美国加州大学Gene W. Yeo和美国约翰霍普金斯大学医学院Wenzhen Duan共同合作，近期取得重要工作进展。他们研究开发了RNA靶向的CRISPR-Cas13d系统，这一系统能缓解亨廷顿模型中疾病相关表型。相关研究成果2022年12月12日在线发表于《自然—神经科学》杂志上。

据介绍，亨廷顿舞蹈病（HD）是一种致命的、显性遗传的神经退行性疾病，由亨廷顿舞蹈症基因（HTT）外显子1中CAG三核苷酸扩增引起。

由于致病性突变HTT mRNA的减少具有治疗作用，研究人员开发了一个对突变等位基因敏感的CAG^EX RNA靶向CRISPR-Cas13d系统（Cas13d-CAG^EX），可以消除来自HD患者成纤维细胞和诱导多能干细胞来源的神经元中有毒CAG^EX RNA。研究人员发现，通过腺病毒相关载体在杂合子zQ175小鼠（HD模型）纹状体内递送Cas13d–CAG^EX，可选择性地降低突变HTT mRNA和蛋白水平。这也改善了运动协调性，减轻了纹状体萎缩，减少了突变HTT蛋白聚集物。这些表型的改善持续了至少八个月，没有不良影响，并且具有最小的脱靶效应。

总之，研究人员证明了RNA靶向CRISPR-Cas13d系统作为HD治疗方法的原理，该策略对治疗其他显性遗传性疾病具有广泛意义。

附：英文原文

Title: An RNA-targeting CRISPR–Cas13d system alleviates disease-related phenotypes in Huntington’s disease models

Author: Morelli, Kathryn H., Wu, Qian, Gosztyla, Maya L., Liu, Hongshuai, Yao, Minmin, Zhang, Chuangchuang, Chen, Jiaxu, Marina, Ryan J., Lee, Kari, Jones, Krysten L., Huang, Megan Y., Li, Allison, Smith-Geater, Charlene, Thompson, Leslie M., Duan, Wenzhen, Yeo, Gene W.

Issue&Volume: 2022-12-12

Abstract: Huntington’s disease (HD) is a fatal, dominantly inherited neurodegenerative disorder caused by CAG trinucleotide expansion in exon 1 of the huntingtin (HTT) gene. Since the reduction of pathogenic mutant HTT messenger RNA is therapeutic, we developed a mutant allele-sensitive CAGEX RNA-targeting CRISPR–Cas13d system (Cas13d–CAGEX) that eliminates toxic CAGEX RNA in fibroblasts derived from patients with HD and induced pluripotent stem cell-derived neurons. We show that intrastriatal delivery of Cas13d–CAGEX via an adeno-associated viral vector selectively reduces mutant HTT mRNA and protein levels in the striatum of heterozygous zQ175 mice, a model of HD. This also led to improved motor coordination, attenuated striatal atrophy and reduction of mutant HTT protein aggregates. These phenotypic improvements lasted for at least eight months without adverse effects and with minimal off-target transcriptomic effects. Taken together, we demonstrate proof of principle of an RNA-targeting CRISPR–Cas13d system as a therapeutic approach for HD, a strategy with implications for the treatment of other dominantly inherited disorders.

DOI: 10.1038/s41593-022-01207-1

Source: https://www.nature.com/articles/s41593-022-01207-1