bims-mascan 2025-03-30 papers

bims-mascan

Biomed News

on Mass spectrometry in cancer research

Issue of 2025–03–30
sixteen papers selected by
Giovanny Rodríguez Blanco, Uniklinikum Graz

Protocol for spatial metabolomics and isotope tracing in the mouse brain.
Novel Charge-Switch Derivatization Method Using 3-(Chlorosulfonyl)benzoic Acid for Sensitive RP-UHPLC/MS/MS Analysis of Acylglycerols, Sterols, and Prenols.
Fatty Acid Metabolism Provides an Essential Survival Signal in OxPhos and BCR DLBCL Cells.
Universal Photosensitizer for Isomer-Selective Lipid Imaging with High Molecular Coverage.
Iridium Isotope Tag-Assisted LC-MS Method for Global Profiling and Quantification of Nonvolatile Serum Fatty Acids in Nonalcoholic Fatty Liver Mice.
Full Window Data-Independent Acquisition Method for Deeper Top-Down Proteomics.
Targeting polyunsaturated fatty acids desaturase FADS1 inhibits renal cancer growth via ATF3-mediated ER stress response.
The roles of enhancer, especially super-enhancer-driven genes in tumor metabolism and immunity.
StageTip: a little giant unveiling the potential of mass spectrometry-based proteomics.
Editorial: Metabolic reprogramming in cancer.
Penalized likelihood optimization for censored missing value imputation in proteomics.
Dereplication of secondary metabolites from Sophora flavescens using an LC-MS/MS-based molecular networking strategy.
Lipid-metabolism-focused CRISPR screens identify enzymes of the mevalonate pathway as essential for prostate cancer growth.
Metabolic and lipid alterations in multiple sclerosis linked to disease severity.
Discovering Novel Short- and Medium-Chain Esters of Hydroxy Fatty Acids in Human Fecal Samples Using Untargeted Liquid Chromatography/Mass Spectrometry.
Targeted analysis of seven selected tryptophan-melatonin metabolites: Simultaneous quantification of plasma analytes using fast and sensitive UHPLC-MS/MS.

STAR Protoc. 2025 Mar 27. pii: S2666-1667(25)00122-4. [Epub ahead of print]6(2): 103716

Protocol for spatial metabolomics and isotope tracing in the mouse brain.

Watit Sontising, Francine Yanchik-Slade, Carlos Rodriguez-Navas, Md Amir Hossen, Manuel Gonzalez-Rodriguez, Jake Vaynshteyn, Shinichi Yamaguchi, Mohamed Nazim Boutaghou, Isaac Marin-Valencia.

  Mass spectrometry imaging enables high-resolution spatial chemical mapping, yet its application for dynamic analysis with tracers poses challenges. Here, we present a protocol for spatial metabolomics and isotope tracing in the mouse brain. We describe steps for tracer administration, tissue collection, and cryosectioning. We then detail procedures for matrix application, ion identification, and data analysis. This protocol delivers high-quality spatial metabolomics data and is well suited for region-specific tracing analysis in the brain.

Keywords:  mass spectrometry; metabolism; neuroscience

DOI:  https://doi.org/10.1016/j.xpro.2025.103716
Anal Chem. 2025 Mar 28.

Novel Charge-Switch Derivatization Method Using 3-(Chlorosulfonyl)benzoic Acid for Sensitive RP-UHPLC/MS/MS Analysis of Acylglycerols, Sterols, and Prenols.

Ondřej Peterka, Yasmin Kadyrbekova, Robert Jirásko, Zuzana Lásko, Bohuslav Melichar, Michal Holčapek.

