Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Perth, WA 6150, Australia.
Perron Institute for Neurological and Translational Science, Nedlands, Perth, WA 6009, Australia.
Proc Natl Acad Sci U S A. 2022 Sep 6;119(36):e2207956119. doi: 10.1073/pnas.2207956119. Epub 2022 Aug 29.
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 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.
近年来，药物开发取得了许多进展，成功地将合成反义寡核苷酸 (ASO) 转化为临床应用。然而，仍存在一些重大障碍需要解决，例如大规模生产的挑战、寡核苷酸的毒性、在特定细胞区室或组织中的定位以及治疗的高成本等问题。硫代吗啉寡核苷酸 (TMO) 是一种最近开发的新型核酸类似物，可能有助于解决这些问题。TMO 由连接硫代磷酸酰胺键的吗啉核苷组成。与目前用于各种剪接转换 ASO 药物的磷酰二胺吗啉寡聚物 (PMO) 不同，TMO 可以使用固相寡核苷酸合成方法合成。在这项研究中，我们合成了各种 TMO，并在体外使用小鼠肌管评估它们在杜氏肌营养不良症 (DMD) 模型中诱导外显子跳跃的效果。我们的实验表明，与常规 PMO 对照和其他广泛使用的核苷酸类似物（如 2'-O-甲基和 2'-O-甲氧基乙基 ASO）相比，TMO 可以有效地内化并诱导出色的外显子 23 跳跃活性。值得注意的是，TMO 在低浓度（5-20 nM）下效果良好。因此，可以最小化剂量，从而提高药物安全性。基于本研究，我们提出 TMO 代表了一类新的有前途的核酸类似物，可用于未来的寡核苷酸治疗开发。
