Abstract：
One of the key areas in stem cell research is the identification of factors capable of promoting the expansion of Neural Stem Cell/Progenitor Cells (NSPCs) and understanding their molecular mechanisms for future use in clinical settings. We previously identified Macrophage Migration Inhibitory Factor (MIF) as a novel factor that can support the proliferation and/or survival of NSPCs based on in vitro functional cloning strategy and revealed that MIF can support the proliferation of human brain tumor-initiating cells (BTICs). However, the detailed downstream signaling for the functions has largely remained unknown. Thus, in the present study, we newly identified translationally-controlled tumor protein-1 (TPT1), which is expressed in the ventricular zone of mouse embryonic brain, as a downstream target of MIF signaling in mouse and human NSPCs and human BTICs. Using gene manipulation (over or downregulation of TPT1) techniques including CRISPR/Cas9-mediated heterozygous gene disruption showed that TPT1 contributed to the regulation of cell proliferation/survival in mouse NSPCs, human embryonic stem cell (hESC) derived-NSPCs, human-induced pluripotent stem cells (hiPSCs) derived-NSPCs and BTICs. Furthermore, gene silencing of TPT1 caused defects in neuronal differentiation in the NSPCs in vitro. We also identified the MIF-CHD7-TPT1-SMO signaling axis in regulating hESC-NSPCs and BTICs proliferation. Intriguingly, TPT1suppressed the miR-338 gene, which targets SMO in hESC-NSPCs and BTICs. Finally, mice with implanted BTICs infected with lentivirus-TPT1 shRNA showed a longer overall survival than control. These results also open up new avenues for the development of glioma therapies based on the TPT1 signaling pathway.
摘要：
干细胞研究的关键领域之一是鉴定能够促进神经干细胞/祖细胞（NSPC）扩增的因子，并了解其分子机制，以便将来在临床环境中使用。我们先前基于体外功能克隆策略将巨噬细胞迁移抑制因子（MIF）确定为可以支持NSPCs增殖和/或存活的新因子，并揭示MIF可以支持人脑肿瘤起始细胞（BTIC）的增殖。然而,功能的详细下游信令在很大程度上仍然未知。因此，在本研究中，我们新发现了翻译控制的肿瘤蛋白-1（TPT1），在小鼠胚胎大脑的脑室区表达，作为小鼠和人NSPC和人BTIC中MIF信号的下游靶标。使用基因操作（TPT1的过度或下调）技术，包括CRISPR/Cas9介导的杂合基因破坏，表明TPT1有助于调节小鼠NSPC的细胞增殖/存活，人胚胎干细胞（hESC）衍生的NSPCs，人诱导多能干细胞（hiPSC）衍生的NSPC和BTIC。此外，TPT1基因沉默导致体外NSPCs神经元分化缺陷。我们还鉴定了MIF-CHD7-TPT1-SMO信号轴在调节hESC-NSPC和BTIC增殖中的作用。有趣的是，TPT1抑制了miR-338基因，以hESC-NSPC和BTIC中的SMO为目标。最后,植入感染慢病毒-TPT1shRNA的BTIC的小鼠显示出比对照更长的总生存期。这些结果也为开发基于TPT1信号通路的神经胶质瘤治疗开辟了新的途径。