Chemical derivatization involves the reaction of an analyte with a derivatization agent to modify its structure, improving the peak shape, chromatographic performance, structural analysis, ionization efficiency, and sensitivity. A novel derivatization method using 3-(chlorosulfonyl)benzoic acid is developed for the determination of monoacylglycerols, diacylglycerols, free sterols, and tocopherols using the reversed-phase ultra-high-performance liquid chromatography-tandem mass spectrometry (RP-UHPLC/MS/MS) method in the negative ion mode. The chromatographic and mass spectrometric properties of derivatized lipids are investigated by using 29 lipid standards spanning four lipid classes. The derivatization process is optimized using pooled plasma spiked by 9 internal standards, achieving an optimal yield with a reaction time of 40 min at 60 °C. The stability of the derivatives is confirmed, with short-term stability maintained for 10 h at 4 °C and long-term stability preserved for 5 days at -80 °C. The repeatability and reproducibility are verified by one/two operator(s), which underscores the simplicity and robustness of the method, and calibration curves with high linear regression coefficients illustrate the accuracy of the method. The derivatization approach, which combines RP-UHPLC/MS/MS and the use of specific fragmentation patterns, significantly reduces limits of detection, reaching 15-25 pmol/mL for free sterols in plasma. The optimized method is applied to the analysis of human plasma, leading to the identification of 92 lipid species in the targeted lipid classes. This represents a substantial improvement in sensitivity and detection capabilities compared to those of previously reported methods.

DOI: https://doi.org/10.1021/acs.analchem.4c06496
Biomedicines. 2025 Mar 13. pii: 707. [Epub ahead of print]13(3):

Fatty Acid Metabolism Provides an Essential Survival Signal in OxPhos and BCR DLBCL Cells.

Aurélie Montagne, Konstantina Kotta, Karoline Kielbassa-Elkadi, Isabelle Martins, José Ángel Martinez-Climent, Guido Kroemer, Catherine Thieblemont, Véronique Baud.

  Backgroung/objectives: Diffuse large B-cell lymphoma (DLBCL) is the most frequent subtype of malignant lymphoma and is a heterogeneous disease with various gene and chromosomal abnormalities. The development of novel therapeutic treatments has improved DLBCL prognosis, but patients with early relapse or refractory disease have a poor outcome (with a mortality of around 40%). Metabolic reprogramming is a hallmark of cancer cells. Fatty acid (FA) metabolism is frequently altered in cancer cells and recently emerged as a critical survival path for cancer cell survival. Methods: We first performed the metabolic characterization of an extended panel of DLBCL cell lines, including lipid droplet content. Then, we investigated the effect of drugs targeting FA metabolism on DLBCL cell survival. Further, we studied how the combination of drugs targeting FA and either mitochondrial metabolism or mTOR pathway impacts on DLBCL cell death. Results: Here, we reveal, using a large panel of DLBCL cell lines characterized by their metabolic status, that targeting of FA metabolism induces massive DLBCL cell death regardless of their OxPhos or BCR/glycolytic subtype. Further, FA drives resistance of DLBCL cell death induced by mitochondrial stress upon treatment with either metformin or L-asparaginase, two FDA-approved antimetabolic drugs. Interestingly, combining inhibition of FA metabolism with that of the mTOR oncogenic pathway strongly potentiates DLBCL cell death. Conclusion: Altogether, our data highlight the central role played by FA metabolism in DLBCL cell survival, independently of their metabolic subtype, and provide the framework for the use of drugs targeting this metabolic vulnerability to overcome resistance in DLBCL patients.

Keywords:  B-cell lymphoma; DLBCL; fatty acid; metabolism; mitochondrial stress; survival

DOI:  https://doi.org/10.3390/biomedicines13030707
Anal Chem. 2025 Mar 25.

Universal Photosensitizer for Isomer-Selective Lipid Imaging with High Molecular Coverage.

Sara Amer, Daisy Unsihuay, Manxi Yang, Julia Laskin.

