Matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI)is an attractive technology for the visualization of metabolite distributions in tissues.However,detection and identification of low-abun...Matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI)is an attractive technology for the visualization of metabolite distributions in tissues.However,detection and identification of low-abundance or poorly ionized metabolites remains challenging.Although on-tissue chemical derivatization(OTCD)holds great promise for improving MALDI MS detection sensitivity and selectivity by modification of specific chemical groups,the available methods for subsequent metabolite annotation are limited.Herein,a laser-assisted chemical transfer(LACT)-based parallel OTCD strategy was established for visualizing and annotating carbonyl metabolites in murine brain tissues.Girard's T and Girard's P reagents were applied for parallel OTCD to generate the characteristic m/z pairs with a 19.969 Da mass shift(±0.020 Da tolerance)for rapid recognition of derivatized metabolites.The similarity of spatial distribution patterns of each m/z pair was further statistically evaluated to remove the ambiguous annotations due to the occurrence of interference compounds.As a result,90 ion pairs were annotated as candidate carbonyl metabolites,66 were previously known and 24 were potential unreported carbonyls.Furthermore,the spatial alterations of carbonyl metabolites in the ischemic rat brain were successfully visualized and characterized,including small molecule aldehydes and ketones,long-chain fatty aldehydes,and monosaccharides.This further emphasizes great potential of parallel OTCD strategy for efficient and confident molecular annotation of spatial submetabolomics data associated with brain diseases.展开更多
On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI)...On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI).Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor.Herein,we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization(AFADESI)-MSI.Taking Girard’s P as a derivatization reagent,easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction.Oxylipins,including 127 fatty aldehydes(FALs)and 71 oxo fatty acids(FAs),were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD.Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue.With this method,we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor,and exhibited a gradual increase trend in tumor over time.These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression,highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.展开更多
Application of matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatiotemporal alterations of lipids in biological tissues has brought many significant results.Howeve...Application of matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatiotemporal alterations of lipids in biological tissues has brought many significant results.However, the presence of structural isomers varying in C=C double bond(DB) locations makes isomerresolved MSI an urgent need. Herein, we introduce a new type of light-driven on-tissue [2 + 2] cycloaddition reaction coupled with MALDI-MS/MS imaging to identify lipid DB position isomers and their spatial signatures in biological tissues. 3-Benzoylpyridine was introduced as a novel derivatization reagent, and it exhibited great reactivity toward lipid C=C bond to form oxetanes under both ultraviolet light and visible light irradiation. With this approach, DB position isomers of lipids were imaged with highly differential levels in distinct regions of rat brain, providing an accurate and spatially resolved approach to study tissue lipidomics.展开更多
Matrix-assisted laser desorption ionization-mass spectrometry imaging(MALDI-MSI)has shown its capability in visualizing the spatial distribution of various kinds of endogenous metabolites.Nevertheless,high quality mas...Matrix-assisted laser desorption ionization-mass spectrometry imaging(MALDI-MSI)has shown its capability in visualizing the spatial distribution of various kinds of endogenous metabolites.Nevertheless,high quality mass imaging of low polar metabolites remains challenging.Herein,a platform for sensitive matrix-assisted laser desorption ionization-mass spectrometry imaging of cholesterol and glycerides has been proposed.In the platform,a vacuum promoted on-tissue derivatization strategy was proposed to constantly make the derivatization reaction proceed towards to the direction of products.Compared with traditional on-tissue derivatization procedure,the strategy improved the acquired intensity of derivatized glycerides about 50%.Additionally,the mass spectrometry image reflecting the signal ratio between 3classes of glycerides was achieved to exploit the metabolic level of glycerides on tissue slice.Finally,the platform was applied to brain slices of Alzheimer’s transgenic mice,type 2 diabetes mice and normal mice.Significant difference was found in mass spectrometry images reflecting the signal ratio of multiple endogenous metabolites.The work constructed a promising platform for mapping of glycerides in tissue by mass spectrometry imaging.展开更多
