Transgenic rat overexpressing miR-21 in vascular smooth muscle cells:functional i

描述（由申请人提供）：微小RNA（miRNA）是一类新的非编码小RNA，其通过降解mRNA或抑制蛋白质翻译来负调节基因表达。研究表明，miRNA在多种疾病中发挥着非常重要的作用，例如癌症、病毒感染、遗传性疾病和心血管疾病。最近我们发现miR-21是一种致癌的miRNA基因，在多种癌症中异常过表达，在小鼠心肌肥厚模型和大鼠颈动脉球囊损伤模型中也上调。通过靶向磷酸酶和张力蛋白同源物（PTEN）基因的3 '非翻译区（UTR）并间接调节血管平滑肌细胞（VSMC）中Bcl-2基因的表达，敲低miR-21诱导血管平滑肌细胞和大鼠颈动脉球囊损伤模型中的凋亡。为了进一步了解miR-21调控血管疾病中重要信号通路基因表达的分子机制，我们构建了一个由大鼠平滑肌细胞特异性启动子（rSM22）驱动的miR-21基因慢病毒载体，并建立了一个在VSMCs中过表达miR-21的转基因大鼠模型。我们发现，几个转基因大鼠创始人表现出一致的表型：生长迟缓和轻微瘫痪的后肢。这种转基因大鼠模型将为理解miRNA在心血管疾病中的功能提供新的思路，并将帮助我们进一步评估miRNA在诊断和测试基于miRNA的心血管疾病治疗中的潜在应用。 公共卫生相关性：本研究拟利用慢病毒载体构建表达miR-21的转基因大鼠模型，通过靶向miR-21基因进入血管平滑肌细胞，研究miR-21的生物学功能。通过研究miR-21如何参与转录后调控，还将使用该转基因大鼠模型检查表型和表型背后的分子机制。

DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) are a new class of non-coding small RNAs that negatively regulate gene expression by either degrading mRNA or inhibiting protein translation. miRNAs have been shown to play very important roles in a variety of diseases, such as cancers, viral infection, genetic disorders, and cardiovascular diseases. Recently we found that miR-21, an oncogenic miRNA gene was aberrantly overexpressed in a variety of cancers, was also upregulated in the mouse cardiac hypertrophy model and rat carotid artery balloon injury model. Knockdown of miR-21 induced apoptosis in vascular smooth muscle cells and in the rat carotid artery balloon-injured model by targeting the 3'untranslated region (UTR) of the phosphatase and tensin homolog (PTEN) gene and indirectly regulated Bcl-2 gene expression in vascular smooth muscle cells (VSMCs). To further understand the molecular mechanism by which miR-21 regulates gene expression on the important signaling pathways, which play pivotal roles in vascular diseases, we constructed a lentiviral vector in which the miR-21 gene was driven by the rat smooth muscle cell specific promoter (rSM22) and generated a transgenic rat model in which miR-21 is overexpressed in VSMCs. We found that several transgenic rat founders display consistent phenotypes: growth retardation and slightly paralyzed hind limbs. This transgenic rat model will certainly provide insight to understanding miRNA functions in cardiovascular diseases and will help us further evaluate potential applications of miRNA in diagnosing and test miRNA based therapy for cardiovascular diseases. PUBLIC HEALTH RELEVANCE: This proposal is to characterize transgenic rats expressing miR-21 using lentiviral vector to address the biological functions of miRNAs by targeting miR-21 gene into vascular smooth muscle cells. The phenotype and molecular mechanisms underlying the phenotypes will also be examined using this transgenic rat models by investigating how miR-21 is involved in the posttranscriptional regulation.