligonucleotide (AO) designed to induce exon-23 skipping in the mouse dystrophin gene transcript. Our results demonstrated that the SNA AO induced exon-23 skipping at all tested concentrations, whereas the corresponding PNA AO failed to induce any exon-23 skipping upon 24 hours of transfection using Lipofectin transfection reagent. Our results further expands the potential of SNA oligonucleotides in therapeutic applications.