A comprehensive understanding of the molecular details at spatial levels within heterogeneous cardiac tissue in heart failure(HF)is paramount for enhancing our knowledge of the pathophysiology of HF and pinpointing po...A comprehensive understanding of the molecular details at spatial levels within heterogeneous cardiac tissue in heart failure(HF)is paramount for enhancing our knowledge of the pathophysiology of HF and pinpointing potential therapeutic targets.Here,we present an analytical strategy for the deep discovery of heterogeneous metabolism and drug response in the heart tissue of rats with HF using airflow-assisted desorption electrospray ionization mass spectrometry imaging(AFADESI-MSI)coupled with bulk RNAsequencing.Spatial metabolomics illustrated pronounced metabolic heterogeneity between the infarct(I),infarct margin(IM),and non-infarct(NI)areas of heart tissue in HF.Integrated transcriptomics showed that increased mRNA expression of ATP citrate lyase disrupted the tricarboxylic acid(TCA)cycle in the NI area.Impairment of the carnitine shuttle system led to a significant accumulation of carnitines,suggesting potential abnormalities in fatty acid(FA)oxidation.Coupling on-tissue chemical derivatization with AFADESI-MSI enabled us to confirm the occurrence of incomplete oxidation of FAs in the NI area.Additionally,we observed a heterogeneous drug response between the anti-HF medications valsartan and Qishen Yiqi Dripping Pills(QDP).Valsartan exhibited a more pronounced effect on metabolic regulation in the I area,whereas QDP exerted stronger regulatory effects on metabolism in the NI area.Utilizing this method,four potential therapeutic targets were identified in HF:CPT1A,PDHB,ACLY,and BCAT2,which were preliminarily validated by western blotting.Overall,integrating spatial metabolomics with transcriptomics facilitates comprehensive analyses that link differential metabolites and genes,enabling a more precise characterization of metabolic changes in heart injury microareas and providing effective methods for elucidating molecular mechanisms and identifying potential therapeutic targets for HF.展开更多
基金supported by the National Natural Science Foundation of China(Nos.82374028 and 81803957)。
文摘Matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI)is an attractive technology for the visualization of metabolite distributions in tissues.However,detection and identification of low-abundance or poorly ionized metabolites remains challenging.Although on-tissue chemical derivatization(OTCD)holds great promise for improving MALDI MS detection sensitivity and selectivity by modification of specific chemical groups,the available methods for subsequent metabolite annotation are limited.Herein,a laser-assisted chemical transfer(LACT)-based parallel OTCD strategy was established for visualizing and annotating carbonyl metabolites in murine brain tissues.Girard's T and Girard's P reagents were applied for parallel OTCD to generate the characteristic m/z pairs with a 19.969 Da mass shift(±0.020 Da tolerance)for rapid recognition of derivatized metabolites.The similarity of spatial distribution patterns of each m/z pair was further statistically evaluated to remove the ambiguous annotations due to the occurrence of interference compounds.As a result,90 ion pairs were annotated as candidate carbonyl metabolites,66 were previously known and 24 were potential unreported carbonyls.Furthermore,the spatial alterations of carbonyl metabolites in the ischemic rat brain were successfully visualized and characterized,including small molecule aldehydes and ketones,long-chain fatty aldehydes,and monosaccharides.This further emphasizes great potential of parallel OTCD strategy for efficient and confident molecular annotation of spatial submetabolomics data associated with brain diseases.
基金supported by the National Natural Science Foundation of China(No.21927808)the Chinese Academy of Medical Science(CAMS)Innovation Fund for Medical Sciences(CIFMS,Nos.2022-I2M-2-002 and 2021-1-I2M-028).
文摘On-tissue chemical derivatization(OTCD)effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging(MSI).Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor.Herein,we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization(AFADESI)-MSI.Taking Girard’s P as a derivatization reagent,easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction.Oxylipins,including 127 fatty aldehydes(FALs)and 71 oxo fatty acids(FAs),were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD.Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue.With this method,we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor,and exhibited a gradual increase trend in tumor over time.These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression,highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.