Spatial lipidomics is a powerful technique for understanding the complexity of the lipidome in biological systems through mass spectrometry imaging (MSI). Recent advancements have enabled isomer-selected MSI (iMSI) of lipids in biological samples using both online and off-line derivatization strategies. Despite these impressive developments, most iMSI techniques are limited to either positive or negative ion mode analysis, restricting the molecular coverage achievable in a single experiment. Additionally, derivatization efficiency often varies across lipid classes, presenting challenges for comprehensive lipid analysis. In this study, we introduce tetrakis(4-carboxyphenyl)porphyrin (TCPP) as a universal photosensitizer that facilitates online lipid derivatization in both positive and negative ionization modes via singlet oxygen (1O2) reaction. This method enables the identification and localization of both acyl chain compositions and lipid carbon-carbon (C═C) isomers in liquid extraction-based ambient ionization techniques. We have also employed sodium fluoride (NaF) as a solvent dopant to enhance the analysis of low-abundance and poorly ionizable biomolecules. By integrating these online derivatization and signal enhancement strategies with nanospray desorption electrospray ionization (nano-DESI), we achieved dual polarity iMSI within the same sample. We demonstrate imaging of low-abundance isomeric lipids, which were otherwise below the noise level. Notably, TCPP significantly enhances the efficiency of the online derivatization of unsaturated fatty acids, for which other photosensitizers are inefficient. This novel approach allows for the imaging of isomeric fatty acids and phospholipids from multiple classes in the same experiment, revealing their distinct spatial localization within biological tissues.

DOI: https://doi.org/10.1021/acs.analchem.4c05538
Anal Chem. 2025 Mar 27.

Iridium Isotope Tag-Assisted LC-MS Method for Global Profiling and Quantification of Nonvolatile Serum Fatty Acids in Nonalcoholic Fatty Liver Mice.

Yongcheng Dai, Beicheng Zhu, Xueting Yan, Xiaobo Xie, Zixuan Zhan, Yi Lv.

Highly accurate and sensitive measurements of fatty acids (FAs) in biological samples are essential for advancing our understanding of their diverse biofunctions. In this work, based on the characteristic isotope pattern of iridium (191/193Ir), we employed an iridium-encoded amine (Ir-NH2) as the derivatization reagent to establish a selective and sensitive liquid chromatography-mass spectrometry (LC-MS) method for rapid identification and accurate quantification of FAs in biological samples. Upon derivatization, nonvolatile FAs were transformed into amide derivatives tagged with a charged iridium tag, exhibiting improved sensitivity and selectivity in the electrospray ionization (ESI) positive ion mode. By leveraging the unique 2.002 Da mass shift and the 3:5 peak intensity ratio from the natural 191Ir and 193Ir isotopes, we can rapidly and efficiently screen the potential carboxyl-containing metabolites from biological samples. Compared to other existing methods, our technique offers higher sensitivity, better signal-to-noise ratio, lower detection limit (1.2-8.4 pg/mL), and easier quantification due to the clear identification of iridium-tagged derivatives. With this method, a total of 58 FAs, including both saturated and unsaturated types, were detected in mice serum lipid extracts, with carbon chain lengths varying from C9 to C24. More importantly, this method was successfully employed for global profiling of nonvolatile serum FAs from mice with nonalcoholic fatty liver disease (NAFLD), providing a novel means for detecting them and offering new avenues for exploring their functional roles and disease associations.

DOI: https://doi.org/10.1021/acs.analchem.4c05310
Anal Chem. 2025 Mar 22.

Full Window Data-Independent Acquisition Method for Deeper Top-Down Proteomics.

Chen Sun, Wenjing Zhang, Mowei Zhou, Martin Myu, Wei Xu.

Top-down proteomics (TDP) is emerging as a vital tool for the comprehensive characterization of proteoforms. However, as its core technology, top-down mass spectrometry (TDMS) still faces significant analytical challenges. While data-independent acquisition (DIA) has revolutionized bottom-up proteomics and metabolomics, they are rarely employed in TDP. The unique feature of protein ions in an electrospray mass spectrum as well as the data complexity require the development of new DIA strategies. This study introduces a machine learning-assisted Full Window DIA (FW-DIA) method that eliminates precursor ion isolation, making it compatible with a wide range of commercial mass spectrometers. Moreover, FW-DIA leverages all precursor protein ions to generate high-quality tandem mass spectra, enhancing signal intensities by ∼50-fold and protein sequence coverage by 3-fold in a modular protein analysis. The method was successfully applied to the analysis of a five-protein mixture under native conditions and Escherichia coli ribosomal proteoform characterization.

DOI: https://doi.org/10.1021/acs.analchem.4c06471
Biomed Pharmacother. 2025 Mar 22. pii: S0753-3322(25)00200-8. [Epub ahead of print]186 118006

Targeting polyunsaturated fatty acids desaturase FADS1 inhibits renal cancer growth via ATF3-mediated ER stress response.

