A Novel Role for Endothelial Epsins in TNF signaling, Inflammation, and Atheroscl

描述（由申请人提供）：动脉粥样硬化是血管壁增厚和硬化的过程，是心血管疾病（美国发病率和死亡率的主要原因）发展的重要促进因素。因此，了解动脉粥样硬化病变（动脉粥样硬化）进展的分子机制在人类疾病和治疗发展具有重要意义。我们最近发现了一种新的作用，内吞衔接蛋白，epsin，作为促动脉粥样硬化和 内皮中的促炎调节剂。具体地，我们观察到，epsin 1和2在西方饮食喂养的ApoE-/-小鼠的主动脉粥样硬化中上调。为了进一步研究epsin在动脉粥样硬化中的作用，我们通过将Epn 1 fl/fl、Epn 2-/-小鼠与组成型VEcad Cre小鼠杂交，然后将它们回交并将它们繁殖到ApoE-/-背景来创建内皮细胞特异性epsin缺陷型ApoE-/-小鼠（ApoE-/-/EC-DKO）。当喂食西方饮食时，与ApoE-/- /WT小鼠相比，我们发现ApoE-/-/EC-DKO小鼠对饮食诱导的动脉粥样硬化有抵抗力。动脉粥样化的发展部分依赖于内皮活化，即粘附分子、选择素、趋化因子和细胞因子的上调表达，其促进免疫和炎性细胞的募集。TNFR-NF B信号传导和随后的下游转录激活是内皮激活所必需的关键级联。因此，我们描述了一个研究策略，以测试的核心假设，即epsins发挥关键作用，动脉粥样硬化，促进TNFR-NF-？B信号传导导致炎症和随后的免疫/炎性细胞向发展中的动脉粥样化的募集。在支持，我们报告说，胰蛋白酶缺乏损害TNF诱导的TNFR-NF-？体外主动脉内皮细胞中的B信号。epsin缺陷型内皮细胞的活化受损与体外巨噬细胞滚动/粘附减少相对应，这是巨噬细胞募集、浸润和泡沫细胞形成的关键步骤。此外，我们有初步的数据暗示一种新的调节机制epsins在TNFR信号复合物组装，独立于其传统的作用，作为一个内吞适配器。因此，我们还提出了一个战略，以表征的分子机制，epsins促进TNFR-NF-？B信令。具体而言，我们的数据表明，epsins在招募和/或稳定TNFR信号复合物的形成中发挥了新的和关键的作用。总之，从该提议中获得的信息将提供新的调节剂和潜在的新治疗靶点， 动脉粥样硬化的发生和发展。此外，它将导致一个新的功能epsins的鉴定和表征，独立的作用，作为内吞衔接。

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 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. To further investigate the role of epsins in atherosclerosis, we created endothelial cell-specific epsin deficient ApoE-/- mice (ApoE-/-/EC-DKO) by crossing Epn1fl/fl, Epn2-/- mice with constitutive VEcad Cre mice then backcrossed and bred them to an ApoE-/- background. When fed western diet, and compared to ApoE-/- /WT mice, we found that ApoE-/-/EC-DKO mice were resistant to diet-induced atherosclerosis. Development of the atheroma is dependent, in part, on endothelial activation, i.e. upregulated expression of adhesion molecules, selectins, chemokines and cytokines, which facilitate the recruitment of immune and inflammatory cells. TNFR-NF-?B signaling and the subsequent downstream transcriptional activation, is a critical cascade necessary for endothelial activation. Therefore, we describe a research strategy to test the central hypothesis that epsins play a critical role in atherosclerosis by promoting TNFR-NF-?B signaling resulting in inflammation and subsequent recruitment of immune/inflammatory cells to the developing atheroma. In support, we report that epsin deficiency impaired TNF¿-induced TNFR-NF-?B signaling in aortic endothelial cells in vitro. Impaired activation of epsin deficient endothelial cells corresponded with decreased macrophage rolling/adhesion in vitro, which is a critical step in macrophage recruitment, infiltration and foam cell formation. Furthermore, we have preliminary data implicating a novel regulatory mechanism for epsins in TNFR signaling complex assembly, independent of its conventional role as an endocytic adaptor. Therefore, we also propose a strategy to characterize the molecular mechanism by which epsins promote TNFR-NF-?B signaling. Specifically, our data suggests epsins play a novel and critical role in recruiting and/or stabilizing TNFR signaling complex formation. 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. In addition, it will result in the identificatin and characterization of a novel function for epsins, independent of their role as endocytic adaptors.