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Cao H, Liu Q, Liu Y, Zhao J, Qiao W, Wang Y, Liu Y, Chen L. Progress in triacylglycerol isomer detection in milk lipids. Food Chem X 2024; 22:101433. [PMID: 38764784 PMCID: PMC11101684 DOI: 10.1016/j.fochx.2024.101433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/21/2024] Open
Abstract
In triacylglycerols (TAGs), position differences of fatty acids on the glycerol skeleton produce various TAG isomers. These TAG isomers have different pathways of digestion, absorption, and utilization in infants, thereby affecting TAG nutritional properties of TAGs. Here, we review the progress of research on methods for detecting TAG isomers, and identify direction and thought for improving these methods, including novel chromatographic combinations, perfect algorithm, and improved equipment. The ensuing optimization of these methods is expected to provide robust guarantee for the gradual improvement of milk-derived TAG isomer detection, and is an important prerequisite for infant formula to mimic the structured lipids of human milk.
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Affiliation(s)
- Huiru Cao
- Key Laboratory of Dairy Science, Ministry of Education, Food Science College, Northeast Agricultural University, Harbin 150030, China
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Qian Liu
- Key Laboratory of Dairy Science, Ministry of Education, Food Science College, Northeast Agricultural University, Harbin 150030, China
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Yan Liu
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Junying Zhao
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Weicang Qiao
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Yuru Wang
- Key Laboratory of Dairy Science, Ministry of Education, Food Science College, Northeast Agricultural University, Harbin 150030, China
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Yan Liu
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
| | - Lijun Chen
- Key Laboratory of Dairy Science, Ministry of Education, Food Science College, Northeast Agricultural University, Harbin 150030, China
- National Engineering Research Center of Dairy Health for Maternal and Child, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
- Beijing Engineering Research Center of Dairy, Beijing Technical Innovation Center of Human Milk Research, Beijing Sanyuan Foods Co. Ltd., Beijing 100163, China
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2
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Shi H, Xia Y. Shotgun Lipidomic Profiling of Sebum Lipids via Photocatalyzed Paternò-Büchi Reaction and Ion Mobility-Mass Spectrometry. Anal Chem 2024; 96:5589-5597. [PMID: 38556723 DOI: 10.1021/acs.analchem.4c00141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Sebum lipids are composed of nonpolar lipids, and they pose challenges for mass spectrometry-based analysis due to low ionization efficiency and the existence of numerous isomers and isobars. To address these challenges, we have developed ethyl 2-oxo-2-(pyridine-3-yacetate as a charge-tagging Paternò-Büchi reagent and Michler's ketone as a highly efficient photocatalyst, achieving ∼90% conversion for C═C derivatization under 440 nm LED irradiation. This derivatization, when coupled with electrospray ionization-tandem mass spectrometry, boosts the detection of sebum lipids and pinpoints C═C location in a chain-specific fashion. Identification and quantitation of isomers are readily achieved for wax esters, a class of underexplored sebum lipids, which have C═C bonds distributed in fatty alcohol and fatty acyl chains. A shotgun analysis workflow has been developed by pairing the offline PB derivatization with cyclic ion mobility spectrometry-mass spectrometry. Besides the dominant n-10 C═C location in unsaturated wax esters, profiling of low abundance isomers, including the rarely reported n-7 and n-13 locations, is greatly enhanced due to separations of C═C diagnostic ions by ion mobility. Over 900 distinct lipid structures from human sebum lipid extract have been profiled at the chain-specific C═C level, including wax esters (500), glycerolipids (393), and cholesterol esters (22), far more exceeding previous reports. Overall, we have developed a fast and comprehensive lipidomic profiling tool for sebum samples, a type of noninvasive biofluids holding potential for the discovery of disease markers in distal organs.
