The heterogeneity of human hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) under stress conditions such as ex vivo expansion is poorly understood. Here, we report that the frequencies of SCID-repopulating cells were greatly decreased in cord blood (CB) CD34⁺ HSCs and HPCs upon ex vivo culturing. Transcriptomic analysis and metabolic profiling demonstrated that mitochondrial oxidative stress of human CB HSCs and HPCs notably increased, along with loss of stemness. Limiting dilution analysis revealed that functional human HSCs were enriched in cell populations with low levels of mitochondrial ROS (mitoROS) during ex vivo culturing. Using single-cell RNA-Seq analysis of the mitoROS low cell population, we demonstrated that functional HSCs were substantially enriched in the adhesion GPCR G1–positive (ADGRG1⁺) population of CD34⁺CD133⁺ CB cells upon ex vivo expansion stress. Gene set enrichment analysis revealed that HSC signature genes including MSI2 and MLLT3 were enriched in CD34⁺CD133⁺ADGRG1⁺ CB HSCs. Our study reveals that ADGRG1 enriches for functional human HSCs under oxidative stress during ex vivo culturing, which can be a reliable target for drug screening of agonists of HSC expansion.

中文翻译：

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ADGRG1 在离体扩增诱导的线粒体氧化应激后富集功能性人类造血干细胞

人类造血干细胞 (HSCs) 和造血祖细胞 (HPCs) 在压力条件下（例如离体扩增）的异质性知之甚少。在这里，我们报告了脐带血 (CB) CD34 ^{+中 SCID 再增殖细胞的频率大大降低}体外培养后的 HSC 和 HPC。转录组学分析和代谢分析表明，人类 CB HSCs 和 HPCs 的线粒体氧化应激显着增加，同时干性丧失。有限稀释分析表明，功能性人类 HSC 在离体培养过程中富含线粒体 ROS (mitoROS) 水平低的细胞群。使用 mitoROS 低细胞群的单细胞 RNA-Seq 分析，我们证明功能性 HSC在离体扩张应激时在CD34 ⁺ CD133 ⁺ CB 细胞的粘附 GPCR G1 阳性 (ADGRG1 ^{+ ) 群中显着富集。}基因集富集分析显示，HSC 特征基因包括MSI2和MLLT3富含 CD34 ⁺ CD133 ⁺ ADGRG1 ⁺ CB HSC。我们的研究表明，ADGRG1 在离体培养期间在氧化应激下富集功能性人类 HSC，这可以成为 HSC 扩增激动剂药物筛选的可靠靶标。