Kiel Mark J, Iwashita Toshihide, Yilmaz Omer H, Morrison Sean J
Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109-0934, USA.
Dev Biol. 2005 Jul 1;283(1):29-39. doi: 10.1016/j.ydbio.2005.03.037.
Most tissues are patterned so that progenitors in different locations are programmed to have different properties. Stem cells from different regions of the nervous system acquire intrinsic differences in their properties as they migrate through distinct environments. Hematopoietic stem cells (HSCs) also migrate through diverse environments throughout life, raising the question of whether HSCs also acquire at least transient changes in their properties as they are exposed to diverse environments. Although we observed significant differences in hematopoiesis between the fetal liver and fetal spleen, we were not able to detect phenotypic, functional, or gene expression differences between the HSCs in these organs. Regional differences in definitive hematopoiesis are therefore not determined by regional differences between HSCs. We were also not able to detect phenotypic, functional, or gene expression differences between HSCs in different adult bone marrow compartments. Our failure to detect differences among stem cells from different regions of the hematopoietic system at the same time during development suggests that the hematopoietic system has evolved mechanisms to prevent the spatial reprogramming of HSC properties as they migrate between distinct environments.
大多数组织都具有特定的模式，使得不同位置的祖细胞被编程具有不同的特性。来自神经系统不同区域的干细胞在迁移通过不同环境时，其特性会获得内在差异。造血干细胞（HSC）在一生中也会迁移通过多种环境，这就提出了一个问题，即造血干细胞在接触不同环境时，其特性是否也会至少发生短暂变化。尽管我们观察到胎儿肝脏和胎儿脾脏之间的造血存在显著差异，但我们无法检测到这些器官中造血干细胞之间的表型、功能或基因表达差异。因此，确定性造血的区域差异不是由造血干细胞之间的区域差异决定的。我们也无法检测到不同成人骨髓腔室中造血干细胞之间的表型、功能或基因表达差异。我们未能在发育过程中的同一时间检测到造血系统不同区域的干细胞之间的差异，这表明造血系统已经进化出机制，以防止造血干细胞在不同环境之间迁移时其特性发生空间重编程。
