In Vitro /In Vivo Approach to Artery Wall Inflammation

在目前的授权期间，正常HDL显示出抑制轻度氧化LDL（MM-LDL）形成的三个步骤。发现HDL的功能（其防止LDL氧化和MM-LDL中的氧化磷脂（Ox-PAPC）的能力）比HDL-胆固醇更好地预测某些患者的动脉粥样硬化。MKP-1是Ox-PAPC诱导内皮细胞产生MCP-1所必需的。发现对氧磷酶（PON）-2是能够使Ox-PAPC失活的细胞内酶，而PON-3被证明是HDL相关酶，其与PON-1一样使Ox-PAPC失活，但与PON-1不同的是不受Ox-PAPC调节。Ox-PAPC通过IL-6调节肝脏PON-1和apoJ，但不调节MCP-1。在小鼠感染甲型流感病毒后，HDL失去了PON活性，失去了保护LDL免受 氧化当将由所有D-氨基酸合成的apoA-I模拟肽（D-4F）经口给予采用西方饮食的LDL受体缺失小鼠或采用普通饮食的apoE缺失小鼠时，HDL抑制LDL氧化的能力显著改善，伴随着不依赖于总血浆或HDL-胆固醇的动脉粥样硬化病变的显著减少。当D-4F给予LDL受体无效小鼠后，西方饮食和流感A感染有巨噬细胞交通到主动脉弓和无名动脉显着减少。在下一个授权期，MKP-1介导Ox-PAPC诱导的炎症反应的机制将在基因工程小鼠中确定。将在小鼠中探索胆固醇逆向转运和LDL氧化之间的联系。将在动脉粥样硬化小鼠模型中确定D-4F的作用机制。D-4F促进形成的能力 还将研究前β HDL样颗粒通过胆固醇反向转运途径的循环。将确定D-4F抑制流感感染后巨噬细胞进入动脉的机制。将确定口服合成磷脂提高HDL和PON水平并降低小鼠模型中动脉粥样硬化的机制。最后，我们将确定HDL功能是否是小鼠和人类动脉粥样硬化存在或不存在的敏感指标。该提案将通过阐明增强或抑制对氧化磷脂的炎症反应的分子和遗传机制来确定潜在的诊断和治疗靶点。

During the current grant period normal HDL was shown to inhibit three steps in the formation of mildly oxidized LDL (MM-LDL). The function of HDL (its ability to prevent LDL oxidation and inactivate oxidized phospholipids (Ox-PAPC) in MM-LDL) was found to better predict atherosclerosis in some patients than HDL-cholesterol. MKP-1 was required for Ox-PAPC to induce endothelial cells to produce MCP-1. Paraoxonase (PON)-2 was found to be an intracellular enzyme capable of inactivating Ox-PAPC while PON-3 was shown to be an HDL associated enzyme that like PON-1 inactivates Ox-PAPC, but unlike PON-1 is not regulated by Ox-PAPC. Ox-PAPC regulated hepatic PON-1 and apoJ, but not MCP-1, via IL-6. Following influenza A infection in mice, HDL lost PON activity and lost the ability to protect LDL against oxidation. When an apoA-I mimetic peptide synthesized from all D-amino acids (D-4F) was given orally to LDL receptor null mice on a Western diet or apoE null mice on a chow diet, there was a dramatic improvement in HDL's ability to inhibit LDL oxidation accompanied by a dramatic decrease in atherosclerotic lesions independent of total plasma or HDL-cholesterol. When D-4F was given to LDL receptor null mice after a Western diet and influenza A infection there was a dramatic reduction in macrophage traffic into the aortic arch and innominate arteries. In the next grant period the mechanisms by which MKP-1 mediates the inflammatory response induced by Ox-PAPC will be determined in genetically engineered mice. A link between reverse cholesterol transport and LDL oxidation will be explored in mice. The mechanisms of action of D-4F will be determined in mouse models of atherosclerosis. The ability of D-4F to promote the formation and cycling of pre-beta HDL-like particles through the reverse cholesterol transport pathway will also be studied. The mechanism by which D-4F inhibits macrophage traffic into arteries after influenza infection will be determined. The mechanisms by which oral administration of a synthetic phospholipid raises HDL and PON levels, and decreases atherosclerosis in mouse models will be determined. Finally we will determine if HDL function is a sensitive indicator of the presence or absence of atherosclerosis in mice and humans. This proposal will identify potential diagnostic and therapeutic targets by elucidating the molecular and genetic mechanisms that enhance or inhibit the inflammatory response to oxidized phospholipids.