ABCG1 and endothelial function

ABCG1 和内皮功能

• 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
• 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in vivo; insight; knock-down; novel; overexpression; particle; protective effect; reconstitution; research study; unpublished works

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.

血浆高密度脂蛋白在动脉粥样硬化中有保护作用，但 其潜在的机制还没有完全被理解。动脉粥样硬化防护的一部分 高密度脂蛋白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 内皮型一氧化氮合酶和细胞黏附分子表达增加 炎性趋化因子和细胞因子。高密度脂蛋白的许多有益影响似乎 与其促进胆固醇和毒性氧化甾醇从细胞外流的能力有关 ATP结合盒转运体ABCA1和Abcg1。Abcg1基因高度表达 并在促进胆固醇和7-羟色胺的外流方面起着重要作用。 氧化甾醇转化为高密度脂蛋白。我们最近的研究表明，高胆固醇饮食喂养的Abcg1-/- 出现严重的eNOS依赖的动脉节段松弛缺陷，相关 随着7-酮胆固醇的积累和活性的二聚体形式的破坏 伊诺斯。在胆固醇负荷的人主动脉内皮细胞(HAEC)中， Abcg1导致eNOS活性降低，并与正常对照组比较差异有统计学意义。这导致了一个中心假设，即 Abcg1在血管内皮细胞具有抗动脉粥样硬化作用。在目标1中，我们建议调查 ENOS活性降低和表达增加的细胞机制 Abcg1缺陷细胞中细胞黏附分子的表达。我们将测试的中心概念是 抑制性eNOS/Caveolin复合体的形成是否增加，增加 涉及NADPH氧化酶的信号复合体的空泡定位和激活。 在目标2和目标3中，我们将使用最近开发的Abcg1Flox/FLOX小鼠来进行内皮- Abcg1的特定敲除。这些小鼠将与Ldlr-/-小鼠杂交，以确定 是否存在eNOS活性降低，细胞黏附表达增加 分子和动脉粥样硬化的增加。我们还将确定这些老鼠是否 抗高密度脂蛋白水平升高所致的动脉粥样硬化保护作用 重组的高密度脂蛋白或载脂蛋白A-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的机制提供新的见解 高密度脂蛋白参与动脉内皮细胞。