HDAC2 is a Critical Regulator of Vascular Endothelial Function

项目摘要 动脉粥样硬化性心血管疾病是美国的主要杀手，占所有死亡人数的40%。血管 内皮细胞（EC）功能通过提供正常的屏障功能和适应性功能来促进心血管健康。 防御氧化应激和血管老化和动脉粥样硬化。这些关键的内皮细胞 功能的损害导致严重的血管疾病，动脉粥样硬化是其中最常见和最具破坏性的。 表观遗传机制已被证明可以维持正常的EC稳态，但这些表观遗传机制的作用和活性是不确定的。 动脉粥样硬化血管中的机制仍然知之甚少。组蛋白去乙酰化酶2（HDAC 2）具有 作为一种重要的基因调节剂，促进EC氧化还原平衡和正常的血管 反应性和响应性。我们的数据记录了EC和小鼠睾丸中HDAC2水平的急剧下降 氧化损伤后，并暗示通过NEDD化的翻译后修饰是HDAC2的原因。 这种氧化损伤的降解。我们还表明HDAC 2增强了转录 通过防止衰老和屏障通透性丧失来保持EC功能的酶-ZMPSTE24 (Zinc金属肽酶STE24）。我们的数据还表明，暴露于环境中的EC中ZMPSTE24水平降低， OxLDL。此外，ZMPSTE24的减少导致了ZMPSTE24的丰度的显著的相互增加。 在动脉粥样硬化和老年小鼠的孤立性动脉粥样硬化中，内皮前层蛋白A，而ZMPSTE24 途径导致过早衰老（早衰症）综合征和深刻加速和恶性 动脉粥样硬化我们开发了最先进的工具和小鼠模型来询问我们的总体 以下一系列事件引发加速动脉粥样硬化形成的假设：氧化损伤减弱 EC中的HDAC 2，导致ZMPSTE24减少; ZMPSTE24的缺乏导致毒性 核支架蛋白前层蛋白A的积累;过量的前层蛋白A促进EC衰老， 损害EC屏障完整性和动脉粥样硬化。在第一个目标中，我们将定义 HDAC 2调控ZMPSTE24在EC中的转录和表达，并决定ZMPSTE24在EC中的作用 体内平衡目的二研究氧化损伤后HDAC 2降解加速的过程， 介导HDAC2的Nedd8修饰的特异性泛素连接酶以及neddylation抑制剂的作用 MLN 4924在体内内皮功能障碍和动脉粥样硬化形成中的作用。第三个目标将确定以下方面的具体影响： HDAC2表达对内皮衰老、屏障功能和动脉粥样硬化形成的影响这些研究将 产生增加HDAC2丰度的策略，支持内皮功能，并设计新的 用于预防或减缓动脉粥样硬化的治疗方案的组分。

PROJECT SUMMARY Atherosclerotic cardiovascular disease is a major killer in America, accounting for 40% of all deaths. Vascular endothelial cell (EC) function promotes cardiovascular health by providing normal barrier function and adaptive defense against oxidative stress and vascular aging and atherosclerosis. Failure of these key endothelial functions leads to critical vascular diseases, and atherosclerosis is the most common and devastating of these. Epigenetic mechanisms have been shown to maintain normal EC homeostasis, but the role and activity of these mechanisms in atherosclerotic vessels remain poorly understood. Histone deacetylase 2 (HDAC2) has emerged from our work as a critical gene regulator that promotes EC redox balance and normal vascular reactivity and responsiveness. Our data document a dramatic fall in HDAC2 levels in EC and mouse aortas after oxidative injury, and implicate post-translational modification via NEDDylation as the cause of HDAC2 degradation with this oxidative insult. We have also shown that HDAC2 enhances the transcription of an enzyme that preserves EC function by preventing senescence and the loss of barrier permeability - ZMPSTE24 (Zinc Metallopeptidase STE24). Our data also show that ZMPSTE24 levels are reduced in EC that are exposed to OxLDL. Moreover, a reduction in ZMPSTE24 causes a dramatic reciprocal increase in the abundance of endothelial prelamin A in isolated aortas from atherosclerotic and aged mice, while mutations in ZMPSTE24 pathways lead to premature aging (progeria) syndromes and profoundly accelerated and malignant atherosclerosis. We have developed state-of-the-art tools and mouse models to interrogate our overarching hypothesis that the following series of events sparks accelerated atherogenesis: Oxidative injury attenuates HDAC2 in EC, resulting in decreased ZMPSTE24; This paucity of ZMPSTE24 results in toxic accumulation of the nuclear scaffold protein prelamin A; Excess prelamin A promotes EC senescence, compromises EC barrier integrity, and atherosclerosis. In the first Aim, we will define mechanisms by which HDAC2 regulates ZMPSTE24 transcription and expression in EC, and determine the role of ZMPSTE24 in EC homeostasis. Aim two focuses on the process of accelerated HDAC2 degradation after oxidative injury, and the specific ubiquitin ligases that mediate Nedd8 modification of HDAC2, and the effects of neddylation inhibitor MLN4924 in endothelial dysfunction and atherogenesis in vivo. The third Aim will define the specific impact of HDAC2 expression on endothelial senescence, barrier function, and atheroma formation. These studies will produce strategies for increasing HDAC2 abundance, supporting endothelial function, and devising novel components for a therapeutic regimen preventing or slowing of atherosclerosis.