RNA interference (RNAi) for spinocerebellar ataxia type 1 can prevent and reverse behavioral deficits and neuropathological readouts in mouse models, with safety and benefit lasting over many months. The RNAi trigger, expressed from adeno-associated virus vectors (AAV.miS1), also corrected misregulated microRNAs (miRNA) such as miR150. Subsequently, we showed that the delivery method was scalable, and that AAV.miS1 was safe in short-term pilot nonhuman primate (NHP) studies. To advance the technology to patients, investigational new drug (IND)-enabling studies in NHPs were initiated. After AAV.miS1 delivery to deep cerebellar nuclei, we unexpectedly observed cerebellar toxicity. Both small-RNA-seq and studies using AAVs devoid of miRNAs showed that this was not a result of saturation of the endogenous miRNA processing machinery. RNA-seq together with sequencing of the AAV product showed that, despite limited amounts of cross-packaged material, there was substantial inverted terminal repeat (ITR) promoter activity that correlated with neuropathologies. ITR promoter activity was reduced by altering the miS1 expression context. The surprising contrast between our rodent and NHP findings highlight the need for extended safety studies in multiple species when assessing new therapeutics for human application.

用于 1 型脊髓小脑共济失调的 RNA 干扰 (RNAi) 可以预防和逆转小鼠模型中的行为缺陷和神经病理学读数，其安全性和益处可以持续数月。从腺相关病毒载体 (AAV.miS1) 表达的 RNAi 触发器也纠正了错误调节的 microRNA (miRNA)，例如 miR150。随后，我们证明了这种传递方法是可扩展的，并且 AAV.miS1 在短期试点非人类灵长类动物 (NHP) 研究中是安全的。为了向患者推广该技术，在 NHP 中启动了研究性新药 (IND) 研究。在 AAV.miS1 递送到小脑深核后，我们意外观察到小脑毒性。small-RNA-seq 和使用没有 miRNA 的 AAV 的研究都表明，这不是内源性 miRNA 加工机制饱和的结果。RNA-seq 和 AAV 产品的测序表明，尽管交叉包装的材料数量有限，但存在与神经病理学相关的大量反向末端重复 (ITR) 启动子活性。ITR 启动子活性通过改变 miS1 表达环境而降低。我们的啮齿动物和 NHP 研究结果之间的惊人对比突显了在评估用于人类应用的新疗法时，需要在多个物种中进行扩展的安全性研究。