Gene-Silencing Potency of Symmetric and Asymmetric Lipid-Conjugated siRNAs and Its Correlation with Dicer Recognition

详细信息    查看全文

• 作者：Takanori Kubo ; Kazuyoshi Yanagihara ; Yuichiro Sato ; Yoshio Nishimura ; Shinichi Kondo ; Toshio Seyama
• 刊名：Bioconjugate Chemistry
• 出版年：2013
• 出版时间：December 18, 2013
• 年：2013
• 卷：24
• 期：12
• 页码：2045-2057
• 全文大小：663K
• 年卷期：v.24,no.12(December 18, 2013)
• ISSN：1520-4812

文摘

Three types of siRNAs and three types of left-overhang siRNAs (LoRNAs) were synthesized along with their conjugations with palmitic acid (C16) to investigate the correlation between Dicer recognition and gene-silencing potency. The siRNA types were composed of 21-nucleotide (nt), 23-nt, and 25-nt lengths of sense and antisense strands with a 2-nt overhang at each 3鈥?end. The three LoRNA types were composed of a 21-nt, a 23-nt, and a 25-nt length of sense strand with a 2-nt DNA at the 3鈥?blunt-end and a 23-nt, a 25-nt, and a 27-nt length of antisense strand with a 2-nt overhang at the 3鈥?end. Additionally, each of these siRNAs and LoRNAs was modified with a C16 at the 5鈥? or 3鈥?end of the sense strand; these were named C16-siRNAs and C16-LoRNAs, respectively. The siRNAs and C16-siRNAs were barely cleaved by Dicer, and their gene-silencing efficacies were not excellent, contrary to our expectations. In contrast, most of the LoRNAs and C16-LoRNAs became substrates of Dicer, and they showed both strong gene-silencing efficacies and high nuclease resistance. Among the LoRNAs, the 25D-C16/27-nt LoRNA, which is composed of a 25-nt sense strand with a 2-nt DNA conjugated with C16 at the 3鈥?end and a 27-nt antisense strand with a 2-nt overhang at the 3鈥?end, showed an excellent gene-silencing effect with high cell membrane permeability and strong resistance against nuclease degradation. Additionally, the Lo25D-C16/27RNA excelled in all three aspects, nuclease resistance, cell membrane permeability, and RNAi efficacy, compared with the cholesterol conjugation. We are certain that Lo25D-C16/27RNA can be useful as a new generation of RNAi molecules with which to overcome some of the limitations of RNAi technology.