Takubo Keiyo
Department of Stem Cell Biology, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
Clin Calcium. 2017;27(6):823-828.
At steady state, hematopoietic stem cells(HSCs), the most undifferentiated cells in the hematological system, are kept quiescent in the cell cycle. Upon hematological stresses, including radiation, anti-cancer medication, infection, and transplantation, bone marrow HSCs enter the cell cycle and robustly repopulate the entire hematopoietic system via multi-lineage differentiation and self-renewal, partly due to the alteration of their surrounding microenvironment or niche. Such hematological repopulation activity is termed "stress hematopoiesis," an activity essential for homeostatic maintenance of blood production. Understanding stress hematopoiesis is also critical to establish efficient methods enabling expansion in vitro of HSCs, since forced activation of the cell cycle by cytokine supplementation induces a stress-like cellular state.
在稳态下，造血干细胞（HSCs）是血液系统中最未分化的细胞，在细胞周期中保持静止。在受到包括辐射、抗癌药物、感染和移植在内的血液学应激时，骨髓造血干细胞进入细胞周期，并通过多谱系分化和自我更新有力地重新填充整个造血系统，部分原因是其周围微环境或生态位的改变。这种血液重新填充活性被称为“应激造血”，这是维持血液生成稳态所必需的活性。了解应激造血对于建立能够在体外扩增造血干细胞的有效方法也至关重要，因为通过补充细胞因子强制激活细胞周期会诱导一种类似应激的细胞状态。
