Inhibition of p38 Mitogen-Activated Protein Kinase Promotes Ex Vivo Hematopoietic Stem Cell Expansion
Inhibition of p38 Mitogen-Activated Protein Kinase Promotes Ex Vivo Hematopoietic Stem Cell Expansion
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抑制 p38 丝裂原激活蛋白激酶促进离体造血干细胞扩增
DOI：
10.1089/scd.2010.0413
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发表时间：
2011-07-01
影响因子：
4
通讯作者：
Zhou, Daohong
中科院分区：
文献类型：
--
作者：
Wang, Yong;Kellner, Joshua;Zhou, Daohong
造血干细胞（HSC）的自我更新受到许多细胞内在调节因子和来自干细胞生态位的各种外在信号之间复杂的串扰的严格调控。在本研究中，我们研究了p38丝裂原活化蛋白激酶（p38）是否是体外负性调节HSC自我更新的内在调节因子之一，以及用小分子抑制剂抑制p38活性是否可以促进体外HSC扩张。本研究结果表明，经筛选的小鼠骨髓Lin(-)Sca1(+)c-kit（+）细胞（LSK（+）细胞）在添加100 ng/mL干细胞因子、血小板生成素和Flt3配体的无血清培养基中培养后，可选择性激活p38。p38的激活与LSK（+）细胞及其后代中hsc的显著减少、凋亡和细胞衰老的诱导有关。在培养物中添加特异性p38抑制剂SB203580 （SB, 5 μ M）抑制LSK（+）细胞中p38的激活，从而导致HSC自我更新和体外扩增的增加，如鹅卵石区域形成细胞试验，竞争性再种群和系列移植所示。HSC扩增的增加可能是由于sb介导的HSC凋亡和衰老的抑制以及HoxB4和CXCR4的上调。这些发现表明p38在体外调节HSC自我更新中起重要作用，用小分子抑制剂抑制p38的激活可能是促进HSC体外扩增的新途径。
Hematopoietic stem cell (HSC) self-renewal is tightly regulated by a complex crosstalk between many cell-intrinsic regulators and a variety of extrinsic signals from the stem cell niche. In this study, we examined whether the p38 mitogen-activated protein kinase (p38) is one of the intrinsic regulators that can negatively regulate HSC self-renewal in vitro and whether inhibition of p38 activity with a small molecule inhibitor can promote HSC expansion ex vivo. The results from this study showed that sorted mouse bone marrow Lin(-)Sca1(+)c-kit(+) cells (LSK(+) cells) exhibited selective activation of p38 after culture in a serum-free medium supplemented with 100 ng/mL stem cell factor, thrombopoietin, and Flt3 ligand. The activation of p38 was associated with a significant reduction in HSCs and induction of apoptosis and cellular senescence in LSK(+) cells and their progeny. Addition of the specific p38 inhibitor SB203580 (SB, 5 mu M) to the culture inhibited the activation of p38 in LSK(+) cells, which led to increase in HSC self-renewal and ex vivo expansion as shown by the cobblestone area forming cell assay, competitive repopulation, and serial transplantation. The increase in HSC expansion is likely attributable to SB-mediated inhibition of HSC apoptosis and senescence and upregulation of HoxB4 and CXCR4. These findings suggest that p38 plays an important role in the regulation of HSC self-renewal in vitro and inhibition of p38 activation with a small molecule inhibitor may represent a novel approach to promote ex vivo expansion of HSCs.