Macrophage-lipoprotein Interactions

巨噬细胞-脂蛋白相互作用

• 批准号: 9384099
• 负责人: Frederick R. Maxfield
• 金额: $ 43.59万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9384099
• 关键词: 1-Phosphatidylinositol 3-Kinase; AGFG1 gene; Acid Lipase; Actins; Arterial Fatty Streak; Atherosclerosis; Biological Assay; Biological Process; Blood Vessels; Bone Marrow; Bone Marrow Transplantation; Cell Culture Techniques; Cell membrane; Cells; Chelating Agents; Cholesterol; Cholesterol Esters; Cyclodextrins; Defect; Dendritic Cells; Deposition; Electron Microscopy; Enzymes; Excision; F-Actin; Female; Filipin; Fluorescence Microscopy; Foam Cells; Functional disorder; Genes; Goals; High Density Lipoprotein Cholesterol; High Density Lipoproteins; Hydrolysis; Immune system; Ions; Knock-out; Knockout Mice; Label; Lead; Lesion; Lipids; Lipoproteins; Low Density Lipoprotein Receptor; Low-Density Lipoproteins; Lysosomes; Macrophage Cell Biology; Mediating; Methods; Microscopy; Molecular; Morphology; Mus; Optics; PGRN gene; Phagocytes; Pharmacology; Polymers; Process; Production; Proteins; Publishing; RNA Interference; Resolution; Role; SNAP receptor; SYK gene; Scanning Electron Microscopy; Signal Transduction; Signaling Molecule; Site; Structure; Synapses; TLR4 gene; Therapeutic Intervention; Transcriptional Activation; Wild Type Mouse; Work; atherogenesis; base; beta-Cyclodextrins; extracellular; improved; in vivo; knock-down; low density lipoprotein inhibitor; macrophage; male; microscopic imaging; monocyte; mouse model; multiphoton imaging; novel; novel therapeutic intervention; novel therapeutics; polymerization; response; seal; tool; transcriptome sequencing

We described a novel mechanism for the hydrolysis of cholesteryl esters in retained and aggregated LDL (agLDL), which is the predominant form of lipoprotein in atherosclerotic lesions. Macrophages (MΦ) create tightly sealed compartments that surround the agLDL. They acidify these compartments and secrete lysosomal enzymes into them, creating a lysosomal synapse. This leads to formation of unesterified cholesterol outside the cell, which can be delivered to the plasma membrane leading to changes in signal transduction and foam cell formation. We hypothesize that this mechanism for degrading agLDL has significant differences compared to phagocytic or endocytic mechanisms and that these differences have important consequences for the pathophysiology and treatment of atherosclerosis. We will study the cellular mechanisms that regulate this process (which we call exophagy); better characterize exophagy in vivo; and explore a novel role for HDL and cyclodextrins in clearing the cholesterol produced by exophagy. (1) Characterize the mechanisms for extracellular hydrolysis of agLDL. We have used MΦ from knockout mice, RNAi, and pharmacological agents to identify a role for TLR4, Myd88, SYK, Akt, PI3 kinases, and other signaling molecules in exophagy. We use three main quantitative assays: lysosome secretion, formation of F- actin where MΦ contact agLDL, and formation of lipid droplets. We will identify the Rab and SNARE proteins required for lysosome secretion, and we will identify genes that are activated during exophagy. (2) Determine the role of lysosomal synapses in atherosclerotic lesions. We will use optical and electron microscopy to analyze the activity of lysosomal synapses in mouse models of atherosclerosis. We will use bone marrow transplants into LDL receptor knockout mice to determine the importance of signaling processes. (3) Characterize HDL interactions with agLDL in contact with MΦ. AgLDL in contact with MΦ has very high levels of unesterified cholesterol. HDL or cholesterol-balanced cyclodextrins can remove excess cholesterol with no loss of cholesterol from cells. We will characterize this process and its impact on foam cell formation.

我们描述了保留和聚集的LDL中胆固醇酯水解的新型机制 （AGLDL），这是动脉粥样硬化病变中脂蛋白的主要形式。巨噬细胞（Mφ）创建 紧密密封的隔室，周围是Agldl。他们酸酸并分泌 溶酶体酶进入其中，形成溶酶体突触。这导致形成未固定的 细胞外的胆固醇，可以输送到质膜，从而导致信号变化 转导和泡沫细胞形成。我们假设这种降解agldl的机制具有 与吞噬或内吞机制相比，显着差异，这些差异具有 对动脉粥样硬化的病理生理学和治疗的重要后果。我们将研究细胞 调节这一过程的机制（我们称之为散热）；更好地表征了体内的散热；和 探索HDL和环糊精在清除流源产生的胆固醇中的新作用。 （1） 表征了AGLDL细胞外水解的机制。我们已经使用了敲除小鼠的Mφ， RNAi和药物鉴定TLR4，MYD88，SYK，AKT，PI3激酶和其他的作用 传销中的信号分子。我们使用三个主要定量测定：溶酶体分泌，F-的形成 肌动蛋白其中Mφ接触AGLDL，并形成脂质液滴。我们将识别rab and nare蛋白 溶酶体分泌所必需的，我们将鉴定出在传销过程中被激活的基因。 （2）确定 溶酶体突触在动脉粥样硬化病变中的作用。我们将使用光学显微镜和电子显微镜 分析动脉粥样硬化小鼠模型中溶酶体突触的活性。我们将使用骨髓 移植到LDL受体敲除小鼠中，以确定信号传导过程的重要性。 （3） 表征与Mφ接触的HDL相互作用。与Mφ接触的AGLDL具有很高的水平 未酯化的胆固醇。 HDL或胆固醇均衡的环糊精可以去除多余的胆固醇 细胞中胆固醇的丧失。我们将表征此过程及其对泡沫细胞形成的影响。