Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.
Bioorg Med Chem. 2022 Oct 15;72:116972. doi: 10.1016/j.bmc.2022.116972. Epub 2022 Aug 25.
The artificial nucleobase 1,3-diaza-2-oxophenoxazine (tC) and its derivative G-clamp strongly bind to guanine and, when incorporated into double-stranded DNA, significantly increase the stability of the latter. As the phenoxazine skeleton is a constituent of major pharmaceuticals, we hypothesized that oligonucleotides (ONs) containing phenoxazine bases would induce property changes related to intracellular uptake and migration in tissues. In this study, we designed and synthesized a novel G-clamp-linker antisense oligonucleotide (ASO) in which a G-clamp base with a flexible linker was introduced into the 5'-end of an ASO targeting mouse long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (mMALAT1). Compared to unconjugated ASO, the G-clamp-linker ASO induced significantly more effective knockdown of mMALAT1 in mouse skeletal muscle. The ASOs conjugated with 2'-deoxyribonucleotide(s) bearing a tC nucleobase at the 5'-end exhibited a similar knockdown effect in skeletal muscle. Thus, it may be possible to improve therapeutic effects against skeletal muscle diseases, such as muscular dystrophy, by using ONs with incorporated phenoxazine nucleobases.
人工核苷碱基 1,3-二氮杂-2-氧杂苯并嗪（tC）及其衍生物 G 夹可与鸟嘌呤强烈结合，并在掺入双链 DNA 时显著提高后者的稳定性。由于苯并嗪骨架是主要药物的组成部分，我们假设含有苯并嗪碱基的寡核苷酸（ONs）会诱导与细胞内摄取和组织迁移相关的性质变化。在这项研究中，我们设计并合成了一种新型的 G 夹连接子反义寡核苷酸（ASO），其中将柔性连接子引入到靶向小鼠长非编码 RNA 转移相关肺腺癌转录本 1（mMALAT1）的 ASO 的 5'端的 G 夹碱基。与未缀合的 ASO 相比，G 夹连接子 ASO 可更有效地诱导小鼠骨骼肌中 mMALAT1 的敲低。在 5'端带有 tC 碱基的 2'-脱氧核苷酸（s）缀合的 ASO 在骨骼肌中表现出相似的敲低效果。因此，通过使用掺入苯并嗪碱基的 ONs，可能有可能改善对骨骼肌疾病（如肌肉营养不良）的治疗效果。
