ABCG1 and endothelial function

ABCG1 和内皮功能

基本信息

批准号：
8207861
负责人：
ALAN richard TALL
金额：
$ 40.25万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-01-03 至 2014-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8207861
关键词：
7-ketocholesterol ATP-Binding Cassette Transporters Animal Model Antiatherogenic Apolipoprotein A-I Apolipoprotein E Apolipoproteins Arterial Fatty Streak Atherosclerosis Biological Availability Breeding Calmodulin Caveolae Caveolins Cell Adhesion Molecules Cell model Cells Characteristics Cholesterol Complex Data Defect Diet Endothelial Cells Endothelium Functional disorder Gene Transfer Techniques Generations Genetic Recombination High Density Lipoproteins Human Inflammatory Infusion procedures Knock-out Link Mediating Mus NADPH Oxidase Plasma Play Relaxation Resistance Role Signal Transduction Small Interfering RNA Sterols Testing Transgenes atherogenesis cadherin 5 caveolin 1 chemokine cytokine feeding human NOS3 protein improved in vivo insight knock-down novel overexpression particle protective effect reconstitution research study unpublished works

项目摘要

Plasma high density lipoproteins (HDL) have a protective effect in atherosclerosis but the underlying mechanisms are incompletely understood. A part of the athero-protective effect of HDL may be related to its ability to reverse endothelial dysfunction, a characteristic feature of early atherosclerotic lesions involving decreased bioavailability of eNOS-derived NO and increased expression of cell adhesion molecules and inflammatory chemokines and cytokines. Many of the beneficial effects of HDL appear to be related to its ability to promote efflux of cholesterol and toxic oxysterols from cells via the ATP binding cassette transporters, ABCA1 and ABCG1. ABCG1 is highly expressed in endothelial cells and has an essential role in promoting efflux of cholesterol and 7- oxysterols to HDL. Our recent studies show that high cholesterol diet-fed Abcg1-/- develop a severe defect in eNOS-dependent relaxation of arterial segments, associated with accumulation of 7-ketocholesterol and disruption of the active, dimeric form of eNOS. In cholesterol-loaded human aortic endothelial cells (HAECs), knock-down of ABCG1 results in decreased eNOS activity and. This leads to the central hypothesis that ABCG1 has an anti-atherogenic role in endothelium. In Aim 1 we propose to investigate cellular mechanisms responsible for decreased eNOS activity and increased expression of cell adhesion molecules in ABCG1-deficient cells. The central concept we will test is whether there is increased formation of inhibitory eNOS/Caveolin complexes, increased caveolar localization and activation of signaling complexes involving NADPH oxidases. In Aims 2 and 3 we will use recently developed Abcg1flox/flox mice to carry out endothelial- specific knock-out of ABCG1. These mice will be crossed with Ldlr-/- mice to determine whether there is reduced eNOS activity, increased expression of cell adhesion molecules and increased atherogenesis. We will also determine if these mice are resistant to the athero-protective effects of increased HDL levels induced by infusions of reconstituted HDL or apoA-1 transgenesis. These studies will use novel animal and cellular models to provide new insights into the mechanisms of athero-protective effects of HDL involving arterial endothelium.

血浆高密度脂蛋白（HDL）对动脉粥样硬化有保护作用，但根本机制尚不完全清楚。动脉粥样硬化保护的一部分 HDL 的作用可能与其逆转内皮功能障碍的能力有关，涉及生物利用度降低的早期动脉粥样硬化病变的特征 eNOS 衍生的 NO 和细胞粘附分子表达增加炎症趋化因子和细胞因子。 HDL 的许多有益作用似乎与其促进胆固醇和有毒氧甾醇从细胞中流出的能力有关 ATP 结合盒转运蛋白 ABCA1 和 ABCG1。 ABCG1 高表达在内皮细胞中，对促进胆固醇和 7- 外流具有重要作用氧甾醇转化为HDL。我们最近的研究表明，高胆固醇饮食喂养的 Abcg1-/- 动脉段 eNOS 依赖性松弛出现严重缺陷，相关随着 7-酮胆固醇的积累和活性二聚体形式的破坏内皮型一氧化氮合酶。在负载胆固醇的人主动脉内皮细胞 (HAEC) 中， ABCG1 导致 eNOS 活性降低。这引出了一个中心假设： ABCG1 在内皮细胞中具有抗动脉粥样硬化作用。在目标 1 中，我们建议进行调查导致 eNOS 活性降低和表达增加的细胞机制 ABCG1 缺陷细胞中细胞粘附分子的变化。我们要测试的中心概念是抑制性 eNOS/Caveolin 复合物的形成是否增加，涉及 NADPH 氧化酶的信号复合物的细胞膜穴定位和激活。在目标 2 和 3 中，我们将使用最近开发的 Abcg1flox/flox 小鼠来进行内皮- ABCG1 的特异性敲除。这些小鼠将与 Ldlr-/- 小鼠杂交以确定 eNOS活性是否降低，细胞粘附表达增加分子并增加动脉粥样硬化形成。我们还将确定这些小鼠是否抵抗由输注引起的高密度脂蛋白水平升高的动脉粥样硬化保护作用重组 HDL 或 apoA-1 转基因。这些研究将使用新的动物和细胞模型为动脉粥样硬化保护作用机制提供新见解 HDL 涉及动脉内皮。