Li Yang, Hong Wan Xing, Lan Baojin, Xu Xiaoyan, Liu Yinan, Kong Lin, Li Yaxuan, Zhou Shixin, Liu Ying, Feng Ruopeng, Jiang Sibo, He Qihua, Tan Jichun
Department of Cell Biology and Stem Cell Research Center, School of Basic Medical Sciences, Peking University, Beijing 100191, China; Shengjing Hospital Affiliated to China Medical University, Shenyang 110004, China.
Departments of Radiology and Surgery, Stanford School of Medicine, Stanford 94305, CA, USA.
Differentiation. 2013 Nov-Dec;86(4-5):141-8. doi: 10.1016/j.diff.2013.11.002. Epub 2014 Jan 28.
Human embryonic germ cells (hEGCs) are a valuable and underutilized source of pluripotent stem cells. Unlike embryonic stem cells, which have been extensively studied, little is known about the factors that regulate hEGC derivation and maintenance. This study demonstrates for the first time a central role for selective activation of PDGFR signaling in the derivation and maintenance of pluripotency in hEGCs. In the study, hEGCs were found to express PDGF receptor α at high levels compared to human embryonic stem cells (hESCs). PDGF significantly improved formation of alkaline phosphatase (AP) positive hEGC colonies. We subsequently determined that PDGF activates the phosphatidylinositol-3-kinase (PI3K) pathway as phosphorylation of AKT was up-regulated in response to PDGF. Furthermore, inhibition of PI3K signaling using small molecular inhibitor LY294002 led to significantly decreased AP positive hEGC colony formation whereas inhibition of MAPK pathway using U0126 had a negligible effect. We established a primary mechanism for PDGF mediated derivation and maintenance of hEGCs by demonstrating that OCT4 was upregulated and PTEN was suppressed in a dose dependent manner in response to PDGF.
人类胚胎生殖细胞（hEGCs）是一种宝贵且未得到充分利用的多能干细胞来源。与已被广泛研究的胚胎干细胞不同，对于调控hEGC的衍生和维持的因素我们知之甚少。这项研究首次证明了血小板衍生生长因子受体（PDGFR）信号的选择性激活在hEGC的多能性衍生和维持中起着核心作用。在该研究中，与人类胚胎干细胞（hESCs）相比，发现hEGCs高水平表达血小板衍生生长因子受体α（PDGF receptor α）。血小板衍生生长因子（PDGF）显著改善了碱性磷酸酶（AP）阳性hEGC集落的形成。随后我们确定，由于AKT的磷酸化响应PDGF而上调，PDGF激活了磷脂酰肌醇-3-激酶（PI3K）信号通路。此外，使用小分子抑制剂LY294002抑制PI3K信号导致AP阳性hEGC集落形成显著减少，而使用U0126抑制丝裂原活化蛋白激酶（MAPK）信号通路的影响可忽略不计。我们通过证明OCT4以剂量依赖的方式响应PDGF而上调且PTEN被抑制，建立了PDGF介导的hEGC衍生和维持的主要机制。
