Novel mechanism of smooth muscle phenotypic modulation and vascular remodeling

平滑肌表型调节和血管重塑的新机制

基本信息

批准号：
8653749
负责人：
Shiyou Chen
金额：
$ 37.25万
依托单位：
UNIVERSITY OF GEORGIA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-02-01 至 2018-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8653749
关键词：
3&apos Untranslated Regions ADAR1 Adenosine Angioplasty Ants Arterial Disorder Arteries Atherosclerosis Blood Platelets Blood Vessels Bypass Cardiovascular Diseases Carotid Arteries Cell physiology Contractile Proteins Contracts DRADA2b protein Data Development Diabetic Angiopathies Disease Down-Regulation Figs - dietary Gene Expression Genes Genetic Goals Growth Hyperplasia Hypertension Injury Inosine Introns Knockout Mice Lead Mediating Messenger RNA Mining Modeling Molecular Mus Muscle Myosin ATPase Myosin Heavy Chains Pathologic Phenotype Platelet-Derived Growth Factor Play Proteins RNA Editing RNA Splicing Rattus Regulation Role Seminal Site Smooth Muscle Smooth Muscle Myocytes Smooth Muscle Myosins Steno Testing Therapeutic Therapeutic Agents Transcript Translations Transplantation United States Vascular Diseases Vascular Proliferation Vascular Smooth Muscle Vascular remodeling Veins calponin dsRNA adenosine deaminase gain of function in vivo injured loss of function mRNA Precursor migration mortality mouse model neointima formation novel platelet-derived growth factor BB protein expression public health relevance restenosis small hairpin RNA teration

项目摘要

DESCRIPTION (provided by applicant): Vascular smooth muscle (SMC) phenotypic modulation, the transition from a contractile to a proliferative phenotype accompanied by neointima formation following vascular injury, plays a critical role in the development and progression of several proliferative cardiovascular diseases such as atherosclerosis, hypertension, restenosis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. The regulatory mechanisms underlying SMC phenotypic modulation, however, are poorly understood. A hallmark feature of the phenotypic modulation is the down-regulation of SMC contractile genes. Platelet-derived growth factor-BB (PDGF-BB), a well-known stimulator of SMC phenotypic modulation, down- regulates SMC gene expression and stimulates SMC proliferation via posttranscriptional regulation of the related genes. The post-transcriptional mechanisms involved in SMC phenotype gene expression, however, remain largely unknown. Our exciting preliminary data indicate that the down-regulation of SMC contractile genes is caused by abnormal RNA editing of their precursor mRNAs (pre-mRNAs). This abnormal pre-mRNA editing is facilitated by adenosine deaminase acting on RNA (ADAR), which converts adenosines to inosines (A->I editing). A-to-I RNA editing of the pre-mRNA transcripts from introns or 3'-untranslated regions alters pre- mRNA splicing, leading to decreased mature mRNA levels and abnormal cellular functions. PDGF-BB induces ADAR1 while down-regulating SMC myosin heavy chain (SMMHC) and calponin (CNN). Knockdown of ADAR1 by shRNA restores PDGF-BB-blocked SMMHC and CNN expression, demonstrating that ADAR1 plays an essential role in SMC phenotype modulation. ADAR1 appears to be also important for PDGF-BB-induced SMC proliferation/survival. In vivo studies show that SMMHC and CNN pre-mRNA is accumulated when their mature mRNA is decreased in balloon-injured rat carotid arteries. Moreover, ADAR1 is highly induced in media layer SMCs initially, and neointima SMCs subsequently following the injury. Of importance, knockdown of ADAR1 dramatically inhibits injury-induced neointima formation, demonstrating a critical role of ADAR1 in vascular remodeling in vivo. These seminal findings strongly support a novel hypothesis that ADAR1/abnormal RNA editing mediates PDGF-BB-induced down-regulation of SMC contractile genes and SMC proliferation/survival, leading to SMC phenotypic modulation and vascular remodeling. Using primary culture of SMCs, in vivo rat balloon injury and mouse wire injury models combining with molecular, cellular and histological approaches, we will 1) determine the role and mechanism whereby ADAR1 modulates SMC phenotype; 2) elucidate the molecular mechanisms underlying ADAR1 function in regulating SMC proliferation/survival; and 3) study the role of ADAR1 in SMC phenotypic modulation and vascular remodeling in vivo. Successful completion of these aims will unravel a novel mechanism governing SMC phenotypic modulation, which will ultimately lead to identification of novel targets for developing therapeuti agents to treat proliferative vascular diseases.

描述（由申请人提供）：血管平滑肌（SMC）表型调节，从收缩到血管损伤后伴随着新神经形成的增殖表型的过渡在几种增殖和进展中起着至关重要的作用移植动脉疾病。然而，SMC表型调制的基础调节机制知之甚少。表型调制的标志性特征是SMC收缩基因的下调。血小板衍生的生长因子BB（PDGF-BB）是SMC表型调节的众所周知的刺激剂，下调调节SMC基因表达，并通过转录后调节相关基因刺激SMC增殖。然而，与SMC表型基因表达有关的转录后机制仍然在很大程度上未知。我们令人兴奋的初步数据表明，SMC收缩基因的下调是由其前体mRNA（前MRNA）异常的RNA编辑引起的。作用在RNA（ADAR）上的腺苷脱氨酶促进了这种异常的MRNA编辑，该腺苷脱氨酶将腺苷转化为插入（A-> I编辑）。来自内含子或3'-非翻译区域的A-to-I RNA编辑，改变了前mRNA剪接，从而导致成熟的mRNA水平降低和异常的细胞功能。 PDGF-BB在下调SMC肌球蛋白重链（SMMHC）和CALPONIN（CNN）时诱导ADAR1。 SHRNA敲低ADAR1可恢复PDGF-BB阻断的SMMHC和CNN表达，表明ADAR1在SMC表型调制中起着至关重要的作用。 ADAR1对于PDGF-BB诱导的SMC增殖/存活率似乎也很重要。体内研究表明，当气囊受伤的大鼠颈动脉减少成熟的mRNA时，SMMHC和CNN Pre-MRNA会累积。此外，ADAR1最初是在介质层中高度诱导的，随后在受伤后Neintima SMC。重要的是，ADAR1的敲低显着抑制了损伤引起的新内膜形成，表明ADAR1在体内血管重塑中的关键作用。这些开创性的发现强烈支持了一个新的假设，即ADAR1/异常RNA编辑介导PDGF-BB诱导的SMC收缩基因的下调和SMC增殖/存活，从而导致SMC表型调节和血管重塑。使用SMC的一级培养，体内大鼠球囊损伤和与分子，细胞和组织学方法结合的小鼠线损伤模型，我们将1）确定ADAR1调节SMC表型的作用和机制； 2）阐明ADAR1在调节SMC增殖/存活中的作用的分子机制； 3）研究ADAR1在体内在SMC表型调节和血管重塑中的作用。这些目标的成功完成将揭示有关SMC表型调节的新型机制，这最终将导致确定开发治疗增殖性血管疾病的疗法剂的新靶标。