UM171体外扩增脐血造血干细胞的机制

Mechanism by which UM171 sustains expansion of umbilical cord blood hematopoietic stem cells in vitro

背景:研究表明UM171可以在体外扩增造血干细胞,但作用机制尚不清楚。目的:通过高通量对接(HTDocking)筛选技术研究UM171作用的靶点,并概述其潜在的作用机制。方法:利用StemCellCKB在线计算平台,找出UM171可能的作用靶点。通过验证实验排除阴性靶点,利用表面等离子体共振(SPR)分析确定UM171和转化生长因子βRⅠ之间的相互作用。Western blot法检测UM171作用于转化生长因子β信号通路的几种重要蛋白质表达变化。结果与结论:(1)根据StemCellCKB计算得分,找出了UM171可能的作用靶点有转化生长因子βRⅠ等;(2)表面等离子体共振分析得出KD_(50)值为62.5μmol/L,说明UM171和转化生长因子βRⅠ有较强的结合能力;(3)转化生长因子β信号通路中转化生长因子βRⅠ、Smad3、p-Smad3、Smad4等主要蛋白质的表达水平显著提高;(4)结果提示UM171通过作用于转化生长因子β信号通路扩增脐血造血干细胞。

BACKGROUND： It has been reported that UM171 enables an ex vivo expansion of human hematopoietic stem cells. However, the intracellular regulatory mechanisms remain unclear. OBJECTIVE： To investigate the compound-target interaction network of UM171 by High-Throughput Docking （HTDocking） screening technology and TargetHunter, and to outline its potential mechanisms of action. METHODS： Using the online StemCellCKB interface, we searched the possible targets of UM171. Negative targets were excluded by validation experiments, and a surface plasmon resonance （SPR） assay was used to identify the interaction between UM171 and transforming growth factor βRI. Several important proteins which are known to regulate this pathway were investigated by western blot.RESULTS AND CONCLUSION： StemCellCKB program automatically calculated the docking scores, which indicated the possible targets of UM171. The KD50 values were calculated as 62.5 μmol/L by SPR, indicating the high affinity between UM171 and its target protein. Western blot analysis results revealed that the expression levels of main proteins in transforming growth factor β signaling pathway, including TGF-βRI, Smad3, p-Smad3, Smad4, were increased significantly in a concentration-depend manner. Overall, UM171 can sustain the expansion of umbilical cord blood hematopoietic stem cells through the transforming growth factor β signaling pathway.