Gioia Heravi, Zhenjie Liu, Mackenzie Herroon, Alexis Wilson, Yang-Yi Fan, Yang Jiang, Nivisa Vakeesan, Li Tao, Zheyun Peng, Kezhong Zhang, Jing Li, Robert S Chapkin, Izabela Podgorski, Wanqing Liu.

   OBJECTIVE: Fatty Acid Desaturase 1 (FADS1) is a rate-limiting enzyme controlling the bioproduction of long-chain polyunsaturated fatty acids (PUFAs). Increasing studies suggest that FADS1 is a potential cancer target. Our previous research has demonstrated the significant role of FADS1 in cancer biology and patient survival, especially in kidney cancers. We aim to explore the underlying mechanism in this study.
METHOD AND RESULTS: We found that pharmacological inhibition or knockdown of the expression of FADS1 significantly reduced the intracellular conversion of long-chain PUFAs, effectively inhibits renal cancer cell proliferation, and induces cell cycle arrest. The stable knockdown of FADS1 also significantly inhibits tumor formation in vivo. Mechanistically, we showed that while FADS1 inhibition induces endoplasmic reticulum (ER) stress, FADS1 expression is augmented by ER-stress inducer, suggesting a necessary role of PUFA production in response to ER stress. FADS1-inhibition sensitized cellular response to ER stress inducers, leading to cell apoptosis. Also, FADS1 inhibition-induced ER stress leads to activation of the PERK/eIF2α/ATF4/ATF3 pathway. Inhibiting PERK or knockdown of ATF3 rescued FADS1 inhibition-induced ER stress and cell growth suppression, while ATF3-overexpression aggravates the FADS1 inhibition-induced cell growth suppression and leads to cell death. Metabolomic analysis revealed that FADS1 inhibition results in decreased level of UPD-N-Acetylglucosamine, a critical mediator of the unfolded protein response, as well as impaired biosynthesis of nucleotides, possibly accounting for the cell cycle arrest.
CONCLUSION: Our findings suggest that PUFA desaturation is crucial for rescuing cancer cells from persistent ER stress, supporting FADS1 as a new therapeutic target.

Keywords:  ATF3; ER stress; FADS1; Kidney cancer; PUFA

DOI:  https://doi.org/10.1016/j.biopha.2025.118006
Int J Biol Macromol. 2025 Mar 23. pii: S0141-8130(25)02966-6. [Epub ahead of print]308(Pt 1): 142414

The roles of enhancer, especially super-enhancer-driven genes in tumor metabolism and immunity.

Songyue Guo, Lu Zhang, Jiao Ren, Zhong Lu, Xiaolin Ma, Xinling Liu, Hongchuan Jin, Jiaqiu Li.

  Abnormal metabolism is a characteristic of malignant tumors. Numerous factors play roles in the regulation of tumor metabolism. As epigenetic regulators, enhancers, especially the super-enhancers (SEs), serve as platforms for transcription factors that regulate the expression of metabolism-related enzymes or transporters at the gene level. In this study, we review the effects of enhancer/ SE-driven genes on tumor metabolism and immunity. Enhancers/SEs play regulatory roles in glucose metabolism (glycolysis, gluconeogenesis, tricarboxylic acid (TCA) cycle, pyruvate, and pentose phosphate pathway, lipid metabolism (cholesterol, fatty acid, phosphatide, and sphingolipid), and amino acid metabolism (glutamine, tryptophan, arginine, and cystine). By regulating tumor metabolism, enhancers and SEs can reprogram tumor microenvironment, especially the status of various immune cells. Therefore, interfering enhancers/SEs that regulate the tumor metabolism is likely to enhance the effectiveness of immunotherapy.

Keywords:  Enhancer; Super-enhancer; Tumor immunity; Tumor metabolism

DOI:  https://doi.org/10.1016/j.ijbiomac.2025.142414
Anal Sci. 2025 Mar 26.

StageTip: a little giant unveiling the potential of mass spectrometry-based proteomics.

