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improved in vivo insight knock-down novel overexpression particle protective effect reconstitution research study unpublished works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）在动脉粥样硬化中具有保护作用，但基本机制尚不完全理解。动脉粥样硬化的一部分 HDL的影响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和细胞粘附分子的表达增加和增加炎性趋化因子和细胞因子。 HDL的许多有益作用似乎与其通过通过细胞从细胞中促进胆固醇和有毒氧甲醇的外排的能力有关 ATP结合盒转运蛋白ABCA1和ABCG1。 ABCG1高度表达在内皮细胞中，在促进胆固醇和7-- 氧化酚至HDL。我们最近的研究表明，高胆固醇饮食喂养的ABCG1 - / - 在动脉片段的eNOS依赖性放松中出现严重的缺陷，相关随着7-酮胆脂酯的积累，并破坏了活性的二聚体形式 eNOS。在胆固醇负载的人主动脉内皮细胞（HAECS）中 ABCG1导致eNOS活性降低。这导致了一个中心假设，即 ABCG1在内皮中具有抗动脉粥样硬化作用。在目标1中，我们建议调查导致eNOS活性降低和表达增加的细胞机制 ABCG1缺陷细胞中的细胞粘附分子。我们将测试的中心概念是抑制性eNOS/小窝蛋白复合物的形成是否增加，增加涉及NADPH氧化酶的信号传导复合物的洞穴定位和激活。在AIMS 2和3中，我们将使用最近开发的ABCG1FLOX/FLOX小鼠进行内皮 - ABCG1的具体敲除。这些小鼠将与LDLR - / - 小鼠交叉以确定 eNOS活性是否减少，细胞粘附的表达增加分子并增加了动脉粥样硬化。我们还将确定这些老鼠是否是耐药的HDL水平增加的动脉保护作用。重构的HDL或APOA-1转基因。这些研究将使用新型动物和细胞模型，以提供有关动脉保护作用机制的新见解涉及动脉内皮的HDL。