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Affiliation(s)
- Hengxue Shi
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 10084, China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 10084, China
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3
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Liu C, Zhang Z, Li B, Huang K, Zhang Y, Li M, Letcher RJ. Lipid Metabolic Disorders Induced by Organophosphate Esters in Silver Carp from the Middle Reaches of the Yangtze River. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4904-4913. [PMID: 38437168 DOI: 10.1021/acs.est.3c08610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
The Yangtze River fishery resources have declined strongly over the past few decades. One suspected reason for the decline in fishery productivity, including silver carp (Hypophthalmichthys molitrix), has been linked to organophosphate esters (OPEs) contaminant exposure. In this study, the adverse effect of OPEs on lipid metabolism in silver carp captured from the Yangtze River was examined, and our results indicated that muscle concentrations of the OPEs were positively associated with serum cholesterol and total lipid levels. In vivo laboratory results revealed that exposure to environmental concentrations of OPEs significantly increased the concentrations of triglyceride, cholesterol, and total lipid levels. Lipidome analysis further confirmed the lipid metabolism dysfunction induced by OPEs, and glycerophospholipids and sphingolipids were the most affected lipids. Hepatic transcriptomic analysis found that OPEs caused significant alterations in the transcription of genes involved in lipid metabolism. Pathways associated with lipid homeostasis, including the peroxisome proliferator-activated receptor (PPAR) signal pathway, cholesterol metabolism, fatty acid biosynthesis, and steroid biosynthesis, were significantly changed. Furthermore, the affinities of OPEs were different, but the 11 OPEs tested could bind with PPARγ, suggesting that OPEs could disrupt lipid metabolism by interacting with PPARγ. Overall, this study highlighted the harmful effects of OPEs on wild fish and provided mechanistic insights into OPE-induced metabolic disorders.
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Affiliation(s)
- Chunsheng Liu
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Zihan Zhang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Boqun Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai Huang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Yongkang Zhang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Meng Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Robert J Letcher
- Departments of Chemistry and Biology, Carleton University, Ottawa K1S 5B6 Ontario, Canada
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4
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Wang D, Xiao H, Lv X, Chen H, Wei F. Mass Spectrometry Based on Chemical Derivatization Has Brought Novel Discoveries to Lipidomics: A Comprehensive Review. Crit Rev Anal Chem 2023:1-32. [PMID: 37782560 DOI: 10.1080/10408347.2023.2261130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Lipids, as one of the most important organic compounds in organisms, are important components of cells and participate in energy storage and signal transduction of living organisms. As a rapidly rising field, lipidomics research involves the identification and quantification of multiple classes of lipid molecules, as well as the structure, function, dynamics, and interactions of lipids in living organisms. Due to its inherent high selectivity and high sensitivity, mass spectrometry (MS) is the "gold standard" analysis technique for small molecules in biological samples. The combination chemical derivatization with MS detection is a unique strategy that could improve MS ionization efficiency, facilitate structure identification and quantitative analysis. Herein, this review discusses derivatization-based MS strategies for lipidomic analysis over the past decade and focuses on all the reported lipid categories, including fatty acids and modified fatty acids, glycerolipids, glycerophospholipids, sterols and saccharolipids. The functional groups of lipids mainly involved in chemical derivatization include the C=C group, carboxyl group, hydroxyl group, amino group, carbonyl group. Furthermore, representative applications of these derivatization-based lipid profiling methods were summarized. Finally, challenges and countermeasures of lipid derivatization are mentioned and highlighted to guide future studies of derivatization-based MS strategy in lipidomics.
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Affiliation(s)
- Dan Wang
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, Hubei, PR China
| | - Huaming Xiao
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, Hubei, PR China
| | - Xin Lv
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, Hubei, PR China
| | - Hong Chen
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, Hubei, PR China
| | - Fang Wei
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, Hubei, PR China
- Hubei Hongshan Laboratory, Wuhan, Hubei, PR China
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Xia T, Jin X, Zhang D, Wang J, Jian R, Yin H, Xia Y. Alternative fatty acid desaturation pathways revealed by deep profiling of total fatty acids in RAW 264.7 cell line. J Lipid Res 2023; 64:100410. [PMID: 37437845 PMCID: PMC10407907 DOI: 10.1016/j.jlr.2023.100410] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/14/2023] Open
Abstract
In-depth structural characterization of lipids provides a new means to investigate lipid metabolism. In this study, we have conducted deep profiling of total fatty acids (FAs) from RAW 264.7 macrophages by utilizing charge-tagging Paternò-Büchi derivatization of carbon-carbon double bond (C=C) and reversed-phase liquid chromatography-tandem mass spectrometry. A series of FAs exhibiting unusual site(s) of unsaturation was unearthed, with their identities being confirmed by observing anticipated compositional alterations upon desaturase inhibition. The data reveal that FADS2 Δ 6-desaturation can generate n-11 C=C in the odd-chain monounsaturated fatty acids (MUFAs) as well as n-10 and n-12 families of even-chain MUFAs. SCD1 Δ 9-desaturation yields n-6, n-8, and n-10 of odd-chain MUFAs, as well as n-5, n-7, and n-9 families of even-chain MUFAs. Besides n-3 and n-6 families of polyunsaturated fatty acids (PUFAs), the presence of n-7 and n-9 families of PUFAs indicates that the n-7 and n-9 isomers of FA 18:1 can be utilized as substrates for further desaturation and elongation. The n-7 and n-9 families of PUFAs identified in RAW 264.7 macrophages are noteworthy because their C=C modifications are achieved exclusively via de novo lipogenesis. Our discovery outlines the metabolic plasticity in fatty acid desaturation which constitutes an unexplored rewiring in RAW264.7 macrophages.
