Mapping human hematopoietic stem cell development

摘要 多能干细胞(PSC)是获得人类白细胞抗原相合或患者特异性造血干细胞的理想来源 用于治疗血液疾病的细胞(HSC)。然而，所有的努力都在产生自我更新 来自PSC的造血干细胞(HSC)已经失败，因为我们对其机制的了解有限 在发展人类HSC中治理“茎”。尽管驱动血液规格的转录因子 相对较好的理解，我们缺乏定义HSC自我更新的计划的知识，以及为什么这些 程序在PSC来源的造血细胞中失败。因此，我们的目标是创建一张单细胞转录组图谱 人肝星状细胞在体内的个体发育和体外培养的干细胞。将人类的HSC与 指定HSC时个体发育的关键阶段(AGM，可能还有胎盘和卵黄囊)和 在胚胎(胎肝和胎骨髓)中扩增和成熟成全功能的HSC将使我们能够 识别对HSC自我更新至关重要的途径，以及区分在体内发育的人类HSC与 那些在体外发育的细胞。这一分析将查明导致ESC功能不佳的关键缺陷 为克服这些分子障碍提供了新的解决方案。因为缺乏HSC 可靠地预测人类HSC功能的表面标志物，有助于正确监测HSC的分化 指定的HSC，我们为关键的HSC调控因子HOXA5、MLLT5和HLF创建了hESC报告行 它的表达在自我更新的人类造血干细胞中高度丰富。然后我们将比较体外衍生的 随着HSC的出现，候选HSC成为人类造血组织单细胞血管谱系图的候选细胞 并在体内扩张。SINE-II RO1是为解决体外培养中的关键障碍步骤而设计的。 这些研究可以扩展到机制研究，以了解人类HSC的调节，并最终 促进造血干细胞移植的转化性研究。

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.