Gori Jennifer L, Butler Jason M, Chan Yan-Yi, Chandrasekaran Devikha, Poulos Michael G, Ginsberg Michael, Nolan Daniel J, Elemento Olivier, Wood Brent L, Adair Jennifer E, Rafii Shahin, Kiem Hans-Peter
J Clin Invest. 2015 Mar 2;125(3):1243-54. doi: 10.1172/JCI79328. Epub 2015 Feb 9.
Pluripotent stem cells (PSCs) represent an alternative hematopoietic stem cell (HSC) source for treating hematopoietic disease. The limited engraftment of human PSC-derived (hPSC-derived) multipotent progenitor cells (MPP) has hampered the clinical application of these cells and suggests that MPP require additional cues for definitive hematopoiesis. We hypothesized that the presence of a vascular niche that produces Notch ligands jagged-1 (JAG1) and delta-like ligand-4 (DLL4) drives definitive hematopoiesis. We differentiated hes2 human embryonic stem cells (hESC) and Macaca nemestrina-induced PSC (iPSC) line-7 with cytokines in the presence or absence of endothelial cells (ECs) that express JAG1 and DLL4. Cells cocultured with ECs generated substantially more CD34+CD45+ hematopoietic progenitors compared with cells cocultured without ECs or with ECs lacking JAG1 or DLL4. EC-induced cells exhibited Notch activation and expressed HSC-specific Notch targets RUNX1 and GATA2. EC-induced PSC-MPP engrafted at a markedly higher level in NOD/SCID/IL-2 receptor γ chain-null (NSG) mice compared with cytokine-induced cells, and low-dose chemotherapy-based selection further increased engraftment. Long-term engraftment and the myeloid-to-lymphoid ratio achieved with vascular niche induction were similar to levels achieved for cord blood-derived MPP and up to 20-fold higher than those achieved with hPSC-derived MPP engraftment. Our findings indicate that endothelial Notch ligands promote PSC-definitive hematopoiesis and production of long-term engrafting CD34+ cells, suggesting these ligands are critical for HSC emergence.
多能干细胞（PSC）是治疗造血疾病的一种替代性造血干细胞（HSC）来源。人PSC衍生的（hPSC衍生的）多能祖细胞（MPP）的植入受限阻碍了这些细胞的临床应用，并表明MPP需要额外的信号来实现确定性造血。我们假设存在产生Notch配体锯齿状蛋白-1（JAG1）和Delta样配体-4（DLL4）的血管龛会驱动确定性造血。我们在有或没有表达JAG1和DLL4的内皮细胞（EC）存在的情况下，用细胞因子分化hes2人胚胎干细胞（hESC）和食蟹猴诱导的PSC（iPSC）系-7。与未与EC共培养或与缺乏JAG1或DLL4的EC共培养的细胞相比，与EC共培养的细胞产生的CD34 + CD45 +造血祖细胞明显更多。EC诱导的细胞表现出Notch激活，并表达HSC特异性Notch靶标RUNX1和GATA2。与细胞因子诱导的细胞相比，EC诱导的PSC-MPP在NOD/SCID/IL-2受体γ链缺陷（NSG）小鼠中的植入水平明显更高，基于低剂量化疗的选择进一步提高了植入率。通过血管龛诱导实现的长期植入和髓系与淋巴系比例与脐血来源的MPP所达到的水平相似，比hPSC衍生的MPP植入所达到的水平高出20倍。我们的研究结果表明，内皮Notch配体促进PSC确定性造血和长期植入的CD34 +细胞的产生，表明这些配体对HSC的出现至关重要。
