School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United State.
Waters Corporation, Milford, Massachusetts 01757, United State.
Anal Chem. 2024 Aug 20;96(33):13598-13606. doi: 10.1021/acs.analchem.4c02394. Epub 2024 Aug 6.
Lipidomics focuses on investigating alterations in a wide variety of lipids that harness important information on metabolic processes and disease pathology. However, the vast structural diversity of lipids and the presence of isobaric and isomeric species creates serious challenges in feature identification, particularly in mass spectrometry imaging experiments that lack front-end separations. Ion mobility has emerged as a potential solution to address some of these challenges and is increasingly being utilized as part of mass spectrometry imaging platforms. Here, we present the results of a pilot mass spectrometry imaging study on rat brains subjected to traumatic brain injury (TBI) to evaluate the depth and quality of the information yielded by desorption electrospray ionization cyclic ion mobility mass spectrometry (DESI cIM MSI). Imaging data were collected with one and six passes through the cIM cell. Increasing the number of passes increased the ion mobility resolving power and the resolution of isobaric lipids, enabling the creation of more specific maps. Interestingly, drift time data enabled the recognition of multiply charged phosphoinositide species in the complex data set generated. These species have not been previously reported in TBI MSI studies and were found to decrease in the hippocampus region following injury. These changes were attributed to increased enzymatic activity after TBI, releasing arachidonic acid that is converted to eicosanoids to control inflammation. A substantial reduction in NAD and alterations in other adenine metabolites were also observed, supporting the hypothesis that energy metabolism in the brain is severely disrupted in TBI.
脂质组学专注于研究广泛存在的脂质的变化，这些脂质提供了有关代谢过程和疾病病理的重要信息。然而，脂质具有巨大的结构多样性，并且存在等质和同质物种，这给特征识别带来了严重的挑战，特别是在缺乏前端分离的质谱成像实验中。离子淌度已成为解决其中一些挑战的潜在方法，并且越来越多地被用作质谱成像平台的一部分。在这里，我们展示了一项针对创伤性脑损伤（TBI）大鼠大脑的质谱成像研究的初步结果，以评估解吸电喷雾电离循环离子淌度质谱（DESI cIM MSI）产生的信息的深度和质量。使用 cIM 细胞进行一次和六次通过收集成像数据。增加通过次数可以提高离子淌度分辨率和等质脂质的分辨率，从而创建更具体的图谱。有趣的是，漂移时间数据能够识别复杂数据集生成的多电荷磷酸肌醇物种。这些物质以前在 TBI MSI 研究中没有报道过，并且在损伤后在海马区减少。这些变化归因于 TBI 后酶活性的增加，释放出花生四烯酸，花生四烯酸转化为类二十烷酸以控制炎症。还观察到 NAD 的大量减少和其他腺嘌呤代谢物的改变，这支持了大脑中能量代谢在 TBI 中严重受损的假说。
