Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390-9041, USA.
Cell. 2012 Aug 31;150(5):895-908. doi: 10.1016/j.cell.2012.08.002.
Mutant huntingtin (HTT) protein causes Huntington disease (HD), an incurable neurological disorder. Silencing mutant HTT using nucleic acids would eliminate the root cause of HD. Developing nucleic acid drugs is challenging, and an ideal clinical approach to gene silencing would combine the simplicity of single-stranded antisense oligonucleotides with the efficiency of RNAi. Here, we describe RNAi by single-stranded siRNAs (ss-siRNAs). ss-siRNAs are potent (>100-fold more than unmodified RNA) and allele-selective (>30-fold) inhibitors of mutant HTT expression in cells derived from HD patients. Strategic placement of mismatched bases mimics micro-RNA recognition and optimizes discrimination between mutant and wild-type alleles. ss-siRNAs require Argonaute protein and function through the RNAi pathway. Intraventricular infusion of ss-siRNA produced selective silencing of the mutant HTT allele throughout the brain in a mouse HD model. These data demonstrate that chemically modified ss-siRNAs function through the RNAi pathway and provide allele-selective compounds for clinical development.
突变型亨廷顿蛋白（HTT）引起亨廷顿病（HD），这是一种不可治愈的神经退行性疾病。使用核酸沉默突变 HTT 将消除 HD 的根本原因。开发核酸药物具有挑战性，而理想的基因沉默临床方法将结合单链反义寡核苷酸的简单性和 RNAi 的效率。在这里，我们描述了由单链 siRNA（ss-siRNA）介导的 RNAi。ss-siRNA 是细胞中突变型 HTT 表达的有效抑制剂（比未经修饰的 RNA 高 100 多倍）和等位基因选择性抑制剂（比野生型高 30 多倍）。错配碱基的策略性放置模拟了 micro-RNA 的识别，并优化了突变型和野生型等位基因之间的区分。ss-siRNA 需要 Argonaute 蛋白，并通过 RNAi 途径发挥作用。在 HD 小鼠模型中，脑室输注 ss-siRNA 可在整个大脑中选择性地沉默突变型 HTT 等位基因。这些数据表明，化学修饰的 ss-siRNA 通过 RNAi 途径发挥作用，并为临床开发提供了等位基因选择性化合物。
