Role of Annexin II in Peripheral Vascular Disease

砷是一种普遍存在的无机环境污染物。长期接触砷通常会导致外周血管疾病，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，纤溶酶是溶解血管系统中的血凝块所必需的。我们发表的关于砷的研究表明，丝氨酸/苏氨酸激酶MEKK 4， 参与砷信号转导，沿着钙结合蛋白膜联蛋白II。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，我们的努力集中在表征与膜联蛋白II相互作用并受膜联蛋白II调节的蛋白质。这一提议的假设是，膜联蛋白II在促进砷依赖性 通过调节纤溶酶的形成来治疗外周血管疾病。为了验证这一假设，我们提出了以下具体目标：1。表征砷依赖性膜联蛋白II的翻译后修饰。我们提出砷甲基化产生同型半胱氨酸，同型半胱氨酸化学修饰膜联蛋白II，从而抑制纤溶酶的产生并促进微血管的凝血。我们建议，同型半胱氨酸-膜联蛋白II可能是砷暴露的指标，我们将探讨使用同型半胱氨酸-膜联蛋白II作为生物标志物的可能性。 2.为了表征膜联蛋白II和MEKK 4之间的相互作用。我们的数据表明膜联蛋白II和MEKK 4之间的相互作用，导致MEKK 4活性。由于MEKK 4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物化学关联将被映射到特定的结构域。3.表征派-1和派-2的砷依赖性调节。我们建议，ERK MAP激酶信号通路，调节膜联蛋白II和MEKK 4，可能是砷依赖性调节派表达的机制。4.评估annexin II的具体功能。我们将创造一种组织特异性基因敲除小鼠， 膜联蛋白II在平滑肌细胞中的表达，以评估整个动物中的砷毒性。 这项研究将进一步了解砷诱导的信号传导过程的重要性，以及它如何对外周血管系统产生不利影响并促进组织损伤。

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.