Long Noncoding RNA Meg3 Regulates Mafa Expression in Mouse Beta Cells by Inactivating Rad21, Smc3 or Sin3α
Long Noncoding RNA Meg3 Regulates Mafa Expression in Mouse Beta Cells by Inactivating Rad21, Smc3 or Sin3α
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DOI：
10.1159/000487983
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发表时间：
2018-03
影响因子：
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通讯作者：
Ning Wang;Ya-nan Zhu;M. Xie;Lintao Wang;Fei-yan Jin;Yihui Li;Qingxin Yuan;W. De
中科院分区：
文献类型：
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作者：
Ning Wang;Ya-nan Zhu;M. Xie;Lintao Wang;Fei-yan Jin;Yihui Li;Qingxin Yuan;W. De
背景/目的：糖尿病的主要致病机制是胰岛β细胞数量减少或功能下降。近年来的研究表明，胰腺长链非编码RNA（lncRNA）具有高度的组织特异性，可能参与胰岛细胞功能的维持和糖尿病的发生发展。本研究的目的是探讨小鼠母体表达基因3（Meg 3）对胰岛胰岛素生物合成的分子调控机制。研究方法：采用染色质免疫沉淀-定量聚合酶链反应（qPCR）和RNA免疫沉淀-qPCR技术研究lncRNA Meg 3通过调节MIN 6 β细胞系中成熟β细胞标志物蛋白A（MafA）v-Maf基因家族在胰岛素生物合成中的分子机制。此外，通过RT-PCR和蛋白质印迹分析Meg 3、Ezh 2、MafA、Rad 21、Smc 3和Sin 3 α在体内和体外的表达水平。结果：胰岛细胞核内lncRNAMeg 3可与Polycomb抑制复合物2的甲基转移酶EZH 2结合。此外，敲低Ezh 2还可以通过干扰胰腺β细胞中的Ezh 2或Meg 3来抑制MafA和Ins 2的表达，而Rad 21、Smc 3和Sin 3 α的表达水平上调。Meg 3的敲低导致EZH 2结合的丧失和Rad 21、Smc 3和Sin 3 α启动子区域的H3 K27三甲基化占据。对直接作用于MafA启动子的Rad 21、Smc 3或Sin 3 α的抑制导致MIN 6细胞和小鼠胰岛中MafA的表达上调。此外，通过抑制这些转录因子，胰岛素的合成和分泌增加。结论：胰腺lncRNA Meg 3可通过EZH 2驱动的H3 K27甲基化调控Rad 21、Smc 3和Sin 3 α的表达。Meg 3通过抑制Rad 21、Smc 3或Sin 3 α的表达，促进MafA的表达并影响胰岛素的产生。
Background/Aims: The main pathogenic mechanism of diabetes is a decrease in the number of islet beta cells or a decline in their function. Recent studies have shown that pancreatic long noncoding RNAs (lncRNAs) have a high degree of tissue specificity and may be involved in the maintenance of islet cells function and the development of diabetes. The aim of this study was to investigate the molecular regulatory mechanism of mouse maternal expressed gene 3 (Meg3) in insulin biosynthesis in pancreatic islets. Methods: Chromatin immunoprecipitation–quantitative polymerase chain reaction (qPCR) and RNA immunoprecipitation–qPCR were used to investigate the molecular mechanism of lncRNA Meg3 in insulin biosynthesis by regulating v-Maf musculoaponeurotic fibrosarcoma oncogene family, protein A (MafA), a mature beta cell marker in the MIN6 beta cell line. Further, the expression levels of Meg3, Ezh2, MafA, Rad21, Smc3, and Sin3α were analyzed in vivo and in vitro by RT-PCR and western blotting. Results: Intranuclear lncRNA Meg3 can bind EZH2, a methyltransferase belonging to the Polycomb repressive complex-2, in pancreatic islet cells. In addition, knockdown of Ezh2 can also inhibit the expression of MafA and Ins2, while expression levels of Rad21, Smc3, and Sin3α are upregulated, by interfering with Ezh2 or Meg3 in pancreatic beta cells. Knockdown of Meg3 resulted in the loss of EZH2 binding and H3K27 trimethylation occupancy of Rad21, Smc3, and Sin3α promoter regions. The inhibition of Rad21, Smc3, or Sin3α, which directly act on the MafA promoter, leads to upregulated expression of MafA in both MIN6 cells and mouse islets. Moreover, the synthesis and secretion of insulin were increased by inhibition of these transcription factors. Conclusions: Pancreatic lncRNA Meg3 can epigenetically regulate the expression of Rad21, Smc3, and Sin3α via EZH2-driven H3K27 methylation. By inhibiting the expression of Rad21, Smc3, or Sin3α, Meg3 promotes the expression of MafA and affects the production of insulin.