Alpha Anomeric, 140 Bis, Rue de Rennes, 75006 Paris, France.
Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
Nucleic Acids Res. 2021 Dec 2;49(21):12089-12105. doi: 10.1093/nar/gkab1097.
Antisense oligonucleotides are small pieces of modified DNA or RNA, which offer therapeutic potential for many diseases. We report on the synthesis of 7',5'-α-bc-DNA phosphoramidite building blocks, bearing the A, G, T and MeC nucleobases. Solid-phase synthesis was performed to construct five oligodeoxyribonucleotides containing modified thymidine residues, as well as five fully modified oligonucleotides. Incorporations of the modification inside natural duplexes resulted in strong destabilizing effects. However, fully modified strands formed very stable duplexes with parallel RNA complements. In its own series, 7',5'-α-bc-DNA formed duplexes with a surprising high thermal stability. CD spectroscopy and extensive molecular modeling indicated the adoption by the homo-duplex of a ladder-like structure, while hetero-duplexes with DNA or RNA still form helical structure. The biological properties of this new modification were investigated in animal models for Duchenne muscular dystrophy and spinal muscular atrophy, where exon splicing modulation can restore production of functional proteins. It was found that the 7',5'-α-bc-DNA scaffold confers a high biostability and a good exon splicing modulation activity in vitro and in vivo.
反义寡核苷酸是经过修饰的 DNA 或 RNA 片段，具有治疗多种疾病的潜力。我们报告了 7'，5'-α-bc-DNA 膦酰胺亚单位构建块的合成，其带有 A、G、T 和 MeC 碱基。通过固相合成构建了包含修饰的胸苷残基的五个寡脱氧核苷酸，以及五个完全修饰的寡核苷酸。修饰物在天然双链体中的掺入导致强烈的不稳定效应。然而，完全修饰的链与平行的 RNA 互补物形成非常稳定的双链体。在其自身系列中，7'，5'-α-bc-DNA 形成具有惊人高热稳定性的双链体。CD 光谱和广泛的分子建模表明，同型双链体采用梯状结构，而与 DNA 或 RNA 的异型双链体仍形成螺旋结构。该新修饰的生物学特性在杜氏肌营养不良症和脊髓性肌萎缩症的动物模型中进行了研究，其中外显子剪接调节可以恢复功能性蛋白质的产生。结果发现，7'，5'-α-bc-DNA 支架在体外和体内均具有高生物稳定性和良好的外显子剪接调节活性。
