Metabolomic Investigation of Biosignatures of Chronic Cocaine Exposure

描述(由申请人提供)：拟议工作的总体目标是探索基于LC-MS的代谢组学方法的应用，以识别和表征外周系统中可能表明先前慢性药物暴露或药物成瘾的内源性小分子代谢物。由于它们在揭示药物滥用状况和监测药物成瘾进展方面具有明显的价值，人们利用生化、基因组、蛋白质组和神经成像方法来寻找慢性药物暴露的生物标志物和生物标志。然而，建立令人信服和适用的慢性药物暴露的生物标志物和生物签名仍然是一个挑战。我们目前的建议是基于这样一个事实，即除了导致中枢神经系统(CNS)功能异常的神经系统变化外，药物滥用和成瘾还通过中枢神经系统的激素信号、转录调节或局部毒性，显著影响心血管系统、肝脏、肾脏的正常功能以及能量代谢，如脂肪酸和碳水化合物代谢。所有这些对代谢系统的干扰都会改变周围系统的化学成分。因此，代表慢性药物暴露不同方面的小分子生物标记物可以利用代谢组学方法在外周系统中潜在地识别出来，以检查与药物成瘾相关的动物模型。由于可卡因的广泛滥用和有害后果，本研究将其作为药物成瘾的典型化合物。在具体目标1中，慢性可卡因暴露后外周代谢组的变化将通过高分辨率LC-MS和多变量化学计量学分析从间歇注射可卡因成瘾模型和自身给药模型中收集的大鼠生物体液样本中确定。在两种动物模型的治疗阶段和戒断阶段，将通过检测对照组和可卡因处理组大鼠的代谢谱来识别可卡因诱导的病理生理事件的生物标志物。这些生物标志物与可卡因诱导的行为之间的相关性将成为构建慢性可卡因暴露的生物特征的基础。在具体目标2中，将使用两种机械上不同的实验化学品--GBR 12909和N-乙酰半胱氨酸来研究干预治疗对可卡因暴露大鼠生物特征图谱的影响。此外，还将通过检测负责产生和消除已识别的小分子生物标记物的基因、蛋白质和酶来探索可卡因诱导的代谢变化背后的机制。 公共卫生相关性：对慢性可卡因暴露的生物特征进行代谢学研究药物滥用会导致身体新陈代谢系统的显著变化，即使在停止使用药物很长时间后也是如此。在这个项目中，我们将应用现代分析技术和药物滥用动物模型来识别代谢系统中可以指示既往药物暴露的小分子标志物。这一研究项目的完成有助于药物滥用新的干预和治疗策略的发展。

DESCRIPTION (provided by applicant): The overall objective of the proposed work is to explore the application of liquid chromatography-mass spectrometry (LC-MS)-based metabolomic approaches to identify and characterize endogenous small-molecule metabolites in the peripheral system that can indicate prior chronic drug exposure or drug addiction. Because of their apparent values for revealing the status of drug abuse and monitoring the progression of drug addiction, biomarkers and biosignatures of chronic drug exposure have been pursued using biochemical, genomic, proteomic and neuroimaging approaches. However, the establishment of convincing and applicable biomarkers and biosignatures of chronic drug exposure is still a challenge. Our current proposal is based on the fact that besides the neurological changes that lead to abnormal function in the central nervous system (CNS), drug abuse and addiction also significantly affect the normal functions of the cardiovascular system, liver, kidney as well as energy metabolism, such as fatty acid and carbohydrate metabolism, through hormonal signals from CNS, transcriptional regulation or local toxicities. All these disturbances on metabolic system can definitely change the chemical composition of peripheral systems. Therefore, small-molecule biomarkers representing different aspects of chronic drug exposure can be potentially identified in the peripheral system using metabolomic approaches to examine animal models related to drug addiction. Because of its widespread abuse and harmful consequence, cocaine will be used as a prototypical compound of drug addiction in this study. In Specific Aim 1, changes in the peripheral metabolome following chronic cocaine exposure will be determined by the high-resolution LC-MS and multivariate chemometric analysis of biofluids samples collected from rats in an intermittent injection model and in a self- administration model of cocaine addiction. Biomarkers of cocaine-induced pathophysiological events will be identified by examining the metabolomic profiles of control and cocaine-treated rats in the treatment phase and withdrawal phase of both animal models. Correlation between these biomarkers and cocaine-elicited behavior will become the foundation for constructing the biosignatures of chronic cocaine exposure. In Specific Aim 2, the influence of intervention treatments on the profile of biosignatures in the cocaine-exposed rats will be examined using two mechanistically different experimental chemicals, GBR 12909 and N-acetylcysteine. In addition, the mechanism behind the cocaine-induced metabolomic changes will be probed by examining the genes, proteins and enzymes that are responsible for the generation and elimination of identified small- molecule biomarkers. PUBLIC HEALTH RELEVANCE: Metabolomic Investigation of Biosignatures of Chronic Cocaine Exposure Drug abuse can result in significant changes in the metabolic system of the body, even long after the drug use has been stopped. In this project, we will apply modern analytical technology and drug abuse animal models to identify small-molecule markers in the metabolic system that can indicate previous drug exposure. The accomplishment of this research project can contribute to the development of novel intervention and therapeutic strategies for drug abuse.