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Affiliation(s)
- Tian Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Xue Jin
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Donghui Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, China
| | - Jitong Wang
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Ruijun Jian
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Hang Yin
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China; Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, China.
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6
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Xia T, Zhou F, Zhang D, Jin X, Shi H, Yin H, Gong Y, Xia Y. Deep-profiling of phospholipidome via rapid orthogonal separations and isomer-resolved mass spectrometry. Nat Commun 2023; 14:4263. [PMID: 37460558 DOI: 10.1038/s41467-023-40046-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 07/05/2023] [Indexed: 07/20/2023] Open
Abstract
A lipidome comprises thousands of lipid species, many of which are isomers and isobars. Liquid chromatography-tandem mass spectrometry (LC-MS/MS), although widely used for lipidomic profiling, faces challenges in differentiating lipid isomers. Herein, we address this issue by leveraging the orthogonal separation capabilities of hydrophilic interaction liquid chromatography (HILIC) and trapped ion mobility spectrometry (TIMS). We further integrate isomer-resolved MS/MS methods onto HILIC-TIMS, which enable pinpointing double bond locations in phospholipids and sn-positions in phosphatidylcholine. This system profiles phospholipids at multiple structural levels with short analysis time (<10 min per LC run), high sensitivity (nM detection limit), and wide coverage, while data analysis is streamlined using a home-developed software, LipidNovelist. Notably, compared to our previous report, the system doubles the coverage of phospholipids in bovine liver and reveals uncanonical desaturation pathways in RAW 264.7 macrophages. Relative quantitation of the double bond location isomers of phospholipids and the sn-position isomers of phosphatidylcholine enables the phenotyping of human bladder cancer tissue relative to normal control, which would be otherwise indistinguishable by traditional profiling methods. Our research offers a comprehensive solution for lipidomic profiling and highlights the critical role of isomer analysis in studying lipid metabolism in both healthy and diseased states.
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Affiliation(s)
- Tian Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Feng Zhou
- Bytedance Technology Co., 201103, Shanghai, China
| | - Donghui Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Department of Precision Instrument, 100084, Beijing, China
| | - Xue Jin
- School of Pharmaceutical Sciences, Tsinghua University, 100084, Beijing, China
| | - Hengxue Shi
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Hang Yin
- School of Pharmaceutical Sciences, Tsinghua University, 100084, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, 100084, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, 100084, Beijing, China
| | - Yanqing Gong
- Department of Urology, Peking University First Hospital, 100034, Beijing, China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, 100084, Beijing, China.