基金supported by the National Natural Science Foundation of China (Nos. 81903571, 21904080)the Taishan Scholars the Taishan Scholars Program (C. Sun, No. tsqn202103096)the Shandong Province “Double-Hundred Talent Plan” Program。
文摘Application of matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatiotemporal alterations of lipids in biological tissues has brought many significant results.However, the presence of structural isomers varying in C=C double bond(DB) locations makes isomerresolved MSI an urgent need. Herein, we introduce a new type of light-driven on-tissue [2 + 2] cycloaddition reaction coupled with MALDI-MS/MS imaging to identify lipid DB position isomers and their spatial signatures in biological tissues. 3-Benzoylpyridine was introduced as a novel derivatization reagent, and it exhibited great reactivity toward lipid C=C bond to form oxetanes under both ultraviolet light and visible light irradiation. With this approach, DB position isomers of lipids were imaged with highly differential levels in distinct regions of rat brain, providing an accurate and spatially resolved approach to study tissue lipidomics.
基金supported by the National Key R&D Program of China(No.2021YFF0701900)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0610000)+1 种基金Shanghai Science and Technology Innovation Action Plan(No.21142200800)the Program of EnShi TuJia&Miao Autonomous Prefecture Bureau of Scientific&Technological Affairs。
文摘Matrix-assisted laser desorption ionization-mass spectrometry imaging(MALDI-MSI)has shown its capability in visualizing the spatial distribution of various kinds of endogenous metabolites.Nevertheless,high quality mass imaging of low polar metabolites remains challenging.Herein,a platform for sensitive matrix-assisted laser desorption ionization-mass spectrometry imaging of cholesterol and glycerides has been proposed.In the platform,a vacuum promoted on-tissue derivatization strategy was proposed to constantly make the derivatization reaction proceed towards to the direction of products.Compared with traditional on-tissue derivatization procedure,the strategy improved the acquired intensity of derivatized glycerides about 50%.Additionally,the mass spectrometry image reflecting the signal ratio between 3classes of glycerides was achieved to exploit the metabolic level of glycerides on tissue slice.Finally,the platform was applied to brain slices of Alzheimer’s transgenic mice,type 2 diabetes mice and normal mice.Significant difference was found in mass spectrometry images reflecting the signal ratio of multiple endogenous metabolites.The work constructed a promising platform for mapping of glycerides in tissue by mass spectrometry imaging.
基金supported by the National Natural Science Foundation of China(No.82374158)National Science and Technology Major Project(No.2018ZX09711001-002-004)+1 种基金the Jiangxi University of Chinese Medicine Science and Technology Innovation Team Development Program(No.CXTD22007)the Medical and Health Technology Innovation Project(No.2022-I2M-1-020).
文摘A comprehensive understanding of the molecular details at spatial levels within heterogeneous cardiac tissue in heart failure(HF)is paramount for enhancing our knowledge of the pathophysiology of HF and pinpointing potential therapeutic targets.Here,we present an analytical strategy for the deep discovery of heterogeneous metabolism and drug response in the heart tissue of rats with HF using airflow-assisted desorption electrospray ionization mass spectrometry imaging(AFADESI-MSI)coupled with bulk RNAsequencing.Spatial metabolomics illustrated pronounced metabolic heterogeneity between the infarct(I),infarct margin(IM),and non-infarct(NI)areas of heart tissue in HF.Integrated transcriptomics showed that increased mRNA expression of ATP citrate lyase disrupted the tricarboxylic acid(TCA)cycle in the NI area.Impairment of the carnitine shuttle system led to a significant accumulation of carnitines,suggesting potential abnormalities in fatty acid(FA)oxidation.Coupling on-tissue chemical derivatization with AFADESI-MSI enabled us to confirm the occurrence of incomplete oxidation of FAs in the NI area.Additionally,we observed a heterogeneous drug response between the anti-HF medications valsartan and Qishen Yiqi Dripping Pills(QDP).Valsartan exhibited a more pronounced effect on metabolic regulation in the I area,whereas QDP exerted stronger regulatory effects on metabolism in the NI area.Utilizing this method,four potential therapeutic targets were identified in HF:CPT1A,PDHB,ACLY,and BCAT2,which were preliminarily validated by western blotting.Overall,integrating spatial metabolomics with transcriptomics facilitates comprehensive analyses that link differential metabolites and genes,enabling a more precise characterization of metabolic changes in heart injury microareas and providing effective methods for elucidating molecular mechanisms and identifying potential therapeutic targets for HF.
