REGULATION OF LYMPHOPOIESIS FROM PLURIPOTENT STEM CELLS

尽管谱系造血细胞的分化阶段已经被很好地描述，但人类淋巴造血干细胞（LHSC）分化的第一步产生的最早祖细胞的鉴定和调控仍然未知。原始淋巴祖细胞体外检测的最新发展现在允许直接研究人类LHSC早期淋巴细胞承诺过程中的事件。我们假设：(1)人类淋巴细胞分化通过两种可能的途径进行，通过普通淋巴细胞祖细胞（CLP）（缺乏骨髓和红细胞潜能）和/或通过B淋巴细胞-髓细胞祖细胞（BMP）（缺乏骨髓和红细胞潜能）和/或通过B淋巴细胞-髓细胞祖细胞（BMP）（缺乏T淋巴细胞和红细胞潜能）。这些祖细胞阶段可以使用免疫表型标记物进行前瞻性鉴定，并且(2)小鼠和人类淋巴样祖细胞的产生（即增殖和分化）受三种细胞因子受体信号通路的协调调节：白细胞介素-7受体α (il - r - α)/共同γ链（γ /c）复合物；IL- rα /胸腺基质衍生淋巴生成蛋白受体（TSLP- R）复合物；和il - 3rα /普通β链（β /c）复合物。本提案的具体目的是：(1)确定人类LHSC向淋巴样细胞分化的免疫表型祖细胞阶段，(2)表征免疫表型和功能定义的人类LHSC和淋巴样祖细胞群体中的差异基因表达，以及(3)确定如何通过il - 7rα和il - 3rα介导的途径调节小鼠和人类LHSC的淋巴样细胞分化和增殖。这些研究将使用我们实验室开发的平行和互补的体外和体内系统来研究小鼠和人类淋巴造血。

Although the differentiation stages in lineage committed hematopoietic cells are well characterized, the identify and regulation of the earliest progenitors produced from the first steps in differentiation of human lympho-hematopoietic stem cells (LHSC) remain unknown. The recent development of in vitro assays for primitive lymphoid progenitors now permits the direct study of events during early lymphoid commitment for human LHSC. We hypothesize that: (1) human lymphoid differentiation proceeds through two possible pathways, through Common Lymphoid Progenitors (CLP) (which lack myeloid and erythroid potential) and/or through B lympho-Myeloid Progenitors (BMP) (which lack myeloid and erythroid potential) and/or through B lympho-Myeloid Progenitors (BMP) (which lack T lymphoid and erythroid potential). These progenitor stages can be identified prospectively using immunophenotypic markers, and (2) the production (i.e. proliferation and differentiation) of murine and human lymphoid progenitor cells is coordinately regulated by three cytokine receptor signaling pathways: the Interleukin-7 Receptor alpha (IL-Ralpha)/Common gamma chain (gamma/c) complex; the IL- Ralpha/Thymic Stroma Derived Lymphopoietic Protein-Receptor (TSLP- R) complex; and the IL-3Ralpha/Common beta chain (beta/c) complex. The Specific Aims of this proposal are to (1) determine immunophenotypically the progenitor stages through which human LHSC differentiate into lymphoid cells, (2) characterize the differential gene expression in immunophenotypically and functionally defined populations of human LHSC and lymphoid progenitors, and (3) determine how lymphoid differentiation and proliferation from murine and human LHSC are regulated through the IL-7Ralpha and IL-3Ralpha mediated pathways. These studies will be performed using parallel and complementary in vitro and in vivo systems developed in our laboratories to study murine and human lympho-hematopoiesis.