The Nitric Oxide Producing Reactions of Hydroxyurea

描述（由申请人提供）：羟基脲代表了一种治疗镰状细胞病的新方法，这种疾病每600名非洲裔美国人中就有1人受到影响。虽然羟基脲如何有益地影响镰状细胞病患者的分子机制仍然未知，但最近的证据表明一氧化氮（NO）在镰状细胞病的病理生理学和治疗中的作用。拟议研究的长期目标是彻底和清楚地了解羟基脲的NO产生反应如何有助于羟基脲治疗的有益效果。这一目标是基于这样的假设，即羟基脲衍生的NO介导了羟基脲治疗镰状细胞病的有益效果。产物分析，动力学和光谱研究将确定在体外从羟基脲产生NO的机制，这应该提供相关的信息，在体内反应。类似的研究适用于与各种组织和纯化的酶的孵育的羟基脲将揭示从羟基脲在体内NO形成的机制和位点。具体地说，这些结果将区分水解和氧化机制的体外和体内NO形成的羟基脲。此外，将通过使用光谱方法和产物分析确定酶活化的程度和这些反应的最终反应产物和动力学来证明与所鉴定的靶蛋白、可溶性鸟苷酸环化酶和无细胞血红蛋白的羟基脲衍生的NO的反应的程度。这些结果将表明羟基脲或羟基脲衍生的NO影响这些靶蛋白或与这些靶蛋白反应的能力，并为羟基脲治疗的有益效果的机制提供证据。独特的基于羟基脲的NO递送系统和水溶性硝酰基供体将通过化学合成制备。这些化合物释放NO的能力将使用光谱和循环伏安法研究来确定，这些结果将揭示这些新系统作为NO或硝酰基供体的能力。这些新化合物也将评估其刺激可溶性鸟苷酸环化酶和与无细胞血红蛋白反应的能力。总之，这些结果将提供重要信息的作用机制，可应用于进一步发展的上级镰状细胞治疗的羟基脲。

DESCRIPTION (provided by applicant): Hydroxyurea represents a new treatment for sickle cell disease, a condition that affects 1 in 600 Americans of African descent. While the molecular mechanisms of how hydroxyurea beneficially affects sickle cell disease patients remain unknown, recent evidence indicates a role for nitric oxide (NO) in both the pathophysiology and treatment of sickle cell disease. The long-term goal of the proposed research is to thoroughly and clearly understand how the NO producing reactions of hydroxyurea contribute to the beneficial effects of hydroxyurea therapy. This goal is based upon the hypothesis that hydroxyurea-derived NO mediates the beneficial effects of hydroxyurea therapy in sickle cell disease. Product analysis, kinetic and spectroscopic studies will determine the mechanism of in vitro NO production from hydroxyurea, which should provide relevant information to the in vivo reaction. Similar studies applied to the incubation of hydroxyurea with various tissues and purified enzymes will reveal both the mechanism and site of in vivo NO formation from hydroxyurea. Specifically, these results will distinguish between hydrolytic and oxidative mechanisms of both in vitro and in vivo NO formation from hydroxyurea. In addition, the extent of the reaction of hydroxyurea-derived NO with the identified target proteins, soluble guanylate cyclase and cell-free hemoglobin, will be demonstrated by determining the extent of enzyme activation and the ultimate reaction products and kinetics of these reactions using spectroscopic methods and product analysis. These results will indicate the ability of hydroxyurea or hydroxyurea derived-NO to influence or react with these target proteins and provide evidence for a mechanism for the beneficial effects of hydroxyurea treatment. Unique hydroxyurea-based NO delivery systems and water-soluble nitroxyl donors will be prepared through chemical synthesis. The ability of these compounds to release NO will be determined using spectroscopic and cyclic voltammetric studies and these results will reveal the ability of these new systems to act as NO or nitroxyl donors. These new compounds will also be evaluated for their ability to stimulate soluble guanylate cyclase and react with cell free hemoglobin. Together, these results will provide important information regarding the mechanism of action of hydroxyurea that can be applied to the further development of superior sickle cell treatments.