REGULATION OF CHOLESTEROL TRAFFICKING IN ARTERIAL WALL CELLS

发展中的动脉粥样硬化病变的早期特征是积聚 动脉壁细胞中的胆固醇。这种积累可以通过以下方式调节： 从细胞内储存的胆固醇转运的细胞途径 细胞表面的细胞膜用于排泄。的总体目标 该项目是表征结构和调节特性， 细胞胆固醇运输途径，并评估的作用， 动脉粥样硬化形成的途径。我们已经证明胆固醇 培养细胞中的运输途径受到调节， 细胞的生长状态和胆固醇状态的变化， 高密度脂蛋白（HDL）与血小板衍生生长相互作用 细胞表面结合位点或受体的血小板源性生长因子（PDGF）。 HDL细胞 相互作用的功能是刺激易位到细胞表面， 分泌细胞内储存的过量胆固醇，而PDGF 受体结合似乎刺激胆固醇转运到 质膜用作新合成的 膜。我们建议利用这些不同的受规管条件， 表征细胞运输途径的特性，并测试 假设功能多样的刺激，HDL和PDGF，可能 通过共同的机制调节这些途径。 我们会研究 参与HDL和PDGF的细胞内区室和结构 使用细胞分级分离技术调节胆固醇转运， 荧光显微术和细胞内转运抑制剂。我们也 建议表征调节HDL介导的细胞内信号 胆固醇运输通过测定细胞激活不同的 磷脂酶，蛋白激酶，和其他相关的信号 刺激胆固醇运输和排泄。 其他研究 将确定参与PDGF介导的胆固醇的信号通路 使用信号传导酶抑制剂的不同亚型的 PDGF和表达不同野生型和突变型PDGF的细胞系。 PDGF受体。最后，我们将评估蛋白质是否参与 固醇运输在病变和非病变区域表达， 动脉壁这些研究将产生关于 胆固醇在细胞中运输的机制，并提供深入了解 动脉壁的脂蛋白和细胞因子环境如何 影响细胞胆固醇稳态并有助于 动脉粥样硬化

An early feature of the developing atherosclerotic lesion is accumulation of cholesterol in artery wall cells. This accumulation may be modulated by cellular pathways that transport cholesterol from intracellular storage compartments to the cell surface for excretion. The overall objective of this project is to characterize the structural and regulatory properties of cellular cholesterol trafficking pathways and to evaluate the role of these pathways in atherogenesis. We have shown that cholesterol trafficking pathways in cultured cells are regulated in response to changes in the growth state and cholesterol status of cells and by the interaction of high.density lipoprotein (HDL) and platelet-derived growth factor (PDGF) with cell-surface binding sites or receptors. HDL cellular interactions function to stimulate translocation to the cell surface and excretion of intracellular stores of excess cholesterol, whereas PDGF receptor binding appears to stimulate cholesterol translocation to the plasma membrane for use as a structural component of newly-synthesized membranes. We propose to use these different regulated conditions to characterize the properties of cellular trafficking pathways and to test the hypothesis that the functionally-diverse stimuli, HDL and PDGF, may modulate these pathways by common mechanisms. We will examine the intracellular compartments and structures involved in HDL- and PDGF- regulated cholesterol transport using cell fractionation techniques, fluorescent microscopy, and intracellular transport inhibitors. We also propose to characterize intracellular signals that modulate HDL-mediated cholesterol trafficking by assaying cells for activation of different phospholipases, protein kinases, and other signals associated with stimulation of cholesterol transport and excretion. Additional studies will identify' signalling pathways involved in PDGF-mediated cholesterol trafficking using signalling enzyme inhibitors, different isoforms of PDGF, and cell lines expressing different wild-type and mutant forms of PDGF receptors. Lastly, we will evaluate whether proteins involved in sterol trafficking are expressed in lesion and non-lesion areas of the artery wall. These studies will generate important information about the mechanisms of cholesterol trafficking in cells and provide insight into how the lipoprotein and cytokine environment of the artery wall may influence cellular cholesterol homeostasis and contribute to atherogenesis.