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7
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Shi H, Tan Z, Guo X, Ren H, Wang S, Xia Y. Visible-Light Paternò-Büchi Reaction for Lipidomic Profiling at Detailed Structure Levels. Anal Chem 2023; 95:5117-5125. [PMID: 36898165 DOI: 10.1021/acs.analchem.3c00085] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
The Paternò-Büchi (PB) derivatization of carbon-carbon double bond (C═C) has been increasingly employed with tandem mass spectrometry to analyze unsaturated lipids. It enables the discovery of altered or uncanonical lipid desaturation metabolism, which would be otherwise undetected by conventional methods. Although highly useful, the reported PB reactions only provide moderate yield (∼30%). Herein, we aim to determine the key factors that affect the PB reactions and develop a system with improved capabilities for lipidomic analysis. An Ir(III) photocatalyst is chosen as the triplet energy donor for the PB reagent under 405 nm light irradiation, while phenylglyoxalate and its charge-tagging version, pyridylglyoxalate, are developed as the most efficient PB reagents. The above visible-light PB reaction system provides higher PB conversions than all previously reported PB reactions. Around 90% conversion can be achieved at high concentrations (>0.5 mM) for different classes of lipids but drops as the lipid concentration decreases. The visible-light PB reaction has then been integrated with shotgun and liquid chromatography-based workflows. The limits of detection for locating C═C in standard lipids of glycerophospholipids (GPLs) and triacylglycerides (TGs) are in the sub-nM to nM range. More than 600 distinct GPLs and TGs have been profiled at the C═C location level or the sn-position level from the total lipid extract of bovine liver, demonstrating that the developed method is capable of large-scale lipidomic analysis.
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Affiliation(s)
- Hengxue Shi
- Department of Chemistry, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 10084, China
| | - Zhenshu Tan
- Department of Chemistry, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 10084, China
| | - Xiangyu Guo
- Department of Precision Instrument, Tsinghua University, Beijing 10084, China
| | - Hanlin Ren
- Department of Chemistry, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 10084, China
| | - Shengzhuo Wang
- Department of Chemistry, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 10084, China
| | - Yu Xia
- Department of Chemistry, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing 10084, China
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Camunas-Alberca SM, Moran-Garrido M, Sáiz J, Gil-de-la-Fuente A, Barbas C, Gradillas A. Integrating the potential of ion mobility spectrometry-mass spectrometry in the separation and structural characterisation of lipid isomers. Front Mol Biosci 2023; 10:1112521. [PMID: 37006618 PMCID: PMC10060977 DOI: 10.3389/fmolb.2023.1112521] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/14/2023] [Indexed: 03/18/2023] Open
Abstract
It is increasingly evident that a more detailed molecular structure analysis of isomeric lipids is critical to better understand their roles in biological processes. The occurrence of isomeric interference complicates conventional tandem mass spectrometry (MS/MS)-based determination, necessitating the development of more specialised methodologies to separate lipid isomers. The present review examines and discusses recent lipidomic studies based on ion mobility spectrometry combined with mass spectrometry (IMS-MS). Selected examples of the separation and elucidation of structural and stereoisomers of lipids are described based on their ion mobility behaviour. These include fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, and sterol lipids. Recent approaches for specific applications to improve isomeric lipid structural information using direct infusion, coupling imaging, or liquid chromatographic separation workflows prior to IMS-MS are also discussed, including: 1) strategies to improve ion mobility shifts; 2) advanced tandem MS methods based on activation of lipid ions with electrons or photons, or gas-phase ion-molecule reactions; and 3) the use of chemical derivatisation techniques for lipid characterisation.
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Affiliation(s)
- Sandra M. Camunas-Alberca
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
| | - Maria Moran-Garrido
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
| | - Jorge Sáiz
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
| | - Alberto Gil-de-la-Fuente
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
- Departamento de Tecnologías de la Información, Escuela Politécnica Superior, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
| | - Coral Barbas
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
| | - Ana Gradillas
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, Boadilla del Monte, Spain
