Targeting the Foam Cell to Prevent Atherosclerosis

针对泡沫细胞预防动脉粥样硬化

• 批准号: 8110006
• 负责人: Antonio Paul
• 金额: $ 39.5万
• 依托单位: ALBANY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-15 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8110006
• 关键词: Ablation; Adenoviruses; Adipose tissue; Adverse effects; Affect; Antiatherogenic; Apolipoprotein A-I; Apolipoprotein E; Apolipoproteins; Apoptosis; Arterial Fatty Streak; Atherosclerosis; Biology; Cells; Cellular biology; Cholesterol; Cholesterol Esters; Co-Immunoprecipitations; Data; Deposition; Development; Diet; Esters; Exposure to; Family; Fatty acid glycerol esters; Foam Cells; Gene Expression; Gene Silencing; Genes; Genomics; Goals; Human; In Vitro; Induction of Apoptosis; Inflammation; Inflammatory Response; Knockout Mice; Lead; Lesion; Lipid-Laden Macrophage; Lipids; Low-Density Lipoproteins; Mediating; Metabolism; Methods; Microarray Analysis; Mitochondria; Molecular; Mouse Protein; Mus; Pharmaceutical Preparations; Phospholipids; Plasma; Play; Prevention; Process; Protein Deficiency; Proteins; Proteomics; RNA; RNA amplification; Role; Rupture; Staging; Stress; Structure; System; Testing; Therapeutic; Therapeutic Intervention; Thinking; Toxic effect; Work; atherogenesis; atheroprotective; base; cholesterol trafficking; comparative; extracellular; feeding; helper-dependent adenoviral vector; hypercholesterolemia; improved; in vitro testing; in vivo; insight; laser capture microdissection; lipid transport; loss of function; macrophage; member; monolayer; novel strategies; prevent; protein expression; public health relevance; research study; response; therapeutic target; uptake

DESCRIPTION (provided by applicant): Summary Lipid-laden macrophages or "foam cells" play crucial roles in all the stages of atherogenesis, from lesion initiation to plaque rupture. However, our current therapeutic arsenal lacks of drugs primarily targeting the foam cell to prevent atherosclerosis development. Macrophages become foam cells by the uptake of modified low- density lipoproteins (mLDL) and accumulation of their lipids, mostly cholesterol (CHOL) esters (CE), in cytoplasmic lipid droplets (LDs). LDs consist of a core of neutral lipid stabilized and circumscribed by phospholipids, free CHOL (FC) and proteins. The main structural LD-associated proteins are the members of the PAT-family, and in macrophages the most abundant PAT-protein is adipose differentiation-related protein (ADFP). We have shown that ADFP plays a key role in foam cell formation, and its absence severely restricts the ability of macrophages to become foam cells in vitro and in vivo. ADFP is upregulated in human and mouse atherosclerotic lesions, and ADFP ablation in apolipoprotein E-null (apoE-/-) mice is atheroprotective. Enhancing CHOL efflux from macrophages, e.g. by increasing the concentration in plasma of CHOL acceptors or by upregulating the expression of CHOL efflux transporters, protects against atherosclerosis. This also seems to be the atheroprotective mechanism associated to the lack of ADFP, since ADFP-deficient macrophages do not accumulate as much CHOL in the form of CE in LDs, and efflux more CHOL to extracellular acceptors. The broad goal of this proposal is to gain insight on the role of ADFP in LD biology, foam cell formation and atherosclerosis development. In the first aim, we will test in vitro the response, in terms of inflammation and apoptosis, of ADFP-deficient macrophages cultured under high lipid stress conditions. We will also check if the atheroprotection observed in ADFP-/- mice fed regular chow is also observed when mice are challenged with a high fat/high CHOL diet. In the second aim, we will increase the plasma concentration of the CHOL acceptor apolipoprotein A1 (apoA1) with a helper-dependent adenovirus (HDAd) vector system, and assess whether two different approaches to increase CHOL efflux (i.e. increasing extracellular acceptors and limiting the cell's ability to store CHOL) will have additive atheroprotective effects. In the third aim, we will perform proteomic analyses to find the main LD-associated proteins and ADFP interactors in macrophages cultured under lipid-storing and lipid-efflux conditions. We will also perform a global gene expression analysis in foam cells directly isolated from lesions of mice that do or do not express ADFP to determine how the foam cell adjusts to the lack of ADFP. From this broad-based analysis of the role of ADFP in foam cell formation and atherosclerosis we expect to obtain a breadth of understanding that may help to set- up the bases for novel strategies to target the foam cell to prevent atherosclerosis development. PUBLIC HEALTH RELEVANCE: By elucidating the response of ADFP-deficient macrophages to high lipid stress conditions, whether preventing cholesterol accumulation in lipid droplets while increasing the ability of the extracellular milieu to accept cholesterol can work synergistically to prevent atherosclerosis, the molecular mechanisms that govern lipid droplet genesis and degradation in macrophages, how ADFP is involved in the processes, and how the foam cell adjust to the lack of ADFP, these studies will provide a breadth of understanding on foam cell biology that may be very useful if drugs to target the lipid droplet to prevent foam cell formation and atheroclerosis are to be developed.

