Polarity-Tuning Derivatization-LC-MS Approach for Probing Global Carboxyl-Containing Metabolites in Colorectal Cancer
作者:Xiqing Bian、Na Li、Binbin Tan、Baoqing Sun、Ming-Quan Guo、Guoxin Huang、Li Fu、W. L. Wendy Hsiao、Liang Liu、Jian-Lin Wu
DOI:10.1021/acs.analchem.8b01873
日期:2018.10.2
Carboxyl-containing metabolites (CCMs) widely exist in living systems and are the essential components for life. Global characteristics of CCMs in biological samples are critical for the understanding of physiological processes and the discovery for the onset of relevant diseases. However, their determination represents a challenge due to enormous polarity differences, structural diversity, high structural similarity, and poor ionization efficiency in mass spectrometry. Herein, 5-(diisopropylamino)amylamine (DIAAA) derivatization coupled with liquid chromatography–mass spectrometry (LC-MS) was developed for mapping the CCMs. With this methodology, the sensitivity was significantly enhanced. More importantly, the hydrophobicity of polar CCMs, amino acids, TCA cycle intermediates, and short-chain fatty acids and the hydrophilicity of low-polar CCMs, long-chain fatty acids, and bile acids were significantly increased, resulting in a remarkable separation efficiency for which 68 CCMs can be simultaneously determined. Furthermore, the polarity-tuning effect was confirmed to be induced by the different impacts of aliphatic chains and nitrogen atom in DIAAA, the latter existing as a cation in the acidic mobile phase, using different derivatization reagents. Finally, this derivatization method was utilized to hunt for the potential biomarkers in colorectal cancer (CRC) patients and 52 CCMs, related with several key metabolic pathways, including amino acids metabolism, TCA cycle, fatty acid metabolism, pyruvate metabolism, and gut flora metabolism were identified. This innovative polarity-tuning derivatization-LC-MS approach was proved to be a valuable tool for probing global metabolome with high separation efficiency and sensitivity in various biological samples.
含羧基代谢物(CCMs)广泛存在于生物系统中,是生命的基本组成部分。CCMs在生物样本中的全球特征对于理解生理过程和发现相关疾病的发生具有重要意义。然而,由于极性差异巨大、结构多样性、高结构相似性和在质谱中的离子化效率较低,它们的测定面临挑战。在此,我们开发了5-(二异丙基氨基)戊胺(DIAAA)衍生化结合液相色谱-质谱(LC-MS)的方法以绘制CCMs的分布。通过这种方法,灵敏度显著提高。更重要的是,极性CCMs、氨基酸、TCA循环中间体和短链脂肪酸的疏水性显著增强,而低极性CCMs、长链脂肪酸和胆汁酸的亲水性也显著增加,从而实现了卓越的分离效率,使得68种CCMs可以同时测定。此外,极性调节效应被证实是由于DIAAA中脂肪链和氮原子的不同影响所引起的,后者在酸性流动相中以阳离子的形式存在,使用不同的衍生化试剂。最后,该衍生化方法被用于寻找结直肠癌(CRC)患者的潜在生物标志物,识别出52种与多条关键代谢通路(包括氨基酸代谢、TCA循环、脂肪酸代谢、丙酮酸代谢和肠道菌群代谢)相关的CCMs。这种创新的极性调节衍生化-LC-MS方法被证明是探测各种生物样本全球代谢组的高分离效率和灵敏度的有价值工具。