- *Correspondence: Ana Gradillas,
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9
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Grooms A, Nordmann AN, Badu-Tawiah AK. Plasma-Droplet Reaction Systems: A Direct Mass Spectrometry Approach for Enhanced Characterization of Lipids at Multiple Isomer Levels. ACS MEASUREMENT SCIENCE AU 2023; 3:32-44. [PMID: 36817012 PMCID: PMC9936802 DOI: 10.1021/acsmeasuresciau.2c00051] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 06/18/2023]
Abstract
Neutral triacylglyceride (TG) lipids are critical in cellular function, signaling, and energy storage. Multiple molecular pathways control TG structure via nonselective routes making them structurally complex and analytically challenging to characterize. The presence of C=C bond positional isomers exacerbates this challenge as complete structural elucidation is not possible by conventional tandem mass spectrometric methods such as collision-induced dissociation (CID), alone. Herein, we report a custom-made coaxial contained-electrospray ionization (ESI) emitter that allows the fusion of plasma discharge with charged microdroplets during electrospray (ES). Etched capillaries were incorporated into this contained-ES emitter, facilitating the generation of reactive oxygen species (ROS) at low (3 kV) ESI voltages and allowing stable ESI ion signal to be achieved at an unprecedented high (7 kV) spray voltage. The analytical utility of inducing plasma discharge during electrospray was investigated using online ionization of neutral TGs, in situ epoxidation of unsaturation sites, and C=C bond localization via conventional CID mass spectrometry. Collisional activation of the lipid epoxide generated during the online plasma-droplet fusion experiment resulted in a novel fragmentation pattern that showed a quadruplet of diagnostic ions for confident assignment of C=C bond positions and subsequent isomer differentiation. This phenomenon enabled the identification of a novel TG lipid, composed of conjugated linoleic acid, that is isomeric with two other TG lipids naturally found in extra virgin olive oil. To validate our findings, we analyzed various standards of TG lipids, including triolein, trilinolein, and trilinolenin, and isomeric mixtures in the positive-ion mode, each of which produced the expected quadruplet diagnostic fragment ions. Further validation was obtained by analyzing standards of free fatty acids expected from the hydrolysis of the TG lipids in the negative-ion mode, together with isomeric mixtures. The chemistry governing the gas-phase fragmentation of the lipid epoxides was carefully elucidated for each TG lipid analyzed. This comprehensive shotgun lipidomic approach has the potential to impact biomedical research since it can be accomplished on readily available mass spectrometers without the need for instrument modification.
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10
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Hynds HM, Hines KM. Ion Mobility Shift Reagents for Lipid Double Bonds Based on Paternò-Büchi Photoderivatization with Halogenated Acetophenones. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1982-1989. [PMID: 36126229 DOI: 10.1021/jasms.2c00211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The Paternò-Büchi (PB) reaction is a cycloaddition reaction between a carbon-carbon double bond (C═C) and a photochemically excited carbonyl-containing compound. The constrained ring formed between the C═C bond and the PB reagent is more susceptible to fragmentation by collision-induced dissociation, which facilitates identification of the C═C position within the fatty acyl tails of lipids. Although the original PB reaction using acetone had a low yield of derivatized lipids and therefore a low yield of diagnostic ions, a new generation of PB reagents based on halogenated acetophenones has improved the reaction yield substantially. In this study, we investigated the use of halogenated PB reagents and ion mobility to improve the identification of PB-derivatized lipids by shifting them out of the densely populated lipid region of ion mobility-mass spectrometry (IM-MS) space. Several halogenated PB reagents containing fluorine, chlorine and bromine were investigated for their ability to decrease the collision cross-section (CCS) values of derivatized lipids and yield sufficient intensity for both the derivatized lipid and its diagnostic ions. We found that 4'-chloro-2',6'-difluoroacetophenone (CDFAP) displayed the best performance, with an average decrease in CCS of 4.4% and yield of derivatized lipids and diagnostic ions comparable to the trifluorinated acetophenone reagent proposed by the Xia group. The unique isotope pattern resulting from the chlorine substituent aided in identification of the derivatized lipids and their diagnostic ions, as well. We further demonstrate that derivatization with CDFAP preserves the separation of lipids classes in IM-MS space.
