Oxidized Phospholipid-Induced Inflammation in Atherosclerosis

描述（由申请人提供）：动脉粥样硬化是一种慢性炎性疾病，其特征在于单核细胞（如单核细胞和T细胞）的特异性浸润，而嗜中性粒细胞在脂肪条纹病变中基本上不存在。动脉粥样硬化病变发展的最早步骤之一是单核细胞与血管壁内皮细胞的粘附。以前证明，如果用最低修饰的LDL（MM-LDL）刺激，内皮细胞被激活以特异性结合单核细胞，但不结合中性粒细胞。随后通过氧化的1-棕榈酰-2-花生四烯酸-S/7-甘油-3-磷酸胆碱（OxPAPC）激活内皮细胞观察到对单核细胞的这种特异性，这意味着脂质氧化产物是慢性炎症的罪魁祸首。我们假设，特定的磷脂氧化产物（OxPL）触发血管炎症，并确定动脉粥样硬化和其他慢性炎症性疾病的单核细胞特异性特征。这些研究的结果将增加我们对动脉粥样硬化是如何开始和传播的理解，并将导致慢性炎症性疾病治疗的新策略。该提案的具体目标是： 具体目标1：从结构上鉴定决定单核细胞特异性炎症的单个OxPL，并研究OxPL诱导的信号传导涉及TLR 4的假设。我们将研究细胞内信号转导途径诱导OxPL导致特异性单核细胞粘附在体外，使用HUVEC以及分离的小鼠主动脉EC。此外，我们将测试的假设，POVPC是一个活性成分的OxPAPC，决定单核细胞特异性和确定结构-功能关系。我们将研究TLR-4的作用和TLR-4衔接蛋白MyD 88和TRIP的参与，以及OxPL介导的信号传导事件中各自的下游元件。 具体目标#2：探索OxPL是体内血管炎症触发因素的假设。为了模拟OxPL在血管壁中的积累，我们将OxPL局部应用于小鼠的颈动脉并测量趋化因子和粘附分子的表达。此外，我们将使用离体灌注的颈动脉来研究OxPL诱导的单核细胞滚动和粘附。 具体目标#3：为了检验假设，OxPL诱导的特异性单核细胞在体内的积累需要一个特定的趋化因子的表达模式，并涉及12脂氧合酶。使用小鼠气囊模型，我们将检查OxPL诱导的体内白细胞蓄积并表征白细胞亚群。我们将研究趋化因子的表达模式，以及表达的时间过程中OxPL诱导相比，LPS诱导的炎症。此外，我们将研究12-LO在OxPL诱导的体内炎症中的作用。

DESCRIPTION (provided by applicant): Atherosclerosis is a chronic inflammatory disease, characterized by specific infiltration of monocytic cells, such as monocytes and T-cells, while neutrophils are essentially absent in the fatty streak lesion. One of the earliest steps in the development of the atherosclerotic lesion is the adhesion of monocytes to endothelial cells of the vessel wall. Previously it was demonstrated that, if stimulated with minimally modified LDL (MM-LDL), endothelial cells are activated to specifically bind monocytes, but not neutrophils. This specificity towards mononuclear cells was subsequently observed with the activation of endothelial cells by oxidized 1-palmitoyl-2-arachidonoyl-s/7-glycero-3-phosphocholine (OxPAPC), implying lipid oxidation products as culprits in chronic inflammation. We hypothesize that specific phospholipid oxidation products (OxPL) trigger vascular inflammation and determine monocyte specificity characteristic of atherosclerosis and other chronic inflammatory diseases. The outcome of the proposed studies will add to our understanding of how atherosclerosis is initiated and propagated and should lead to new strategies in the treatment of chronic inflammatory disorders. The specific aims addressed in this proposal are: Specific Aim #1: To structurally identify individual OxPL that determine monocyte specific inflammation and to investigate the hypothesis that OxPL-induced signaling involves TLR4. We will investigate intracellular signaling pathways induced by OxPL that lead to specific monocyte adhesion in vitro, using HUVEC as well as isolated murine aortic EC. Furthermore, we will test the hypothesis that POVPC is one active component in OxPAPC that determines monocyte specificity and determine structure-function relationships. We will examine the role of TLR-4 and the involvement of the TLR-4 adaptor proteins MyD88 and TRIP, as well as respective downstream elements in OxPL-mediated signalling events. Specific Aim #2: To explore the hypothesis that OxPL are triggers of vascular inflammation in vivo. To mimic accumulation of OxPL in the vascular wall, we will topically apply OxPL to carotid arteries in mice and measure chemokine and adhesion molecule expression. Furthermore, we will use ex vivo perfused carotid arteries to study OxPL-induced monocyte rolling and adhesion. Specific Aim #3: To examine the hypothesis that OxPL-induced specific mononuclear cell accumulation in vivo requires a specific chemokine expression pattern and involves 12 lipoxygenase. Using the mouse air pouch model, we will examine OxPL-induced leukocyte accumulation in vivo and characterize leukocyte subsets. We will investigate the chemokine expression pattern as well as time course of expression in OxPL-induced compared to LPS-induced inflammation. Furthermore, we will investigate the role of 12-LO in OxPL-induced inflammation in vivo.