新研究探究了人类造血干细胞的碱基编辑治疗_基因编辑治疗

美国哈佛医学院Daniel E. Bauer团队的一项研究探究了人类造血干细胞（HSC）的碱基编辑治疗。相关论文于2020年3月16日在线发表在《自然-医学》上。

在这项研究中，研究人员纯化了A3A（N57Q）-BE3碱基编辑器，这是人类外周血动员时CD34 +造血干细胞和祖细胞（HSPC）核糖核蛋白（RNP）的电穿孔素。

研究人员观察到BCL11A红系增强子在+58处频繁发生靶点胞嘧啶碱基编辑。红细胞子代中的胎儿血红蛋白（HbF）在碱基编辑或核酸酶编辑后相似。针对BCL11A增强子一个位点的碱基编辑治疗，分别预防了镰状细胞病中类红细胞子代镰状化和β地中海贫血患者来源HSPC诱导的血红蛋白链失衡。

此外，BCL11A红系增强子破坏与HBB -28A> G启动子突变纠正相结合可以实现多重有效编辑。后，正如在主要和次要受体动物中的测定结果，在多谱系衍生的自我更新人类HSCs中可以产生高频率的碱基编辑，从而在体内有效诱导HbF。

总的来说，这些结果揭示了人类HSPC的RNP碱基编辑可以作为靶向HSC治疗基因组修饰替代方法的潜能。

研究人员表示，将核苷酸脱氨酶与可编程DNA结合蛋白结合起来进行碱基编辑的方法，是长久治愈血液疾病的潜在治疗方式，但这一方法是否适用于造血干细胞仍有待探究。

附：英文原文

Title: Therapeutic base editing of human hematopoietic stem cells

Author: Jing Zeng, Yuxuan Wu, Chunyan Ren, Jasmine Bonanno, Anne H. Shen, Devlin Shea, Jason M. Gehrke, Kendell Clement, Kevin Luk, Qiuming Yao, Rachel Kim, Scot A. Wolfe, John P. Manis, Luca Pinello, J. Keith Joung, Daniel E. Bauer

Issue&Volume: 2020-03-16

Abstract: Base editing by nucleotide deaminases linked to programmable DNA-binding proteins represents a promising approach to permanently remedy blood disorders, although its application in engrafting hematopoietic stem cells (HSCs) remains unexplored. In this study, we purified A3A (N57Q)-BE3 base editor for ribonucleoprotein (RNP) electroporation of human-peripheral-blood-mobilized CD34+ hematopoietic stem and progenitor cells (HSPCs). We observed frequent on-target cytosine base edits at the BCL11A erythroid enhancer at +58 with few indels. Fetal hemoglobin (HbF) induction in erythroid progeny after base editing or nuclease editing was similar. A single therapeutic base edit of the BCL11A enhancer prevented sickling and ameliorated globin chain imbalance in erythroid progeny from sickle cell disease and β-thalassemia patient-derived HSPCs, respectively. Moreover, efficient multiplex editing could be achieved with combined disruption of the BCL11A erythroid enhancer and correction of the HBB 28A>G promoter mutation. Finally, base edits could be produced in multilineage-repopulating self-renewing human HSCs with high frequency as assayed in primary and secondary recipient animals resulting in potent HbF induction in vivo. Together, these results demonstrate the potential of RNP base editing of human HSPCs as a feasible alternative to nuclease editing for HSC-targeted therapeutic genome modification.

DOI: 10.1038/s41591-020-0790-y

Source: https://www.nature.com/articles/s41591-020-0790-y