Liu Jingjing, Hsu Andrew, Lee Jen-Fu, Cramer Daniel E, Lee Menq-Jer
Jingjing Liu, Andrew Hsu, Jen-Fu Lee, Menq-Jer Lee, Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48202, United States.
World J Biol Chem. 2011 Jan 26;2(1):1-13. doi: 10.4331/wjbc.v2.i1.1.
Most hematopoietic stem progenitor cells (HSPCs) reside in bone marrow (BM), but a small amount of HSPCs have been found to circulate between BM and tissues through blood and lymph. Several lines of evidence suggest that sphingosine-1-phosphate (S1P) gradient triggers HSPC egression to blood circulation after mobilization from BM stem cell niches. Stem cells also visit certain tissues. After a temporary 36 h short stay in local tissues, HSPCs go to lymph in response to S1P gradient between lymph and tissue and eventually enter the blood circulation. S1P also has a role in the guidance of the primitive HSPCs homing to BM in vivo, as S1P analogue FTY720 treatment can improve HSPC BM homing and engraftment. In stress conditions, various stem cells or progenitor cells can be attracted to local injured tissues and participate in local tissue cell differentiation and tissue rebuilding through modulation the expression level of S1P(1), S1P(2) or S1P(3) receptors. Hence, S1P is important for stem cells circulation in blood system to accomplish its role in body surveillance and injury recovery.
大多数造血干祖细胞（HSPCs）存在于骨髓（BM）中，但已发现少量HSPCs通过血液和淋巴在骨髓与组织之间循环。多项证据表明，鞘氨醇-1-磷酸（S1P）梯度在造血干细胞从骨髓干细胞龛动员后触发其进入血液循环。干细胞也会进入某些组织。在局部组织中短暂停留36小时后，HSPCs会响应淋巴与组织之间的S1P梯度进入淋巴，最终进入血液循环。S1P在引导原始HSPCs在体内归巢至骨髓方面也发挥作用，因为S1P类似物FTY720治疗可改善HSPCs归巢至骨髓并实现植入。在应激条件下，各种干细胞或祖细胞可被吸引至局部损伤组织，并通过调节S1P(1)、S1P(2)或S1P(3)受体的表达水平参与局部组织细胞分化和组织重建。因此，S1P对于血液系统中干细胞的循环很重要，有助于其在身体监测和损伤恢复中发挥作用。
