School of Life Science, Beijing Institute of Technology, No.5 Yard, Zhongguancun South Street, Haidian District, Beijing, 100081, China.
State Key Laboratory of Bioactive Substances and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, A2 Nanwei Road, Xicheng District, Beijing, 100050, China.
Talanta. 2023 Aug 15;261:124643. doi: 10.1016/j.talanta.2023.124643. Epub 2023 May 12.
Unsaturated lipids play an essential role in living organisms, and their different isomers show significant functional differences. Therefore, in situ characterization of unsaturated lipids in tissues needs to be extended to isomer level. However, the exposure of tissue sections to an open environment for a long time may cause cell autolysis or corruption, and current unsaturated lipid imaging methods still face challenges in efficiency. This paper proposes an imaging method based on photoepoxidation coupled with air-flow-assisted desorption electrospray ionization mass spectrometry (AFADESI-MS) to rapidly realize the spatial characterization of unsaturated lipids at the isomer level. The technique has a fast response speed, high epoxide yield (>80%), and high diagnostic ion abundance. After 0.5 min of photoepoxidation, the derivation product yield ratio reached 24.6%. This method rapidly identified six glycerophospholipid isomers containing an 18:1 acyl chain in normal rat liver tissue. Then the imaging method was applied in nude mice lung cancer tissue and human thyroid cancer tissue, with only 3 min photoepoxidation. Results successfully characterized the location and range of unsaturated lipid isomers and revealed their enrichment in tumor tissue. In addition, the experiment shows that the variational trend of the ratio of unsaturated lipid isomers in different types of tumor samples is different. Based on the advantages of efficiency and convenience, this method is prospective for screening unsaturated lipid markers and pathological research of related diseases.
不饱和脂质在生物体内发挥着重要作用，其不同的异构体表现出显著的功能差异。因此，需要将组织中不饱和脂质的原位表征扩展到异构体水平。然而，组织切片长时间暴露在开放环境中可能会导致细胞自溶或腐败，目前的不饱和脂质成像方法在效率方面仍然面临挑战。本文提出了一种基于光氧化偶联与气流辅助解吸电喷雾电离质谱（AFADESI-MS）的成像方法，以快速实现异构体水平的不饱和脂质空间特征化。该技术具有快速响应速度、高环氧化物产率（>80%）和高诊断离子丰度。经过 0.5 分钟的光氧化，衍生产物产率比达到 24.6%。该方法快速鉴定了正常大鼠肝组织中含有 18:1 酰基链的六种甘油磷脂异构体。然后将该成像方法应用于裸鼠肺癌组织和人甲状腺癌组织，只需 3 分钟的光氧化。结果成功表征了不饱和脂质异构体的位置和范围，并揭示了它们在肿瘤组织中的富集。此外，实验表明，不同类型肿瘤样本中不饱和脂质异构体比例的变化趋势不同。基于效率和便利性的优势，该方法有望用于筛选不饱和脂质标志物和相关疾病的病理研究。
