Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK.
Mol Ther Nucleic Acids. 2012 Aug 7;1(8):e34. doi: 10.1038/mtna.2012.29.
Exploiting the properties of stem cells by microRNA (miRNA) profiling offers an attractive approach to identify new regulators of stem cell fate. Although numerous miRNA have been screened from hematopoietic stem cells (HSC), the targets corresponding to many of these miRNA have not yet been fully elucidated. By miRNA profiling in a subpopulation of CD34+ cells isolated from peripheral blood, we have identified eight clusters of miRNA that were differentially expressed. Further analysis of one of the clusters by bioinformatics revealed that a miRNA, miR-181a*, which is highly expressed in the adherent CD34+ cells, affects the expression levels of Nanog, a stem cell surrogate marker. We show specifically by reporter assay and mutational analysis that miR-181a* targets a seedless 3' compensatory site in the 3'UTR of Nanog and affects gene expression. We demonstrate that inhibiting miR-181a* upregulates the Nanog expression level, in addition to an increase in alkaline phosphatase activity. Our studies suggest that miR-181a* may be important in controlling the expression level of Nanog in a subpopulation of CD34+ cells.
通过 miRNA 图谱分析来挖掘干细胞的特性，为鉴定新的干细胞命运调控因子提供了一种很有吸引力的方法。尽管已经从造血干细胞 (HSC) 中筛选出了大量的 miRNA，但其中许多 miRNA 的靶标尚未完全阐明。通过对从外周血中分离的 CD34+细胞亚群进行 miRNA 图谱分析，我们鉴定出了 8 个差异表达的 miRNA 簇。通过生物信息学进一步分析其中一个簇，发现 miR-181a*，在贴壁 CD34+细胞中高表达，影响干细胞替代标志物 Nanog 的表达水平。我们通过报告基因检测和突变分析表明，miR-181a* 靶向 Nanog 3'UTR 中的无种子 3'互补位点，并影响基因表达。我们证明，抑制 miR-181a* 可上调 Nanog 的表达水平，同时碱性磷酸酶活性也增加。我们的研究表明，miR-181a* 可能在控制 CD34+细胞亚群中 Nanog 的表达水平方面发挥重要作用。
