du Rand Alex, Hunt John, Verdon Daniel, Buttle Ben, Dunbar P Rod, Purvis Diana, Feisst Vaughan, Sheppard Hilary
School of Biological Sciences, The University of Auckland, Auckland, New Zealand.
Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand.
JID Innov. 2024 Dec 24;5(3):100343. doi: 10.1016/j.xjidi.2024.100343. eCollection 2025 May.
Gene editing facilitated by homology-directed repair represents a promising strategy for precisely correcting pathogenic variants underlying monogenic disorders, including the life-threatening skin blistering condition junctional epidermolysis bullosa (JEB). Frequent reports of unintended off-target genotoxicity associated with conventional Cas9 nuclease editing have increasingly led to the adoption of dual-Cas9 nickases (dual-Cas9n) owing to their improved safety profile. However, rates of precise repair obtained with such strategies remain low. In this study, we establish a dual-Cas9n approach targeting , using electroporation to deliver Cas9-nickase ribonucleoproteins and modified single-stranded oligodeoxynucleotide repair templates into primary JEB keratinocytes. Targeting a hotspot pathogenic variant (c.1903C>T, p.R635∗), we report perfect correction efficiencies of up to 54% based on standard next-generation sequencing. Using a high-fidelity Cas9 nuclease, we also report perfect repair of up to 74% when using a small-molecule modulator of DNA repair. Dual-Cas9n-corrected JEB keratinocytes demonstrated restored laminin-332 expression and secretion , leading to improved cellular adhesion and accurate laminin-332 localization in engineered skin equivalents. This protocol represents a significant improvement in precision gene repair using Cas9 nickases for epidermolysis bullosa, with the potential to be applied to a large cohort of patients harboring this prevalent pathogenic variant.
由同源定向修复促进的基因编辑是一种很有前景的策略,可精确校正单基因疾病潜在的致病变异,包括危及生命的皮肤水疱病交界性大疱性表皮松解症(JEB)。与传统Cas9核酸酶编辑相关的意外脱靶基因毒性的频繁报道,使得双Cas9切口酶(dual-Cas9n)因其安全性提高而越来越多地被采用。然而,用这种策略获得的精确修复率仍然很低。在本研究中,我们建立了一种靶向的双Cas9n方法,通过电穿孔将Cas9切口酶核糖核蛋白和修饰的单链寡脱氧核苷酸修复模板递送至原发性JEB角质形成细胞中。针对一个热点致病变异(c.1903C>T,p.R635∗),我们基于标准的下一代测序报告了高达54%的完美校正效率。使用一种高保真Cas9核酸酶,当使用一种DNA修复的小分子调节剂时,我们还报告了高达74%的完美修复率。双Cas9n校正的JEB角质形成细胞表现出层粘连蛋白-332表达和分泌的恢复,导致工程化皮肤等效物中细胞粘附改善和层粘连蛋白-332定位准确。该方案代表了使用Cas9切口酶进行大疱性表皮松解症精确基因修复的显著改进,有可能应用于一大批携带这种常见致病变异的患者。