FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.
Molecular Education, Technology and Research Innovation Center (METRIC), North Carolina State University, Raleigh, North Carolina 27695, United States.
J Proteome Res. 2022 Mar 4;21(3):747-757. doi: 10.1021/acs.jproteome.1c00636. Epub 2021 Nov 22.
Due to the high association of glutathione metabolism perturbation with a variety of disease states, there is a dire need for analytical techniques to study glutathione kinetics. Additionally, the elucidation of microenvironmental effects on changes in glutathione metabolism would significantly improve our understanding of the role of glutathione in disease. We therefore present a study combining a multiple infusion start time protocol, stable isotope labeling technology, infrared matrix-assisted laser desorption electrospray ionization, and high-resolution accurate mass-mass spectrometry imaging to study spatial changes in glutathione kinetics across in sectioned mouse liver tissues. After injecting a mouse with the isotopologues [2-C,N]-glycine, [1,2-C]-glycine, and [1,2-C,N]-glycine at three different time points, we were able to fully resolve and spatially map their metabolism into three isotopologues of glutathione and calculate their isotopic enrichment in glutathione. We created a tool in the open-source mass spectrometry imaging software MSiReader to accurately compute the percent isotope enrichment (PIE) of these labels in glutathione and visualize them in heat-maps of the tissue sections. In areas of high flux, we found that each label enriched an approximate median of 1.6%, 1.8%, and 1.5%, respectively, of the glutathione product pool measured in each voxel. This method may be adapted to study the heterogeneity of glutathione flux in diseased versus healthy tissues.
由于谷胱甘肽代谢紊乱与多种疾病状态密切相关，因此迫切需要分析技术来研究谷胱甘肽动力学。此外，阐明微环境对谷胱甘肽代谢变化的影响将极大地提高我们对谷胱甘肽在疾病中的作用的理解。因此，我们提出了一项结合多次输注起始时间方案、稳定同位素标记技术、红外基质辅助激光解吸电喷雾电离和高分辨率精确质量-质量质谱成像技术的研究，以研究在切片小鼠肝组织中谷胱甘肽动力学的空间变化。在给老鼠注射三种不同时间点的同位素标记物[2-C，N]-甘氨酸、[1，2-C]-甘氨酸和[1，2-C，N]-甘氨酸后，我们能够完全解析并在空间上映射它们的代谢产物成三种谷胱甘肽的同位素标记物，并计算它们在谷胱甘肽中的同位素丰度。我们在开源质谱成像软件 MSiReader 中创建了一个工具，以准确计算这些标记物在谷胱甘肽中的百分比同位素丰度（PIE），并将其可视化在组织切片的热图中。在通量较高的区域，我们发现每个标记物分别富集了每个体素中测量的谷胱甘肽产物池的约 1.6%、1.8%和 1.5%。该方法可以适应研究疾病与健康组织中谷胱甘肽通量的异质性。
