The Role of Apolipoprotein A-II in the Modulation of HDL Function

心血管疾病(CVD)是美国的头号杀手，几乎占美国人口的1/3。 每年有一百万条生命。众所周知，高密度脂蛋白(HDL)及其主要成分 蛋白质成分载脂蛋白(Apo)A-L在降低心血管疾病风险方面发挥着重要作用。然而， 载脂蛋白A-L I是高密度脂蛋白中含量第二丰富的蛋白质，其功能尚未得到研究 下定决心。对载脂蛋白A-11的研究导致了关于支持或反对载脂蛋白的结论不一。 高密度脂蛋白中载脂蛋白A-11的致动脉粥样硬化作用这项研究将检验载脂蛋白A-11与 载脂蛋白A-L在高密度脂蛋白中以一种位点特异性的方式调节高密度脂蛋白的功能。此外，这种效果是基于 关于载脂蛋白A-L：载脂蛋白A-11在给定的高密度脂蛋白颗粒中的相对含量在指导阶段 在这个项目中，我将确定apoA-11的掺入对盘状结构中apoA-L结构的影响 重组的高密度脂蛋白颗粒。特定载脂蛋白A溶剂可及性的相对变化--L 混合粒子VS载脂蛋白A-L中的序列仅高密度脂蛋白将使用氢氚进行评估 交换技术结合质谱仪(HDX-MS)。然后，我将把研究扩展到 高密度脂蛋白中载脂蛋白A-11引起的载脂蛋白A-L构象变化的独立时相定位 人类血浆中的微粒。这将分阶段完成。首先，我会重建 通过加入不同比例的载脂蛋白A-L：载脂蛋白A-11而形成类似天然高密度脂蛋白的球形高密度脂蛋白颗粒 以及天然的高密度脂蛋白。我还将生成本地混合高密度脂蛋白粒子，方法是 分离的载脂蛋白A-11进入天然的高密度脂蛋白颗粒中，只含有载脂蛋白A-L。载脂蛋白A-11诱导 然后，载脂蛋白A-L溶剂暴露的修改将与功能特性相关，包括 激活多种高密度脂蛋白重塑因子，包括卵磷脂：胆固醇酰基转移酶(LCAT)， 肝脂酶(HL)和内皮脂酶(EL)。我预计这项工作将提供重要的 载脂蛋白A-11在脂蛋白代谢中作用的新信息，并可能提出新的治疗方法 防治心血管疾病的方法。

Cardiovascular disease (CVD) is the number one killer in the United States, taking nearly a million lives each year. It is well established that high density lipoprotein (HDL) and its major protein constituent apolipoprotein (apo) A-l play a major role in reducing the risk of CVD. However the function of apolipoprotein A-l I, the second most abundant protein in HDL, has not been determined. Studies on apoA-ll have led to mixed conclusions concerning the pro- or anti- atherogenicity of apoA-ll in HDL. This study will test the hypothesis that apoA-ll interacts with apoA-l in HDL in a site-specific manner to modulate HDL function. Furthermore, the effect is based on the relative amounts of apoA-l: apoA-ll present in a given HDL particle. In the Mentored Phase of this project, I will determine how the incorporation of apoA-ll affects apoA-l structure in discoidal reconstituted HDL particles. Relative changes in the solvent accessibility of specific apoA-l sequences in mixed particles vs apoA-l only HDL will be assessed using the hydrogen deuterium exchange technique combined with mass spectrometry (HDX-MS). I will then extend the studies in the Independent Phase to locate conformational changes in apoA-l caused by apoA-ll in HDL particles from human plasma. This will be accomplished in stages. First, I will reconstitute spherical HDL particles that resemble native HDL by incorporating varying ratios of apoA-l:apoA-ll along with native HDL lipids. I will also generate native hybrid HDL particles by incorporating isolated apoA-ll into native HDL particles containing apoA-l only. The apoA-ll induced modifications of apoA-l solvent exposure will then be correlated to functional properties including activation of various HDL remodeling factors including lecithin:cholesterol acyl transferase (LCAT), hepatic lipase (HL), and endothelial lipase (EL). I anticipate that this work will provide significant new information on the role of apoA-ll in lipoprotein metabolism and may suggest new therapeutic approaches for fighting CVD.