Eisuke Kanao, Yasushi Ishihama.

  This review highlights the growing impact of StageTips (Stop and Go Extraction Tips), a pipette tip-based LC column in MS-based proteomics. By packing standard pipette tips with reversed-phase, ion-exchange, or metal oxide materials, StageTips enable efficient peptide desalting, fractionation, selective enrichment, and in-tip reactions with minimal sample loss. Recent improvements, including new resin designs and integrated workflows, have further expanded the applications to phosphoproteomics, protein terminomics, and single-cell proteomics. With their simplicity, high reproducibility, and low cost, StageTips offer a versatile platform that can be seamlessly integrated into automated pipelines, increasing the throughput and the depth of proteome analysis. As materials and protocols continue to evolve, StageTips will continue to develop as an essential keystone for robust sample preparation in next-generation proteomics research.

Keywords:  LC/MS/MS; Proteomics; Sample preparation; StageTip

DOI:  https://doi.org/10.1007/s44211-025-00749-1
Front Pharmacol. 2025 ;16 1583986

Editorial: Metabolic reprogramming in cancer.

Valentina Audrito, Elisa Giovannetti.



Keywords:  cancer; metabolic pathways; metabolic plasticity; metabolic reprogramming; metabolites; tumor microenvironment; tumorigenesis

DOI:  https://doi.org/10.3389/fphar.2025.1583986
Biostatistics. 2024 Dec 31. pii: kxaf006. [Epub ahead of print]26(1):

Penalized likelihood optimization for censored missing value imputation in proteomics.

Lucas Etourneau, Laura Fancello, Samuel Wieczorek, Nelle Varoquaux, Thomas Burger.

  Label-free bottom-up proteomics using mass spectrometry and liquid chromatography has long been established as one of the most popular high-throughput analysis workflows for proteome characterization. However, it produces data hindered by complex and heterogeneous missing values, which imputation has long remained problematic. To cope with this, we introduce Pirat, an algorithm that harnesses this challenge using an original likelihood maximization strategy. Notably, it models the instrument limit by learning a global censoring mechanism from the data available. Moreover, it estimates the covariance matrix between enzymatic cleavage products (ie peptides or precursor ions), while offering a natural way to integrate complementary transcriptomic information when multi-omic assays are available. Our benchmarking on several datasets covering a variety of experimental designs (number of samples, acquisition mode, missingness patterns, etc.) and using a variety of metrics (differential analysis ground truth or imputation errors) shows that Pirat outperforms all pre-existing imputation methods. Beyond the interest of Pirat as an imputation tool, these results pinpoint the need for a paradigm change in proteomics imputation, as most pre-existing strategies could be boosted by incorporating similar models to account for the instrument censorship or for the correlation structures, either grounded to the analytical pipeline or arising from a multi-omic approach.

Keywords:  covariance matrix estimation; imputation of missing not at random values; mass spectrometry based proteomics; multi-omic imputation; penalized likelihood maximization

DOI:  https://doi.org/10.1093/biostatistics/kxaf006
Sci Rep. 2025 Mar 24. 15(1): 10148

Dereplication of secondary metabolites from Sophora flavescens using an LC-MS/MS-based molecular networking strategy.

Hua Wang, Hui Ding.

  A dereplication strategy was developed for the screening of secondary metabolites from Sophora flavescens. The strategy consisted of 4 procedures. First, the extract of the Sophora flavescens root was subjected to LC-MS/MS analysis with both data-independent acquisition (DIA) mode and data-dependent acquisition (DDA) mode. Then the DIA results were used to construct a molecular networking (MN) according to the GNPS workflow and consequently obtain annotations. In parallel, the DDA results were projected to both MN analysis and direct databases matching to obtain annotations. Finally, the isomers were discriminated and annotated by their extracted ion chromatogram. Through the combination of these approaches, a total of 51 compounds were annotated and dereplicated in the Sophora flavescens samples. The annotation results showed DIA and DDA approach are complementary to each other. MN on GNPS can overcome the challenges of trace compound identification compared to direct DB matching. This strategy provides a powerful tool for the dereplication study in plant chemistry.

