Mechanism of chymase activation in endothelial cells

描述(申请人提供)：这项研究的目的是探索内皮细胞(ECs)中凝乳酶表达增加的机制，并验证我们的假设，即组蛋白修饰导致先兆子痫(PE)血管内皮细胞中凝乳酶的激活。凝乳酶是一种凝乳酶样丝氨酸蛋白酶(CLP)，是引起高血压和糖尿病等心血管疾病的重要因素。糜酶是一种血管紧张素转换酶，不依赖于血管紧张素转换酶。血管紧张素转换酶II是一种有效的血管收缩因子，在PE血管收缩增强中起关键作用。与正常血压对照组相比，PE患者母体血管内皮细胞中的凝乳酶表达增加。胎盘来源的CLP/Chymase不仅可激活EC糜酶，还可促进胎盘sFlt-1在PE中的释放。然而，乳糜酶激活的机制仍然不清楚。为了探讨EC糜酶在PE中的激活机制，在我们的初步研究中，利用模拟EC糜酶在PE中表达增加的体外模型系统，我们发现特异性的HDAC抑制直接参与了糜酶的调节。在这项研究中，我们首次提出了胎盘介导的内皮细胞糜酶激活的表观遗传学基础，特别是我们将检验异常的表观遗传调节(组蛋白修饰)在PE中介导内皮糜酶激活的假说。这一假设将在两个具体目标中得到检验。目标1将 演示胎盘因子介导组蛋白修饰如何导致PE中内皮细胞糜酶的表达，AIM 2将演示组蛋白乙酰化如何导致内皮细胞中的糜酶激活。利用最先进的技术、凝乳酶基因转移方法、siRNA和靶分子的特异性抑制剂和阻断剂，我们将确定组蛋白修饰如何介导PE患者EC中的凝乳酶表达。这些研究是首次尝试研究表观遗传调控的作用，表观遗传调控将胎盘功能障碍、糜酶激活和发生在PE中的EC表型变化联系在一起。本研究结果将对凝乳酶激活及其对内皮细胞功能的病理影响提供新的机制解释，并将为开发治疗凝乳酶激活相关血管疾病和代谢紊乱的新的治疗策略提供理论依据。

DESCRIPTION (provided by applicant): The objective of this study is to explore the mechanism of increased chymase expression in endothelial cells (ECs) and to test our hypothesis that histone modification leads to chymase activation in vascular ECs in preeclampsia (PE). Chymase, a chymotrypsin-like serine protease (CLP), is a significant contributor to cardiovascular diseases, including hypertension and diabetes. Chymase is an ACE-independent angiotensin II (Ang II) converting enzyme. Ang II, a potent vasoconstrictor, plays a key role in increased vasoconstriction in PE. Chymase expression is increased in maternal vessel endothelium in women with PE compared to normotensive controls. CLP/chymase derived from PE placenta is not only responsible for triggering EC chymase activation, but also contributes to placental sFlt-1 release in PE. However, the mechanism that underlies chymase activation remains elusive. To explore the mechanism of EC chymase activation in PE, in our preliminary study that using an in vitro model system that mimics the increased EC chymase expression in PE, we found that specific HDAC inhibition directly contributes to chymase regulation. In this study, we propose for the first time to explore the epigenetic basis of placenta-mediated activation of chymase in the endothelium, specifically, we will test the hypothesis that aberrant epigenetic regulation (histone modification) mediated endothelial chymase activation in PE. This hypothesis will be tested in 2 specific aims. Aim 1 will demonstrate how placental factor-mediated histone modification leads to endothelial chymase expression in PE and Aim 2 will demonstrate how histone acetylation leads to chymase activation in ECs. Using state-of-the-art techniques, chymase gene transfer approach, siRNA and specific inhibitors and blockers of target molecules, we will define how histone modification mediates chymase expression in EC in PE. These studies represent the first attempt to investigate the role of epigenetic regulation, which connects placenta dysfunction, chymase activation, and EC phenotypic changes that occur in PE. Results obtained from this study will lead to novel mechanistic explanation of chymase activation and its pathological effects on endothelial function in PE and will provide rationale for developing a new therapeutic strategy to treat chymase activation associated vascular diseases and metabolic disorders.