HDL Dysfunction and Vascular Inflammation

描述(由申请人提供)：本申请的总体目标是确定血管炎症损害血管扩张的机制。本实验室最近的报告显示，载脂蛋白A-L类似物4F显著改善了两种不同的血管疾病模型-高胆固醇血症和镰状细胞病小鼠的内皮和eNOS依赖的血管扩张。在载脂蛋白A-L类似物旨在改善高密度脂蛋白功能的基础上，我们假设氧化应激和炎症导致高密度脂蛋白功能紊乱，进而损害血管扩张。在这一应用中，我们将在疾病状态和小鼠模型中测试这一假设，其血管功能障碍与炎症的关系比高脂血症、镰状细胞病(SCD)更密切。虽然SCD主要是一种遗传性疾病，但许多人认为慢性炎症状态在SCD损害血管扩张的机制中发挥了作用。这项应用通过确定镰状红细胞如何产生新的“犯罪伙伴”来引发血管疾病，来研究炎症在损害血管功能障碍中发挥核心作用的概念。这项应用的目的是确定炎症、高密度脂蛋白功能和促炎脂质之间的相互作用，希望找到其他下游的“伴侣(S)”，他们与镰刀状的红细胞合作，损害血管扩张。我们将研究急性时相蛋白、促炎高密度脂蛋白、促炎脂类和黄嘌呤氧化酶在转基因SCD小鼠血管功能中的作用。严重和非严重SCD患者和对照受试者的血浆生物分析将被用来识别和排名损害血管扩张和改变血管壁中一氧化氮(-NO)和超氧阴离子(O2.-)生成平衡的潜在伴侣。机制将在血管水平进行调查，以确定SCD是如何导致内皮细胞功能障碍的。干细胞移植(HSCT)的SCD基因工程小鼠将被用来测试替代假设，即低密度脂蛋白有助于SCD的血管扩张受损。将干细胞移植到表达载脂蛋白A-L缺陷高密度脂蛋白的载脂蛋白A-L基因敲除小鼠中，将用于检验D-4F不能改善高密度脂蛋白功能以恢复血管扩张的替代假说。D-4F在改善预后方面的作用将在生存水平、缺血损伤机制、器官病理生物学和高密度脂蛋白与其他炎症介质相互作用的蛋白质组学方面进行测试。在D-4F改善其他系统血管扩张的基础上，我们的数据表明，靶向高密度脂蛋白可能是保护以慢性炎症状态为特征的疾病的血管功能的有效手段。通过这些研究，可能实现新的治疗方式，以预防以氧化应激和炎症增加为特征的各种疾病的血管功能障碍。

DESCRIPTION (provided by applicant): The overall goal of this application is to determine the mechanisms by which vascular inflammation impairs vasodilation. Recent reports from this laboratory demonstrate that an apoA-l mimetic, 4F, dramatically improves endothelium-and eNOS-dependent vasodilation in two distinct murine models of vascular disease-hypercholesterolemia and sickle cell disease (SCD). On the basis that apoA-l mimetics were designed to improve HDL function, we hypothesize that oxidative stress and inflammation induce HDL dysfunction, which in turn impairs vasodilation. In this application, we will test this hypothesis in a disease state and a murine model whose vascular dysfunction is more closely associated with inflammation than hyperlipidemia, sickle cell disease (SCD). Although SCD is primarily a genetic disease, many consider the chronic state of inflammation to play a role in the mechanisms by which SCD impairs vasodilation. This application investigates the concept that inflammation plays a central role in impairing vascular dysfunction by determining how the sickling red cell raises up new "partner in crime" to induce vascular disease. The objectives of this application are to determine the interactions between inflammation, HDL function and proinflammatory lipids in hopes of identifying other down-stream "partner(s)" who team up with the sickling red cell to impair vasodilation. We will investigate the role of acute phase proteins, proinflammatory HDL, proinflammatory lipids and xanthine oxidase on vascular function in transgenic SCD mice. Bioassays of plasma from severe and non-severe SCD patients and control subjects will be used to identify and rank potential partners that impair vasodilation and shift the balance of nitric oxide (-NO) and superoxide anion (O2.-) generation in the vessel wall. Mechanisms will be investigated at the vascular level to determine how SCD induces endothelial cell dysfunction. Hematopoietic stem cell transplantation (HSCT) of SCD into genetically engineered mice will be used to test alternative hypotheses that low-density lipoprotein contributes to impaired vasodilation in SCD. HSCT of SCD into an apoA-l knockout mouse that expresses apoA-l-deficient HDL will be used to test the alternative hypothesis that D-4F does not improve HDL function to restore vasodilation. The utility of D-4F in improving outcomes will be tested at the level of survival, mechanisms of ischemic injury, organ pathobiology and proteomics of HDL interactions with other inflammatory mediators. On the basis that D-4F improves vasodilation in other systems, our data suggest that targeting HDL may be an effective means of protecting vascular function in diseases characterized by chronic states of inflammation. Through these studies, new treatment modalities may be realized for preventing vascular dysfunction in a variety of diseases characterized by increases in oxidative stress and inflammation.