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Affiliation(s)
- Hannah M Hynds
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Kelly M Hines
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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11
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Wang DH, Vidovic D, McKay AI, Darwish T, Park HG, Garza SM, Shields SW, Brodbelt JS, Wang Z, Lacombe RJS, Shmanai VV, Lysenko IL, Bekish AV, Schmidt K, Redfield C, Brenna JT, Shchepinov MS. Quantitative High-Field NMR- and Mass Spectrometry-Based Fatty Acid Sequencing Reveals Internal Structure in Ru-Catalyzed Deuteration of Docosahexaenoic Acid. Anal Chem 2022; 94:12971-12980. [PMID: 36098546 DOI: 10.1021/acs.analchem.2c00923] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ru-based catalysis results in highly unsaturated fatty acid (HUFA) ethyl esters (EE) deuterated to various extents. The products carry 2H (D) mainly at their bis-allylic positions, where they are resistant to autoxidation compared to natural HUFA and are promising as neurological and retinal drugs. We characterized the extent of deuteration at each allylic position of docosa-4,7,10,13,16,19-hexaenoic acid deuterated to completion at bis-allylic and allylic positions (D-DHA) by two-dimensional (2D) and high-field (600 and 950 MHz) NMR. In separate experiments, the kinetics of docosahexaenoic acid (DHA) EE deuteration was evaluated using Paternò-Büchi (PB) reaction tandem mass spectrometry (MS/MS) analysis, enabling deuteration to be quantitatively characterized for isotopologues (D0-D14 DHA) at each internal allylic position. NMR analysis shows that the net deuteration of the isotopologue mixture is about 94% at the bis-allylic positions, and less than 1% remained as the protiated -CH2-. MS analysis shows that deuteration kinetics follow an increasing curve at bis-allylic positions with higher rate for internal bis-allylic positions. Percent D of bis-allylic positions increases linearly from D1 to D9 in which all internal bis-allylic positions (C9, C12, C15) deuterate uniformly and more rapidly than external bis-allylic positions (C6, C18). The mono-allylic positions near the methyl end (C21) show a steep increase of D only after the D10 isotopologue has been deuterated to >90%, while the mono-allylic position near the carboxyl position, C3, deuterates last and least. These data establish detailed methods for the characterization of Ru-catalyzed deuteration of HUFA as well as the phenomenological reaction kinetics as net product is formed.
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Affiliation(s)
- Dong Hao Wang
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States
- Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States
| | - Dragoslav Vidovic
- School of Chemistry, Monash University, Clayton, Victoria 3800 Australia
| | - Alasdair I McKay
- School of Chemistry, Monash University, Clayton, Victoria 3800 Australia
| | - Tamim Darwish
- National Deuteration Facility-ANSTO, Sydney, New Illawarra Rd, Lucas Heights, NSW 2234, Australia
| | - Hui Gyu Park
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States
- Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States
| | - Secilia Martinez Garza
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712 United States
| | - Samuel W Shields
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712 United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712 United States
| | - Zhen Wang
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States
- Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States
| | - R J Scott Lacombe
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States
| | - Vadim V Shmanai
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, 13 Surganova Street, Minsk 220072, Belarus
| | - Ivan L Lysenko
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, 13 Surganova Street, Minsk 220072, Belarus
| | - Andrei V Bekish
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, 13 Surganova Street, Minsk 220072, Belarus
| | | | - Christina Redfield
- Dept of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K
| | - J Thomas Brenna
- Dell Pediatric Research Institute, Departments of Pediatrics, of Chemistry, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, Texas 78723, United States
- Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712 United States
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12
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Tang S, Chen X, Ke Y, Wang F, Yan X. Voltage-Controlled Divergent Cascade of Electrochemical Reactions for Characterization of Lipids at Multiple Isomer Levels Using Mass Spectrometry. Anal Chem 2022; 94:12750-12756. [PMID: 36087069 PMCID: PMC10386884 DOI: 10.1021/acs.analchem.2c02375] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cascading divergent reactions in a single system is highly desirable for their intrinsic efficiency and potential to achieve multilevel structural characterization of complex biomolecules. In this work, two electrochemical reactions, interfacial electro-epoxidation and cobalt anodic corrosion, are divergently cascaded in nanoelectrospray (nESI) and can be switched at different voltages. We applied these reactions to lipid identification at multiple isomer levels using mass spectrometry (MS), which remains a great challenge in structural lipidomics. The divergent cascade reactions in situ derivatize lipids to produce epoxidized lipids and cobalt-adducted lipids at different voltages. These lipids are then fragmented upon low-energy collision-induced dissociation (CID), generating diagnostic fragments to indicate C═C locations and sn-positions that cannot be achieved by the low-energy CID of native lipids. We have demonstrated that lipid structural isomers show significantly different profiles in the analysis of healthy and cancerous mouse prostate samples using this strategy. The application of divergent cascade reactions in lipid identification allows the four-in-one analysis of lipid headgroups, fatty acyl chains, C═C locations, and sn-positions simply by tuning the nESI voltages within a single experiment. This feature as well as its low sample consumption, no need for an extra apparatus, and quantitative analysis capability show its great potential in lipidomics.