描述（由申请人提供）：总结载脂巨噬细胞或“泡沫细胞”在动脉粥样硬化形成的所有阶段（从病变开始到斑块破裂）中发挥着至关重要的作用。然而，我们目前的治疗手段缺乏主要针对泡沫细胞来预防动脉粥样硬化发展的药物。巨噬细胞通过摄取修饰的低密度脂蛋白（mLDL）并在细胞质脂滴（LD）中积累其脂质（主要是胆固醇（CHOL）酯（CE））而成为泡沫细胞。 LD 由稳定的中性脂质核心组成，并由磷脂、游离 CHOL (FC) 和蛋白质包围。主要结构 LD 相关蛋白是 PAT 家族的成员，巨噬细胞中最丰富的 PAT 蛋白是脂肪分化相关蛋白 (ADFP)。我们已经证明 ADFP 在泡沫细胞形成中起着关键作用，它的缺失严重限制了巨噬细胞在体外和体内成为泡沫细胞的能力。 ADFP 在人类和小鼠动脉粥样硬化病变中上调，载脂蛋白 E 缺失 (apoE-/-) 小鼠中 ADFP 消融具有动脉粥样硬化保护作用。增强巨噬细胞的 CHOL 流出，例如通过增加血浆中 CHOL 受体的浓度或上调 CHOL 外流转运蛋白的表达，可预防动脉粥样硬化。这似乎也是与缺乏 ADFP 相关的动脉粥样硬化机制，因为缺乏 ADFP 的巨噬细胞不会在 LD 中以 CE 形式积累那么多的 CHOL，并且会将更多的 CHOL 流出到细胞外受体。该提案的总体目标是深入了解 ADFP 在 LD 生物学、泡沫细胞形成和动脉粥样硬化发展中的作用。第一个目标是，我们将在体外测试在高脂质应激条件下培养的 ADFP 缺陷型巨噬细胞在炎症和细胞凋亡方面的反应。我们还将检查当小鼠接受高脂肪/高胆固醇饮食挑战时，在常规饲料喂养的 ADFP-/- 小鼠中观察到的动脉粥样硬化保护是否也能观察到。在第二个目标中，我们将使用辅助依赖性腺病毒 (HDAd) 载体系统增加 CHOL 受体载脂蛋白 A1 (apoA1) 的血浆浓度，并评估是否有两种不同的方法来增加 CHOL 流出（即增加细胞外受体和限制细胞储存胆固醇的能力）将具有额外的动脉粥样硬化保护作用。第三个目标是，我们将进行蛋白质组学分析，以找到在脂质储存和脂质流出条件下培养的巨噬细胞中主要的 LD 相关蛋白和 ADFP 相互作用因子。我们还将对直接从表达或不表达 ADFP 的小鼠病变中分离的泡沫细胞进行全局基因表达分析，以确定泡沫细胞如何适应 ADFP 的缺乏。通过对 ADFP 在泡沫细胞形成和动脉粥样硬化中作用的广泛分析，我们期望获得广泛的理解，这可能有助于为针对泡沫细胞预防动脉粥样硬化发展的新策略奠定基础。 公共健康相关性：通过阐明 ADFP 缺陷型巨噬细胞对高脂质应激条件的反应，防止胆固醇在脂滴中积聚，同时增加细胞外环境接受胆固醇的能力是否可以协同预防动脉粥样硬化，动脉粥样硬化是控制脂质的分子机制。巨噬细胞中液滴的生成和降解、ADFP 如何参与该过程以及泡沫细胞如何适应 ADFP 的缺乏，这些研究将为如果要开发针对脂滴的药物以防止泡沫细胞形成和动脉粥样硬化，那么对泡沫细胞生物学的广泛了解可能非常有用。