Accelerated NO/02 Reactions in Low Density Lipoprotein

这项研究将主要在乌拉圭的蒙得维的亚共和国大学医学院物理生物化学实验室和生物化学系进行，与Denicola博士合作，作为NIH赠款1 R01 HL074391-02的延伸；7/10/03-6/30/07。FIRCA申请中描述的实验目标解决了西化国家发病率和死亡率的主要来源--动脉粥样硬化的基本机制。具体地说，父母拨款中提出的问题，即疏水相如何影响NO与O2反应的动力学和机理，将考虑到与临床相关的疏水环境：低密度脂蛋白(LDL)。假设循环中的低密度脂蛋白的疏水室起催化和集中NO与O2反应的作用，产生次级亚硝基(RNO)和硝化(RNO2)产物，翻译NO的细胞信号活动。具体地说，提出了一种在生物条件下研究亚硝化与硝化的相对位移的机械原理。为了解决这一概念，将追求两个关键的实验目标：1)描述NO/O2在低密度脂蛋白颗粒内反应的动力学、机制和新产物的形成(亚硝化和硝化)；2)确定NO/O2修饰的低密度脂蛋白的血管信号作用(血管扩张和血管抗炎作用)。这些研究将为理解NO和O2反应对低密度脂蛋白氧化和随后的动脉粥样硬化事件的影响以及对血管炎症的影响的机制基础提供强有力的基础。

This research will be done primarily in Uruguay at the Physical Biochemistry Laboratory, School of Science as well as the Biochemistry Department, School of Medicine at the University of the Republic, Montevideo, in collaboration with Dr. Denicola as an extension of NIH grant 1 R01 HL074391-02; 7/10/03 - 6/30/07. The experimental goals described in this FIRCA application address fundamental mechanisms underlying the principal source of morbidity and mortality in westernized countries, atherosclerosis. Specifically, the questions arose in the parent grant, how hydrophobic phases influence the kinetics and mechanism of NO reaction with O2, will be extended considering a clinically relevant hydrophobic environment:: the low density lipoprotein (LDL). It is hypothesized that the hydrophobic compartment of circulating LDL serves to catalyze and focus the reaction of NO with O2, yielding secondary nitroso (RNO) and nitrated (RNO2) products that translate the cell signaling actions of NO. Specifically, a mechanistic rationale is proposed for examining a relative shift in nitrosation vs. nitration under biological conditions. To address this concept, two key experimental aims will be pursued: 1) delineate the kinetics, mechanisms and novel product formation (nitrosation and nitration) from NO/O2 reaction within the LDL particle, and 2) identify the vascular signaling actions.(vasodilation and vascular anti-inflammatory action) of the NO/O2-modified LDL. The proposed investigations will provide a strong foundation for understanding the mechanistic basis of the effects of NO and O2 reaction on LDL oxidation and consequent atherogenic events in particular, and on vascular inflammation in general.