MicroRNA-22 Regulates Smooth Muscle Cell Differentiation From Stem Cells by Targeting Methyl CpG–Binding Protein 2
MicroRNA-22 Regulates Smooth Muscle Cell Differentiation From Stem Cells by Targeting Methyl CpG–Binding Protein 2
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DOI：
10.1161/atvbaha.114.305212
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发表时间：
2014-12
期刊：
影响因子：
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通讯作者：
Hanqing Zhao;Guanmei Wen;Yuan-Ping. Huang;Xiaotian Yu;Qishan Chen;T. Afzal;L. Luong;Jianhua Zhu
中科院分区：
文献类型：
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作者：
Hanqing Zhao;Guanmei Wen;Yuan-Ping. Huang;Xiaotian Yu;Qishan Chen;T. Afzal;L. Luong;Jianhua Zhu
目的—在本研究中，我们试图揭示 microRNA-22 (miR-22) 及其靶基因在平滑肌细胞 (SMC) 分化中的功能影响，并描绘所涉及的分子机制。方法和结果——发现 miR-22 在胚胎干细胞和外膜干/祖细胞分化为 SMC 的过程中显着上调。通过其模拟物强制表达 miR-22，同时通过其 antagomiR 敲低 miR-22，分别促进或抑制 SMC 从胚胎干细胞和外膜干/祖细胞分化。预期，干细胞中 miR-22 的过度表达可促进 SMC 体内分化。甲基 CpG 结合蛋白 2 (MECP2) 被预测为 miR-22 的首要靶标之一。有趣的是，MECP2的基因表达水平在SMC分化过程中显着降低，并且在miR-22过表达的细胞中MECP2显着降低，但在分化干细胞中当miR-22被敲低时MECP2显着增加。重要的是，荧光素酶测定显示 miR-22 显着抑制野生型而非突变型 MECP2-3' 非翻译区荧光素酶活性。此外，MECP2表达水平的调节会影响分化胚胎干细胞中多种SMC特异性基因的表达。从机制上讲，我们的数据表明 MECP2 可以通过调节各种 SMC 转录因子以及几种经过验证的 SMC 分化调节因子来转录抑制 SMC 基因表达。证据还表明，MECP2 过表达显着增加了 SMC 分化调节基因启动子区域周围 H3K9 三甲基化的富集。最后，在 SMC 分化过程中，血小板源性生长因子-BB 和转化生长因子-通过转录机制上调 miR-22。结论：miR-22 在 SMC 分化中发挥重要作用，并且 miR-22 介导的 SMC 分化需要通过 MECP2 进行表观遗传调控。
Objective— In this study, we attempted to uncover the functional impact of microRNA-22 (miR-22) and its target gene in smooth muscle cell (SMC) differentiation and delineate the molecular mechanism involved. Approach and Results— miR-22 was found to be significantly upregulated during SMC differentiation from embryonic stem cells and adventitia stem/progenitor cells. Enforced expression of miR-22 by its mimic, while knockdown of miR-22 by its antagomiR, promotes or inhibits SMC differentiation from embryonic stem cells and adventitia stem/progenitor cells, respectively. Expectedly, miR-22 overexpression in stem cells promoted SMC differentiation in vivo. Methyl CpG–binding protein 2 (MECP2) was predicted as one of the top targets of miR-22. Interestingly, the gene expression levels of MECP2 were significantly decreased during SMC differentiation, and MECP2 was dramatically decreased in miR-22 overexpressing cells but significantly increased when miR-22 was knockdown in the differentiating stem cells. Importantly, luciferase assay showed that miR-22 substantially inhibited wild-type, but not mutant MECP2-3′ untranslated region-luciferase activity. In addition, modulation of MECP2 expression levels affects multiple SMC-specific gene expression in differentiated embryonic stem cells. Mechanistically, our data showed that MECP2 could transcriptionally repress SMC gene expression through modulating various SMC transcription factors, as well as several proven SMC differentiation regulators. Evidence also revealed that enrichment of H3K9 trimethylation around the promoter regions of the SMC differentiation regulators genes were significantly increased by MECP2 overexpression. Finally, miR-22 was upregulated by platelet-derived growth factor-BB and transforming growth factor- through a transcriptional mechanism during SMC differentiation. Conclusions— miR-22 plays an important role in SMC differentiation, and epigenetic regulation through MECP2 is required for miR-22 mediated SMC differentiation.