Mapping human hematopoietic stem cell development

总结 多能干细胞（Pluripotent stem cells，PSC）是获得HLA配型或患者特异性造血干细胞的理想来源 细胞（HSC）用于治疗血液疾病。然而，在生产自我更新的 PSC的造血干细胞（HSC）已经失败了，这是由于我们对PSC的机制的理解有限， 在发展人类HSC中控制“干性”。虽然驱动血液特化的转录因子 相对较好地理解，我们缺乏定义HSC自我更新的程序的知识，以及为什么这些 程序在PSC衍生的造血细胞中失败。因此，我们的目标是创建一个单细胞转录组图谱， 体内人HSC个体发生和体外产生的ESC衍生细胞。比较人类HSC与 当HSC被指定时，个体发育的关键阶段（AGM，可能还有胎盘和卵黄囊）， 在孕体（胎儿肝脏和胎儿骨髓）中扩增并成熟为功能齐全的HSC将使我们能够 鉴定对HSC自我更新至关重要的途径，并将体内发育的人HSC与 那些在试管中发育的。该分析将查明导致ESC功能不佳的关键缺陷， 造血细胞，并为克服这些分子障碍提供新的解决方案。由于缺乏HSC 表面标志物，将可靠地预测人类HSC功能，以帮助监测分化的适当 我们创建了hESC报告细胞系，用于关键HSC调节因子HOXA 5、MLLT 5和HLF 其表达在自我更新的人HSC中高度富集。然后，我们将比较体外衍生的 当HSC出现时，将候选HSC添加到人造血组织的单细胞血管谱系图中 并在体内扩张。该SHINE-II RO 1旨在解决体外HSC生成中的关键障碍步骤。 这些研究可以扩展到机制研究，以了解人类HSC的调控，并最终 翻译研究，以改善HSC移植。

SUMMARY Pluripotent stem cells (PSC) are an ideal source for deriving HLA-matched or patient specific hematopoietic stem cells (HSC) for the treatment of blood disorders. However, all the efforts in producing self-renewing hematopoietic stem cells (HSC) from PSC have failed due to our limited understanding of the mechanisms that govern “stemness” in developing human HSC. Although the transcription factors that drive blood specification are relatively well understood, we lack knowledge of the programs that define HSC self-renewal, and why these programs fail in PSC derived hematopoietic cells. Thus, we aim to create a single cell transcriptome map of human HSC ontogeny in vivo and ESC derived cells generated in vitro. The ability to compare human HSC from the critical stages of ontogeny when HSCs are specified (AGM, and possibly the placenta and yolk sac) and expand and mature into fully functional HSC in the conceptus (fetal liver and fetal bone marrow) will allow us to identify pathways that are critical for HSC self-renewal, and that distinguish human HSCs developing in vivo from those that develop in vitro. This analysis will pinpoint key defects that underlie the poor function of ESC derived hematopoietic cells, and offer new solutions for overcoming these molecular barriers. As there is a lack of HSC surface markers that would reliably predict human HSC function, to help monitor the differentiation of properly specified HSCs, we created hESC reporter lines for critical HSC regulatory factors HOXA5, MLLT5 and HLF whose expression is highly enriched in self-renewing human HSCs. We will then compare the in vitro derived candidate HSC to the single cell hemato-vascular lineage map of human hematopoietic tissues as HSCs emerge and expand in vivo. This SHINE-II RO1 is designed to address critical hurdle steps in in vitro HSC generation. These studies can be expanded to mechanistic studies to understand human HSC regulation, and ultimately to translational studies to improve HSC transplantation.