Editing the +58 region of the BCL11A erythroid enhancer has shown promise in treating β-globin disorders. To address variations in fetal hemoglobin (HbF) response, we investigated editing both +58 and +55 enhancers. Rhesus macaques transplanted with edited hematopoietic stem/progenitor cells (HSPCs) following busulfan conditioning exhibited durable, high-level (∼90%) editing frequencies post transplantation with sustained HbF reactivation over 4 years, without hematological perturbations. HbF levels were further boosted by stress erythropoiesis or hydroxyurea. Bone marrow analysis revealed that gene edits were predominantly programmed deletions, programmed inversions, and short indels, each disrupting the enhancer core TGN_7–9WGATAR half E-box/GATA binding motifs. Nonprogrammed long deletions were disfavored in engrafting cells. CD45 antibody-drug conjugate (ADC) conditioning achieved comparable engraftment and HbF reactivation, whereas lentiviral vector tracking showed polyclonal reconstitution with dynamics similar to animals conditioned with total body irradiation (TBI) or busulfan. Joining CD45-ADC conditioning with combined enhancer editing presents an effective strategy for β-hemoglobinopathies, enabling durable HbF reactivation without chemotherapy.

中文翻译：

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BCL11A +58/+55 增强子编辑促进 CD45 抗体-药物偶联物条件的恒河猴猕猴的 HSPC 植入和 HbF 诱导


编辑 BCL11A 红细胞增强子的 +58 区域在治疗 β-珠蛋白疾病方面显示出前景。为了解决胎儿血红蛋白 （HbF） 反应的变化，我们研究了编辑 +58 和 +55 增强子。白消安调节后用编辑的造血干细胞/祖细胞 （HSPC） 移植的恒河猴在移植后表现出持久的、高水平的 （∼90%） 编辑频率，并在 4 年内持续 HbF 再激活，没有血液学干扰。应激红细胞生成或羟基脲进一步提高 HbF 水平。骨髓分析显示，基因编辑主要是程序化缺失、程序性倒位和短插入缺失，每一种都破坏增强子核心 TGN_7-9WGATAR 半 E-box/GATA 结合基序。非程序性长缺失在移植细胞中不受欢迎。CD45 抗体-药物偶联物 （ADC） 调节实现了相当的植入和 HbF 再激活，而慢病毒载体追踪显示多克隆重建，动力学类似于用全身照射 （TBI） 或白消安调节的动物。将 CD45-ADC 调节与联合增强子编辑相结合为 β-血红蛋白病提供了一种有效的策略，无需化疗即可实现持久的 HbF 再激活。