Application of Metabonomics in Predictive Toxicology

描述（由申请人提供）：本提案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性肝损伤（DILI）可预测性的因素，并表征受内在毒素和特异性肝毒素差异影响的生化途径。为了实现这些目标，将在小鼠或大鼠中通过比较药物及其异构体/类似物的转录组学和代谢组学特征来研究三种已知会导致人类DILI的药物及其区域异构体和/或结构相似物，这些药物和异构体/类似物会导致显著不同的毒理学反应。具体来说，我们将比较转录组学和代谢组学/代谢组学特征：1)乙酰苯胺镇痛/解热药物对乙酰氨基酚（一种内在肝毒性药物）与其毒性较小的区域异构体3'-羟基乙酰苯胺；2)含噻吩的药物噻苯酸（一种免疫介导的毒性药物）与其引起内在肝细胞损伤的区域异构体；3)硝基芳香抗雄性激素药物氟他胺（一种特异性肝毒性药物）与其毒性较小的氰基类似物。使用同分异构体和紧密结构类似物将允许更精确地搜索DILI的潜在生物标志物，因为它们相似的物理化学特性和药理反应应该有助于区分毒理学效应与治疗和脱靶药理效应。这种模式也应该有助于表征其毒性的机制和途径。基因失调将通过对动物肝脏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液相色谱-质谱法对收集的动物血清样本进行评估。方差分析和化学计量学方法的结合将用于整合从转录组学和代谢组学/代谢组学研究中获得的信息。目标是了解基因和代谢途径随时间的变化，这些变化受到导致肝损伤的药物的影响。药物不良反应会导致严重的发病率和死亡率，由于DILI，许多药物要么被从市场上撤下，要么有“黑盒”警告。拟议的研究结果应该有助于制药工业选择更安全的候选药物进行开发，并且还应该提供为什么有些人比其他人更容易患DILI的见解。最终，生物标记物可以在容易获得的人体液体（如血液和尿液）中测量，可用于识别那些服用某些药物后风险最大的个体。

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.