The molecular basis for high density lipoprotein heterogeneity

描述(申请人提供)：高密度脂蛋白(高密度脂蛋白)是由蛋白质和脂质组成的血液传播的大分子复合体，在预防心血管疾病(CVD)方面发挥关键作用，心血管疾病是美国死亡的主要原因，目前正在加紧研究，以此作为当前降脂药物的潜在增强剂。这些复合体是多分散的，可以包含多达50种不同的蛋白质，每种蛋白质都可能能够调节宿主高密度脂蛋白颗粒的新陈代谢和潜在的益处/病理。其中一些蛋白质在补体调节、蛋白酶抑制和先天免疫等过程中发挥着令人惊讶的作用。这一应用领域的研究旨在了解高密度脂蛋白异质性的分子基础。我们将检验这一假设，即高密度脂蛋白由许多不同的颗粒亚群组成，每个亚群都有独特的蛋白质组合，这些亚群在预防心血管疾病方面发挥着不同的生理作用。在目标1中，将用四种正交色谱方法从正常人血浆中分离高密度脂蛋白颗粒，并对每一种分离出的组份的蛋白质组成进行我们开发的一种新的基于质谱学的模式分析。在多种分离技术中持续存在的蛋白质相关性将成为不同的高密度脂蛋白亚颗粒的候选者，并将使用免疫亲和力下拉技术进行验证。在目标2中，从目标1分离的高密度脂蛋白亚组分将被同源双功能和新型亲和标记的交联剂共价连接到紧密相互作用的蛋白质上，通过质谱仪进行鉴定。这种方法将获得相互作用蛋白质的序列特定结构信息，并作为高密度脂蛋白亚粒子鉴定的补充模式。我们预见，这些信息将成为未来治疗研究的基础，这些研究旨在专门调节某些心脏保护高密度脂蛋白亚颗粒的水平或模拟它们的效果。这项研究还可能确定可用作预测心血管疾病保护或易感性的生物标志物的高密度脂蛋白亚型。 与公共健康相关：高密度脂蛋白(高密度脂蛋白)是所谓的“好胆固醇”，因为它们可以预防心血管疾病，但我们不知道为什么。这项建议中的研究将确定以前未知的高密度脂蛋白亚种，这些亚种可能特别具有保护性。这一知识可能对开发预测性生物标记物和开发心血管疾病的预防性治疗有用。

DESCRIPTION (provided by applicant): High density lipoproteins (HDL) are blood-borne macromolecular complexes composed of protein and lipid that play critical roles in the prevention of cardiovascular disease (CVD), the major cause of mortality in the United States, and are under intense study as a potential enhancement to current lipid-lowering medications. These complexes are polydisperse and can contain up to 50 different proteins, each likely able to modulate the metabolism and potential benefit/pathology of the host HDL particle. Some of these proteins have surprising roles in processes such as complement regulation, protease inhibition and innate immunity. The studies in this application are aimed at understanding the molecular basis of HDL protein heterogeneity. We will test the hypothesis that HDL is composed of numerous distinct particle subpopulations, each with unique protein combinations, which play distinct physiological roles related to the protection against CVD. In Aim 1, HDL particles will be separated from normal human plasma by four orthogonal chromatographic approaches and the protein composition of fractions from each separation will be subjected to a new mass spectrometry-based pattern analysis we have developed. Protein correlations that persist across multiple separation techniques will become candidates for distinct HDL subparticles and will be verified using immunoaffinity pull-down techniques. In Aim 2, isolated HDL subfractions from Aim 1 will be subjected to homobifunctional and novel affinity-tagged cross-linking agents to covalently join closely interacting proteins to be identified by mass spectrometry. This approach will derive sequence specific structural information on the interacting proteins and serve as a complementary mode of HDL subparticle identification. We envision that this information will form a basis for future therapeutic investigations designed to specifically modulate the levels of certain cardioprotective HDL subparticles or to mimic their effects. The study may also identify HDL subspecies that can be used as biomarkers to predict protection or susceptibility to CVD. PUBLIC HEALTH RELEVANCE: High density lipoproteins (HDL) are the so-called "good cholesterol" because they protect against cardiovascular disease, but we don't understand why. The studies in this proposal will identify previously unknown HDL subspecies that may be particularly protective. This knowledge may be useful for developing predictive biomarkers and for developing preventative treatments for cardiovascular disease.