Synthesis and Biological Activity of Short Interfering RNAs Having Several Consecutive Amide Internucleoside Linkages
Synthesis and Biological Activity of Short Interfering RNAs Having Several Consecutive Amide Internucleoside Linkages
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DOI：
10.1002/chem.201903754
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发表时间：
2019-12-17
影响因子：
4.3
通讯作者：
Rozners, Eriks
中科院分区：
文献类型：
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作者：
Kotikam, Venubabu;Viel, Julien A.;Rozners, Eriks
RNA干扰(RNAi)作为一种研究工具和潜在的治疗方法的成功，重新激发了人们对RNA化学修饰的兴趣。用中性酰胺取代带负电荷的磷酸盐有望改善对体内应用至关重要的小干扰RNA(SiRNAs)的生物利用度和细胞摄取。在本研究中，我们在siRNA双链的引导链的3‘端引入了多达7个连续的酰胺键。当具有四个连续的酰胺键的修饰导向链与在其5‘端的第一和第二核苷之间具有一个酰胺修饰的乘客链配对时，保持了高的RNAi活性。修饰次数的进一步增加降低了RNAi活性；然而，具有6个和7个酰胺键的siRNAs仍然显示出有用的靶向沉默。虽然具有9个酰胺键的siRNA双链保留了一些沉默活性，但负电荷的部分减少并不能使HeLa细胞被动摄取。我们的结果表明，除了酰胺键之外，还需要进一步的化学修饰，以便在没有转染剂的情况下使细胞能够摄取siRNAs。
The success of RNA interference (RNAi) as a research tool and potential therapeutic approach has reinvigorated interest in chemical modifications of RNA. Replacement of the negatively charged phosphates with neutral amides may be expected to improve bioavailability and cellular uptake of small interfering RNAs (siRNAs) critical for in vivo applications. In this study, we introduced up to seven consecutive amide linkages at the 3 '-end of the guide strand of an siRNA duplex. Modified guide strands having four consecutive amide linkages retained high RNAi activity when paired with a passenger strand having one amide modification between its first and second nucleosides at the 5 '-end. Further increase in the number of modifications decreased the RNAi activity; however, siRNAs with six and seven amide linkages still showed useful target silencing. While an siRNA duplex having nine amide linkages retained some silencing activity, the partial reduction of the negative charge did not enable passive uptake in HeLa cells. Our results suggest that further chemical modifications, in addition to amide linkages, are needed to enable cellular uptake of siRNAs in the absence of transfection agents.