The role of apolipoprotein A-II in the modulation of HDL function

心血管疾病(CVD)是美国头号杀手疾病，每年夺去近100万人的生命 年。高密度脂蛋白(HDL)及其主要蛋白成分载脂蛋白 (载脂蛋白)A-L在降低心血管疾病风险方面发挥了重要作用。然而，ApoA-11的功能仅次于 高密度脂蛋白中含有丰富的蛋白质，目前还没有确定。关于载脂蛋白A-11的研究得出了复杂的结论 关于载脂蛋白A-11在高密度脂蛋白中的促或抗动脉粥样硬化作用。这项研究将检验载脂蛋白A-11的假设 与高密度脂蛋白中的载脂蛋白A-L以位点特异性的方式相互作用，调节其功能。此外，其效果是 根据载脂蛋白A-L的相对含量：载脂蛋白A-11存在于给定的高密度脂蛋白颗粒中。在指导阶段 在本项目中，我们将确定apoA-11的掺入对光盘中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-L序列的溶剂可及性的相对变化 混合粒子与载脂蛋白A-只有高密度脂蛋白将使用氢-氚交换技术进行评估 与质谱仪(HDX-MS)联用。然后，我们将在独立阶段将我们的研究扩展到 人血浆高密度脂蛋白颗粒中载脂蛋白A-11引起的载脂蛋白A-L的构象变化这将分阶段完成。首先，我们将通过加入不同比例的载脂蛋白A-L：载脂蛋白A-11以及天然高密度脂蛋白来重建类似天然高密度脂蛋白的球形高密度脂蛋白颗粒。我们还将通过将分离的载脂蛋白A-11掺入只含有载脂蛋白A-L的天然高密度脂蛋白中来产生天然杂交高密度脂蛋白颗粒。ApoA-11诱导的apoA-L溶剂暴露的修饰将与功能特性相关，包括激活各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)、胆固醇酯转移蛋白(CETP)、肝脂酶和内皮脂肪酶，此外，还将监测受体与cubilin的相互作用。我们预计这项工作将为载脂蛋白A-IL在脂蛋白代谢中的作用提供重要的新信息，并可能为抗击心血管疾病提供新的治疗方法。

Cardiovascular disease (CVD) is the number one killer disease in the USA talking 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 ApoA-ll, the second most abundant protein in HDL, has not been determined. Studies on apoA-ll have lead 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 its 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, we will determine how the incorporation of apoA-ll affects apoA-l structure in discbidal reconstituted HDL particles. Relative changes in the solvent accessibility^ of specific apoA-l sequences in mixed particles vs apoA-| only HDL will assessed using the hydrogen deuterium exchange technique combined with mass spectrometry (HDX-MS). We will then extend our 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, we will reconstitute spherical HDL particles that resemble native HDL by incorporating varying ratios of apoA-l:apoA-ll along with native HDL lipids. We will also generate native hybrid HDL particles by incorporating isolated apoA-ll into native HDL containing apoA-l only. The apoA-ll induced modifications of apoA-l solvent exposure will then be conrelated to functional properties including activation of various HDL remodeling factors including lecithin:cholesterol acyl transferase (LCAT), cholesteryl ester transfer protein (CETP), hepatic lipase, and endothelial lipase, in addition, receptor interactions with cubilin will be monitored. We anticipate that this work will provide significant new information on the role of apoA-il in lipoprotein metabolism and may suggest new therapeutic approaches for fighting CVD.