Suppressing Pitx2 inhibits proliferation and promotes differentiation of iHepSCs
Suppressing Pitx2 inhibits proliferation and promotes differentiation of iHepSCs
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抑制 Pitx2 可抑制 iHepSC 的增殖并促进其分化。
DOI：
10.1016/j.biocel.2016.09.024
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发表时间：
2016-11-01
影响因子：
4
通讯作者：
Hu, Yi-Ping
中科院分区：
文献类型：
--
作者：
Chen, Fei;Yao, Hao;Hu, Yi-Ping
诱导的肝干细胞（iHepSCs）由于其自我更新和双向分化的能力而具有作为肝细胞治疗的供体的巨大潜力。然而，调控iHepSC增殖和分化的分子机制知之甚少。在这项研究中，我们提供的证据表明，同源结构域转录因子Pitx 2是维持iHepSC干细胞特性所必需的。通过慢病毒介导的特异性shRNA抑制iHepSC中Pitx 2的表达显著降低了肝干细胞相关基因（Lgr 5，EpCAM和Sox 9）的表达，同时通过阻断G1/s期转变抑制增殖，并且这些表型变化在Pitx 2的重新表达后逆转。Pitx 2敲低也导致p53诱导的Cdk抑制剂p21的上调，以及其下游效应物CDK 2-细胞周期蛋白E激酶复合物的下调。此外，我们观察到，与未操作的iHepSC相比，当Pitx 2表达被抑制时，iHepSC被更有效地诱导分化为肝细胞和胆管细胞。这些发现表明，Pitx 2表达可以用来控制iHepSC在体外扩增期间的状态，从而为iHepSC在肝细胞治疗中的进一步应用提供策略。(C)2016爱思唯尔有限公司版权所有。
Induced hepatic stem cells (iHepSCs) have great potential as donors for liver cell therapy due to their abilities for self-renewal and bi-potential differentiation. However, the molecular mechanism regulating proliferation and differentiation of iHepSCs is poorly understood. In this study, we provide evidence that the homeodomain transcription factor, Pitx2, is essential to maintain iHepSCs stem cell characteristics. Suppressing Pitx2 expression in iHepSCs by lentivirus mediated specific shRNA markedly reduced the expression of the hepatic stem cell-associated genes (Lgr5, EpCAM, and Sox9) with concomitant inhibition of proliferation by blocking the G1/s phase transition, and these phenotypic changes were reversed upon re-expression of Pitx2. Pitx2 knockdown also resulted in up-regulation of the p53-induced Cdk inhibitor p21, and down-regulation of its downstream effector CDK2-Cyclin E kinase complex. Furthermore, we observed that iHepSCs were more efficiently induced to differentiate into both hepatocytes and cholangiocytes when Pitx2 expression was suppressed, as compared to unmanipulated iHepSCs. These findings reveal that Pitx2 expression may be leveraged to control the status of iHepSCs during expansion in vitro to provide a strategy for further application of iHepSCs in liver cell therapy. (C) 2016 Elsevier Ltd. All rights reserved.