Chen Yanyan, Song Yuanyuan, Yang Zhu, Ru Yi, Xie Peisi, Han Jing, Chai Xuyang, Wang Jianing, Cai Zongwei
State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong SAR 999077, China.
Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR 999077, China.
Anal Chem. 2025 Jan 14;97(1):499-507. doi: 10.1021/acs.analchem.4c04600. Epub 2024 Dec 27.
Spatial stable isotope tracing metabolic imaging is a cutting-edge technique designed to investigate tissue-specific metabolic functions and heterogeneity. Traditional matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) techniques often struggle with low coverage of low-molecular-weight (LMW) metabolites, which are often crucial for spatial metabolic studies. To address this, we developed a high-coverage spatial isotope tracing metabolic method that incorporates optimized matrix selection, sample preparation protocols, and enhanced post-ionization (MALDI2) techniques. We employed this approach to mouse kidney, brain, and breast tumors to visualize the spatial dynamics of metabolic flow. Our results revealed diverse regional distributions of nine labeled intermediates derived from C-glucose across glycolysis, glycogen metabolism, and the tricarboxylic acid (TCA) cycle in kidney tissues. In brain sections, we successfully mapped six intermediates from the TCA cycle and glutamate-glutamine (Glu-Gln) cycle simultaneously in distinct neurological regions. Furthermore, in breast cancer tumor tissues, our approach facilitated the mapping of nine metabolic intermediates in multiple pathways, including glycolysis, the pentose phosphate pathway (PPP), and the TCA cycle, illustrating metabolic heterogeneity within the tumor microenvironment. This methodology enhances metabolite coverage, enabling more comprehensive imaging of isotope-labeled metabolites and opening new avenues for exploring the metabolic landscape in various biological contexts.
空间稳定同位素示踪代谢成像技术是一项前沿技术，旨在研究组织特异性代谢功能和异质性。传统的基质辅助激光解吸电离质谱成像（MALDI-MSI）技术常常难以应对低分子量（LMW）代谢物的低覆盖率问题，而这些代谢物对于空间代谢研究往往至关重要。为了解决这一问题，我们开发了一种高覆盖率的空间同位素示踪代谢方法，该方法结合了优化的基质选择、样品制备方案以及增强的电离后（MALDI2）技术。我们将这种方法应用于小鼠肾脏、大脑和乳腺肿瘤，以可视化代谢流的空间动态。我们的结果揭示了源自¹³C-葡萄糖的九种标记中间体在肾脏组织中糖酵解途径、糖原代谢和三羧酸（TCA）循环中的不同区域分布。在脑切片中，我们成功地在不同神经区域同时绘制了TCA循环和谷氨酸-谷氨酰胺（Glu-Gln）循环中的六种中间体。此外，在乳腺癌肿瘤组织中，我们的方法有助于绘制包括糖酵解、磷酸戊糖途径（PPP）和TCA循环在内的多个途径中的九种代谢中间体，展示了肿瘤微环境内的代谢异质性。这种方法提高了代谢物覆盖率，能够更全面地成像同位素标记的代谢物，并为探索各种生物学背景下的代谢格局开辟了新途径。
