MiR-133a Modulates Osteogenic Differentiation of Vascular Smooth Muscle Cells
MiR-133a Modulates Osteogenic Differentiation of Vascular Smooth Muscle Cells
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MiR-133a 调节血管平滑肌细胞的成骨分化。
DOI：
10.1210/en.2012-2236
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发表时间：
2013-09-01
期刊：
影响因子：
4.8
通讯作者：
Yuan, Ling-Qing
中科院分区：
文献类型：
--
作者：
Liao, Xiao-Bo;Zhang, Zhi-Yuan;Yuan, Ling-Qing
动脉钙化是动脉粥样硬化、冠状动脉疾病和外周血管疾病等血管疾病的重要病理组成部分。这种病理过程的一个标志是血管平滑肌细胞（VSMC）向成骨细胞样细胞的表型转变。一些研究表明，microRNAs（miRNAs）调节成骨细胞分化，但目前尚不清楚是否miRNAs也调节VSMC介导的动脉钙化。在本研究中，我们试图描述miR-133 a在调控VSMC介导的动脉钙化中的作用。北方印迹分析表明，在成骨分化过程中，miR-133 a的表达显著降低。过表达miR-133 a可抑制VSMC转分化为成骨样细胞，表现为碱性磷酸酶活性、骨钙素分泌、Runx 2表达和矿化结节形成减少。相反，使用miR-133 a抑制剂敲低miR-133 a通过增加碱性磷酸酶活性、骨钙素分泌和Runx 2表达促进VSMC的成骨分化。通过在VSMC中与含有Runx 2的野生型或突变体3 '非翻译区序列的荧光素酶报告质粒进行共转染实验，将Runx 2鉴定为miR-133 a的直接靶点。此外，miR-133 a抑制剂的促成骨作用在Runx 2敲低的细胞中被消除，并且前体miR-133 a对成骨分化的抑制被Runx 2的过表达逆转，提供了miR-133 a在成骨分化中的作用是通过靶向Runx 2介导的功能证据。这些结果表明，miR-133 a是VSMC成骨分化的关键负调控因子。
Arterial calcification is a key pathologic component of vascular diseases such as atherosclerosis, coronary artery disease, and peripheral vascular disease. A hallmark of this pathological process is the phenotypic transition of vascular smooth muscle cells (VSMCs) to osteoblast-like cells. Several studies have demonstrated that microRNAs (miRNAs) regulate osteoblast differentiation, but it is unclear whether miRNAs also regulate VSMC-mediated arterial calcification. In the present study, we sought to characterize the role of miR-133a in regulating VSMC-mediated arterial calcification. Northern blotting analysis of VSMCs treated with β-glycerophosphate demonstrated that miR-133a was significantly decreased during osteogenic differentiation. Overexpression of miR-133a inhibited VSMC transdifferentiation into osteoblast-like cells as evidenced by a decrease in alkaline phosphatase activity, osteocalcin secretion, Runx2 expression, and mineralized nodule formation. Conversely, the knockdown of miR-133a using an miR-133a inhibitor promoted osteogenic differentiation of VSMCs by increasing alkaline phosphatase activity, osteocalcin secretion, and Runx2 expression. Runx2 was identified as a direct target of miR-133a by a cotransfection experiment in VSMCs with luciferase reporter plasmids containing wild-type or mutant 3'-untranslated region sequences of Runx2. Furthermore, the pro-osteogenic effects of miR-133a inhibitor were abrogated in Runx2-knockdown cells, and the inhibition of osteogenic differentiation by pre-miR-133a was reversed by overexpression of Runx2, providing functional evidence that the effects of miR-133a in osteogenic differentiation were mediated by targeting Runx2. These results demonstrate that miR-133a is a key negative regulator of the osteogenic differentiation of VSMCs.