OXPAPC induction of Tissue Factor

描述(申请人提供)：动脉粥样硬化斑块破裂导致的动脉血栓形成是急性血栓形成导致死亡的主要原因。先前的研究表明，高脂血症通过激活凝血功能显著增加动脉血栓形成的风险。当单核细胞暴露于氧化的脂蛋白时，凝血级联的细胞激活剂组织因子(TF)被诱导。单核细胞的激活会导致随后释放转铁蛋白阳性微粒(MPS)，这代表了处于高凝状态的循环转铁蛋白的来源。一类氧化程度最低的脂蛋白，包括磷脂氧化产物oxPAPC，先前已被证明激活Toll-like 4(TLR4)受体。我们将验证氧化的脂蛋白通过与单核细胞上的TLR4结合并诱导TF的表达和TF阳性的MPS的释放而与凝血系统的激活有关的假设。我的建议分为两个目标。目的1探讨oxPAPC诱导单核细胞表达转铁蛋白的机制及转铁蛋白阳性MPS的产生。我们将检测oxPAPC处理的单核/巨噬细胞中TF的表达。我们将利用缺乏TLR4的小鼠单核/巨噬细胞，以及具有抑制性抗TLR4抗体的人单核细胞。目的2阐明单核细胞来源的MP-TF在高脂血症小鼠凝血激活中的作用。在高脂血症小鼠模型中，将使用TF中和抗体来确定TF阻断对凝血酶-抗凝血酶(TAT)的影响，凝血酶-抗凝血酶(TAT)是凝血激活的标志。进一步的分析将使用低Tf或髓系缺陷Lys-M Tf的骨髓移植到LDLR-/-小鼠中。这将确定在动脉血栓形成的小鼠模型中，减少单核细胞来源的、TF阳性的MPS是否能减少TAT和闭塞时间。这些研究将增加我们对血脂如何调节循环Tf水平以及Tf阳性MPS的主要来源是否是单核细胞的理解。在美国，超过8000万人患有一种或多种形式的心血管疾病(CVD)，其中每年有超过85万人死亡，使其成为美国的头号杀手。斑块破裂和随后的动脉血栓形成是动脉粥样硬化导致急性血管综合征(如心肌梗死和中风)的关键事件。加深对心血管疾病血栓形成机制的了解，将使科学界和医学界在治疗和治疗策略方面取得进展。

DESCRIPTION (provided by applicant): Arterial thrombosis resulting from disruption of atherosclerotic plaques is a leading cause of death due to acute thrombosis. Previous studies have demonstrated that hyperlipidemia significantly increases the risk of arterial thrombosis via activation of coagulation. Tissue factor (TF), the cellular activator of the clotting cascade, is induced when monocytes are exposed to oxidized lipoproteins. Activation of monocytes results in the subsequent release of TF-positive microparticles (MPs), which represent a source of circulating TF in hypercoagulable states. A class of minimally oxidized lipoproteins, including the phospholipid oxidation product oxPAPC, have previously been demonstrated to activate the Toll-like 4 (TLR4) receptor. We will test the hypothesis that oxidized lipoproteins are associated with activation of the coagulation system by binding to TLR4 on monocytes and inducing the expression of TF and the release of TF-positive MPs. My proposal is divided into two aims. Aim 1 will determine the mechanism by which oxPAPC induces TF expression in monocytes and the generation of TF-positive MPs. We will measure TF expression in oxPAPC treated monocytes/macrophages. We will utilize mouse monocytes/macrophages deficient in TLR4, and human monocytes with an inhibitory anti-TLR4 antibody. Aim 2 will delineate the role of monocyte-derived MP TF in the activation of coagulation in hyperlipidemic mice. The effects of TF blockade on thrombin-antithrombin (TAT), a marker of activation of coagulation, will be determined using TF neutralizing antibody in a mouse model of hyperlipidemia. Further analyses will be performed using bone marrow transplantation of either low TF or myeloid deficient Lys-M TF, into LDLr-/- mice. This will determine if reducing monocyte-derived, TF-positive MPs reduces TAT and time to occlusion in a mouse model of arterial thrombosis. These studies will increase our understanding of how lipidemia modulates levels of circulating TF and whether the major source of TF-positive MPs is monocytes. Over 80,000,000 people in the Unites States suffer from one or more forms of cardiovascular disease (CVD) and over 850,000 of these cases result in death every year, making it the number one killer in America. Plaque disruption and subsequent arterial thrombosis is a critical event in atherosclerosis resulting in acute vascular syndromes, such as myocardial infarction and stroke. Increased understanding of the mechanisms of thrombosis in CVD will enable the scientific and medical communities to make advances in therapeutics and treatment strategies.