Abkowitz Janis L, Chen Jing
Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195-7710, USA.
Blood. 2007 Jun 15;109(12):5186-90. doi: 10.1182/blood-2006-08-044503. Epub 2007 Mar 8.
Three properties define hematopoietic stem cells (HSCs): their capacity for quiescence and long survival, their ability to self-renew, and their ability to give rise to a multilineage clone of differentiating and maturing blood cells. Although it is likely that different signals regulate these events, this has been difficult to dissect on a molecular level, since HSC division, their fate decisions, and the earliest differentiation events cannot be directly visualized. Our studies of c-Mpl, the cellular receptor for the cytokine thrombopoietin, suggest that c-Mpl does not control HSC numbers, as had been previously argued, but rather facilitates the early expansion of differentiating clones. These experiments provide a strategy to distinguish the actions of HSCs from earliest progenitor cells in vivo and demonstrate that a selective growth advantage at a level distal to HSC can result in a profound effect on multilineage hematopoiesis.
造血干细胞（HSCs）具有三个特性：它们具有静止和长期存活的能力、自我更新的能力以及产生分化和成熟血细胞多谱系克隆的能力。尽管可能是不同的信号调节这些过程，但由于造血干细胞的分裂、它们的命运决定以及最早的分化事件无法直接观察到，因此很难在分子水平上进行剖析。我们对细胞因子血小板生成素的细胞受体c-Mpl的研究表明，c-Mpl并不像之前所认为的那样控制造血干细胞的数量，而是促进分化克隆的早期扩增。这些实验提供了一种策略，可在体内区分造血干细胞与最早祖细胞的作用，并证明在造血干细胞远端水平的选择性生长优势可对多谱系造血产生深远影响。
