Division of Hematology/Oncology, Brown University, Rhode Island Hospital, Providence, RI, 02903, USA.
Division of Hematology, Brigham and Women's Hospital, Boston, MA, 02115, USA.
Leukemia. 2022 Dec;36(12):2784-2792. doi: 10.1038/s41375-022-01715-w. Epub 2022 Oct 28.
Current dogma is that there exists a hematopoietic pluripotent stem cell, resident in the marrow, which is quiescent, but with tremendous proliferative and differentiative potential. Furthermore, the hematopoietic system is essentially hierarchical with progressive differentiation from the pluripotent stem cells to different classes of hematopoietic cells. However, results summarized here indicate that the marrow pluripotent hematopoietic stem cell is actively cycling and thus continually changing phenotype. As it progresses through cell cycle differentiation potential changes as illustrated by sequential changes in surface expression of B220 and GR-1 epitopes. Further data indicated that the potential of purified hematopoietic stem cells extends to multiple other non-hematopoietic cells. It appears that marrow stem cells will give rise to epithelial pulmonary cells at certain points in cell cycle. Thus, it appears that the marrow "hematopoietic" stem cell is also a stem cell for other non-hematopoietic tissues. These observations give rise to the concept of a universal stem cell. The marrow stem cell is not limited to hematopoiesis and its differentiation potential continually changes as it transits cell cycle. Thus, there is a universal stem cell in the marrow which alters its differentiation potential as it progresses through cell cycle. This potential is expressed when it resides in tissues compatible with its differentiation potential, at a particular point in cell cycle transit, or when it interacts with vesicles from that tissue.
目前的观点认为，骨髓中存在一种造血多能干细胞，它处于静止状态，但具有巨大的增殖和分化潜能。此外，造血系统本质上是分级的，从多能干细胞逐渐分化为不同类别的造血细胞。然而，这里总结的结果表明，骨髓多能造血干细胞是活跃地进行细胞周期循环的，因此不断地改变其表型。随着细胞周期的进行，其分化潜能发生变化，这可以通过 B220 和 GR-1 表位的顺序表达变化来说明。进一步的数据表明，纯化的造血干细胞的潜能可以延伸到其他多种非造血细胞。似乎骨髓干细胞在细胞周期的某些特定点会产生肺上皮细胞。因此，骨髓“造血”干细胞似乎也是其他非造血组织的干细胞。这些观察结果引出了一个普遍的干细胞概念。骨髓干细胞不仅限于造血，其分化潜能随着细胞周期的进行而不断变化。因此，骨髓中有一个普遍的干细胞，它在细胞周期中不断改变其分化潜能。当它处于与分化潜能相兼容的组织中，在细胞周期转移的特定点，或者当它与来自该组织的小泡相互作用时，这种潜能就会被表达出来。
