Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, MD 21702, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD 20817, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Toxicology. 2020 Aug;441:152493. doi: 10.1016/j.tox.2020.152493. Epub 2020 May 30.
Early diagnosis of liver injuries caused by drugs or occupational exposures is necessary to enable effective treatments and prevent liver failure. Whereas histopathology remains the gold standard for assessing hepatotoxicity in animals, plasma aminotransferase levels are the primary measures for monitoring liver dysfunction in humans. In this study, using Sprague Dawley rats, we investigated whether integrated analyses of transcriptomic and metabolomic data with genome-scale metabolic models (GSMs) could identify early indicators of injury and provide new insights into the mechanisms of hepatotoxicity. We obtained concurrent measurements of gene-expression changes in the liver and kidneys, and expression changes along with metabolic profiles in the plasma and urine, from rats 5 or 10 h after exposing them to one of two classical hepatotoxicants, acetaminophen (2 g/kg) or bromobenzene (0.4 g/kg). Global multivariate analyses revealed that gene-expression changes in the liver and metabolic profiles in the plasma and urine of toxicant-treated animals differed from those of controls, even at time points much earlier than changes detected by conventional markers of liver injury. Furthermore, clustering analysis revealed that both the gene-expression changes in the liver and the metabolic profiles in the plasma induced by the two hepatotoxicants were highly correlated, indicating commonalities in the liver toxicity response. Systematic GSM-based analyses yielded metabolites associated with the mechanisms of toxicity and identified several lipid and amino acid metabolism pathways that were activated by both toxicants and those uniquely activated by each. Our findings suggest that several metabolite alterations, which are strongly associated with the mechanisms of toxicity and occur within injury-specific pathways (e.g., of bile acid and fatty acid metabolism), could be targeted and clinically assessed for their potential as early indicators of liver damage.
早期诊断药物或职业暴露引起的肝损伤对于有效治疗和预防肝功能衰竭至关重要。虽然组织病理学仍然是评估动物肝毒性的金标准，但血浆氨基转移酶水平是监测人类肝功能障碍的主要指标。在这项研究中，我们使用 Sprague Dawley 大鼠，研究了转录组和代谢组数据与基因组规模代谢模型（GSM）的综合分析是否可以识别损伤的早期指标，并为肝毒性机制提供新的见解。我们同时测量了暴露于两种经典肝毒物（乙酰氨基酚（2 g/kg）或溴苯（0.4 g/kg）后 5 或 10 小时大鼠肝脏和肾脏的基因表达变化，以及血浆和尿液中的表达变化和代谢谱。全局多变量分析表明，即使在比传统肝损伤标志物更早的时间点，毒物处理动物的肝脏基因表达变化和血浆代谢谱与对照动物也有所不同。此外，聚类分析表明，两种肝毒物引起的肝脏基因表达变化和血浆代谢谱高度相关，表明肝毒性反应存在共同性。基于系统的 GSM 分析产生了与毒性机制相关的代谢物，并鉴定了几个脂质和氨基酸代谢途径，这些途径被两种毒物激活，也被每种毒物单独激活。我们的研究结果表明，几种与毒性机制密切相关且发生在损伤特异性途径中的代谢物改变（例如胆汁酸和脂肪酸代谢途径）可能成为潜在的早期肝损伤指标，并可进行临床评估。
