Hui Yang1,2, Wenliang Ji1, Ming Guan1,2, Shilei Li1,2, Yangyang Zhang1, Zhenwen Zhao3,4, Lanqun Mao5,6. 1. Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Beijing Mass Spectrum Center, Institute of Chemistry Chinese Academy of Sciences, Beijing, China. 2. Graduate School, University of Chinese Academy of Sciences, Beijing, China. 3. Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Beijing Mass Spectrum Center, Institute of Chemistry Chinese Academy of Sciences, Beijing, China. zhenwenzhao@iccas.ac.cn. 4. Graduate School, University of Chinese Academy of Sciences, Beijing, China. zhenwenzhao@iccas.ac.cn. 5. Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Beijing Mass Spectrum Center, Institute of Chemistry Chinese Academy of Sciences, Beijing, China. lqmao@iccas.ac.cn. 6. Graduate School, University of Chinese Academy of Sciences, Beijing, China. lqmao@iccas.ac.cn.
Abstract
INTRODUCTION: In-situ detection and in particular comprehensive analysis of small molecule metabolites (SMMs, m/z < 500) using matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) remain a challenge, mainly due to ion suppression effects from more abundant molecules in tissue section like lipids. OBJECTIVE: A strategy based on organic washes to remove most ionization-suppressing lipids from tissue section was firstly explored for improved analysis of SMMs by MALDI MSI. METHODS: The tissue sections after rinse with different organic solvents were analyzed by MALDI MSI, and the results were compared for the optimized washing conditions. RESULTS: The rinse with chloroform for 15 s at - 20 °C significantly removed most glycerophospholipids and glycerolipids from tissue section. Consequentially, ATP-related energy metabolites, amino acids and derivatives, glucose derivatives, glycolysis pathway metabolites and other SMMs were able to be well-visualized with enhanced ion intensity and good reproducibility. The organic washes-based MALDI MSI was applied to the metabolic pathway analysis in rat brain following status epilepticus (SE) model, which was, as far as we know, the first report about in-situ detection of a broad range of metabolites in the model of SE by MALDI MSI technique. The alterations of cyclic adenosine monophosphate (cyclic AMP), inosine, glutamine, glutathione, taurine and spermine during SE were observed. CONCLUSION: A simple organic washing protocol enables comprehensive analysis of tissue SMMs in MALDI MSI by removing ionization-suppressing lipids. The application in the SE model indicates that MALDI MSI analysis potentially provides new insight for understanding the disease mechanism.
INTRODUCTION: In-situ detection and in particular comprehensive analysis of small molecule metabolites (SMMs, m/z < 500) using matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) remain a challenge, mainly due to ion suppression effects from more abundant molecules in tissue section like lipids. OBJECTIVE: A strategy based on organic washes to remove most ionization-suppressing lipids from tissue section was firstly explored for improved analysis of SMMs by MALDI MSI. METHODS: The tissue sections after rinse with different organic solvents were analyzed by MALDI MSI, and the results were compared for the optimized washing conditions. RESULTS: The rinse with chloroform for 15 s at - 20 °C significantly removed most glycerophospholipids and glycerolipids from tissue section. Consequentially, ATP-related energy metabolites, amino acids and derivatives, glucose derivatives, glycolysis pathway metabolites and other SMMs were able to be well-visualized with enhanced ion intensity and good reproducibility. The organic washes-based MALDI MSI was applied to the metabolic pathway analysis in rat brain following status epilepticus (SE) model, which was, as far as we know, the first report about in-situ detection of a broad range of metabolites in the model of SE by MALDI MSI technique. The alterations of cyclic adenosine monophosphate (cyclic AMP), inosine, glutamine, glutathione, taurine and spermine during SE were observed. CONCLUSION: A simple organic washing protocol enables comprehensive analysis of tissue SMMs in MALDI MSI by removing ionization-suppressing lipids. The application in the SE model indicates that MALDI MSI analysis potentially provides new insight for understanding the disease mechanism.
Entities:
Keywords:
MALDI MSI; Metabolites; Organic wash; Status epilepticus
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