The miR-143/145 Cluster Is a Novel Transcriptional Target of Jagged-1/Notch Signaling in Vascular Smooth Muscle Cells
The miR-143/145 Cluster Is a Novel Transcriptional Target of Jagged-1/Notch Signaling in Vascular Smooth Muscle Cells
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DOI：
10.1074/jbc.m111.221945
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发表时间：
2011-08-12
影响因子：
4.8
通讯作者：
Liaw, Lucy
中科院分区：
文献类型：
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作者：
Boucher, Joshua M.;Peterson, Sarah M.;Liaw, Lucy
血管平滑肌细胞（VSMC）中Jagged-1 （Jagged-1）激活Notch信号可促进以收缩蛋白表达增加为特征的分化表型。最近的研究表明microRNAs (miR)-143/145调控VSMC表型。血清反应因子(SRF)/心肌素复合物结合CArG序列激活miR-143/145转录，但在VSMC中没有其他已知的调节因子。使用miR阵列，我们发现miR-143/145诱导了组成活性Notch1胞内结构域（N1ICD）的表达。我们假设miR-143/145是jag1 / notch诱导的VSMC分化所必需的。jag1激活Notch受体导致cbf1依赖性miR-143/145上调，分化增加，增殖减少。相反，抑制基础Notch信号会降低miR-143/145的稳态水平。通过SRF敲除，我们发现jag1 /Notch诱导miR-143/145是SRF独立的，尽管完全获得收缩标记需要SRF。通过构建miR-143/145启动子报告子，我们发现jag1 /Notch增加了启动子活性，这依赖于启动子内完整的CBF1共识位点。染色质免疫沉淀（ChIP）分析显示，含有n1icd的复合物与miR-143/145启动子中的CBF1位点结合。我们还在内源性人miR-143/145启动子中发现了与CBF1位点结合的N1ICD复合物。使用miR-143/145干扰寡核苷酸，我们证明了jag1 /Notch信号需要诱导miR-143和miR-145来促进VSMC收缩表型。因此，miR-143/145是VSMC中jag1 /Notch信号的一个新的转录靶点。我们提出miR-143/145在平行通路中被jag1 /Notch和SRF独立激活。汇聚在miR-143/145上的多种途径为VSMC分化信号的微调或放大提供了可能。
Activation of Notch signaling by Jagged-1 (Jag-1) in vascular smooth muscle cells (VSMC) promotes a differentiated phenotype characterized by increased expression of contractile proteins. Recent studies show that microRNAs (miR)-143/145 regulates VSMC phenotype. The serum response factor (SRF)/myocardin complex binds to CArG sequences to activate miR-143/145 transcription, but no other regulators are known in VSMC. Using miR arrays, we found miR-143/145 induced following expression of a constitutively active Notch1 intracellular domain (N1ICD). We hypothesized that miR-143/145 is required for Jag-1/Notch-induced VSMC differentiation. Activation of Notch receptors by Jag-1 caused CBF1-dependent up-regulation of miR-143/145, increased differentiation, and decreased proliferation. Conversely, inhibiting basal Notch signaling decreased steady state levels of miR-143/145. Using SRF knockdown, we found that Jag-1/Notch induction of miR-143/145 is SRF independent, although full acquisition of contractile markers requires SRF. Using miR-143/145 promoter reporter constructs we show Jag-1/Notch increases promoter activity, and this is dependent on intact CBF1 consensus sites within the promoter. Chromatin immunoprecipitation (ChIP) assays revealed that N1ICD-containing complexes bind to CBF1 sites in the miR-143/145 promoter. We also identified N1ICD complex binding to CBF1 sites within the endogenous human miR-143/145 promoter. Using miR-143/145-interfering oligonucleotides, we demonstrate that Jag-1/Notch signaling requires induction of both miR-143 and miR-145 to promote the VSMC contractile phenotype. Thus, miR-143/145 is a novel transcriptional target of Jag-1/Notch signaling in VSMC. We propose miR-143/145 as activated independently by Jag-1/Notch and SRF in parallel pathways. Multiple pathways converging on miR-143/145 provides potential for fine-tuning or amplification of VSMC differentiation signals.