期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：36
DOI：10.1073/pnas.2207956119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Splice-switching antisense oligonucleotides (ASOs) represent a unique class of drug molecules with the US Food and Drug Administration approval of Exondys 51, Vyondys 53, Amondys 45, and Viltepso for the treatment of Duchenne muscular dystrophy (DMD). Phosphorodiamidate morpholino oligomer (PMO) chemistry currently utilized for these drugs has significant limitations. PMOs show rapid kidney clearance and poor cellular uptake that leads to high and costly dosages. Therefore, it is crucial to develop next-generation splice-switching oligonucleotide chemistries with improved efficacy, safety, and biodistribution. The research outlined in this manuscript is highly significant as it demonstrates the impact of “Thiomorpholinos” as a robust and cost-effective splice-switching ASO platform that can be tested for enhanced biological activity and reduced toxicity relative to other chemistries.
Recent advances in drug development have seen numerous successful clinical translations using synthetic antisense oligonucleotides (ASOs). However, major obstacles, such as challenging large-scale production, toxicity, localization of oligonucleotides in specific cellular compartments or tissues, and the high cost of treatment, need to be addressed. Thiomorpholino oligonucleotides (TMOs) are a recently developed novel nucleic acid analog that may potentially address these issues. TMOs are composed of a morpholino nucleoside joined by thiophosphoramidate internucleotide linkages. Unlike phosphorodiamidate morpholino oligomers (PMOs) that are currently used in various splice-switching ASO drugs, TMOs can be synthesized using solid-phase oligonucleotide synthesis methodologies. In this study, we synthesized various TMOs and evaluated their efficacy to induce exon skipping in a Duchenne muscular dystrophy (DMD) in vitro model using
H2K mdx mouse myotubes. Our experiments demonstrated that TMOs can efficiently internalize and induce excellent exon 23 skipping potency compared with a conventional PMO control and other widely used nucleotide analogs, such as 2′-O-methyl and 2′-O-methoxyethyl ASOs. Notably, TMOs performed well at low concentrations (5–20 nM). Therefore, the dosages can be minimized, which may improve the drug safety profile. Based on the present study, we propose that TMOs represent a new, promising class of nucleic acid analogs for future oligonucleotide therapeutic development.