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Affiliation(s)
- Shuli Tang
- Department of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
| | - Xi Chen
- Department of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
| | - Yuepeng Ke
- Center for Translational Cancer Research, Texas A&M Institute of Biosciences and Technology, Texas A&M University, Houston, Texas 77030, United States
| | - Fen Wang
- Center for Translational Cancer Research, Texas A&M Institute of Biosciences and Technology, Texas A&M University, Houston, Texas 77030, United States
| | - Xin Yan
- Department of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
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13
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Schmitz OJ, Meckelmann S, Wittenhofer P, Tštsch K. Supercritical Fluid Chromatography Coupled with Drift Time Ion Mobility Quadrupole Time-of-Flight Mass Spectrometry as a Tool for Lipid Characterization of HepG2 Cells. LCGC EUROPE 2022. [DOI: 10.56530/lcgc.eu.xq5675w3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Lipidomic studies are often conducted using shotgun mass spectrometry (MS) or reversed-phase liquid chromatography coupled with MS (LC–MS). However, chromatographic separation offers several advantages such as an additional identification parameter (retention time), lower ion suppression, and separation of isobaric species. In contrast, quantification is more difficult because ion suppression is not the same over the whole analysis, and as a consequence more standards are needed to compensate for this. Supercritical fluid chromatography (SFC) offers orthogonal separation compared to reversed-phase LC. While the separation of lipids in reversed-phase LC is mainly based on the length of the carbon chain and the number of double bonds, lipids in SFC are mainly separated according to their lipid classes, which simplifies quantification with standards. In this study, SFC coupled with drift time ion mobility quadrupole time-of-flight mass spectrometry (DTIMS-QTOF-MS)was used to characterize the HepG2 lipidome.
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14
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Zhang W, Jian R, Zhao J, Liu Y, Xia Y. Deep-lipidotyping by mass spectrometry: recent technical advances and applications. J Lipid Res 2022; 63:100219. [PMID: 35489417 PMCID: PMC9213770 DOI: 10.1016/j.jlr.2022.100219] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/18/2022] Open
Abstract
In-depth structural characterization of lipids is an essential component of lipidomics. There has been a rapid expansion of mass spectrometry methods that are capable of resolving lipid isomers at various structural levels over the past decade. These developments finally make deep-lipidotyping possible, which provides new means to study lipid metabolism and discover new lipid biomarkers. In this review, we discuss recent advancements in tandem mass spectrometry (MS/MS) methods for identification of complex lipids beyond the species (known headgroup information) and molecular species (known chain composition) levels. These include identification at the levels of carbon-carbon double bond (C=C) location and sn-position as well as characterization of acyl chain modifications. We also discuss the integration of isomer-resolving MS/MS methods with different lipid analysis workflows and their applications in lipidomics. The results showcase the distinct capabilities of deep-lipidotyping in untangling the metabolism of individual isomers and sensitive phenotyping by using relative fractional quantitation of the isomers.
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Affiliation(s)
- Wenpeng Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, P. R. China
| | - Ruijun Jian
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
| | - Jing Zhao
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
| | - Yikun Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, P. R. China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biological, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China.
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15
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Zhang B, Wang Y, Zhou BW, Cheng J, Xu Q, Zhang L, Sun TQ, Zhang J, Guo YL. Chloramine-T-Enabled Mass Spectrometric Analysis of C═C Isomers of Unsaturated Fatty Acids and Phosphatidylcholines in Human Thyroids. Anal Chem 2022; 94:6216-6224. [PMID: 35420783 DOI: 10.1021/acs.analchem.1c05607] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Specific locations of carbon-carbon double bonds (C═C) in lipids often play an essential role in biological processes, and there has been a booming development in C═C composition analysis by mass spectrometry. However, a universal derivatization and fragmentation pattern for the annotation of C═C positions in lipids is still challenging and attractive. To expand this field in lipidomics, a flexible and convenient N-tosylaziridination method was developed, with high derivatization efficiency, sensitivity, and specificity. The derivatization was very fast (15 s), and C═C numbers as well as locations could be pinpointed specifically in tandem mass spectra. By qualitative and quantitative studies of paratumor and tumor thyroid tissues of human beings, the total content of unsaturated fatty acids was suggested to be increased in tumor tissues, and good correlations in and between lysophosphatidylcholines and phosphatidylcholines were revealed by Spearman analysis. Further studies of C═C isomers showed that n-6/n-3 ratios were closely associated with human thyroid tumorigenesis, and high ratios of n-6/n-3 isomers seemed to suffer a high risk of carcinogenesis. Other isomers were not very representative; however, C═C in n-9/n-7 could also be significant for oncology research. Generally, it is supposed that both total amounts and C═C isomer ratios were related to cancer, and N-tosylaziridine derivatization could provide an alternative strategy for the C═C isomer study of disease models.