Keywords:   Sophora flavescens ; Alkaloids; Dereplication; Flavonoids; Metabolites; Molecular networking

DOI:  https://doi.org/10.1038/s41598-025-94958-3
Cell Rep. 2025 Mar 26. pii: S2211-1247(25)00241-4. [Epub ahead of print]44(4): 115470

Lipid-metabolism-focused CRISPR screens identify enzymes of the mevalonate pathway as essential for prostate cancer growth.

Gio Fidelito, Izabela Todorovski, Leonie Cluse, Stephin J Vervoort, Renea A Taylor, Matthew J Watt.

  Dysregulated lipid metabolism plays an important role in prostate cancer, although the understanding of the essential regulatory processes in tumorigenesis is incomplete. We employ a CRISPR-Cas9 screen using a custom human lipid metabolism knockout library to identify essential genes for prostate cancer survival. Screening in three prostate cancer cell lines reveals 63 shared dependencies, with enrichment in terpenoid backbone synthesis and N-glycan biosynthesis. Independent knockout of key genes of the mevalonate pathway reduces cell proliferation. Further investigation focuses on NUS1, a subunit of cis-prenyltransferase required for dolichol synthesis. NUS1 knockout decreases tumor growth in vivo and viability in patient-derived xenograft (PDX)-derived organoids. Mechanistic studies reveal that loss of NUS1 promotes oxidative stress, lipid peroxidation and ferroptosis sensitivity, endoplasmic reticulum (ER) stress, and G1 cell-cycle arrest, and it dampens androgen receptor (AR) signaling, collectively leading to growth arrest. This study highlights the critical role of the mevalonate-dolichol-N-glycan biosynthesis pathway, particularly NUS1, in prostate cancer survival and growth.

Keywords:  CP: Cancer; CP: Metabolism; CRISPR screen; cancer metabolism; lipid metabolism; prostate cancer

DOI:  https://doi.org/10.1016/j.celrep.2025.115470
Mult Scler. 2025 Mar 27. 13524585251325468

Metabolic and lipid alterations in multiple sclerosis linked to disease severity.

Rezvan Noroozi, Hui-Hsin Tsai, Ketian Yu, Paola Bronson, Karunakar Samuel, Kien Trinh, Ru Wei, Ellen Tsai, Farren Bs Briggs, Pavan Bhargava, Kathryn C Fitzgerald.

   BACKGROUND: The circulating metabolome incorporates multiple levels of biological interactions and is an emerging field for biomarker discovery. However, few studies have linked metabolite levels with quantitative neurologic function assessments in people with multiple sclerosis (pwMS).
OBJECTIVES: We quantified metabolomic differences between pwMS and healthy controls (HCs) and assessed the association of metabolites with disease severity.
METHODS: We profiled 517 metabolites using liquid chromatography-mass spectrometry (Biocrates Inc.) for participants from the MS Partners Advancing Technology and Health Solutions (MS PATHS). We conducted a multicenter cross-sectional study and applied linear regression to assess the association between metabolites and neurological function measures in multiple sclerosis (MS), including walking speed, manual dexterity, and processing speed.
RESULTS: Among 1010 participants (837 MS; 71.2% relapsing-remitting MS; 173 HC; mean age: 44.5 (standard deviation (SD): 11.4); 73.9% female; 12.7% non-white), pwMS showed decreased levels of phosphatidylcholines (PCs) and different amino acids (AAs) but increased triglycerides (TGs). Metabolites showed an association with worse neurologic function; for instance, a 1-SD decrease in PC aa C36:6 was associated with 21.36% (95% confidence interval (CI): 11.07-30.46; p = 1.35E-04) slower walking speed.
CONCLUSIONS: This large study identified lipid alterations linked to MS severity. Future longitudinal studies will evaluate if these metabolite levels predict MS outcomes.

Keywords:  Multiple sclerosis; lipidomics; metabolomics; multiple sclerosis performance test; neurological function

DOI:  https://doi.org/10.1177/13524585251325468
Rapid Commun Mass Spectrom. 2025 Apr 30. 39(12): e10032

Discovering Novel Short- and Medium-Chain Esters of Hydroxy Fatty Acids in Human Fecal Samples Using Untargeted Liquid Chromatography/Mass Spectrometry.

