Assessment of hydrogen sulfide in vascular biology

描述（由申请人提供）：硫化氢（H2S）在许多哺乳动物组织中产生，在血液和脑组织中以微摩尔的量被检测到。虽然其参与细胞信号传导的潜力是明确的，但其生物学作用尚不清楚。H2S类似于一氧化氮（NO），由氨基酸代谢产生，容易在组织中扩散，并迅速被氧化。H2S是一种有效的亲核试剂和还原剂，能够对翻译后的蛋白质进行修饰，如血红素铁的配体置换和二硫醇还原。此外，H2S在生理条件下很容易与s -亚硝基硫醇（RSNO）发生化学计量反应，释放NO。控制细胞H2S水平的H2S生产和消耗的动态过程响应细胞氧化还原状态。在氧化应激下，胱硫氨酸合成酶（CBS）的活性增加，催化H2S的产生和同型半胱氨酸（Hcy）的分解。与动脉粥样硬化和神经变性的发展有关，并损害一氧化氮介导的血管松弛。高同型半胱氨酸血症的血管功能障碍可能是H2S水平降低的结果。H2S是一种有效的血管信号，可以根据氧水平和组织调节血管收缩或松弛。在大鼠主动脉中，H2S浓度在一个O2水平下介导快速收缩，会在较低的O2水平下引起快速松弛。这些结果和其他结果表明，H2S血管活性机制包括no独立和no依赖途径，如RSNO代谢。脓毒症模型可能被证明是这些现象的理想实验操作。脓毒症发展过程中血管NO和RSNO水平升高可导致低血压性休克。在这些条件下，RSNO的H2S代谢会导致NO的生物利用度增加，并可能加剧血管张力的丧失。由于H2S和NO一样会被迅速氧化，我的实验室发明的一种新型极谱硫化物传感器（PSS）已经成为定义H2S对血管功能影响的主要方法工具。我们建议验证中心假设，即在血管中，H2S是生理和病理条件下血管功能的关键o2依赖调节剂。这一假设的组成部分将在以下具体目标中进行探讨。目的1。确定直接调节H2S产生和消耗的稳态机制，重点是可以扰乱细胞氧化还原状态的条件。确定正常和炎症疾病条件下o2依赖性H2S控制血管张力的机制。

DESCRIPTION (provided by applicant): Hydrogen sulfide (H2S) is produced in many mammalian tissues and has been detected in micromolar amounts in blood and brain tissue. Although its potential to participate in cell signaling is clear, this biological role is not well understood. H2S, analogous to nitric oxide (NO), is produced by amino acid metabolism, readily diffuses through tissue, and is rapidly oxidized. H2S is a competent nucleophile and reductant, capable of post-translational protein modification such as ligand displacement from heme iron and dithiol reduction. In addition, H2S under physiological conditions can readily react stoichiometrically with S-nitrosothiols (RSNO) to release NO. The dynamic processes of H2S production and consumption that control cellular H2S levels respond to cellular redox status. Activity of cystathionine beta synthase (CBS) increases under oxidative stress to catalyze both H2S production and homocysteine (Hcy) breakdown. Hey, is linked to the development of atherosclerosis and neurodegeneration, and impairs NO-mediated vasorelaxation. The vascular dysfunction in hyperhomocysteinemia may be a result of decreased H2S levels. H2S is a potent vascular signal that can mediate vasoconstriction or vasorelaxation depending on O2 level and tissue. In the rat aorta, H2S concentrations that mediate rapid constriction at one O2 level will cause rapid relaxation at lower O2 levels. These results and others indicate that H2S vasoactive mechanisms include both NO-independent and NO-dependent pathways such as RSNO metabolism. The sepsis model may prove ideal for the experimental manipulation of these phenomena. Elevated vascular NO and RSNO levels during the development of sepsis contribute to hypotensive shock. H2S metabolism of RSNO under these conditions would lead to increased bioavailability of NO and may exacerbate loss of vessel tone. Because H2S, like NO, is rapidly oxidized, a novel polarographic sulfide sensor (PSS) invented in my laboratory has been a major methodological tool used to define H2S effects on vascular function. We propose to test the central hypothesis that, in the vascular, H2S is a key O2-dependent regulator of vascular function under physiological and pathological conditions. The components of this hypothesis will be explored in the following specific aims. AIM 1. Determine the homeostatic mechanisms that directly regulate H2S production and consumption with emphasis on conditions that can perturb cellular redox status AIM 2. Determine the mechanisms of O2-dependent H2S control of vessel tension under normal and inflammatory disease conditions.