2013年2月5日，《美國科學院院報》(PNAS)在線發(fā)表了同濟大學生命科學與技術學院康九紅教授研究組關于miR-200/ZEB2在關鍵轉錄因子Oct4/Sox2誘導iPSC細胞形成中的重要功能和作用機制的研究成果,。該成果是由汪貴英老師和博士生郭旭東共同完成的,。
誘導多能干細胞(iPS)技術的創(chuàng)立,，為基于干細胞的個性化治療和再生醫(yī)學帶來光明的前景。因此,，Yamanaka教授獲得了2012年諾貝爾生理學與醫(yī)學獎,。康九紅教授組先前的系列研究顯示,，miRNAs在Oct4等轉錄因子誘導iPS細胞形成過程中具有調(diào)節(jié)p53等信號通路和DNMT3a/3b的重要作用,，相關研究發(fā)表于2012年的Plos One (7: e40849)、Stem Cells (30: 1645-54) 和2013年的Cell Res (23: 142-56),。
他們發(fā)表在PNAS的研究發(fā)現(xiàn),，在iPS細胞形成過程中，miR-200家族的miRNAs表達水平呈現(xiàn)逐步升高的趨勢,。miR-200家族包括5個miRNAs,，分別位于染色體Chr.4和Chr.6，形成兩個簇,，這兩個簇如何協(xié)同作用是非常有趣的科學問題,。汪貴英等的研究發(fā)現(xiàn)iPS細胞形成中起關鍵作用的Oct4和Sox2分別結合到該miRNAs家族簇的兩個啟動子區(qū)域協(xié)同激活miR-200s的轉錄表達，從而在早期階段有效促進iPS細胞的形成,。研究還發(fā)現(xiàn),，miR-200直接作用的下游基因是ZEB2，從而也揭示了ZEB2在iPS細胞形成中的新功能,。Oct4/Sox2-miR-200-ZEB2通路調(diào)節(jié)iPS細胞形成的研究成果豐富了人們對iPS細胞形成機制網(wǎng)絡的了解,。
本研究工作得到科技部973項目、科技部國際合作項目,、國家自然科學基金委項目,、教育部創(chuàng)新團隊以及上海市科委項目等的支持。(生物谷Bioon.com)
doi: 10.1073/pnas.1212769110
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PMID:
Critical regulation of miR-200/ZEB2 pathway in Oct4/Sox2-induced mesenchymal-to-epithelial transition and induced pluripotent stem cell generation
Guiying Wang, Xudong Guo, Wujun Hong, Qidong Liu, Tingyi Wei, Chenqi Lu, Longfei Gao, Dan Yea, Yi Zhou, Jie Chen, Jianmin Wang, Minjuan Wu, Houqi Liu, and Jiuhong Kang
Fibroblasts can be reprogrammed to induced pluripotent stem cells (iPSCs) by application of transcription factors octamer-binding protein 4 (Oct4), SRY-box containing gene 2 (Sox2), Kruppel-like factor 4 (Klf4), and c-Myelocytomatosis oncogene (c-Myc) (OSKM), but the underlying mechanisms remain unclear. Here, we report that exogenous Oct4 and Sox2 can bind at the promoter regions of mir-141/200c and mir-200a/b/429 cluster, respectively, and induce the transcription activation of miR-200 family during the OSKM-induced reprogramming. Functional suppression of miR-200s with specific inhibitors significantly represses the OSKM-caused mesenchymal-to-epithelial transition (MET, an early event in reprogramming of fibroblasts to iPSCs) and iPSC generation, whereas overexpression of miR-200s promotes the MET and iPSC generation. Mechanistic studies showed that miR-200s significantly repress the expression of zinc finger E-box binding homeobox 2 (ZEB2) through directly targeting its 3′ UTR and direct inhibition of ZEB2 can mimic the effects of miR-200s on iPSC generation and MET process. Moreover, the effects of miR-200s during iPSC generation can be blocked by ZEB2 overexpression. Collectively, our findings not only reveal that members of the miR-200 family are unique mediators of the reprogramming factors Oct4/Sox2, but also demonstrate that the miR-200/ZEB2 pathway as one critical mechanism of Oct4/Sox2 to induce somatic cell reprogramming at the early stage.