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Affiliation(s)
- Bo Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yunjun Wang
- Department of Head and Neck Surgery, Department of Oncology, Shanghai Medical College, Fudan University Shanghai Cancer Center, Fudan University, 270 Dongan Road, Shanghai 200032, China
| | - Bo-Wen Zhou
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jie Cheng
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Qi Xu
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Li Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Tuan-Qi Sun
- Department of Head and Neck Surgery, Department of Oncology, Shanghai Medical College, Fudan University Shanghai Cancer Center, Fudan University, 270 Dongan Road, Shanghai 200032, China
| | - Jing Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yin-Long Guo
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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16
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Gazárková T, Plachká K, Svec F, Nováková L. Current state of supercritical fluid chromatography-mass spectrometry. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116544] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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17
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Wolrab D, Peterka O, Chocholoušková M, Holčapek M. Ultrahigh-Performance Supercritical Fluid Chromatography / Mass Spectrometry in the Lipidomic Analysis. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116546] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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18
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Ma X, Zhang W, Li Z, Xia Y, Ouyang Z. Enabling High Structural Specificity to Lipidomics by Coupling Photochemical Derivatization with Tandem Mass Spectrometry. Acc Chem Res 2021; 54:3873-3882. [PMID: 34570464 DOI: 10.1021/acs.accounts.1c00419] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lipids have pivotal roles in many biological processes, including energy storage, signal transduction, and plasma membrane formation. A disruption of lipid homeostasis is found to be associated with a range of diseases, such as cardiovascular diseases, diabetes, and cancer. Fundamental lipid biology and disease diagnostics can benefit from monitoring lipid changes in cells, tissues, organs, or the whole biological system. Therefore, it is important to develop lipid analysis tools to achieve comprehensive lipid characterization and quantitation. Over the past two decades, mass spectrometry (MS) has become the method of choice for qualitative and quantitative analyses of lipids, owing to its high sensitivity, multiplexed analysis, and soft ionization features. With the rapid development and adoption of ultrahigh-resolution MS, isobaric lipids can now be routinely resolved. By contrast, the structural characterization and quantitation of isomeric lipids remain an analytical challenge. Although some lipid C═C location or sn-isomers can be resolved by chromatography, ion mobility, or selective ionization approaches, a detailed structural characterization on the lipidome-wide level needs to be achieved.Over the past six years, we have successfully combined the Paternò-Büchi (PB) reaction, which is a UV-promoted photocycloaddition reaction specific to the C═C, with tandem MS (MS/MS) to locate the C═C in lipids and quantify lipid C═C location isomers. The PB reactions have analytical advantages such as a simple experimental setup, rapid lipid C═C derivatization, and highly specific C═C cleavage during PB-MS/MS to produce abundant diagnostic ions. More importantly, without a need of isomer separation or a comparison to authentic standards, PB-MS/MS can be directly applied to identify and quantify a mixture of lipid C═C location isomers, often coexisting with molar ratios sensitive to the biological state of the system. The PB-MS/MS method is compatible with conventional shotgun lipidomics employing a nanoelectrospray ionization or a large-sale lipid structural analysis via liquid chromatography (LC) coupled to any mass spectrometer with tandem MS capability. The PB-MS/MS method is highly versatile, as a variety of PB reagents can be tailored to a broad range of applications. Besides UV-promoted PB reactions, visible-light PB reactions have also been developed to offer more flexibility for a lipid analysis. By using selected PB reagents, the sn-positions of fatty acyls can be resolved together with C═C locations in phospholipids. This method has been used in lipidomic analyses of tissue, blood, and plasma from animal models and clinical samples, demonstrating the potential of using lipid C═C or sn-location isomer ratios for phenotyping and disease diagnostics. Lipid isomer-resolving MS imagings of tissues and single-cell lipid analysis have also been demonstrated by a proper implementation of PB-MS/MS.
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Affiliation(s)
- Xiaoxiao Ma
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Wenpeng Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Zishuai Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
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