State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica , Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing 100050 , People's Republic of China.
Anal Chem. 2019 Apr 2;91(7):4504-4512. doi: 10.1021/acs.analchem.8b05337. Epub 2019 Mar 18.
Cholesteryl esters (CEs) are formed by the 3-hydroxyl group of cholesterol and a fatty acyl chain through an ester bond and function as a biologically inert storage form of cholesterol. Abnormal CE levels are often related to various diseases, particularly hyperlipidemia and atherosclerosis. Herein, we developed a mathematical model-assisted ultrahigh performance liquid chromatography-mass spectrometry (UHPLC-MS) method for the untargeted identification to targeted quantification of CEs in plasma, different density lipoprotein samples from humans, rats, and golden hamsters. Using UHPLC-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS), 81 CE candidates were detected in the above samples, of which 24 CEs were reported in the Human Metabolome Database and 57 CEs were newly identified based on an in-house database of theoretically possible CEs, including the computationally generated precursor ion m/ z mass of CE, carbon number and double bond numbers of the fatty acyl chain. Then three mathematical models based on the characteristic chromatographic retention behavior related to structural features were established and validated using commercial and synthetic CE standards. The mathematical model-assisted UHPLC-MS/MS strategy was proposed to provide a global profiling and identification of CEs, especially unknown CEs. With the efficient strategy, 74 CEs in the plasma of golden hamsters were identified and then quantified in normal and hyperlipidemic golden hamsters by dynamic multiple reaction monitoring (dMRM). A total of 21 CEs among 35 shared potential biomarkers were newly found for hyperlipidemia. Our work will contribute to the in-depth study of the functions of CEs and the discovery of disease biomarkers.
胆固醇酯 (CEs) 是胆固醇的 3-羟基与脂肪酸链通过酯键形成的，是胆固醇的一种生物惰性储存形式。CE 水平异常通常与各种疾病有关，特别是高血脂和动脉粥样硬化。在此，我们开发了一种数学模型辅助的超高效液相色谱-质谱联用 (UHPLC-MS) 方法，用于对人体、大鼠和金黄地鼠的血浆、不同密度脂蛋白样本中的 CE 进行非靶向鉴定和靶向定量。使用 UHPLC-四极杆飞行时间质谱 (UHPLC-QTOF-MS)，在上述样本中检测到 81 种 CE 候选物，其中 24 种 CE 被人代谢组数据库报道，57 种 CE 是基于理论上可能的 CE 内部数据库，包括计算生成的 CE 前体离子 m/z 质量、脂肪酸链的碳原子数和双键数，新鉴定的。然后，建立并验证了三个基于与结构特征相关的特征色谱保留行为的数学模型，这些模型使用商业和合成 CE 标准。提出了基于数学模型的 UHPLC-MS/MS 策略，用于对 CE 进行全面分析和鉴定，特别是对未知 CE 的分析和鉴定。利用这种高效策略，在正常和高血脂金黄地鼠的血浆中鉴定出 74 种 CE，并通过动态多重反应监测 (dMRM) 对其进行定量。在 35 种潜在的生物标志物中，共发现 21 种与高血脂相关的新的 CE。我们的工作将有助于深入研究 CE 的功能和发现疾病生物标志物。
