Structural stability and functional remodeling of high-density lipoproteins

描述（由申请人提供）：高密度脂蛋白（HDL，或好胆固醇）是异质纳米颗粒，可通过称为反向胆固醇转运（RTC）的复杂过程去除细胞胆固醇。 HDL 可预防心血管疾病、炎症、中风和其他重大疾病。了解 HDL 亚类的独特功能特性及其在随机对照试验期间的重塑对于提高 HDL 质量是必要的，也是当前寻找新的诊断工具和疗法以补充他汀类药物、贝特类药物和其他降脂药物的主旨。我们的工作将为这一努力提供必要的分子基础。 我们的长期目标是阐明脂蛋白的能量-结构-功能关系，以更好地理解和控制脂质转运的分子机制。该项目的重点是血浆 HDL 及其主要蛋白 apoA-I 的结构稳定性和功能重塑。 ApoA-I 在 HDL 上形成结构支架，并通过激活血浆因子来指导 HDL 代谢。 ApoA-I 不稳定可导致淀粉样变性。 在目标 1 中，我们将测试 apoA-I 适应胆固醇运输过程中 HDL 中脂质负荷增加的新的基于结构的机制。我们将使用一种综合方法，将现有的生物物理和生化方法与场循环核磁共振等创新技术相结合，来表征 HDL 表面动力学。这将得到目标 2 的补充：在 RCT 的关键早期步骤中，对细胞胆固醇流出至贫脂 apoA-I 和新生 HDL 的功能研究。 目标 3 将测试系统性淀粉样变性中 apoA-I 不稳定和错误折叠的新结构机制。 我们的研究将为了解 60 多种 HDL 相关蛋白在健康和疾病中的功能提供必要的结构和动态框架，指导寻找具有改进特性的 HDL，以便将来用作心血管疾病的诊断标记和基于 HDL 的个性化疗法，并帮助确定 apoA-I 淀粉样变性（一种无法治疗的破坏性疾病）的治疗靶点。

DESCRIPTION (provided by applicant): High-density lipoproteins (HDL, or Good Cholesterol) are heterogeneous nanoparticles that remove cell cholesterol via a complex process termed reverse cholesterol transport (RTC). HDL protect against cardiovascular disease, inflammation, stroke and other major diseases. Understanding distinct functional properties of HDL subclasses and their remodeling during RCT is necessary to improve HDL quality, and is the current thrust in search for novel diagnostic tools and therapies to complement statins, fibrates and other lipid-lowering drugs. Our work will provide the molecular basis necessary for this effort. Our long-term goal is to elucidate the energetics-structure-function relationship in lipopo- teins to better understand and control the molecular mechanisms of lipid transport. This project is focused on the structural stability and functional remodeling of plasma HDL and their main protein, apoA-I. ApoA-I forms a structural scaffold on HDL and directs HDL metabolism by activating plasma factors. ApoA-I destabilization can cause amyloidosis. In Aim 1, we will test the new structure-based mechanism of apoA-I adaptation to the increasing lipid load in HDL during cholesterol transport. We will use an integrated approach combining established biophysical and biochemical methods with innovative techniques such as field-cycling NMR to characterize HDL surface dynamics. This will be complemented by Aim 2: functional studies of cell cholesterol efflux to lipid-poor apoA-I and to nascent HDL at the critical early steps of RCT. Aim 3 will test the new structure- based mechanism of apoA-I destabilization and misfolding in systemic amyloidosis. Our studies will provide a structural and dynamic framework necessary for understanding functions of over 60 HDL-associated proteins in health and disease, guide the search for HDL with improved properties for future use as diagnostic markers and personalized HDL-based therapies for cardiovascular disease, and help identify therapeutic targets for apoA-I amyloidosis, a devastating disease for which there is no treatment.