Plasmalogen-derived bioactive lipids in atherosclerosis

描述（由申请人提供）：动脉粥样硬化性血管疾病是工业化国家死亡和发病的主要原因。了解导致动脉粥样硬化的生化机制可能会带来新的治疗和预防措施。髓过氧化物酶（MPO）和MPO衍生产物的水平已被证明在动脉粥样硬化组织中升高，并可能介导促动脉粥样硬化机制。激活后，单核细胞和巨噬细胞释放MPO并产生其底物过氧化氢，导致MPO催化生成反应性氯化物质（RCS）次氯酸。我们发现RCS的目标是磷脂的乙烯醚键，导致1-氯脂肪醛（1-ClFALD）的产生，并表明1-ClFALD水平在人类动脉粥样硬化组织中增加了1400倍。我们发现1-ClFALD被代谢为1-氯脂肪酸和1-氯脂肪醇，它们与1-ClFALD一起是一种新型氯化脂质组的主要成员。初步研究表明，1-氯脂肪酸：1)在活化的人单核细胞和人动脉粥样硬化组织中升高；2)抑制内皮型一氧化氮合酶；3)诱导巨噬细胞和平滑肌细胞的神经酰胺积累；4)引起巨噬细胞凋亡；5)刺激巨噬细胞产生促炎细胞因子，6)存在于人血浆中。在这一提议中，我们将检验1-ClFALD代谢物是动脉粥样硬化介质的假设。这一假设将通过三个具体目标来检验。Specific Aim 1将验证1- clfld代谢物是动脉粥样硬化的候选介质和生物标志物的假设。基于质谱的筛选将用于鉴定人类单核细胞和巨噬细胞以及人类动脉粥样硬化组织中的1-ClFALD代谢物。将进行一项病例对照研究，以确定1- ClFALD的代谢物作为人类冠状动脉疾病的生物标志物。1- clfld代谢物也将在动脉粥样硬化组织和LDL受体-/-小鼠的血浆中被鉴定出来，这些小鼠在动脉粥样硬化饮食中巨噬细胞过度表达人MPO。特异性目的2将验证1- clfld代谢物介导促炎和促动脉粥样硬化机制的假设。氯代脂质介导的eNOS功能障碍的机制将被检查。1- clfld代谢物作为促炎细胞因子释放介质的作用将被研究。Aim 2的一个子假设是氯化脂质代谢物增加新生神经酰胺生物合成和随后的细胞凋亡。特异性目的3将检验氯代脂质导致动脉粥样硬化的假设。我们将对载脂蛋白E-/-和低密度脂蛋白受体-/-小鼠进行动脉粥样硬化检查，这些小鼠被喂食添加了2-氯铝酸的食物和促动脉粥样硬化饮食。血浆和尿液中氯代脂质代谢物的水平以及动脉粥样硬化水平将与Aim 1研究中hMPO和MPO-/-小鼠在促动脉粥样硬化饮食中的水平进行比较。综上所述，拟议的研究将使用多学科的方法来确定氯化脂类作为动脉粥样硬化的新型介质。

DESCRIPTION (provided by applicant): Atherosclerotic vascular disease is the leading cause of death and morbidity in industrialized nations. Understanding the biochemical mechanisms leading to atherosclerosis may lead to new therapies and preventative measures. Levels of myeloperoxidase (MPO) and MPO-derived products have been shown to be elevated in atherosclerotic tissue and potentially mediate pro-atherosclerotic mechanisms. Upon activation, monocytes and macrophages release MPO and produce its substrate, hydrogen peroxide, resulting in MPO-catalyzed production of the reactive chlorinating species (RCS), hypochlorous acid. We have discovered that RCS target the vinyl ether bond of the plasmalogen phospholipids resulting in 1-chlorofatty aldehyde (1-ClFALD) production and have shown that 1-ClFALD levels are increased 1400-fold in human atherosclerotic tissue. We found that 1-ClFALD is metabolized to 1-chlorofatty acid and 1-chlorofatty alcohol, which along with 1-ClFALD are primary members of a novel chlorinated lipidome. Preliminary studies show that 1-chlorofatty acid: 1) is elevated in activated human monocytes and in human atherosclerotic tissue; 2) inhibits endothelial nitric oxide synthase; 3) elicits ceramide accumulation in macrophages and smooth muscle cells; 4) causes macrophage apoptosis; 5) stimulates the production of pro-inflammatory cytokines by macrophages and 6) is present in human plasma. In this proposal we will test the hypothesis that 1-ClFALD metabolites are mediators of atherosclerosis. This hypothesis will be tested by three specific aims. Specific Aim 1 will test the hypothesis that 1-ClFALD metabolites are candidate mediators and biomarkers of atherosclerosis. Mass spectrometry- based screens will be employed to identify 1-ClFALD metabolites in human monocytes and macrophages, as well as human atherosclerotic tissue. A case-control study will be performed to identify metabolites of 1- ClFALD as biomarkers of human coronary artery disease. 1-ClFALD metabolites will also be identified in atherosclerotic tissue and plasma from LDL receptor-/- mice on an atherogenic diet that overexpress human MPO in their macrophages. Specific Aim 2 will test the hypothesis that 1-ClFALD metabolites mediate pro-inflammatory and proatherogenic mechanisms. Mechanisms responsible for chlorinated lipid mediated eNOS dysfunction will be examined. The role of 1-ClFALD metabolites as mediators for the release of pro-inflamma- tory cytokines will be examined. A sub-hypothesis of Aim 2 is that chlorinated lipid metabolites increase de novo ceramide biosynthesis and subsequent apoptosis. Specific Aim 3 will test the hypothesis that chlorinated lipids cause atherosclerosis. Atherosclerosis will be examined in apo E-/- and LDL receptor-/- mice that are fed chow and pro-atherogenic diets that are supplemented with 2-chloropalmitic acid. Plasma and urine levels of chlorinated lipid metabolites, as well as the level of atherosclerosis, will be compared to those levels in both hMPO and MPO-/- mice on pro-atherogenic diets in studies from Aim 1. Taken together, the proposed studies will use a multi-disciplinary approach to identify chlorinated lipid species as novel mediators of atherosclerosis. PUBLIC HEALTH RELEVANCE: Cardiovascular disease is the leading cause of death and morbidity in industrialized nations. Understanding the biochemical mechanisms leading to atherosclerosis may lead to new therapies and the development of new biomarkers. In this proposal we will test the hypothesis that novel chlorinated lipid species are important mediators of atherosclerosis.