Davis Scott, Lollo Bridget, Freier Susan, Esau Christine
Isis Pharmaceuticals 1896 Rutherford Road, Carlsbad, CA 92008, USA.
Nucleic Acids Res. 2006 May 11;34(8):2294-304. doi: 10.1093/nar/gkl183. Print 2006.
MicroRNAs (miRNAs) are a class of 20-24 nt noncoding RNAs that regulate target mRNAs post-transcriptionally by binding with imperfect complementarity in the 3'-untranslated region (3'-UTR) and inhibiting translation or RNA stability. Current understanding of miRNA biology is limited, and antisense oligonucleotide (ASO) inhibition is a powerful technique for miRNA functionalization in vitro and in vivo, and for therapeutic targeting of miRNAs. Identification of optimal ASO chemistries for targeting miRNAs is therefore of great interest. We evaluated a number of 2'-sugar and backbone ASO modifications for their ability to inhibit miR-21 activity on a luciferase reporter mRNA. ASO modifications that improved target affinity improved miRNA ASO activity, yet the positioning of high-affinity modifications also had dramatically different effects on miRNA activity, suggesting that more than affinity determined the effectiveness of the miRNA ASOs. We present data in which the activity of a modified miRNA ASO was inversely correlated to its tolerability as an siRNA passenger strand, suggesting that a similar mechanism could be involved in the dissociation of miRNA ASOs and siRNA passenger strands. These studies begin to define the factors important for designing improved miRNA ASOs, enabling more effective miRNA functionalization and therapeutic targeting.
微小RNA（miRNA）是一类20 - 24个核苷酸的非编码RNA，它们通过在3'非翻译区（3'-UTR）与靶mRNA不完全互补结合，在转录后水平调节靶mRNA，抑制其翻译或影响RNA稳定性。目前对miRNA生物学的了解有限，反义寡核苷酸（ASO）抑制是一种在体外和体内实现miRNA功能化以及对miRNA进行治疗性靶向的强大技术。因此，确定用于靶向miRNA的最佳ASO化学结构备受关注。我们评估了多种2'-糖基和骨架ASO修饰对荧光素酶报告基因mRNA上miR-21活性的抑制能力。改善靶标亲和力的ASO修饰提高了miRNA ASO活性，但高亲和力修饰的位置对miRNA活性也有显著不同的影响，这表明决定miRNA ASO有效性的因素不止亲和力。我们提供的数据表明，修饰后的miRNA ASO活性与其作为小干扰RNA（siRNA）过客链的耐受性呈负相关，这表明miRNA ASO和siRNA过客链的解离可能涉及类似机制。这些研究开始确定设计改良型miRNA ASO的重要因素，从而实现更有效的miRNA功能化和治疗性靶向。
