Regulation of Exocytosis in the Post-Ischemic Myocardium

缺血再灌流引起血管内皮细胞颗粒的快速释放 炎症和血栓形成，包括P-选择素、白介素8和von Willebrand因子。P-选择素是 从内皮细胞内部转移到外表面，在那里它调节白细胞 黏附于内皮壁。白介素8被释放到血液中，在那里它可以激活白细胞， 增加白细胞与内皮细胞之间的相互作用。因此，内皮细胞胞吐是一个早期步骤。 在白细胞进入缺血心肌的过程中。 这个项目的总体目标是描述内皮颗粒胞吐的机制。 导致缺血后心肌损伤。我们之前已经确定了胞外的成分 内皮细胞的机械。我们随后发现，一氧化氮通过以下途径抑制血管炎症 抑制介导胞吐作用的特定蛋白质。然后我们开发了一种新的多肽，它可以干扰 胞吐机制，抑制胞吐作用，减少血管炎症。我们现在建议延长 这些研究旨在探讨缺血后心肌胞吐作用的机制。 我们首先计划研究低氧如何激活胞吐作用。我们将重点介绍信令的作用 中间体，如钙调神经磷酸酶，通过胞外的翻译后修饰来调节胞吐作用 机械设备。然后我们将描述细胞外排出机制的一个特殊成分在缺血后的作用。 发炎。我们最终将定义一种新的机制来调节主要的应激反应 低氧内皮细胞中的通路。每个目标都包括广泛的研究，从重组 从蛋白质到转导细胞到动物实验。这些研究将增加我们对 调控内皮细胞胞吐的分子机制，并将导致抑制 对缺血后心肌的炎症和损伤。

Ischemia and reperfusion trigger the rapid release of endothelial granules containing mediators of vascular inflammation and thrombosis, including P-selectin, interleukin-8, and von Willebrand factor. P-selectin is translocated from the interior of the endothelial cell to the exterior surface, where it mediates leukocyte adherence to the endothelial wall. Interleukin-8 is released into the blood, where it can activate leukocytes, increasing the interactions between leukocytes and endothelial cells. Endothelial exocytosis is thus an early step in leukocyte trafficking into the ischemic myocardium. The over-all goal of this project is to characterize the mechanisms by which exocytosis of endothelial granules leads to injury in the post-ischemic myocardium. We have previously identified components of the exocytic machinery of endothelial cells. We subsequently discovered that nitric oxide inhibits vascular inflammation by inhibiting specific proteins that mediate exocytosis. We then developed a novel polypeptide that interferes with the exocytic machinery, inhibits exocytosis, and decreases vascular inflammation. We now propose to extend these studies to explore the mechanisms of exocytosis in post-ischemic myocardium. We first plan to study how hypoxia activates exocytosis. We will focus on the role of signaling intermediates such as calcineurin which regulate exocytosis by post-translational modifications of the exocytic machinery. We will then characterize the role of one particular component of the exocytic machinery in postischemic inflammation. We will finally define a novel mechanism which regulates a major stress response pathway in hypoxic endothelial cells. Each of these aims includes a wide range of studies, from recombinant proteins to transduced cells to animal experiments. These studies will increase our understanding of the molecular mechanisms regulating endothelial exocytosis, and will lead to novel therapies that inhibit inflammation and injury to the post-ischemic myocardium.