School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Medical Metabolomics Center, Nanjing University of Chinese Medicine, No.138 Xianlin Avenue, Nanjing, 210023, China.
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
J Pharm Biomed Anal. 2019 Jul 15;171:171-179. doi: 10.1016/j.jpba.2019.04.022. Epub 2019 Apr 12.
Energy synthesis in aerobic organisms relies on two major metabolic pathways, i.e. tricarboxylic acid (TCA) cycle and glycolysis, the metabolites of which are highly affected by many diseases. Cells are the basic unit of the organism and have independent, ordered and self-controlled metabolic systems. Therefore, it is necessary to quantify intracellular metabolites in TCA cycle and glycolysis. In this study, we established a repeatable gas chromatography-tandem mass spectrometry (GC-MS/MS) method with selected reaction monitoring (SRM) mode for simultaneous quantification of several primary metabolites in these two pathways, including glucose, 3-phosphoglycerate, phosphoenolpyruvate (PEP), pyruvate, lactate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate and malate. There are many solvents to extract the metabolites in these two pathways, however, which one is more effective still remains unclear. Sample pretreatment was optimized for solvent types and volumes to advance the extraction efficiency of metabolites. 500 μL of 75% methanol-methyl tert-butyl ether (MTBE) was finally selected for the extraction of targeted metabolites in cells due to its highest extraction efficiency. Activated carbon as an effective adsorbent was successfully applied to the removal of endogenous targeted metabolites in cells for getting the analyte-free surrogate matrices. A series of methodological studies verified the validity of this optimized approach which was applied to quantify and compare the targeted metabolites in three common hepatic cells. The developed GC-MS/MS method provided a better way to determine the metabolites of energy metabolism in cellular metabolomics, facilitating the application of targeted quantification metabolomics to precisely discover the metabolic alterations.
在需氧生物中,能量合成依赖于两种主要的代谢途径,即三羧酸(TCA)循环和糖酵解,其代谢物受许多疾病的影响很大。细胞是生物体的基本单位,具有独立、有序和自我控制的代谢系统。因此,有必要定量测定 TCA 循环和糖酵解中的细胞内代谢物。在本研究中,我们建立了一种可重复的气相色谱-串联质谱(GC-MS/MS)方法,采用选择反应监测(SRM)模式,可同时定量测定这两种途径中的几种主要代谢物,包括葡萄糖、3-磷酸甘油酸、磷酸烯醇丙酮酸(PEP)、丙酮酸、乳酸、柠檬酸、顺乌头酸、异柠檬酸、α-酮戊二酸、琥珀酸、延胡索酸和苹果酸。然而,这两种途径中有许多溶剂可以提取代谢物,哪种溶剂更有效仍不清楚。我们对溶剂类型和体积进行了优化,以提高代谢物的提取效率。由于其最高的提取效率,最终选择 500μL 的 75%甲醇-叔丁基甲基醚(MTBE)用于细胞中目标代谢物的提取。活性炭作为一种有效的吸附剂,成功地应用于细胞内内源性目标代谢物的去除,以获得无分析物的替代基质。一系列方法学研究验证了该优化方法的有效性,该方法已应用于定量和比较三种常见肝细胞中的目标代谢物。所开发的 GC-MS/MS 方法为细胞代谢组学中能量代谢代谢物的测定提供了更好的方法,有助于靶向定量代谢组学的应用,精确发现代谢变化。