Role of Annexin II in Peripheral Vas

膜联蛋白 II 在外周血管中的作用

• 批准号: 6901465
• 负责人: RICHARD R VAILLANCOURT
• 金额: $ 16.25万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6901465
• 关键词: annexins; arsenic; biological signal transduction; biomarker; environmental exposure; environmental toxicology; enzyme activity; genetically modified animals; homocysteine; laboratory mouse; methylation; peripheral blood vessel disorder; plasmin; plasminogen activator inhibitors; posttranslational modifications; serine threonine protein kinase

Arsenic (As) is an inorganic environmental contaminant of major concern due to its ubiquitous presence. Chronic exposure to arsenic frequently results in peripheral vascular disease, as well as skin, lung, bladder, and kidney cancer. Recent evidence demonstrates that arsenite inhibits the production of plasmin which is necessary to dissolve blood clots in the vasculature. Our published studies with arsenic have demonstrated that the serine/threonine kinase, MEKK4, is involved in arsenic signal transduction, along with the calcium binding protein, annexin II. To understand the molecular mechanism by which arsenic causes its deleterious effects on the vascular system and how the activity of annexin II contributes to arsenic toxicity, our efforts have focused on characterizing the proteins that interact with and are regulated by annexin II. The hypothesis of this proposal is that annexin II plays a role in promoting arsenic-dependent peripheral vascular disease by modulating the formation of plasmin. To test this hypothesis, we propose the following specific aims: 1. To characterize arsenic-dependent post-translational modifications of annexin II. We propose that arsenic methylation produces homocysteine, which chemically modifies annexin II, thus inhibiting the production of plasmin and promoting clotting of the microvasculature. We propose that homocysteine-annexin II may be an indicator of arsenic exposure and we will explore the possibility of using homocysteine-annexin II as a biomarker. 2. To characterize the interaction between annexin II and MEKK4. Our data indicate interaction between annexin II and MEKK4, resulting in MEKK4 activity. Since MEKK4 appears to function downstream of annexin II, the biochemical association between these proteins will be mapped to specific domains. 3. To characterize arsenic-dependent regulation of PAI-1 and PAI-2. We propose that the ERK MAP kinase signaling pathway, regulated by annexin II and MEKK4, may be a mechanism for arsenic-dependent regulation of PAI expression. 4. To assess specific functions of annexin II. We will create a tissue-specific knockout mouse, selectively disrupting annexin II expression in smooth muscle cells, to evaluate arsenic toxicity in a whole animal. The proposed research will provide a further understanding of the importance of the arsenic-induced signaling processes and how it adversely affects the peripheral vascular system and promotes tissue injury.

砷 (As) 因其普遍存在而成为备受关注的无机环境污染物。长期接触砷经常会导致周围血管疾病以及皮肤癌、肺癌、膀胱癌和肾癌。最近的证据表明，亚砷酸盐抑制纤溶酶的产生，而纤溶酶是溶解脉管系统中血栓所必需的。我们发表的砷研究表明，丝氨酸/苏氨酸激酶 MEKK4 是 与钙结合蛋白膜联蛋白 II 一起参与砷信号转导。为了了解砷对血管系统产生有害影响的分子机制以及膜联蛋白 II 的活性如何导致砷毒性，我们的工作重点是表征与膜联蛋白 II 相互作用并受膜联蛋白 II 调节的蛋白质。该提案的假设是膜联蛋白 II 具有促进砷依赖性的作用。 通过调节纤溶酶的形成来治疗外周血管疾病。为了检验这一假设，我们提出以下具体目标： 1. 表征膜联蛋白 II 的砷依赖性翻译后修饰。我们认为砷甲基化产生同型半胱氨酸，它对膜联蛋白 II 进行化学修饰，从而抑制纤溶酶的产生并促进微血管的凝血。我们认为同型半胱氨酸-膜联蛋白 II 可能是砷暴露的指标，我们将探索使用同型半胱氨酸-膜联蛋白 II 作为生物标志物的可能性。 2. 表征annexin II 和MEKK4 之间的相互作用。我们的数据表明膜联蛋白 II 和 MEKK4 之间的相互作用，导致 MEKK4 活性。由于 MEKK4 似乎在膜联蛋白 II 的下游发挥作用，因此这些蛋白质之间的生化关联将被映射到特定的域。 3. 表征 PAI-1 和 PAI-2 的砷依赖性调节。我们提出，受膜联蛋白 II 和 MEKK4 调节的 ERK MAP 激酶信号通路可能是砷依赖性 PAI 表达调节的机制。 4.评估annexin II的具体功能。我们将创建一种组织特异性基因敲除小鼠，选择性破坏 平滑肌细胞中膜联蛋白 II 的表达，以评估整个动物的砷毒性。 拟议的研究将进一步了解砷诱导的信号传导过程的重要性以及它如何对周围血管系统产生不利影响并促进组织损伤。