Macrophage-lipoprotein Interactions

巨噬细胞-脂蛋白相互作用

• 批准号: 8185032
• 负责人: Frederick R. Maxfield
• 金额: $ 42.25万
• 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 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8185032
• 关键词: 1-Phosphatidylinositol 3-Kinase; Acid Lipase; Actins; American; Arterial Fatty Streak; Atherosclerosis; Binding; Biological Markers; Biopsy; Blood; Blood Vessels; Cell Maintenance; Cell Surface Receptors; Cells; Cessation of life; Cholesterol; Cholesterol Esters; Dendritic Cells; Deposition; Development; Electron Microscopy; Endosomes; Enzymes; Event; Extracellular Matrix; Foam Cells; Freezing; Goals; Heart Diseases; Hydrolysis; Image; Immune system; Inflammation; Injection of therapeutic agent; Knockout Mice; Label; Lead; Lipase; Lipids; Lipoproteins; Low-Density Lipoproteins; Membrane; Methods; Microscopy; Modeling; Molecular; Mus; Phospholipids; Process; RNA Interference; Receptor Signaling; Research; Resolution; Role; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Signaling Molecule; Staging; Sterols; Stream; Stroke; Surface; Synapses; TLR4 gene; Tissues; base; cardiovascular risk factor; disability; extracellular; improved; insight; macrophage; monocyte; novel; polymerization; pressure; prevent; receptor; rho GTP-Binding Proteins; synaptogenesis; syndecan-4; therapy development; vacuolar H+-ATPase

DESCRIPTION (provided by applicant): In early stages of atherosclerosis, macrophages (MF) in the wall of blood vessels encounter lipoprotein deposits that have been extensively modified. These lipoproteins have been acted upon by lipases, causing them to become aggregated, and they are tightly bound to the extracellular matrix. They are also chemically modified (e.g., oxidized). Studies that have used soluble lipoproteins cannot capture essential aspects of the interactions of MF with these retained and aggregated lipoproteins (agLDL) that lead to foam cell formation. Advanced microscopy methods will be used to describe a novel type of interaction in which MF form an extracellular lysosome (a lysosomal synapse), which digests the agLDL. The following aims will be pursued to characterize lysosomal synapse formation by MF: Aim 1. Continue to characterize the novel mechanisms for extracellular hydrolysis of aggregated lipoproteins. A. Determine the molecular mechanisms for lysosomal secretion B. Analyze the mechanisms for transfer of sterol and other metabolites to cells (e.g., role of NPC2) C. Examine the interaction of MF with agLDL in extracellular matrix models that mimic the subintimal space D. Carry out 3D electron microscopy analysis of lysosomal synapses E. Determine whether dendritic cells also form lysosomal synapses with agLDL Aim 2. Analyze the receptors and signal transduction pathways involved in interaction of MF with agLDL A. Examine the role of PI3 Kinase, Akt, and other signaling molecules in the formation and function of the lysosomal synapse using cells from knockout mice, RNAi, and pharmacological agents B. Examine the role of TLR4, Syndecan 4 and other potential surface receptors C. Examine the role of cholesterol and lipid metabolites in activating signaling Aim 3. Examine the formation of lysosomal synapses in mouse atherosclerotic lesions A. Use multiphoton microscopy, injection of fluorescent lipoproteins, and labeled monocytes to determine whether lysosomal synapses can be seen in excised atherosclerotic tissue B. Use rapid biopsies and high pressure freezing followed by 3D electron microscopy to obtain high resolution images of the interaction of MF with agLDL in atherosclerotic lesions. While the importance of immune system cells, especially MFs, in plaque development has been recognized for years, there are many fundamental aspects of the role of these immune system cells that are poorly understood. A major goal is to characterize the signaling events that are triggered by the interaction of MF with agLDL. This may lead to improved understanding of the relationship between atherosclerosis and inflammation. Such insights may help in developing therapies as well as providing deeper understanding of the underlying basis for cardiovascular risk factors such as elevated biomarkers for inflammation. PUBLIC HEALTH RELEVANCE: This project examines the early steps leading to an atherosclerotic lesion as a consequence of the interaction between an immune system cell, the macrophage, with lipoproteins in the wall of blood vessels. These atherosclerotic lesions can lead to heart disease and stroke, which are major causes of disability and death of Americans. Research findings based on these studies may lead to new treatments to prevent or reverse the formation of atherosclerotic lesions.

描述（由申请人提供）：在动脉粥样硬化的早期，血管壁中的巨噬细胞（MF）遇到已广泛修饰的脂蛋白沉积物。这些脂蛋白已由脂肪酶作用，导致它们聚集，并与细胞外基质紧密结合。它们也被化学修饰（例如，氧化）。使用可溶性脂蛋白的研究无法捕获MF与这些保留和聚集的脂蛋白（AGLDL）相互作用的基本方面，从而导致泡沫细胞的形成。晚期显微镜方法将用于描述一种新型的相互作用，其中MF形成细胞外溶酶体（一种溶酶体突触），从而消化了AGLDL。将追求以下目标来表征MF：AIM 1的溶酶体突触形成。 A.确定溶酶体分泌的分子机制B.分析固醇和其他代谢物向细胞转移的机制（例如，NPC2的作用）C。检查MF在外细胞基质模型中的相互作用，这些模型模拟于下突击空间。使用AgLDL AIM 2。分析与MF与Agldl A相互作用的受体和信号转导途径。检查PI3激酶，AKT和其他信号分子在使用敲除小鼠，RNAI和药理学剂的作用的PI3激酶和其他信号分子在溶酶体突触的形成和功能中的作用。脂质代谢产物在激活信号传导目标中3。检查小鼠动脉粥样硬化病变中溶酶体突触的形成A.使用多光子显微镜，注射荧光脂蛋白蛋白和标记的单核细胞以及在溶酶体的快速循环中可以看到溶酶体的较高的循环。 MF与AGLDL在动脉粥样硬化病变中相互作用的分辨率图像。 尽管多年来已经认识到免疫系统细胞（尤其是MF）的重要性，但这些免疫系统细胞的作用有许多基本方面，这些方面知之甚少。一个主要目标是表征由MF与AGLDL的相互作用触发的信号事件。这可能会导致人们对动脉粥样硬化与炎症之间关系的了解得到改善。这种见解可能有助于开发疗法，并为心血管危险因素（例如炎症升高的生物标志物升高）提供更深入的了解。 公共卫生相关性：该项目研究了由于免疫系统细胞（巨噬细胞）与血管壁上脂蛋白之间的相互作用而导致动脉粥样硬化病变的早期步骤。这些动脉粥样硬化病变会导致心脏病和中风，这是美国人残疾和死亡的主要原因。基于这些研究的研究结果可能会导致新的治疗方法，以防止或扭转动脉粥样硬化病变的形成。