Jayashankar Jayaprakash, Divyavani Gowda, Rachana M Gangadhara, Shalini Jain, Hariom Yadav, Siddabasave Gowda B Gowda, Shu-Ping Hui.

   RATIONALE: Exploring novel metabolites produced by host gut microbiome communication is crucial for understanding their roles in various disease pathologies. We previously uncovered a novel class of lipids, short-chain fatty acid esters of hydroxy fatty acids (SFAHFAs), in mouse fecal samples and demonstrated their promising physiological functions in mammals. However, the discovery of SFAHFAs in human samples remains unexplored.
METHODS: This study aimed to analyze the SFAHFAs and their structural analogs in human fecal samples using liquid chromatography/mass spectrometry.
RESULTS: We identified 26 isomeric lipid species, including SFAHFAs and novel medium-chain fatty acid esters of hydroxy fatty acids (MFAHFAs). The detected SFAHFAs and MFAHFAs were characterized by accurate mass measurements using MSn analysis. The results were validated by matching the mass spectral fragmentation and retention time with authentic standards. Two new MFAHFAs, enanthic acid and caprylic acid esters of long-chain hydroxy fatty acids (C24 and C26), were detected and characterized for the first time in human fecal samples. Among the 26 isomeric lipid species, SFAHFA 2:0/24:0 or 4:0/22:0 and SFAHFA 2:0/24:1 were most abundant among the saturated and unsaturated SFAHFAs, respectively.
CONCLUSIONS: This study offers the first insights into detecting and characterizing novel gut microbial lipids in human fecal samples. Further investigations are essential to recognize the metabolism and function of these lipids in the human gut.

Keywords:  LC/MS; MFAHFAs; MSn analysis; SFAHFAs; human fecal

DOI:  https://doi.org/10.1002/rcm.10032
J Chromatogr B Analyt Technol Biomed Life Sci. 2025 Feb 13. pii: S1570-0232(25)00072-8. [Epub ahead of print]1256 124520

Targeted analysis of seven selected tryptophan-melatonin metabolites: Simultaneous quantification of plasma analytes using fast and sensitive UHPLC-MS/MS.

Michal Kaleta, Bhagya S Kolitha, Ondřej Novák, Farshid Mashayekhy Rad, Jonas Bergquist, S J Kumari A Ubhayasekera.

  Tryptophan-derived metabolites, a group of neurotransmitters essential for various brain functions, play key roles in regulating mood, movement, sleep, and cognition. However, the comprehensive characterisation of tryptophan-melatonin pathway metabolites is challenging due to factors such as their structural diversity, chemical complexity, low concentrations, and instability of these metabolites. In this study, we developed and validated an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) methodology with electrospray ionisation for the simultaneous separation and quantification of tryptophan metabolites in human plasma. The analytical calibration ranges in plasma were 0.50-200 ng/mL for serotonin, 0.01-5 ng/mL for N-acetylserotonin, 0.01-20 ng/mL for tryptamine, 0.01-20 ng/mL for 6-sulfatoxymelatonin, 0.01-20 ng/mL for 6-hydroxymelatonin, 0.01-100 ng/mL for melatonin, and 0.10-20 ng/mL for N-acetyltryptamine, with correlation coefficients ranging from 0.954 for N-acetyltryptamine to 0.997 for tryptamine. The intraday and interday precision remained consistently below 15 % for all analytes. Most analytes met the accuracy criteria, except for N-acetyltryptamine at the lowest quality control level (0.2 ng/mL), where the intraday and interday accuracy were 22.4 % and 17.4 %, respectively. In conclusion, this novel method allows for rapid identification of tryptophan-melatonin pathway intermediates in less than ten minutes, including seven distinct melatonin-related analytes. This suggests that it may find use in everyday clinical and scientific endeavours.

Keywords:  Liquid chromatography; Mass spectrometry; Melatonin; Plasma; Tryptophan metabolites

DOI:  https://doi.org/10.1016/j.jchromb.2025.124520