Mechanism of Polyphenolic Inhibition of NADPH Oxidase

描述(申请人提供)：多酚是植物提取物中的常见成分，可在非处方药营养制剂中获得，也可在不同的水果和蔬菜、橄榄油以及红酒和茶等饮料中找到。越来越多的证据表明，多酚的化学保护作用与抑制ROS生成有关，而不是简单地清除自由基。最近的研究表明，NADPH氧化酶是血管壁三种主要细胞类型(如内皮细胞、血管平滑肌细胞和外膜成纤维细胞)中ROS的主要来源。人们对血管NADPH氧化酶的研究越来越感兴趣，很大程度上是因为人们认识到氧化应激在动脉粥样硬化等血管疾病的发病机制中起着关键作用。本课题组和其他人进行的初步研究表明，邻甲氧基酚，如罗布麻素，在体内可被过氧化物酶激活，其氧化产物似乎是NADPH氧化酶组装和激活的抑制剂，尽管氧化产物的确切身份和抑制机制尚未完全阐明。这些信息对于最终开发安全有效的血管NADPH氧化酶抑制剂至关重要。在目前的应用中，我们建议获得关于载脂蛋白类化合物的活性代谢物的结构信息，以及它们与NADPH氧化酶复合体结合并抑制其组装和激活的生化反应。本R21应用的具体目标是：(1)阐明载脂蛋白活性代谢产物的化学结构，这些代谢产物与内皮细胞的p47Phox、p67Phox和p22Phox肽序列结合，并确认这些化合物也与NADPH氧化酶的p47Phox和p67Phox蛋白亚基上的相同结构域结合；(2)确定载脂蛋白氧化产物是否破坏参与成熟NADPH氧化酶组装的特定蛋白质-蛋白质相互作用。这些研究的结果将为更详细地了解载脂蛋白类化合物抑制NADPH氧化酶的组装和激活的化学结构和分子过程奠定基础。

DESCRIPTION (provided by applicant): Polyphenols are common constituents in botanical extracts available in over-the-counter nutraceutical preparations as well as being found in different fruits and vegetables, olive oil, and beverages like red wine and tea. Based on a growing body of evidence it is thought that the chemoprotective effect of polyphenols involves the inhibition of reactive oxygen species (ROS) generation rather than simply scavenging the radicals. Recent studies indicate that NADPH oxidase is the major source of ROS in the three principal cell types of the blood vessel wall (e.g., endothelial cells (EC), vascular smooth muscle cells (VSMC), and adventitial fibroblasts). There has been growing interest in the vascular NADPH oxidases, largely because it is recognized that oxidative stress plays a critical role in the pathogenesis of vascular diseases, such as atherosclerosis. Preliminary studies performed in our group and others have demonstrated that ortho- methoxyphenols, such as apocynin, are activated by peroxidases in vivo and that their oxidation products appear to act as inhibitors of NADPH oxidase assembly and activation, although the exact identity of the oxidation products and the mechanism of inhibition have not been fully elucidated. Such information is critical for the ultimate development of safe and effective inhibitors of vascular NADPH oxidases. In the present application, we propose to obtain structural information on the active metabolites of apocynin-like compounds and the biochemical reactions by which they bind to and inhibit the assembly and activation of the NADPH oxidase complex. Specific goals of this R21 application are to: (1) Elucidate the chemical structures of the active metabolites of apocynin that bind to endothelial p47phox, p67phox, and p22phox peptide sequences and confirm that these compounds also bind to the same domains on the p47phox and p67phox protein subunits of NADPH oxidase; (2) Determine whether apocynin oxidation products disrupt specific protein-protein interactions that are involved in the assembly of mature NADPH oxidase. The outcome of these studies will be the foundation of a more detailed understanding of the chemical structure and molecular process by which apocynin-like compounds inhibit the assembly and activation of NADPH oxidase.