A nitric oxide(NO)-based metabonomic approach to investigate tobacco addiction

描述(申请人提供)：尼古丁与大脑中特定受体的相互作用已知会触发一些神经递质的释放，包括一氧化氮(NO)。虽然后者已被证实在烟草产品成瘾的发展中发挥重要作用，但潜在的分子途径仍不清楚。目前抑制NO释放的药理学方法包括抑制NO的形成和清除NO。然而，这两种方法都不是治疗尼古丁成瘾的可行选择，因为内源性NO在细胞内稳态和信号转导中发挥核心作用，以及全身性减少NO供应的有害后果。此外，NO是烟草烟雾的一种成分，对其对尼古丁下游效应机制的作用知之甚少。尼古丁代谢与氧化还原活性副产物的形成有关，这些副产物可以通过形成活性氧物种(ROS)而引起氧化应激。由于后者与NO有很强的相互作用，尼古丁诱导的ROS很可能在全球范围内影响NO在大脑和其他器官中的去向和生物学行为，导致生物分子的局部亚硝化、硝化和氧化，从而导致蛋白质功能和活性的深刻变化。这一建议的中心假设是，局部组织氧化还原平衡和尼古丁诱导的ROS形成是触发或促进成瘾发展的NO代谢命运的关键决定因素(阶段I)。如果是真的，这些决定因素的调节可能提供一种新的有针对性的方法来抑制这一与尼古丁相关的NO途径，而不会产生与全球NO生物利用度降低相关的不良影响(第二阶段)。为了验证这一假设，将使用一种新的代谢组学方法，在补充抗氧化剂和不添加抗氧化剂的情况下，在啮齿动物模型中研究NO、尼古丁和香烟烟雾的影响，以同时在体内定量游离和蛋白质结合的亚硝基、亚硝基和亚硝酸基以及亚硝酸盐和硝酸盐。此外，还将测量cGMP水平、尼古丁代谢物和氧化生物标志物的区域变化。这些研究的结果有望为体内ROS与NO和重要的NO递送形式的相互作用提供前所未有的洞察，为第二阶段的应用提供“积木”和概念性框架，该阶段的应用重点是新颖的、有针对性的烟草成瘾干预策略。烟草使用是一个重大的世界性健康问题，每年夺走300万人的生命。尽管近年来的研究工作和公共卫生教育有助于降低发达国家的吸烟率，但在美国和其他地方，烟草使用仍然是可预防的死亡的最大单一原因。尼古丁成瘾的悲惨后果强调了解开其中的分子机制的重要性。

DESCRIPTION (provided by applicant): The interaction of nicotine with specific receptors in the brain is known to trigger the release of a number of neurotransmitters, including nitric oxide (NO). While the latter has been established to play an important role in the development of addiction to tobacco products, the underlying molecular pathways remain unclear. Current pharmacological methods for countering the release of NO include inhibition of NO formation and NO scavenging. However, neither one is a viable option for the treatment of nicotine addiction due to the central role endogenous NO plays in cell homeostasis and signaling, and to the deleterious consequences of a systemic reduction in NO availability. Moreover, NO is a constituent of tobacco smoke, and little is known about its actions on downstream effector mechanisms of nicotine. Nicotine metabolism is associated with the formation of redox-active byproducts that can cause oxidative stress through formation of reactive oxygen species (ROS). Because the latter are known to interact strongly with NO, it is likely that nicotine-induced ROS production globally affects the fate and biological actions of NO in the brain and other organs, leading to local nitrosation, nitration and oxidation of biomolecules with profound alterations in protein function and activity. The central hypothesis of this proposal is that local tissue redox poise and nicotine-induced ROS formation are key determinants of the metabolic fate of NO that triggers or facilitates the development of addiction (Stage I). If true, modulation of these determinants may provide a novel targeted approach for suppressing this nicotine-related NO pathway without the adverse effects associated with a global reduction in NO bioavailability (Stage II). To examine this hypothesis, the effects of NO, nicotine and cigarette smoke will be investigated in rodent models of oxidative stress with and w/o antioxidant supplementation or NO pretreatment using a novel metabonomic approach for simultaneous in vivo quantification of free and protein-bound nitroso, nitro and nitrosyl species as well as nitrite and nitrate. In addition, regional changes in cGMP levels, nicotine metabolites and oxidant biomarkers will be measured. Results from these studies are expected to offer an unprecedented insight into the interplay of ROS with NO and important NO-delivery forms in vivo, providing the "building blocks" and conceptual framework for a Stage II application that focuses on novel, targeted intervention strategies in tobacco-related addiction. Tobacco use is a major, worldwide health problem which claims >3 million lives each year. Although the research efforts and public health education in recent years have helped reducing the smoking prevalence in developed countries tobacco use remains the largest single cause of preventable death in the United States and elsewhere. The tragic consequences of nicotine addiction stress the importance of unraveling the molecular mechanisms involved.