Division of Pediatric Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Stem Cell Program, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Division of Pediatric Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Stem Cell Program, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Stem Cell Reports. 2020 May 12;14(5):956-971. doi: 10.1016/j.stemcr.2020.03.020. Epub 2020 Apr 16.
Studies of hematopoietic stem cell (HSC) development from pre-HSC-producing hemogenic endothelial cells (HECs) are hampered by the rarity of these cells and the presence of other cell types with overlapping marker expression profiles. We generated a Tg(Runx1-mKO2; Ly6a-GFP) dual reporter mouse to visualize hematopoietic commitment and study pre-HSC emergence and maturation. Runx1-mKO2 marked all intra-arterial HECs and hematopoietic cluster cells (HCCs), including pre-HSCs, myeloid- and lymphoid progenitors, and HSCs themselves. However, HSC and lymphoid potential were almost exclusively found in reporter double-positive (DP) cells. Robust HSC activity was first detected in DP cells of the placenta, reflecting the importance of this niche for (pre-)HSC maturation and expansion before the fetal liver stage. A time course analysis by single-cell RNA sequencing revealed that as pre-HSCs mature into fetal liver stage HSCs, they show signs of interferon exposure, exhibit signatures of multi-lineage differentiation gene expression, and develop a prolonged cell cycle reminiscent of quiescent adult HSCs.
从产生造血干细胞 (HSC) 的前 HSC 产生血源性内皮细胞 (HEC) 研究造血干细胞的发育受到这些细胞的稀有性和具有重叠标记表达谱的其他细胞类型的存在的阻碍。我们生成了一种 Tg(Runx1-mKO2; Ly6a-GFP) 双报告小鼠，以可视化造血承诺，并研究前 HSC 的出现和成熟。Runx1-mKO2 标记了所有动脉内 HEC 和造血簇细胞 (HCC)，包括前 HSC、髓系和淋巴祖细胞以及 HSCs 本身。然而，HSC 和淋巴样潜能几乎仅存在于报告基因双阳性 (DP) 细胞中。在胎盘的 DP 细胞中首次检测到强大的 HSC 活性，反映了该龛位在胎儿肝脏阶段之前对 (前)HSC 成熟和扩增的重要性。通过单细胞 RNA 测序的时间过程分析表明，随着前 HSCs 成熟为胎儿肝脏阶段的 HSCs，它们表现出干扰素暴露的迹象，表现出多谱系分化基因表达的特征，并发展出类似于静止的成人 HSCs 的延长细胞周期。
