CAUSES AND EFFECTS OF ARGINASE ACTIVITY AFTER TRAUMA

创伤后精氨酸酶活性的原因和影响

• 批准号: 6179985
• 负责人: Juan B. Ochoa
• 金额: $ 9.74万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2001-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6179985
• 关键词: adrenalectomy; aminoacid biosynthesis; aminoacid metabolism; animal tissue; arginase; arginine; biological signal transduction; cyclic AMP; enzyme activity; enzyme inhibitors; gene expression; lipopolysaccharides; nitric oxide; nitric oxide synthase; phosphodiesterase inhibitors; polyamines; tissue /cell culture; trauma

The urea cycle is essential for the detoxification of the increased nitrogen waste generated during the metabolic response to trauma. Arginase I, a key enzyme of the urea cycle, generates L-ornithine and urea from L-arginine. Arginase has gained prime importance with the discovery of a second isoenzyme (arginase II) and the discovery of complex physiologic roles for both arginases. Our laboratory has recently observed a significant increase in arginase activity in macrophages and lymphocytes after surgical trauma in mice. The cause and physiologic effects of increased arginase activity after trauma are unknown and constitute the main focus of this research. This grant proposes the following specific aims: 1) characterize changes in tissue arginases caused by trauma. This aim will test the hypothesis that the pattern of arginase production secondary to trauma is distinct from that caused by endotoxin stimulation. We will evaluate the temporal response of arginase activity after trauma, define the patterns of response of the two isoenzymes, and establish the cells and tissues where it is expressed, 2) Identify "factors" that increase arginase activity in tissues after trauma. This aim will test the hypothesis that specific factors (cytokines and/or hormones) involved in the stress response, increase arginase activity. Using complimentary in-vivo and in-vitro experiments, we will test the effects these factors on arginase activity, gene and protein expression, 3) Determine the effects of increased arginase activity after trauma on the metabolic fate of L-arginine and the potential physiologic consequences. We will evaluate the production of nitric oxide, L-ornithine, polyamines and proline under conditions of increased arginase activity after trauma. We believe that increased arginase activity decreases L-arginine availability for the production of nitric oxide. We expect an increased production of proline and polyamines conducive to an environment that favors cellular proliferation and repair. We plan to perform this project using a surgical trauma model that has been well characterized in the laboratory. This project has significant clinical implications providing important links between the metabolic changes of the stress response and the alterations in L-arginine metabolism described after trauma. The new insights into L-arginine metabolism gained by this study provide a novel approach towards understanding the stress response to trauma. A major strength of this project is that it combines the clinical background of the PI with the expertise of two established scientists. The completion of this grant should provide the basis for development of sound, translational research and the progress of the PI into an independent investigator.

尿素周期对于对创伤的代谢反应期间产生的氮废物的排毒至关重要。 精氨酸酶I是尿素周期的关键酶，从L-精氨酸产生L-雌激素和尿素。 十精氨酸酶的第二个同工酶（精氨酸酶II）和两个精氨酸酶的复杂生理作用都具有重要的重要性。 我们的实验室最近观察到小鼠手术创伤后巨噬细胞和淋巴细胞中精氨酸酶活性的显着增加。 创伤后精氨酸酶活性增加的原因和生理效应是未知的，构成了这项研究的主要重点。 该赠款提出以下特定目的：1）表征由创伤引起的组织精氨酸酶的变化。 该目的将检验以下假设，即精氨酸酶产生继发性创伤的模式与内毒素刺激引起的模式不同。 我们将评估创伤后精氨酸酶活性的时间反应，定义两个同工酶的反应模式，并在表达表达的地方建立细胞和组织，2）确定创伤后组织中组织中精氨酸酶活性的“因子”。 该目标将检验以下假设：应激反应涉及的特定因素（细胞因子和/或激素）增加精氨酸酶活性。 使用免费的体内和体外实验，我们将测试这些因素对精氨酸酶活性，基因和蛋白质表达的影响，3）确定创伤后精氨酸酶活性增加对L-精氨酸代谢命运的影响以及潜在的生理学命运结果。 在创伤后精氨酸酶活性的条件下，我们将评估一氧化氮，L-雌激素，多胺和脯氨酸的产生。 我们认为，精氨酸酶活性的增加会降低一氧化氮生产的L-精氨酸的可用性。 我们预计脯氨酸和多胺的产生有利于有利于细胞增殖和修复的环境。 我们计划使用在实验室中表征得很好的手术创伤模型执行该项目。 该项目具有重大的临床意义，提供了压力反应的代谢变化与创伤后描述的L-精氨酸代谢的变化之间的重要联系。 这项研究获得的对L-精氨酸代谢的新见解为理解对创伤的压力反应提供了一种新颖的方法。 该项目的一个主要优势在于，它将PI的临床背景与两位知名科学家的专业知识相结合。 该赠款的完成应为发展，转化研究以及PI发展为独立研究者的发展提供基础。