Macrophage-lipoprotein Interactions

巨噬细胞-脂蛋白相互作用

• 批准号: 10117551
• 负责人: Frederick R. Maxfield
• 金额: $ 36.42万
• 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 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10117551
• 关键词: 1-Phosphatidylinositol 3-Kinase; AKT1 gene; Actins; Adipocytes; Affect; Alzheimer' s Disease; Amyloid; Amyloid beta-Protein; Area; Arterial Fatty Streak; Atherosclerosis; Biochemical; Biological; Biological Assay; Biotin; Bone Marrow; Cell Culture Techniques; Cells; DNA Sequence Alteration; Data; Dementia; Dendritic Cells; Deposition; Development; Dextrans; Digestion; Dyes; Enzymes; F-Actin; Fluorescein-5-isothiocyanate; Fluorescence; Frontotemporal Dementia; Genetic; Hydrolysis; Image; Incubated; Individual; Inflammatory; Knockout Mice; Label; Laboratories; Link; Lipoproteins; Low-Density Lipoproteins; Lysosomes; Macrophage Activation; Macrophage Colony-Stimulating Factor; Measures; Methods; Microglia; Modeling; Molecular; Mouse Strains; Mus; Mutant Strains Mice; Mutation; Nerve Degeneration; Neurodegenerative Disorders; PGRN gene; Pathway interactions; Phagocytes; Predisposition; Process; Proteins; Reporting; Risk Factors; Role; SYK gene; Senile Plaques; Signal Pathway; Signal Transduction; Signaling Molecule; Streptavidin; Synapses; TLR4 gene; TREM2 gene; TYROBP gene; Time; Vendor; Wild Type Mouse; age related; extracellular; insight; macrophage; mutant; novel; parent grant; polymerization; public health relevance; sex

Abstract We have characterized a novel process carried out by phagocytes that we have called "digestive exophagy". We have shown that macrophages and dendritic cells create extracellular, acidified lysosomal compartments to digest large objects such as aggregates of LDL or dead adipocytes that are too large to be phagocytosed. We have found that genetic mutations associated with neurodegenerative disorders (e.g., frontotemporal dementia and Alzheimer's disease) also affect the digestive exophagy of aggregated LDL (agLDL), such as that found in atherosclerotic plaques. This is consistent with similar cellular mechanisms being involved in both cases. In this supplement, we propose to apply the methods we have developed to study digestive exophagy of amyloid Aβ by microglia. We will also continue to examine mutants identified in neurodegeneration studies for their effect on digestion of agLDL by macrophages. We have reported that macrophages lacking progranulin (GRN) have greatly increased exophagy of aggregated LDL. Mutations or reduced expression of GRN are linked to AD as well as frontotemporal dementia. TLR4 and other signaling molecules are required for digestive exophagy, and these same signaling pathways are modulated by TREM2, a protein that is highly expressed in microglia. Mutations in TREM2 are strongly linked to increased susceptibility for AD. Preliminary studies have shown that microglia create similar acidic compartments upon contact with large aggregates of fAβ, and they secrete lysosomal contents into them. In Aim 1 we will characterize the mechanism by which microglia degrade large aggregates of fAβ. We expect to confirm preliminary observations of lysosome secretion and compartment acidification. We will use fluorescently labeled fAβ to observe and quantify the degradation of fAβ deposits. These studies will be carried out using primary mouse microglia. In Aim 2 we will analyze signaling mechanisms that regulate lysosome secretion and degradation of amyloid Aβ by microglia. Interestingly, preliminary data have shown that lack of Dap12, an effector of TREM2 signaling, in bone marrow macrophages leads to a large increase in lysosome secretion upon contact with LDL aggregates or Aβ deposits. Similar studies will be carried out in microglia from wild type and knockout mice contacting Aβ deposits to determine if there is a role for GRN, Trem2, Dap12, Tlr4 and other proteins. As illustrated by the Dap12 results, proteins identified in the Alzheimer's studies may reveal new signaling in macrophages to be studied in the parent grant.

抽象的 我们已经表征了一个新的吞噬细胞进行的新过程，我们称之为“消化 我们已经表明，巨噬细胞和树突状细胞会产生细胞外酸化的溶酶体 消化大型物体的隔室，例如LDL的聚集体或死脂肪细胞，这些物体太大而无法为 吞噬。我们发现与神经退行性疾病相关的遗传突变（例如， 额颞痴呆和阿尔茨海默氏病）也影响了聚集的LDL的消化源 （agldl），例如在动脉粥样硬化斑块中发现的。这与类似的细胞机制一致 参与这两种情况。在此补充中，我们建议将开发的方法应用于 小胶质细胞对淀粉样蛋白Aβ的研究消化出海外。我们还将继续检查在 神经变性研究对巨噬细胞对AGLDL消化的影响。我们报告了 缺乏程序努力蛋白（GRN）的巨噬细胞大大增加了聚集的LDL的散热。突变或 GRN的表达降低与AD以及额颞痴呆有关。 TLR4和其他信号传导 分子是消化疫苗所必需的，并且这些相同的信号通路由 TREM2，一种在小胶质细胞中高度表达的蛋白质。 TREM2中的突变与增加密切相关 广告的敏感性。 初步研究表明，小胶质细胞在与 FAβ的大骨料，并将溶酶体含量分泌到其中。在AIM 1中，我们将表征 小胶质细胞降解大型FAβ的机制。我们希望确认初步 观察溶酶体分泌和室酸化。我们将使用荧光标记为FAβ 观察并量化FAβ沉积物的降解。这些研究将使用主要 小鼠小胶质细胞。在AIM 2中，我们将分析调节溶酶体分泌的信号传导机制 小胶质细胞降解淀粉样蛋白Aβ。有趣的是，初步数据表明缺乏 DAP12是trem2信号传导的效应子，在骨髓巨噬细胞中导致溶酶体大大增加 与LDL聚集体或Aβ沉积物接触后的分泌。类似的研究将在小胶质细胞中进行 从野生型和敲除小鼠接触Aβ沉积的小鼠，以确定GRN，TREM2是否有作用 DAP12，TLR4和其他蛋白质。如DAP12结果所示，在阿尔茨海默氏症中鉴定的蛋白质 研究可能会揭示巨噬细胞中要研究的巨噬细胞中的新信号传导。