Pro-inflammatory role of microrna-200 in vascular smooth muscle cells from diabetic mice.
Pro-inflammatory role of microrna-200 in vascular smooth muscle cells from diabetic mice.
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DOI：
10.1161/atvbaha.111.241109
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
Natarajan R
中科院分区：
文献类型：
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作者：
Reddy MA;Jin W;Villeneuve L;Wang M;Lanting L;Todorov I;Kato M;Natarajan R
来自2型糖尿病db/db小鼠（db/dbVSMC）的血管平滑肌细胞（VSMC）表现出与加速的血管并发症有关的增强的促炎反应。我们研究了microRNA-200（miR-200）家族成员及其靶基因Zeb1（一种E-box结合转录抑制因子）在这些事件中的作用。与对照db/+小鼠相比，db/db小鼠VSMC和平滑肌细胞中miR-200 b、miR-200 c和miR-429的表达水平升高，而Zeb1的蛋白水平降低。miR-200 mimics转染VSMC后，通过靶向Zeb1的3 ′-UTR下调Zeb1的表达，上调炎症基因环氧合酶-2（考克斯-2）和单核细胞趋化蛋白-1（MCP-1）的表达，促进db/+ VSMC与单核细胞的结合。相反，miR-200抑制剂逆转db/db VSMC的增强的单核细胞结合。用siRNA沉默Zeb1基因也增加了db/+ VSMC中的这些促炎反应，证实了Zeb1的负调节作用。miR-200模拟物和Zeb1 siRNA均增加了考克斯-2启动子的转录活性。染色质免疫沉淀显示，在db/dbVSMC中，炎症基因启动子处的Zeb1占用减少。此外，Zeb1敲除增加了miR-200水平，证明了反馈调节环。糖尿病条件下miR-200和Zeb1之间相互负调控环的破坏增强了与血管并发症有关的VSMC的促炎反应。
Vascular smooth muscle cells (VSMC) from type 2 diabetic db/db mice (db/dbVSMC) exhibit enhanced pro-inflammatory responses implicated in accelerated vascular complications. We examined the role of microRNA-200 (miR-200) family members and their target Zeb1, an E-box binding transcriptional repressor, in these events. The expression levels of miR-200b, miR-200c and miR-429 were increased while protein levels of Zeb1 were decreased in VSMC and aortas from db/db mice relative to control db/+ mice. Transfection of miR-200 mimics into VSMC downregulated Zeb1 by targeting its 3′-UTR, upregulated the inflammatory genes cyclooxygenase-2 (COX-2) and monocyte chemoattractant protein-1, and promoted monocyte binding in db/+ VSMC. In contrast, miR-200 inhibitors reversed the enhanced monocyte binding of db/db VSMC. Zeb1 gene silencing with siRNAs also increased these pro-inflammatory responses in db/+ VSMC confirming negative regulatory role of Zeb1. Both miR-200 mimics and Zeb1 siRNAs increased COX-2 promoter transcriptional activity. Chromatin immunoprecipitation showed that Zeb1 occupancy at inflammatory gene promoters was reduced in db/dbVSMC. Furthermore, Zeb1 knockdown increased miR-200 levels demonstrating a feedback regulatory loop. Disruption of the reciprocal negative regulatory loop between miR-200 and Zeb1 under diabetic conditions enhances pro-inflammatory responses of VSMC implicated in vascular complications.