APOE AND ATHEROGENESIS

描述(改编自《调查者摘要》)：本提案源于 根据首席研究员的观察，巨噬细胞- 人载脂蛋白E在载脂蛋白E缺失(apoE-/-)中的特异性表达 小鼠可减少动脉粥样硬化的发展。然而，目前还不清楚 如果ApoE+/+小鼠巨噬细胞正常产生apoE的水平 提供最大限度的保护。因此，调查人员设计了 他们的实验回答了四个关键问题：a)将提高水平 野生型小鼠巨噬细胞表达载脂蛋白E可降低 动脉粥样硬化病变的形成？B)将载脂蛋白E在 巨噬细胞发生动脉粥样硬化病变后引起 损伤可以消退或阻止其进展吗？C)载脂蛋白E的表达 在动脉粥样硬化病变中增加胆固醇外流？D)是否有apoE 动脉粥样硬化病变形成与同型异构体的特异性差异 回归？因此，建议的具体目标如下：这里 他们将产生带有巨噬细胞-1的C57BL/6小鼠，以确定 巨噬细胞特异性过表达apoE3对其形成的影响 动脉粥样硬化病变中apoE3的表达，然后他们将 研究这种表达在饮食诱导的动脉粥样硬化中的作用。2) 检测巨噬细胞特异性表达人载脂蛋白E3的作用 在野生型和载脂蛋白E-/-小鼠中存在的动脉粥样硬化病变。 在这里，他们将培育野生型和四环素载脂蛋白E-/-小鼠- 受调控的巨噬细胞特异性载脂蛋白E的表达。到时候他们就会 检测载脂蛋白E3在动脉粥样硬化病变中的表达 这些小鼠的进展或退化。最后，他们将确定 巨噬细胞特异性表达载脂蛋白E3对ApoE3释放的影响 动脉粥样硬化病变中的胆固醇。3)确定载脂蛋白E2、 ApoE3和ApoE4促进胆固醇的能力不同 ApoE3和ApoE4对细胞外排的影响是否不同 动脉粥样硬化病变的形成和消退。在这里，他们将检查 载脂蛋白E-/-小鼠血浆与巨噬细胞特异性结合的能力 载脂蛋白E_2、载脂蛋白E_3或载脂蛋白E_4的表达诱导胆固醇外流 富含胆固醇的细胞。他们会比较腹膜的能力 巨噬细胞和稳定表达APOE2、ApoE3或 ApoE4释放胆固醇。他们将决定 载脂蛋白E3和载脂蛋白E4促进胆固醇外流的差异 并形成γ-LPE(一种低脂脂蛋白颗粒，与-γ- 以载脂蛋白E为其唯一载脂蛋白的电泳性 选民)。最后，他们将检查巨噬细胞的作用- 载脂蛋白E4在动脉粥样硬化发生、发展中的特异性表达 回归。

DESCRIPTION (Adapted from Investigator's Abstract): This proposal stems from the observation made by the principal investigator that macrophage- specific expression of human apolipoprotein E in apoE-null (Apoe-/-) mice reduces the development of atherosclerosis. However it is not known if the level of apoE normally produced by macrophages in ApoE +/+ mice gives maximal protection. Therefore the investigators have designed their experiments to answer four key questions: a) Will increased levels of expression of apoE by macrophages in wild-type mice decrease the formation of atherosclerotic lesions? b) Will expression of apoE in macrophages after the development of atheroslerotic lesions cause lesions to regress or halt their progression? c) Does expression of apoE in atherosclerotic lesions enhance cholesterol efflux? d) Are there apoE isoform-specific differences on atherosclerotic lesion formation and regression? The proposed specific aims are therefore as follows:. Here they will generate C57BL/6 mice with macrophage-1) To determine the effect of macrophage-specific over-expression of apoE3 on the formation of atherosclerotic lesions expression of apoE3, and then they will examine the effect this expression on diet-induced atherosclerosis. 2) To determine the effect of macrophage-specific expression of human apoE3 on existing atherosclerotic lesions in wild-type and in ApoE-/- mice. Here they will produce wild-type and ApoE-/- mice with tetracycline- regulated, macrophage-specific expression of apoE. They will then determine the effect of ApoE3 expression on atherosclerotic lesion progression or regression in these mice. Finally they will determine the effect of macrophage-specific expression of ApoE3 on the release of cholesterol from atherosclerotic lesions. 3) To determine if ApoE2, ApoE3, and ApoE4 differ in their abilities to facilitate cholesterol efflux from cells and if ApoE3 and ApoE4 differ in their effects on atherosclerotic lesion formation and regression. Here they will examine the ability of plasma from ApoE-/- mice with macrophage-specific expression of ApoE2, ApoE3, or ApoE4 to induce cholesterol efflux from cholesterol-loaded cells. They will compare the ability of peritoneal macrophages and of stably transfected cells expressing ApoE2, ApoE3, or ApoE4 to release cholesterol. They will determine the mechanism of the differential abilities of ApoE3 and ApoE4 to promote cholesterol efflux and to form gammaLPE (a lipid-poor lipoprotein particle with gamma- electrophoretic motility that contains apoE as its only apolipoprotein constituent). Finally they will examine the effect of macrophage- specific expression of ApoE4 on atherosclerosis development and regression.