Application of Metabonomics in Predictive Toxicology

描述(由申请人提供)：这项研究的主要长期目标是确定提高反应性代谢物介导的药物诱导的肝损伤(DILI)的可预测性的因素，并表征受固有肝毒素和特有肝毒素不同影响的生化途径。为实现这些目标，将通过比较药物及其异构体/类似物的转录和代谢组学特征，在小鼠或大鼠身上研究三种已知导致人类DILI的药物及其区域异构体和/或引起显著不同毒理学反应的紧密结构类似物。具体地说，我们将比较乙酰苯胺止痛/解热药物对乙酰氨基酚与其毒性较低的区域异构体3‘-羟基乙酰苯胺的转录和代谢组学/代谢组学特征，2)含噻吩类药物替尼酸与导致固有肝细胞损伤的区域异构体，以及3)硝基芳香族抗雄激素药物氟他胺与其毒性较低的氰基类似物。使用同分异构体和紧密的结构类似物将允许更精细地寻找DILI的潜在生物标记物，因为它们相似的物理化学特征和药理反应应有助于区分毒理作用和治疗和非靶点的药理作用。这一范例还应有助于确定其毒性所涉及的机制和途径。基因的失调将通过动物肝脏RNA的微阵列杂交分析来评估，代谢变化将通过高场核磁共振和通过时间收集的动物血清样本的液-质联用来评估。将结合方差分析和化学计量学方法，整合从转录组和代谢组学/代谢组学研究中获得的信息。其目标是了解随着时间的推移，遗传和代谢途径的变化，这些变化会受到导致肝脏损伤的药物的影响。药物不良反应会导致严重的发病率和死亡率，许多药物因为DILI已被下架或有黑匣子警告。拟议的研究结果应该有助于选择更安全的候选药物供制药业开发，还应该提供关于为什么一些人比其他人更容易感染DILI的见解。最终，可以在容易获得的人体体液(例如血液和尿液)中测量生物标记物，这些体液可以用来识别如果服用某些药物风险最大的个人。

DESCRIPTION (provided by applicant): The major long-term objectives of the research in this proposal are to identify factors that improve the predictability of reactive metabolite-mediated drug-induced liver injury (DILI) and to characterize biochemical pathways that are differentially affected by intrinsic vs. idiosyncratic hepatotoxins. To address these objectives, three drugs that are known to cause DILI in humans, and their regioisomers and/or close structural analogues that cause significantly different toxicological responses, will be investigated in mice or rats by comparing transcriptomic and metabonomic profiles of the drugs and their isomers/analogues. Specifically, we will compare transcriptomic and metabonomic/metabolomic profiles 1) of the acetanilide analgesic/anfipyretic drug, acetaminophen, an intrinsic hepatotoxicant, to its less toxic regioisomer, 3'-hydroxyacetanilide, 2) of the thiophene-containing drug, tienilic acid, an immune-mediated toxicant, to a regioisomer that causes intrinsic hepatocellular injury, and 3) of the nitroaromafic anti-androgen drug, flutamide, an idiosyncratic hepatotoxicant, to its less toxic cyano analogue. The use of isomers and close structural analogues will allow for a more refined search for potential biomarkers of DILI since their similar physicochemical characterisfics and pharmacological responses should help differenfiate toxicological effects from therapeutic and off-target pharmacological effects. This paradigm also should aid in characterization of mechanisms and pathways involved in their toxicity. Whereas dysregulation of genes will be assessed by microarray hybridization analysis of RNA from animal livers, metabolic changes will be assessed by high field nuclear magnefic resonance and liquid chromatography-mass spectrometry of animal serum samples collected through time. A combination of analysis of variance and chemometric approaches will be used to integrate the information obtained from the transcriptomics and metabonomics/ metabolomics studies. The goal is to understand changes in genetic and metabolic pathways over time that are affected by drugs that cause liver injury. Adverse drug reacfions cause significant morbidity and mortality, and many drugs have either been removed from the market or have "Black Box" warnings because of DILI. Results of the proposed research should help in the selection of safer drug candidates for development by the pharmaceutical industry, and also should provide insights into why some individuals are more susceptible to DILI than others. Ultimately, biomarkers may be measured in readily accessible human fluids (e.g., blood and urine) that can be used to identify those individuals who are most at risk if they take certain drugs.