Restoring T and B cell generation in X-linked severe combined immunodeficiency mice through hematopoietic stem cells adenine base editing

Lu Zhang; Kai Li; Zhiwei Liu; Lisha An; Haikun Wei; Shanshan Pang; Zongfu Cao; Xingxu Huang; Xiaohua Jin; Xu Ma

doi:10.1016/j.ymthe.2024.03.028

Restoring T and B cell generation in X-linked severe combined immunodeficiency mice through hematopoietic stem cells adenine base editing

Mol Ther. 2024 Mar 26:S1525-0016(24)00169-2. doi: 10.1016/j.ymthe.2024.03.028. Online ahead of print.

Authors

Lu Zhang¹, Kai Li², Zhiwei Liu³, Lisha An¹, Haikun Wei¹, Shanshan Pang¹, Zongfu Cao¹, Xingxu Huang⁴, Xiaohua Jin⁵, Xu Ma⁶

Affiliations

¹ National Research Institute for Family Planning, Beijing 100081, China; National Human Genetic Resources Center, Beijing 102206, China.
² State Key Laboratory of Genetic Engineering and Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Institutes of Biomedical Sciences, Human Phenome Institute, Fudan University, Shanghai 200433, China.
³ Cambridge-Suda Genomic Resource Center, Suzhou Medical College of Soochow University, Suzhou 215123, China.
⁴ School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
⁵ National Research Institute for Family Planning, Beijing 100081, China; National Human Genetic Resources Center, Beijing 102206, China. Electronic address: jinxiaohua@nrifp.org.cn.
⁶ National Research Institute for Family Planning, Beijing 100081, China; National Human Genetic Resources Center, Beijing 102206, China. Electronic address: maxu_fg@nrifp.org.cn.

PMID: 38532630
DOI: 10.1016/j.ymthe.2024.03.028

Abstract

Base editing of hematopoietic stem/progenitor cells (HSPCs) is an attractive strategy for treating immunohematologic diseases. However, the feasibility of using adenine-base-edited HSPCs for treating X-linked severe combined immunodeficiency (SCID-X1), the influence of dose-response relationships on immune cell generation, and the potential risks have not been demonstrated in vivo. Here, a humanized SCID-X1 mouse model was established, and 86.67% ± 2.52% (n = 3) of mouse hematopoietic stem cell (HSC) pathogenic mutations were corrected, with no single-guide-RNA (sgRNA)-dependent off-target effects detected. Analysis of peripheral blood over 16 weeks post-transplantation in mice with different immunodeficiency backgrounds revealed efficient immune cell generation following transplantation of different amounts of modified HSCs. Therefore, a large-scale infusion of gene-corrected HSCs within a safe range can achieve rapid, stable, and durable immune cell regeneration. Tissue-section staining further demonstrated the restoration of immune organ tissue structures, with no tumor formation in multiple organs. Collectively, these data suggest that base-edited HSCs are a potential therapeutic approach for SCID-X1 and that a threshold infusion dose of gene-corrected cells is required for immune cell regeneration. This study lays a theoretical foundation for the clinical application of base-edited HSCs in treating SCID-X1.

Keywords: HSCs; X-SCID; base editing; gene therapy; immune reconstitution.