MicroRNA 223-dependent expession of LMO2 regulates normal erythropoiesis
MicroRNA 223-dependent expession of LMO2 regulates normal erythropoiesis
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DOI：
10.3324/haematol.2008.002345
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发表时间：
2009-04-01
期刊：
影响因子：
--
通讯作者：
Marziali, Giovanna
中科院分区：
文献类型：
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作者：
Felli, Nadia;Pedini, Francesca;Marziali, Giovanna
研究背景MicroRNA是一类非编码小分子RNA，通过降解mRNA或抑制翻译来调控基因表达。microRNA正在成为正常造血和血液恶性肿瘤的关键调节因子。几种miRNA在造血过程中差异表达，并且它们的特异性表达调节参与造血谱系分化的关键功能蛋白。本研究重点探讨microRNA-223（miR-223）在红细胞分化中的功能作用。设计与方法纯化的脐带血CD 34（+）造血祖细胞在严格控制的条件下，在饱和剂量的红细胞生成素的存在下生长，以选择性诱导红细胞分化。结果在脐血CD 34（+）造血祖细胞的单系红系培养中，miR-223表达下调，而红系分化必需蛋白LMO 2表达上调。功能研究表明，miR-223的强制表达通过与LMO 2 3' UTR结合而降低LMO 2的mRNA和蛋白水平，并损害红系细胞的分化。因此，通过短干扰RNA敲低LMO 2模拟了miR-223的作用。此外，用miR-223转导的造血祖细胞显示出其红系克隆形成能力的显著降低，提示下调该miRNA是红系祖细胞募集和定型所必需的。223是红系细胞分化的重要事件，其导致成红细胞扩增，至少部分由未阻断LMO 2蛋白介导表情
BackgroundMicroRNAs are small non-coding RNAs that regulate gene expression through mRNA degradation or translational inhibition. MicroRNAs are emerging as key regulators of normal hematopoiesis and hematologic malignancies. Several miRNAs are differentially expressed during hematopoiesis and their specific expression regulates key functional proteins involved in hematopoietic lineage differentiation. This study focused on the functional role of microRNA-223 (miR-223) on erythroid differentiation.Design and MethodsPurified cord blood CD34(+) hematopoietic progenitor cells were grown in strictly controlled conditions in the presence of saturating dosage of erythropoietin to selectively induce erythroid differentiation. The effects of enforced expression of miR-223 in unilineage erythroid cultures were evaluated in liquid phase culture experiments and clonogenic studies.ResultsIn unilineage erythroid culture of cord blood CD34(+) hematopoietic progenitor cells miR-223 is down-regulated, whereas LMO2, an essential protein for erythroid differentiation, is up-regulated. Functional studies showed that enforced expression of miR-223 reduces the mRNA and protein levels of LMO2, by binding to LMO2 3' UTR, and impairs differentiation of erythroid cells. Accordingly, knockdown of LMO2 by short interfering RNA mimics the action of miR-223. Furthermore, hematopoietic progenitor cells transduced with miR-223 showed a significant reduction of their erythroid clonogenic capacity, suggesting that downmodulation of this miRNA is required for erythroid progenitor recruitment and commitment.ConclusionsThese results show that the decline of miR-223 is an important event for erythroid differentiation that leads to the expansion of erythroblast cells at least partially mediated by unblocking LMO2 protein expression.