Université Paris Cité, Imagine Institute, Laboratory of chromatin and gene regulation during development, INSERM UMR 1163, 75015, Paris, France.
Université Paris Cité, Imagine Institute, Laboratory of Human Lymphohematopoiesis, INSERM UMR 1163, 75015, Paris, France.
Nat Commun. 2022 Nov 4;13(1):6618. doi: 10.1038/s41467-022-34493-1.
Sickle cell disease and β-thalassemia affect the production of the adult β-hemoglobin chain. The clinical severity is lessened by mutations that cause fetal γ-globin expression in adult life (i.e., the hereditary persistence of fetal hemoglobin). Mutations clustering ~200 nucleotides upstream of the HBG transcriptional start sites either reduce binding of the LRF repressor or recruit the KLF1 activator. Here, we use base editing to generate a variety of mutations in the -200 region of the HBG promoters, including potent combinations of four to eight γ-globin-inducing mutations. Editing of patient hematopoietic stem/progenitor cells is safe, leads to fetal hemoglobin reactivation and rescues the pathological phenotype. Creation of a KLF1 activator binding site is the most potent strategy - even in long-term repopulating hematopoietic stem/progenitor cells. Compared with a Cas9-nuclease approach, base editing avoids the generation of insertions, deletions and large genomic rearrangements and results in higher γ-globin levels. Our results demonstrate that base editing of HBG promoters is a safe, universal strategy for treating β-hemoglobinopathies.
镰状细胞病和β-地中海贫血影响成人β-珠蛋白链的产生。通过突变导致成人中胎儿γ-珠蛋白表达（即胎儿血红蛋白的遗传性持续存在），可减轻临床严重程度。簇集在 HBG 转录起始位点上游约 200 个核苷酸的突变要么降低 LRF 抑制剂的结合，要么募集 KLF1 激活剂。在这里，我们使用碱基编辑在 HBG 启动子的-200 区域产生各种突变，包括四个到八个γ-珠蛋白诱导突变的有效组合。对患者造血干/祖细胞进行编辑是安全的，可导致胎儿血红蛋白重新激活并挽救病理表型。创建 KLF1 激活剂结合位点是最有效的策略-即使在长期重编程造血干/祖细胞中也是如此。与 Cas9 核酸酶方法相比，碱基编辑避免了插入、缺失和大片段基因组重排，并导致更高的γ-珠蛋白水平。我们的结果表明，HBG 启动子的碱基编辑是治疗β-地中海贫血症的一种安全、通用的策略。
