Mechanisms of Urokinase-induced Vascular Disease

描述（由申请人提供）：尽管动脉粥样硬化及其并发症的医学和外科治疗取得了重大进展，动脉粥样硬化性血栓性疾病（包括心肌梗死、中风和周围血管疾病）仍然导致显著的发病率和死亡率。为了进一步降低动脉粥样硬化的发病率和死亡率，需要确定新的靶点并开发针对新的和现有靶点的新疗法。本研究的重点是验证由动脉壁巨噬细胞表达的尿激酶纤溶酶原激活物（uPA）参与动脉粥样硬化的进展和并发症的中心假设。该提案还应用从uPA加速动脉粥样硬化机制的研究中获得的见解来设计和表达一种uPA分子，这种分子将是一种高效的局部抗血栓药物，但不会加速动脉粥样硬化。有3个具体目的：(1)验证巨噬细胞表达的uPA通过受体依赖性激活纤溶酶原加速动脉粥样硬化的假设。这一目标将通过将巨噬细胞靶向的uPA转基因引入纤溶酶原或uPA受体缺乏的小鼠中来实现。(2)验证巨噬细胞表达的uPA在Apoe-/-小鼠体内低水平和高水平均可致动脉粥样硬化的假设，以及晚期动脉粥样硬化病变中巨噬细胞中uPA表达升高可导致动脉粥样硬化斑块破裂的假设。这一目标将通过骨髓移植来调控小鼠巨噬细胞中uPA的表达来实现。(3)为了验证uPA在动脉壁上的表达增加，由于uPA受体（uPAR）依赖的蛋白水解活性导致血管收缩、内膜生长和管腔损失，这些病理效应可以通过固定在内皮细胞表面的uPA突变体的表达来避免。这一目标将通过腺病毒介导的野生型和突变型uPA基因转移到兔颈动脉来实现。通过了解uPA加速动脉粥样硬化的机制，我们希望获得能够设计和开发靶向治疗的见解，以减缓动脉粥样硬化的进展，防止斑块破裂，并抑制血管内血栓形成。

DESCRIPTION (provided by applicant): Despite major advances in the medical and surgical management of atherosclerosis and its complications, atherothrombotic diseases (including myocardial infarction, stroke, and peripheral vascular disease) still cause significant morbidity and mortality. Identification of new targets and development of novel therapies directed at new and existing targets are needed to achieve further decrements in the morbidity and mortality of atherosclerosis. This proposal is focused on testing the central hypothesis that urokinase plasminogen activator (uPA), expressed by artery wall macrophages, contributes to the progression and complications of atherosclerosis. The proposal also applies insights derived from investigations of the mechanisms of uPAaccelerated atherosclerosis to design and express a uPA molecule that would be a highly effective local antithrombotic agent but would not accelerate atherosclerosis. There are 3 specific aims: (1) To test the hypothesis that macrophage-expressed uPA accelerates atherosclerosis by receptor-dependent activation of plasminogen. This aim will be accomplished by introducing a macrophage-targeted uPA transgene into mice that are deficient in plasminogen or the uPA receptor. (2) To test the hypotheses that macrophage-expressed uPA is atherogenic at low as well as high levels in Apoe-/- mice, and that atherosclerotic plaque rupture can be caused by elevated uPA expression in macrophages in advanced atherosclerotic lesions. This aim will be accomplished by using bone marrow transplantation to manipulate uPA expression in mouse macrophages. (3) To test the hypothesis that increased expression of uPA in the artery wall causes vasoconstriction, intimal growth, and lumen loss due to uPA receptor (uPAR)-dependent proteolytic activity and that these pathologic effects can be avoided by expression of a uPA mutant that is anchored to the endothelial cell surface. This aim will be accomplished using adenovirus-mediated gene transfer of wild-type and mutant uPA to the rabbit carotid artery. By understanding the mechanisms through which uPA accelerates atherosclerosis, we expect to obtain insights that will permit the design and development of targeted therapies that slow the progression of atherosclerosis, prevent plaque rupture, and inhibit intravascular thrombosis.