Inflammation and Inhibition of Cholesterol Transport

描述（由申请人提供）：该提案集中于阐明高密度脂蛋白载脂蛋白A-I在胆固醇逆向转运中的作用，因为它涉及预防炎症和动脉粥样硬化的进展。为了研究和阐明HDL apoA-1刺激去除外周组织胆固醇、调节炎症和预防动脉粥样硬化进展的机制，我们已经产生并表征了一种新的双敲除动物模型，LDL受体-/-和apoA-I -/-小鼠。先前在高胆固醇血症小鼠中的研究表明HDL apoA-I起两个重要作用。第一，涉及从外周组织中去除胆固醇，防止胆固醇在动脉壁内积聚。其次，apoA-I用于调节动脉内衬的内皮细胞上粘附分子的表达，并调节氧化应激和炎症的诱导。我们小组的初步研究表明，与仅LDL受体-/-小鼠相比，喂食含有0.1%胆固醇和10%脂肪的西方饮食的LDL受体-/-，apoA-I -/-小鼠显示出约12倍的外周组织中胆固醇蓄积。因此，在本提案中，我们计划检验我们的主要假设，即在缺乏血浆HDL apoA-I的情况下，胆固醇向肝脏的反向转运受到严重限制，从而导致泡沫细胞衍生的胆固醇酯在外周组织中的显著积累、炎症的发生和动脉粥样硬化的发展。为了验证这一假设，我们计划测量体内胆固醇通量，包括：在食物和饮食喂养的LDL受体-/-、apoA-I -/-小鼠中的吸收、肝脏胆固醇合成和分泌、肝外胆固醇合成、获取和胆固醇周转，并与仅LDL受体-/-和apoA-I -/-小鼠进行比较。我们还计划通过使用辅助依赖性腺病毒技术将血浆HDL apoA-I浓度恢复至LDL受体-/-，apoA-I-/-小鼠来检验LDL受体-/-，apoA-I-/-小鼠中胆固醇逆向转运的抑制和炎症发作是可逆的这一假设。我们相信，这些研究将导致重要的新信息apoA-I在动脉粥样硬化发展的初始阶段的作用，并确定高胆固醇血症和炎症之间的联系，以及它们各自在动脉粥样硬化发病机制中的作用。

DESCRIPTION (provided by applicant): This proposal is focused on elucidating the role of high density lipoprotein apolipoprotein A-l in reverse cholesterol transport as it relates to the prevention of inflammation and progression of atherosclerosis. We have produced and characterized a new double knockout animal model, the LDL receptor -/- and apoA-I -/- mouse in order to study and elucidate mechanisms by which HDL apoA-1 stimulates the removal of peripheral tissue cholesterol, modulates inflammation, and prevents the progression of atherosclerosis. Previous studies in hypercholesterolemic mice indicate that HDL apoA-I plays two important roles. The first, involves the removal of cholesterol from peripheral tissues preventing accumulation within the artery wall. Secondly, apoA-l serves to modulate the expression of adhesion molecules on endothelial cells lining the artery and modulates the induction of oxidative stress and inflammation. Preliminary studies from our group have shown that LDL receptor -/-, apoA-I -/- mice fed a Western diet containing 0.1% cholesterol and 10% fat show an approximate approximately 12-fold greater accumulation of cholesterol in peripheral tissues when compared to LDL receptor -/- only mice. Therefore, in this proposal we plan to test our main hypothesis that in the absence of plasma HDL apoA-I reverse cholesterol transport to the liver is severely limited, allowing for dramatic accumulation of foam cell derived cholesterol ester in peripheral tissues, the onset of inflammation, and the development of atherosclerosis. To test this hypothesis, we plan to measure cholesterol flux in vivo including; absorption, hepatic cholesterol synthesis and secretion, extrahepatic cholesterol synthesis, acquisition and cholesterol turnover in chow and diet-fed LDL receptor -/-, apoA-I -/- mice and compare to LDL receptor -/- and apoA-I -/- only mice. We also plan to test the hypothesis that inhibition of reverse cholesterol transport and the onset of inflammation in LDL receptor -/-, apoA-I-/- mice is reversible by restoring plasma HDL apoA-I concentration to LDL receptor -/-, apoA-l -/- mice using helper-dependent adenoviral technology. We believe that these studies will lead to important new information regarding the role of apoA-l in the initial stages of atherosclerosis development and define the link between hypercholesterolemia and inflammation and their respective roles in the pathogenesis of atherosclerosis.