The Role of Signaling Adaptor Protein Epsin in Atherosclerosis

描述(申请人提供)：由内皮下层的低密度脂蛋白氧化引起的动脉炎症反应是导致动脉粥样硬化斑块发生、发展甚至破裂的关键过程。然而，由于缺乏适当的目标，目前还没有有效的药物或疗法来扰乱炎症过程。Epsins是一组与胞内蛋白结合的蛋白质，参与胞内包裹的囊泡的内吞作用。我们的研究表明，内皮细胞表达的内皮肽在动脉粥样硬化的发病机制中起着重要作用。Epsin 1基因的缺失 内皮细胞中的(Epn1)和epsin 2(Epn2)基因可显著缩小载脂蛋白E缺陷(ApoE-/-)小鼠的动脉粥样硬化病变范围，而不影响全身性高胆固醇血症。我们还观察到，用siRNAs敲除Epn1和Epn2都会影响NF-kB信号转导，并抑制基线和TNFa诱导的内皮细胞VCAM-1和P-选择素的表达。因此，我们推测，内皮肽通过促进肿瘤坏死因子诱导的核因子-kB的激活，对动脉炎症反应起关键调节作用，从而增强动脉粥样硬化斑块的形成。我们将使用体外和体内模型系统来描述epsins 1和2在动脉粥样硬化中的作用以及动脉炎症过程的分子机制。在目标1中，我们将研究EPSINS促进肿瘤坏死因子诱导的内皮细胞中的NF-kB信号转导的分子机制。在目标2中，我们将利用流式细胞术、免疫组织化学和免疫荧光的多因素方法来研究内皮胰岛素是如何通过增强内皮细胞的激活来促进动脉粥样硬化的形成。这些研究将提供内啡肽和斑块形成之间的机制联系。在目标3中，我们将确定靶向斑块中的内啡肽是否阻止载脂蛋白E-/-鼠的动脉粥样硬化进展。这些研究将阐明控制动脉粥样硬化的新途径，并可能导致动脉粥样硬化的新治疗。

DESCRIPTION (provided by applicant): The arterial inflammatory responses initiated by the oxidation of LDL trapped in the subendothelium are a key process that drives the initiation, progression, and even rupture of atherosclerotic plaques. However, there have been no effective medicines or therapies available to disrupt the inflammatory process due to lack of appropriate targets. Epsins are a group of proteins that bind clathrin and are involved in the endocytosis of clathrin-coated vesicles. Our studies have shown that epsins expressed in endothelial cells play a major role in the pathogenesis of atherosclerosis. Deletion of the epsin 1 (Epn1) and epsin 2 (Epn2) genes in endothelial cells results in a dramatic reduction in atherosclerotic lesion sizes in apolipoprotein E-deficient (ApoE-/-) mice without affecting systemic hypercholesterolemia. We have also observed that knockdown of both Epn1 and Epn2 with siRNAs affects NF-kB signaling transduction and suppresses both baseline and TNFa-induced VCAM-1 and P-selectin expression in endothelial cells. Therefore, we hypothesize that epsins critically regulate arterial inflammatory responses and consequently potentiate atherosclerotic plaque formation by enhancing TNF-induced NF-kB activation. The role of epsins 1 and 2 in atherosclerosis and molecular mechanisms underlying the arterial inflammatory processes will be characterized using both in vitro and in vivo model systems. In Aim 1, we will investigate molecular mechanisms by which epsins enhance TNF-induced NF-kB signaling in endothelial cells. In Aim 2, we will utilize multifactorial approaches employing both flow cytometry and immunohistochemistry and immunofluorescence to investigate how epsins promote atherogenesis by potentiating endothelial cell activation. These studies will provide mechanistic links between epsins and plaque formation. In Aim 3, we will determine whether targeting epsins in plaques impedes atheroma progression in ApoE-/- mice. These studies will shed light on new pathways that control atherosclerosis and may lead to new treatment of atherosclerosis.