Phosphorothioate modification improves exon-skipping of antisense oligonucleotides based on sulfonyl phosphoramidates in mdx mouse myotubes

Su, Y., Raguraman, P., Veedu, R.N. and Filichev, V.V. (2022) Phosphorothioate modification improves exon-skipping of antisense oligonucleotides based on sulfonyl phosphoramidates in mdx mouse myotubes. Organic & Biomolecular Chemistry (18).

Abstract

2′-O-Methyl (2′-OMe) antisense oligonucleotides (AOs) possessing a various number of 4-(trimethylammonio)butylsulfonyl or tosyl phosphoramidates (N+ and Ts-modifications, respectively) instead of a native phosphodiester linkage were designed to skip exon-23 in dystrophin pre-mRNA transcript in mdx mice myotubes. AOs bearing several zwitterionic N+ modifications in the sequence had remarkably increased thermal stability towards complementary mRNA in comparison with 2′-OMe-RNAs having negatively charged Ts and phosphorothioate (PS) linkages. However, only Ts-modified AOs exhibited a similar level of exon skipping in comparison with fully modified PS-containing 2′-OMe-RNA, whereas the exon skipping induced by N+ modified AOs was much lower with no exon-skipping detected for AOs having seven N+ modifications. The level of exon-skipping was improved once Ts and especially N+ moieties were used in combination with PS-modification, most likely through improved cellular and nuclear uptake of AOs. These results provide new insights on expanding the design of novel chemically modified AOs based on phosphate modifications.

Item Type:	Journal Article
Murdoch Affiliation(s):	Centre for Molecular Medicine and Innovative Therapeutics (CMMIT)
Publisher:	Royal Society of Chemistry
Copyright:	© 2022 Royal Society of Chemistry
URI:	http://researchrepository.murdoch.edu.au/id/eprint/64669

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