Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada.
Michael G. DeGroote School of Medicine, McMaster University, 1200 Main Street West, MDCL 5029, Hamilton, ON L8N 3Z5, Canada.
Cells. 2022 Jun 13;11(12):1915. doi: 10.3390/cells11121915.
The generation of human hematopoietic stem cells (HSCs) from human pluripotent stem cells (hPSCs) represents a major goal in regenerative medicine and is believed would follow principles of early development. HSCs arise from a type of endothelial cell called a "hemogenic endothelium" (HE), and human HSCs are experimentally detected by transplantation into SCID or other immune-deficient mouse recipients, termed SCID-Repopulating Cells (SRC). Recently, SRCs were detected by forced expression of seven transcription factors (TF) (ERG, HOXA5, HOXA9, HOXA10, LCOR, RUNX1, and SPI1) in hPSC-derived HE, suggesting these factors are deficient in hPSC differentiation to HEs required to generate HSCs. Here we derived PECAM-1-, Flk-1-, and VE-cadherin-positive endothelial cells that also lack CD45 expression (PFV) which are solely responsible for hematopoietic output from iPSC lines reprogrammed from AML patients. Using HEs derived from AML patient iPSCs devoid of somatic leukemic aberrations, we sought to generate putative SRCs by the forced expression of 7TFs to model autologous HSC transplantation. The expression of 7TFs in hPSC-derived HE cells from an enhanced hematopoietic progenitor capacity was present in vitro, but failed to acquire SRC activity in vivo. Our findings emphasize the benefits of forced TF expression, along with the continued challenges in developing HSCs for autologous-based therapies from hPSC sources.
从人类多能干细胞（hPSC）生成人类造血干细胞（HSC）代表了再生医学的主要目标，并且被认为将遵循早期发育的原则。HSC 来源于一种称为“造血内皮细胞”（HE）的内皮细胞，并且通过移植到 SCID 或其他免疫缺陷小鼠受体中，即 SCID 再殖细胞（SRC）来实验性地检测到人类 HSC。最近，在 hPSC 衍生的 HE 中强制表达七个转录因子（TF）（ERG、HOXA5、HOXA9、HOXA10、LCOR、RUNX1 和 SPI1）检测到 SRC，表明这些因子在 hPSC 分化为产生 HSC 所需的 HE 中缺失。在这里，我们从 AML 患者重编程的 iPSC 系中衍生出了PECAM-1、Flk-1 和 VE-cadherin 阳性的内皮细胞，这些细胞也缺乏 CD45 表达（PFV），它们是唯一负责从 iPSC 系产生造血输出的细胞。使用源自 AML 患者 iPSC 的缺乏体细胞白血病异常的 HE，我们试图通过强制表达 7TF 来生成假定的 SRC，以模拟自体 HSC 移植。在体外，hPSC 衍生的 HE 细胞中存在增强的造血祖细胞能力的 7TF 表达，但在体内未能获得 SRC 活性。我们的研究结果强调了强制 TF 表达的好处，同时也强调了从 hPSC 来源开发用于自体治疗的 HSC 所面临的持续挑战。
