MACROPHAGE ACTIVATION AND LIPOPROTEIN METABOLISM

我们已经证明，含LDL的免疫复合物的摄取 人单核细胞衍生的巨噬细胞对低密度脂蛋白-IC的作用诱导转化 将这些细胞转化为泡沫细胞，并促进它们的活化， LDL受体细胞表面表达的反常增加， 释放细胞因子。 在这项提案中，我们计划分析负责的分子机制 LDL受体细胞表面表达的增加。我们将 确定LDL受体表达的增加， 由含LDL的免疫复合物（LDL-IC）刺激的人巨噬细胞， 是由于低密度脂蛋白受体基因转录增加， 稳定性，mRNA翻译增加，LDL受体蛋白减少 LDL受体蛋白降解或增加的易位到 细胞膜我们还将研究LDL的增加是否 受体的表达是继发于细胞内 胆固醇调节池，如果是这样，是否会耗尽 调节池是次要的，以增强固醇动员到ACAT 底物池。此外，我们将确定是否释放的因素 在巨噬细胞活化过程中介导或促进LDL的增加 受体细胞表面表达。我们还将调查 刺激LDL受体细胞表面表达是 特定Fc对含LDL的免疫复合物的摄取 受体亚型（Fc-γ-RI、Fc-γ-RII或Fc-γ-RIII）。以来 HMGCoA还原酶活性和LDL受体活性通常具有 协调调节，我们将确定是否HMGCoA还原酶活性 在LDL-IC刺激的巨噬细胞中也增加。 该项目将涉及细胞培养，细胞分离和细胞培养。 分级程序，细胞内脂质代谢的研究， 受体结合研究、免疫印迹和分子生物学技术。 我们的总体目标是深入了解 抗低密度脂蛋白抗体和巨噬细胞活化可能有助于 发展（动脉硬化过程的加速）。

We have demonstrated that the uptake of LDL-containing immune complexes (LDL-IC) by human monocyte-derived macrophages induces the transformation of these cells into foam cells and promotes their activation leading to a paradoxical increase in LDL receptor cell surface expression and to the release of cytokines. In this proposal we plan to analyze the molecular mechanisms responsible for the increase in LDL receptor cell surface expression. We will determine whether the increase in LDL receptor expression, observed in human macrophages stimulated by LDL-containing immune complexes (LDL-IC), is due to increased transcription of the LDL receptor gene, increased mRNA stability, increased mRNA translation, decreased LDL receptor protein degradation or increased translocation of the LDL receptor protein to the cell membrane. We will also investigate whether this increase in LDL receptor expression is secondary to a decrease in the intracellular cholesterol regulatory pool and if so, whether the depletion in this regulatory pool is secondary to enhanced sterol mobilization to the ACAT substrate pool. Furthermore, we will determine whether factors released during macrophage activation mediate or facilitate the increase in LDL receptor cell surface expression. We will also investigate whether the stimulation of LDL receptor cell surface expression is a consequence of the uptake of the LDL-containing immune complexes by a specific Fc receptor subtype (Fc-gamma-RI, Fc-gamma-RII or Fc-gamma-RIII). Since HMGCoA reductase activity and LDL receptor activity usually have a coordinate regulation, we will determine whether HMGCoA reductase activity is also increased in LDL-IC-stimulated macrophages. This project will involve cell culture, cell isolation and cell fractionation procedures, studies of intracellular lipid metabolism, receptor binding studies, immunoblotting and molecular biology techniques. Our overall objective is to provide insight into the mechanisms by which anti-LDL antibodies and macrophage activation may contribute to the development(acceleration of the arteriosclerotic process.