环境污染物2,3,7,8-四氯二苯并对二恶英导致的丙酮酸激酶同工型转换与肝脏代谢重编程
Pyruvate Kinase Isoform Switching and Hepatic Metabolic Reprogramming by the Environmental Contaminant 2,3,7,8-Tetrachlorodibenzo-p-Dioxin.
作者信息
Nault Rance, Fader Kelly A, Kirby Mathew P, Ahmed Shaimaa, Matthews Jason, Jones A Daniel, Lunt Sophia Y, Zacharewski Timothy R
机构信息
*Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, Institute for Integrative Toxicology.
*Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824.
出版信息
Toxicol Sci. 2016 Feb;149(2):358-71. doi: 10.1093/toxsci/kfv245. Epub 2015 Nov 17.
The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elicits dose-dependent hepatotoxicity that includes fat accumulation, inflammation, and fibrosis that may progress to hepatocellular carcinoma. To further investigate these effects, RNA-Seq data were integrated with computationally identified putative dioxin response elements, and complementary targeted metabolomic and aryl hydrocarbon receptor (AhR) ChIP-Seq data from female C57BL/6 mice gavaged with TCDD every 4 days for 28 days. Data integration using CytoKEGG with manual curation identified dose-dependent alterations in central carbon and amino acid metabolism. More specifically, TCDD increased pyruvate kinase isoform M2 (PKM2) gene and protein expression. PKM2 has lower catalytic activity resulting in decreased glycolytic flux and the accumulation of upstream intermediates that were redirected to the pentose phosphate pathway and serine/folate biosynthesis, 2 important NADPH producing pathways stemming from glycolysis. In addition, the GAC:KGA glutaminase (GLS1) protein isoform ratio was increased, consistent with increases in glutaminolysis which serves an anaplerotic role for the TCA cycle and compensates for the reduced glycolytic flux. Collectively, gene expression, protein, and metabolite changes were indicative of increases in NADPH production in support of cytochrome P450 activity and ROS defenses. This AhR-mediated metabolic reprogramming is similar to the Warburg effect and represents a novel advantageous defense mechanism to increase anti-oxidant capacity in normal differentiated hepatocytes.
环境污染物2,3,7,8-四氯二苯并对二恶英(TCDD)会引发剂量依赖性肝毒性,包括脂肪堆积、炎症和纤维化,这些情况可能会发展为肝细胞癌。为了进一步研究这些影响,将RNA测序数据与通过计算识别出的假定二恶英反应元件进行整合,并结合了来自雌性C57BL/6小鼠的靶向代谢组学和芳烃受体(AhR)染色质免疫沉淀测序(ChIP-Seq)数据,这些小鼠每4天经口灌胃给予TCDD,持续28天。使用CytoKEGG并经人工整理进行数据整合,确定了中心碳代谢和氨基酸代谢中的剂量依赖性变化。更具体地说,TCDD增加了丙酮酸激酶同工型M2(PKM2)的基因和蛋白表达。PKM2具有较低的催化活性,导致糖酵解通量降低以及上游中间体积累,这些中间体被重定向到磷酸戊糖途径和丝氨酸/叶酸生物合成,这是糖酵解产生2种重要还原型辅酶II(NADPH)的途径。此外,谷氨酰胺酶(GLS1)蛋白同工型的GAC:KGA比例增加,这与谷氨酰胺分解增加一致,谷氨酰胺分解对三羧酸循环起补充作用,并补偿糖酵解通量的降低。总体而言,基因表达、蛋白质和代谢物的变化表明NADPH生成增加,以支持细胞色素P450活性和活性氧防御。这种AhR介导的代谢重编程类似于瓦伯格效应,代表了一种在正常分化肝细胞中增加抗氧化能力的新型有利防御机制。