Molecular Mechanisms Regulating Epsin-Dependent LRP-1 Internalization and Degradation in Atherosclerosis

 描述(申请人提供)：动脉粥样硬化，血管壁增厚和硬化的过程，是心血管疾病发展的一个重要因素(在美国是发病率和死亡率的主要原因)。因此，了解动脉粥样硬化性病变进展的分子机制对人类疾病和治疗的发展具有重要意义。我们最近确定了内吞接头蛋白epsin的一个新的作用，它是一种促动脉粥样硬化和 内皮细胞中的促炎调节因子。具体地说，我们观察到，在西方饮食喂养的ApoE-/-小鼠的主动脉动脉粥样硬化中，epsins 1和2上调。此外，我们还发现，巨噬细胞中的内毒素缺失部分地通过损害脂蛋白的积累和泡沫细胞的发育来保护动脉粥样硬化。这一表型与LRP-1缺陷小鼠的表型形成了直接对比，表明内毒素功能和LRP-1调节之间存在联系，这是以前从未研究过的。因此，在这项建议中，我们描述了一种研究策略来检验这一中心假设，即EPINS与LRP-1相互作用并促进LRP-1的内化，从而损害泡沫化并促进泡沫细胞成熟和动脉粥样硬化的发展。在支持方面，我们报道了在体外巨噬细胞中，内毒素缺乏与总LRP-1和细胞表面LRP-1表达的增加有关。此外，我们有初步数据表明，epsin 1和LRP-1在体外相互作用。因此，我们提出了一种研究策略，以表征Epins与巨噬细胞中LRP-1相互作用的分子机制，并确定这种相互作用是否导致LRP-1下调，从而导致泡沫化和动脉粥样硬化的损害。综上所述，从这项建议中获得的信息将为动脉粥样硬化的发展和进展提供一个新的调节因素和潜在的新的治疗靶点。

 DESCRIPTION (provided by applicant): Atherosclerosis, the process of vascular wall thickening and hardening, is a significant contributing factor in the development of cardiovascular disease (the leading cause of morbidity and mortality in the U.S.). Therefore, understanding the molecular mechanisms involved in atherosclerotic lesion (atheroma) progression has significant relevance in human disease and therapeutic development. We recently identified a novel role for the endocytic adaptor protein, epsin, as a pro-atherogenic and pro-inflammatory regulator in the endothelium. Specifically, we observed that epsins 1 and 2 are upregulated in the aortic atheroma of western diet fed ApoE-/- mice. Furthermore, we found that epsin-depletion in macrophages protects against atherosclerosis in part by impairing lipoprotein accumulation and foam cell development. This phenotype is in direct contrast to that of LRP-1-deficient mice suggesting a link between epsin function and LRP-1 regulation, which has never before been investigated. Therefore, in this proposal we describe a research strategy to test the central hypothesis that epsins interact with and facilitate the internalization of LRP-1, thus impairing efferocytosis and contributing to foam cell maturation and atheroma development. In support, we report that epsin deficiency is associated with increased total and cell surface LRP-1 expression in macrophages in vitro. Furthermore, we have preliminary data suggesting that epsin 1 and LRP-1 interact in vitro. Therefore, we propose a research strategy to characterize the molecular mechanisms by which epsins interact with LRP-1 in macrophages and to determine if this interaction results in the downregulation of LRP-1 resulting in impaired efferocytosis and atheroma development. In summary, the information gained from this proposal will provide a novel regulator, and potential new therapeutic target, for the development and progression of atherosclerosis.