REGULATION OF EXPRESSION OF NO SYNTHASE

NO合酶表达的调节

• 批准号: 2842819
• 负责人: LOUIS J IGNARRO
• 金额: $ 29.17万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2842819
• 关键词: arginase; enzyme activity; enzyme induction /repression; free radical oxygen; gel mobility shift assay; hydrogen peroxide; isozymes; laboratory rat; macrophage activating factor; messenger RNA; nitric oxide; nitric oxide synthase; oxidoreductase inhibitor; regulatory gene; superoxides; vascular endothelium; vascular smooth muscle; western blottings; arginase; enzyme activity; enzyme induction /repression; free radical oxygen; gel mobility shift assay; hydrogen peroxide; isozymes; laboratory rat; macrophage activating factor; messenger RNA; nitric oxide; nitric oxide synthase; oxidoreductase inhibitor; regulatory gene; superoxides; vascular endothelium; vascular smooth muscle; western blottings

Nitric oxide (NO) is a key molecule mediating physiological and pathophysiological processes in mammals, many of which involve the vascular system. Many physiological actions of NO are mediated by cyclic GMP, and both NO and cyclic GMP have relatively short durations of action. NO is labile and is not stored, released, or inactivated by conventional mechanisms. Reactivity of NO with reactive oxygen species and with iron and sulfur containing molecules causes rapid inactivation of NO. Cyclic GMP is also unstable due to hydrolysis by specific phosphodiesterases. Thus, NO is rapidly inactivated by naturally-occurring chemical processes and cyclic GMP is rapidly inactivated by phosphodiesterases in cells, yielding half lives for each of less than 1-second. Therefore, the actions of NO are highly dependent on its biosynthesis from L-arginine by NO synthase (NOS). Accordingly, the regulation or modulation of NO biosynthesis is the most important process dictating the pharmacodynamics of NO. The principal objective of the proposed studies is to elucidate several potentially novel mechanisms by which NO biosynthesis may be controlled. These targeted mechanisms involve changes in NOS mRNA expression, NOS protein expression and stability, arginase expression and catalytic activity, arginine substrate availability, and the production of reactive oxygen species by NOS. The central hypothesis to be tested is that cellular NO production is tightly regulated by various endogenous factors affecting transcriptional, translational and posttranslational expression of NOS isoforms. Three Specific Aims are proposed to achieve this objective: (1) to elucidate the molecular mechanisms by which NO downregulates the expression of inducible NOS (iNOS) and endothelial NOS (eNOS); (2) to elucidate the mechanisms by which arginase upregulates the expression of iNOS and eNOS; and (3) to elucidate the role of arginase in modulating the production of superoxide anion and hydrogen peroxide by iNOS and eNOS. The proposed research represents a continuing long-term effort to elucidate the biological factors influencing the vascular and related actions of NO in health and disease.

一氧化氮（NO）是介导哺乳动物的生理和病理生理过程的关键分子，其中许多涉及血管系统。 NO的许多生理作用都是由环状GMP介导的，NO和环状GMP的作用持续时间相对较短。 否是不稳定的，不会被常规机制存储，释放或灭活。反应性氧的反应性以及含铁和硫的分子的反应性会导致NO的快速失活。由于特定的磷酸二酯酶水解，环状GMP也不稳定。 因此，NO被天然化的化学过程迅速灭活，并且环状GMP被细胞中的磷酸二酯酶迅速灭活，在小于1秒的情况下产生了一半的生命。 因此，NO的作用高度依赖于L-精氨酸的生物合成（NO）（NOS）。 因此，没有生物合成的调节或调节是决定NO的药效学的最重要过程。 拟议研究的主要目标是阐明无法控制生物合成的几种潜在新型机制。 这些靶向机制涉及NOS mRNA表达，NOS蛋白表达和稳定性，精氨酸酶表达和催化活性，精氨酸底物的可用性以及NOS产生活性氧。 要测试的中心假设是细胞不产生受到影响转录，翻译和翻译后表达的各种内源性因素的严格调节。提出了三个特定的目的来实现这一目标：（1）阐明没有下调诱导型NOS（Inos）和内皮NOS（ENOS）表达的分子机制； （2）阐明精氨酸酶上调iNOS和eNOS的表达的机制； （3）阐明精氨酸在通过iNOS和eNOS调节超氧化阴离子和过氧化氢的产生中的作用。 拟议的研究代表了持续的长期努力，以阐明影响NO在健康和疾病中的血管和相关作用的生物学因素。