Homeostasis in Adult Vessels

 描述（由申请方提供）：本研究的长期目标是确定在动脉粥样硬化和炎症的初始阶段可以为内皮提供固有保护的因素。在本提案中，我们将重点关注NOTCH 1，这是一种细胞表面受体和转录因子，根据初步数据，它为静止（稳态）内皮提供抗炎表型。NOTCH 1在体内由小鼠和人血管的成体内皮组成性表达。在没有任何额外损伤的情况下，体外人内皮细胞中NOTCH 1转录物的减少或小鼠中Notch 1的遗传失活触发炎症反应。内皮细胞暴露于西方饮食、氧化磷脂（Ox-PAPC）以及炎性细胞因子导致内源性NOTCH 1（连同其靶基因）的快速减少。使用来自147名人类供体的内皮细胞的微阵列分析，我们观察到基础和Ox-PAPC处理的NOTCH 1水平的差异，并确定了与Ox-PAPC引起的内皮细胞对NOTCH 1的反应相关的位点。在包括100，000人的大规模GWAS中，同一位点也与HDL水平相关。本项目的研究将检验循环脂质减少NOTCH 1有助于 与动脉粥样硬化病变的典型炎症有关。事实上，在动脉粥样硬化易感背景（Apoe或Ldlr敲除小鼠）中NOTCH 1水平的降低促进动脉粥样硬化的加速并导致更大的病变。此外，Notch 1在成年小鼠内皮中的基因失活导致白细胞浸润、脱离和内皮细胞损失 从内膜上。此外，与内皮稳态和炎症抑制中的作用一致，使用ChIP方法，我们发现NOTCH 1调节三曲脯氨酸，一种靶向3 'UTR中战神序列的RNA结合蛋白，导致编码一组炎性细胞因子的mRNA不稳定。本申请的中心假设是内皮中的NOTCH 1对于维持血液和组织之间的抗炎界面是必不可少的。为了验证这一假设，我们提出了两个具体目标：1。确定控制成人动脉内皮中NOTCH 1表达和功能的机制;和2.确定NOTCH 1在静止动脉内皮中维持抗炎状态的分子途径。

 DESCRIPTION (provided by applicant): The long term goal of this line of investigation is to identify the factors that can provide inherent protection to the endothelium during the initial stages of atherosclerosis and inflammation. In this proposal, we will focus on NOTCH1, a cell surface receptor and transcription factor that, based on preliminary data, provides an anti-inflammatory phenotype to quiescent (homeostatic) endothelium. NOTCH1 is constitutively expressed by the adult endothelium of mouse and human vessels in vivo. Reduction of NOTCH1 transcripts in human endothelium in vitro or genetic inactivation of Notch1 in mice triggers an inflammatory response in the absence of any additional insult. Exposure of endothelial cells to Western diet, oxidized phospholipids (Ox- PAPC), as well as inflammatory cytokines, results in a rapid reduction in endogenous NOTCH1 (together with its target genes). Using microarray analyses of endothelial cells from 147 human donors, we observed differences in basal and Ox-PAPC treated levels of NOTCH1 and identified a locus that was associated with the response of endothelial cells to NOTCH1 by Ox-PAPC. This same locus was also associated with HDL levels in a large scale GWAS including 100,000 humans. Studies in this project will test the hypothesis that reduction of NOTCH1 by circulating lipids contributes to the prolonged inflammation typical of atherosclerosis lesions. In fact, reduction of NOTCH1 levels in an athero-susceptible background (Apoe or Ldlr null mice) promotes acceleration of atherosclerosis and results in larger lesions. Furthermore, genetic inactivation of Notch1 in the endothelium of adult mice leads to leukocyte infiltration, detachment and loss of endothelial cells from the intima. In addition and consistent with a role in endothelial homeostasis and suppression of inflammation, using a ChIP approach we found that NOTCH1 regulates tristetraprolin, an RNA binding protein that targets to AREs sequences in the 3'UTR causing destabilization of mRNAs encoding a cohort of inflammatory cytokines. The central hypothesis of this application is that NOTCH1 in the endothelium is essential to maintain an anti-inflammatory interface between blood and tissue. To test this hypothesis, we propose two specific aims: 1. To determine the mechanism(s) that control NOTCH1 expression and function in adult arterial endothelium; and 2. To identify the molecular pathways by which NOTCH1 maintains an anti-inflammatory status in the endothelium of quiescent arteries.