Alagia Adele, Terrazas Montserrat, Eritja Ramon
Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), CIBER-BBN Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Jordi Girona 18-26, Barcelona 08034, Spain.
Molecules. 2014 Nov 4;19(11):17872-96. doi: 10.3390/molecules191117872.
The RNA interference pathway (RNAi) is a specific and powerful biological process, triggered by small non-coding RNA molecules and involved in gene expression regulation. In this work, we explored the possibility of increasing the biological stability of these RNA molecules by replacing their natural ribose ring with an acyclic L-threoninol backbone. In particular, this modification has been incorporated at certain positions of the oligonucleotide strands and its effects on the biological properties of the siRNA have been evaluated. In vitro cellular RNAi assays have demonstrated that the L-threoninol backbone is well tolerated by the RNAi machinery in both double and single-stranded fashion, with activities significantly higher than those evinced by the unmodified RNAs and comparable to the well-known phosphorothioate modification. Additionally, this modification conferred extremely strong resistance to serum and 3'/5'-exonucleases. In view of these results, we applied this modification to the knockdown of a therapeutically relevant human gene such as apolipoprotein B (ApoB). Further studies on the activation of the innate immune system showed that L-threoninol-modified RNAs are slightly less stimulatory than unmodified RNAs.
RNA干扰途径（RNAi）是一种由小的非编码RNA分子触发并参与基因表达调控的特定且强大的生物学过程。在这项工作中，我们探索了通过用无环L-苏糖醇主链取代天然核糖环来提高这些RNA分子生物学稳定性的可能性。特别是，这种修饰已被引入到寡核苷酸链的特定位置，并评估了其对siRNA生物学特性的影响。体外细胞RNAi分析表明，L-苏糖醇主链在双链和单链形式下都能被RNAi机制很好地耐受，其活性显著高于未修饰的RNA，且与著名的硫代磷酸酯修饰相当。此外，这种修饰赋予了对血清和3'/5'-外切核酸酶极强的抗性。鉴于这些结果，我们将这种修饰应用于敲低治疗相关的人类基因，如载脂蛋白B（ApoB）。对先天免疫系统激活的进一步研究表明，L-苏糖醇修饰的RNA的刺激性略低于未修饰的RNA。
