Transcriptional Regulation by Angiotensin II in Vascular Smooth Muscle Cells

描述（由申请人提供）：动脉粥样硬化性和高血压性心血管疾病（cvd）是发病率和死亡率的主要原因，对我们的医疗系统造成了严重的压力。肽激素血管紧张素II （Ang II）由于其在靶细胞如血管平滑肌细胞（VSMC）中的血管收缩、促氧化、生长和炎症特性而在这些病理中起主要作用。一些研究已经记录了Ang II在VSMC中通过1型受体（AT1R）作用的生化和信号传导机制。然而，AngII诱导病理基因转录调控的核表观遗传机制尚不清楚。人们越来越认识到染色质结构的深刻改变，包括组蛋白的表观遗传翻译后修饰（PTMs）的变化，如组蛋白H3 -赖氨酸甲基化（H3Kme）可以调节基因的“活性”或“非活性”状态。最近的证据也证明了microRNAs （miRs）通过转录后机制在基因调控中的关键作用。我们的目标是评估这种表观遗传和miR机制在Ang II的作用，以揭示新的治疗靶点。我们假设组蛋白H3Kme的失调和关键miRs的异常表达导致了Ang II诱导的与各种心血管疾病相关的VSMC功能障碍。这将通过3个特定目标进行测试，使用最先进的全基因组分析和生物信息学方法在细胞培养中以及相关小鼠模型中进行测试。具体目的1是对使用和不使用Ang II处理的VSMC中关键染色质组蛋白H3Kme标记进行表观基因组分析，评估调节这些标记的染色质酶，然后评估它们在VSMC中的功能作用。具体目标2是分析VSMC中响应Ang II的miR特征，然后确定关键差异表达的miR的功能相关性。特异性目的3是评估Ang II作用增加的特异性小鼠模型，以确定目的1和2中发现的表观遗传标记和mir的体内相关性。一旦完成，这项工作将产生新的数据，描述angii处理条件下VSMC的表观遗传和miR谱，并为血管生物学领域带来新的下一代基因组测序技术。结果可以增加我们对Ang II作用的理解，并确定可能作为高血压和动脉粥样硬化等心血管疾病临床治疗的新靶点。

DESCRIPTION (provided by applicant): Atherosclerotic and hypertensive cardiovascular diseases (CVDs) are major causes of morbidity and mortality and a severe strain on our healthcare system. The peptide hormone Angiotensin II (Ang II) plays a major role in these pathologies due to its vasoconstrictive, pro-oxidant, -growth and -inflammatory properties in target cells such as vascular smooth muscle cells (VSMC). Several studies have documented the biochemical and signaling mechanisms of Ang II actions via the type 1 receptor (AT1R) in VSMC. However, the precise nuclear epigenetic mechanisms involved in AngII induced transcriptional regulation of pathological genes are not clear. It is increasingly recognized that profound alterations in chromatin structure, including changes in epigenetic posttranslational modifications (PTMs) of histones, such as Histone H3 -lysine methylation (H3Kme) can regulate the "active" or "inactive" state of genes. Recent evidence has also demonstrated the key roles of microRNAs (miRs) in gene regulation by posttranscriptional mechanisms. Our goal is to evaluate such epigenetic and miR mechanisms in Ang II actions in order to unravel new therapeutic targets. We hypothesize that the dysregulation of histone H3Kme and aberrant expression of key miRs contribute to Ang II induced VSMC dysfunction associated with various CVDs. This will be tested via 3 Specific Aims using state-of-the-art genome-wide profiling and bioinformatics approaches in cell culture along with relevant mouse models. Specific Aim 1 is to perform epigenome profiling of key chromatin histone H3Kme marks in VSMC treated with and without Ang II, evaluate the chromatin enzymes regulating these marks, and then their functional roles in VSMC. Specific Aim 2 is to profile the miR signatures in VSMC in response to Ang II and then determine the functional relevance of key differentially expressed miRs. Specific Aim 3 is to evaluate specific mouse models of increased Ang II action in order to determine the in vivo relevance of the epigenetic marks and miRs uncovered in Aims 1 and 2. When completed, the proposed work will yield novel new data describing the epigenetic and miR profiles of VSMC under Ang II treated conditions, and also bring in new next generation genome sequencing technologies to the field of vascular biology. The results can increase our understanding of Ang II actions, and identify new targets that might be developed as clinical therapies for CVDs such as hypertension and atherosclerosis. PUBLIC HEALTH RELEVANCE: Despite the availability of several therapies, the rates of cardiovascular diseases such as atherosclerosis and hypertension are soaring. Furthermore, these vascular complications are significantly higher in the diabetic population. Together, they are a severe drain on our healthcare resources. Since Angiotensin II is a major player in these pathologies, we propose to identify novel new epigenetic and micro-RNA based mechanisms responsible for Angiotensin II- induced expression of pathologic genes in vascular smooth muscle cells. We will use state-of- the-art profiling technologies to achieve our Specific Aims and thereby advance our long-term goal to identify new mechanisms and drug targets for cardiovascular diseases.