HDL prevention of cholesterol crystal inflammation in HIV disease

描述（由申请方提供）：HIV感染和抗逆转录病毒治疗与动脉粥样硬化性血管疾病的增加相关，动脉粥样硬化性血管疾病在晚期表现为富含结晶胆固醇的坏死病变。这种病变易于发生灾难性破裂，引发血栓性血管闭塞、心肌梗死和中风，这些是HIV感染个体死亡的重要原因。在显微镜下可识别为组织切片中的裂缝，长期存在的理论认为结晶胆固醇是动脉粥样硬化的终末期产物。在这里，使用共聚焦荧光和激光反射显微镜的一种新的组合的证据，显示，与公认的教条，胆固醇晶体（CC）形成动脉粥样硬化的进展早期，这些晶体激活NLRP 3炎性小体，导致IL-12细胞因子的生产和促进动脉粥样硬化负担的小鼠。重要的是，我们表明，来自健康个体的人血浆可以溶解巨噬细胞胆固醇晶体，并从我们的初步数据推测，高密度脂蛋白（HDL）是一种重要的血清因子，负责防止血管壁胆固醇晶体形成。此外，我们假设HIV感染引起的个体炎症状态的变化导致HDL蛋白质组和脂质含量的重塑，并改变颗粒防止血管壁胆固醇的能力。 晶体含量和动脉粥样硬化负荷。为了探索这一假设并测试人类心血管疾病的风险是否与HDL防止胆固醇晶体形成的能力相关，我们将：1）在动脉粥样硬化的LDLR-/-小鼠模型中，使用一系列脂肪含量增加的饮食，确定胆固醇结晶与血浆VLDL/LDL水平成比例：2）在LDLR-/-背景下使用apoA-I-/-和人apoA-I转基因模型评估apoA-I表达是否调节胆固醇在动脉粥样硬化病变中结晶的倾向：3）评估用重建的胆固醇缺乏的HDL进行急性治疗是否导致LDLR-/-小鼠的动脉粥样硬化病变中建立的胆固醇晶体的消退，并测试HDL的这些作用是否依赖于ABCA 1胆固醇流出转运蛋白; 4）测定来自正常和HIV感染个体的队列的HDL颗粒蛋白质组和脂质含量，并测试与CC溶解、抗炎能力和CVD疾病风险的相关性，如通过冠状动脉计算机断层扫描测量的，以及与病变炎症状态的相关性，如通过18 F-氟脱氧葡萄糖-PET成像评估的。这项提议将检验HDL功能与其防止胆固醇晶体形成的能力有关的新假设 并且这种功能的变异性与个体患心血管疾病的风险相关。如果被证明是真的，通过使用质谱法来定量个体的HDL蛋白质和脂质含量，并将其与晶体溶解效力和心血管疾病相关联，这项工作有望确定HDL功能的新生物标志物。这些生物标志物将有助于寻找治疗靶点，以减少艾滋病毒感染背景下的心血管疾病，并可能在一般人群中。

DESCRIPTION (provided by applicant): HIV infection and antiretroviral therapy has been associated with increased atherosclerotic vascular disease, which at an advanced stage presents as necrotic lesions rich in crystalline cholesterol. Such lesions are prone to catastrophic rupture that initiates thrombotic vessel occlusion, myocardial infarcts and stroke, now important causes of mortality in HIV infected individuals. Microscopically discernable as clefts in histologic sections, long standing theory considers crystalline cholesterol as an end stage product of atherosclerosis. Here evidence is presented using a novel combination of confocal fluorescent and laser reflection microscopy that shows, in contrast to accepted dogma, cholesterol crystals (CCs) form early in the progression of atherosclerosis and that these crystals activate the NLRP3 inflammasome, leading to IL-12 cytokine production and the promotion of atheroma burden in mice. Importantly, we show that human plasma from healthy individuals can dissolve macrophage cholesterol crystals and postulate from our preliminary data that high-density lipoproteins (HDL) are an important serum factor responsible for preventing vessel wall cholesterol crystal formation. Further, we hypothesize that variation in an individual's inflammatory status as driven by HIV infection causes remodeling of the proteomic and lipid content of HDL, and alters the ability of the particle to prevent vessel wall cholesterol crystal content and atherosclerotic burden. To explore this hypothesis and test whether risk of cardiovascular disease in man is correlated to the ability of HDL to prevent cholesterol crystal formation we will; 1) Establish that cholesterol crystallization is proportional to plasma VLDL/LDL levels in the LDLR-/- mouse model of atherosclerosis using a series of diets with increasing fat content: 2) Assess if apoA-I expression modulates the propensity of cholesterol to crystallize in atherosclerotic lesions using the apoA-I-/- and human apoA-I transgenic models on an LDLR-/- background: 3) Assess whether acute treatment with reconstituted cholesterol poor HDL causes regression of established cholesterol crystals in atherosclerotic lesions of LDLR-/- mice and test if these effects of HDL depend on ABCA1 cholesterol efflux transporter; 4) Determine the HDL particle proteomic and lipid content from a cohort of normal and HIV infected individuals and test for correlations to CC dissolution, anti-inflammatory capacity and CVD disease risk as measured by coronary computed tomography and lesion inflammatory status as assessed by 18F-fluorodeoxyglucose-PET imaging. This proposal will test the novel hypothesis that HDL functionality is linked to its ability to prevent cholesterol crystal formation and that variability in this function is correlated to an individual's risk of cardiovascular diseae. If proven true, by using mass spectrometry to quantitate an individual's HDL protein and lipid content and correlating this with crystal dissolution potency and cardiovascular disease this work expects to identify new biomarkers for HDL function. Such biomarkers will help in the search for therapeutic targets to reduce cardiovascular disease in the context of HIV infection and likely in the general population.