In Vitro /In Vivo Approach to Artery Wall Inflammation

在目前的授权期内，正常的高密度脂蛋白被证明可以抑制轻度氧化低密度脂蛋白(MM-LDL)形成的三个步骤。在某些患者中，高密度脂蛋白的功能(防止低密度脂蛋白氧化和灭活氧化磷脂(Ox-PAPC)的能力)被发现比高密度脂蛋白更好地预测动脉粥样硬化。Ox-PAPC诱导内皮细胞产生MCP-1需要MKP-1。对氧磷酶(PON)-2被发现是一种能够灭活Ox-PAPC的胞内酶，而PON-3与PON-1一样是一种高密度脂蛋白相关酶，可以使Ox-PAPC失活，但与PON-1不同，PON-1不受Ox-PAPC的调节。OX-PAPC通过IL-6调节肝脏PON-1和apoJ，但不调节MCP-1。小鼠感染甲型流感后，高密度脂蛋白失去PON活性并失去保护低密度脂蛋白的能力 氧化。当将由所有D-氨基酸合成的apoA-I模拟肽(D-4F)口服给西方饮食的低密度脂蛋白受体缺失小鼠或饮食中的载脂蛋白E缺失小鼠时，高密度脂蛋白抑制低密度脂蛋白氧化的能力显著提高，同时动脉粥样硬化病变显著减少，与总血浆或高密度脂蛋白-胆固醇无关。在西方饮食和甲型流感感染后，给低密度脂蛋白受体缺失的小鼠服用D-4F后，进入主动脉弓和无名动脉的巨噬细胞流量显著减少。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得到确定。将在小鼠身上探索胆固醇反向运输和低密度脂蛋白氧化之间的联系。D-4F的作用机制将在小鼠动脉粥样硬化模型中确定。D-4F促进形成的能力 还将研究前β-高密度脂蛋白样颗粒通过反向胆固醇运输途径的循环。将确定D-4F在感染流感后抑制巨噬细胞进入动脉的机制。在小鼠模型中，口服合成磷脂提高高密度脂蛋白和PON水平并降低动脉粥样硬化的机制将被确定。最后，我们将确定高密度脂蛋白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。这项建议将通过阐明增强或抑制氧化磷脂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.