The Annexin 2 Stress Response in Vascular Cells

动脉粥样硬化是发达国家心血管疾病的主要原因。在这种疾病中， 内皮细胞获得促凝血特性，而活化的平滑肌细胞和巨噬细胞 积聚在动脉壁上。本项目的总体目标是了解 膜联蛋白2（A2）为基础的蛋白水解级联，启动纤溶酶，在血管细胞表面。A2是 内皮细胞、活化的平滑肌细胞上表达的主要纤溶原受体，以及 巨噬细胞A2将纤溶酶的生成加速几个数量级，并在纤溶酶的生成中起核心作用。 在定向血管细胞迁移和基质重塑中，通过激活额外的下游 蛋白酶初步数据表明，A2易位到细胞表面是一个主要的机制， 其中血管细胞（内皮细胞、平滑肌细胞和巨噬细胞）上调细胞表面 蛋白水解活性在这个建议中，我们将阐明的分子途径，管理运输A2 在血管细胞受到应激和/或损伤时，在此之前，我们证明了A2 从细胞质区室通过非经典的高尔基体/内质网转运到细胞表面。 由短暂的热应激启动的非网状通路。我们发现这种调节反应 需要A2结合蛋白p11（S100 A10）的参与，这使得src样激酶- 介导的酪氨酸-23磷酸化开关，启动易位反应。拟议 研究，我们将研究[1]内皮细胞，平滑肌细胞， 巨噬细胞在损伤时将A2转运到细胞表面，[2] ATP结合盒的作用 转运蛋白A1（ABCA 1）在这一过程中的作用，[3] A2结合蛋白，p11，在A2 [4] A2转运在体内血管损伤反应中的意义。这些 研究将利用包括体外培养系统和转基因小鼠的组合方法。 包括我们实验室创建的A2和p11 -nulls。我们将继续与 项目III和V的研究人员利用他们在研究生长因子信号传导方面的专业知识， 和胆固醇转运机制。

Atherosclerosis is a major cause of cardiovascular disease in developed countries. In this disorder, endothelial cells acquire procoagulant properties, while activated smooth muscle cells and macrophages accumulate in the arterial wall. The overall objective of this project will be to understand the regulation of the annexin 2 (A2)-based proteolytic cascade, initiated by plasmin, on the surface of vascular cells. A2 is a major profibrinolytic receptor expressed on endothelial cells, activated smooth muscle cells, and macrophages. A2 accelerates plasmin generation by several orders of magnitude, and plays a central role in directed vascular cell migration and matrix remodeling, through the activation of additional downstream proteases. Preliminary data suggest that translocation of A2 to the cell surface is a primary mechanism by which vascular cells (endothelial cells, smooth muscle cells, and macrophages) upregulate cell surface proteolytic activity. In this proposal, we will elucidate the molecular pathways that govern the transport of A2 to the cell surface in response to stress and/or injury to vascular cells. Previously, we demonstrated that A2 is exported from a cytoplasmic compartment to the cell surface through a non-classical, Golgi/endoplasmic reticulum-independent pathway initiated by brief heat stress. We showed that this regulated response requires the participation of the A2 binding protein, p11 (S100A10), which enables a src-like, kinase- mediated tyrosine-23 phosphorylation switch that initiates the translocation response. In the proposed studies, we will examine [1] the mechanism by which endothelial cells, smooth muscle cells, and macrophages translocate A2 to the cell surface in response to injury, [2] the role of the ATP binding cassette transporter A1 (ABCA1) in this process, [3] the specific role of the A2-binding protein, p11, in A2 translocation, and [4] the significance of A2 transport in the response to vascular injury in vivo. These studies will utilize combined approaches involving in vitro culture systems and genetically modified mouse models, including A2 and p11 -nulls created in our laboratory. We will continue to collaborate with investigators in Projects III and V to capitalize on their expertise in the study of the growth factor signalling and cholesterol transporter mechanisms.