The ss-siRNA activity in vivo requires a metabolically stable 5′-phosphate analog. In this report we used crystal structure of the 5′-phosphate binding pocket of Ago-2 bound with guide strand to design and synthesize ss-siRNAs containing various 5′-phosphate analogs. Our results indicate that the electronic and spatial orientation of the 5′-phosphate analog was critical for ss-siRNA activity. Chemically modified ss-siRNA targeting human apoC III mRNA demonstrated good potency for inhibiting ApoC III mRNA and protein in transgenic mice. Moreover, ApoC III ss-siRNAs were able to reduce the triglyceride and LDL cholesterol in transgenic mice demonstrating pharmacological effect of ss-siRNA. Our study provides guidance to develop surrogate phosphate analog for ss-siRNA and demonstrates that ss-siRNA provides an alternative strategy for therapeutic gene silencing.
体内的ss-siRNA活性需要一个代谢稳定的5′-
磷酸盐类物质。在本报告中,我们利用与引导链结合的Ago-2的5′-
磷酸结合口袋的晶体结构,设计并合成了含有不同5′-
磷酸盐类物质的ss-siRNA。我们的结果表明,5′-
磷酸盐类物质的电子和空间取向对ss-siRNA活性至关重要。
化学修饰的ss-siRNA靶向人类apoC III mRNA,显示出对转
基因小鼠中ApoC III mRNA和蛋白质的良好抑制效力。此外,ApoC III ss-siRNA能够降低转
基因小鼠中的
甘油三酯和低密度脂蛋白
胆固醇,表现出ss-siRNA的药理效应。我们的研究为开发ss-siRNA的替代
磷酸盐类物质提供了指导,并证明ss-siRNA提供了一种治疗性
基因沉默的替代策略。