Glycerophospholipid Classes Research Articles

Deep profiling of plasmalogens by coupling the Paternò-Büchi derivatization with tandem mass spectrometry.

Plasmalogens are a special class of glycerophospholipids characterized by a vinyl ether bond (-C = C-O-) at the sn-1 position of the glycerol backbone. Altered plasmalogen profiles have been observed in neurodegenerative diseases and cancers. Profiling of plasmalogens requires specifying the vinyl ether bond and differentiating them from various types of isobars and isomers. Herein, by coupling C = C derivatization via offline Paternò-Büchi reaction with liquid chromatography-tandem mass spectrometry, we have developed a sensitive workflow for analysis of plasmalogens from biological samples. Using bovine heart lipid extract as a model system, we profiled more than 100 distinct structures of plasmenylethanolamines (PE-Ps) and plasmenylcholines (PC-Ps) at the C = C location level, far exceeding previous reports. Analysis of human glioma and normal brain tissue samples revealed elevated n-10 C = C isomers of PE-Ps in the glioma tissue samples. These findings suggest that the developed workflow holds potential in aiding the study of altered metabolism of plasmalogens in clinical samples.

M2 tumor-associated macrophages and CXCL2 induce lipid remodeling in hepatocellular carcinoma cell lines.

Primary hepatocellular carcinoma (HCC) is one of the most common malignant tumors, but its pathogenesis remains incompletely elucidated. Recently, many studies indicated that lipid remodeling plays an important role in the occurrence and development of HCC. Furthermore, lipids have been proven to be indispensable mediators in promoting communication between tumor cells and extracellular matrix in the tumor microenvironment. Thus, this study aims to comprehensively investigate the process of lipid remodeling during HCC metastasis based on the LC-electrospray ionization-MS (LC-ESI-MS) combined with multiple reaction monitoring technology. M2 tumor-associated macrophages and the recombinant human protein CXCL2 were used to simulate the tumor microenvironment. After co-incubating SMMC7721 and MHCC97-H cell lines with M2 tumor-associated macrophages or the recombinant human protein CXCL2 for 48 h, LC-ESI-MS was used to quantify the levels of two major classes of lipid molecules, namely, glycerophospholipids and sphingolipids. Our results suggest that lipid remodeling in the tumor microenvironment may promote the migration and invasion of HCC cell lines.

Differences in metabolomic profiles of APOE4 carrier vs non‐carrier patients undergoing therapeutic plasma exchange with albumin replacement as a treatment for Alzheimer’s disease

AbstractBackgroundApolipoprotein E is the major apolipoprotein found in plasma, involved in lipid transport and metabolism. Carrying the ε4 allele of the APOE gene (ApoE4) is a risk factor for developing Alzheimer’s disease (AD) and is associated with altered plasma lipid levels and lipoprotein particle distribution. The AMBAR phase 2b/3 trial is a therapeutic approach for AD patients (MMSE:18‐26) based on a 14‐month program comprising 18 plasma‐exchange procedures with albumin replacement (PE‐Alb) to remove pathological substances from plasma, slowing AD progression. The aim of this study was to assess PE‐Alb differential effects on metabolites across the AMBAR trial between ApoE4 carriers and non‐carriers.Method442 metabolites were quantified in serum samples of 296 ApoE‐genotyped patients included in the AMBAR trial (225 PE‐Alb‐treated and 71 placebo), at 3 time‐points, using high‐throughput UHPLC‐MS (OWL‐Metabolomics, Spain). Data was stratified by ApoE4 carriers (n = 145) and non‐carriers (n = 151) and analyzed through a mixed model for repeated measures. Differences from placebo were assessed through month*treatment group interaction estimates. Reported p‐values were adjusted by Benjamini‐Hochberg procedure.ResultBaseline differences between ApoE4 carriers and non‐carriers were found according to what has been reported in the literature. In ApoE4 carriers, 29 metabolites significantly changed (Adjusted p‐value<0.05) in PE‐Alb‐treated patients compared to placebo at end of study (month 14). Eleven of them, which were in the free Fatty Acids (FA) class (6 monounsaturated‐FA, 3 polyunsaturated‐FA, 2 saturated‐FA), were down regulated. This would agree with the previously reported finding that free‐FA levels increase in blood from AD patients and participate in the pathogenesis of AD by multiple mechanisms. In Non‐carriers, 19 metabolites showed statistically significant change at month 14, 2 of them being downregulated. In both stratifications, most upregulated metabolites were in the Glycerophospholipid class (21/35) which has been reported to be decreased in AD. All other metabolites were in the Glycerolipids (4), Sphingolipids (4), Sterols (3), Bile acids (2) and Amino Acids (1) classes.ConclusionThese results demonstrate modulation of fatty acid metabolism in PE‐Alb‐treated patients from the AMBAR trial in relation to its ApoE genotype. Furthermore, treatment induced positive metabolite changes compared to placebo. These results deserve further investigation.

Plasmalogen Improves Memory Function by Regulating Neurogenesis in a Mouse Model of Alzheimer's Diseases.

Adult hippocampal neurogenesis (AHN) is associated with hippocampus-dependent cognitive function, and its initiation is attributed to neural stem cells (NSCs). Dysregulated AHN has been identified in Alzheimer's disease (AD) and may underlie impaired cognitive function in AD. Modulating the function of NSCs and stimulating AHN are potential ways to manipulate AD. Plasmalogen (PLA) are a class of cell membrane glycerophospholipids which exhibit neuroprotective properties. However, the effect of PLA on altered AHN in AD has not been investigated. In our study, PLA(10μg/mL) -attenuated Aβ (1-42) (5μM) induced a decrease in NSC viability and neuronal differentiation of NSCs, partially through regulating the Wnt/β-catenin pathway. Additionally, AD mice were supplemented with PLA (67mg/kg/day) for 6 weeks. PLA treatment improved the impaired AHN in AD mice, including increasing the number of neural stem cells (NSCs) and newly generated neurons. The memory function of AD mice was also enhanced after PLA administration. Therefore, it was summarized that PLA could regulate NSC differentiation by activating the Wnt/β-catenin pathway and ameliorate AD-related memory impairment through up-regulating AHN.

Maternal Magnolol Supplementation during Pregnancy and Lactation Promotes Antioxidant Capacity, Improves Gut Health, and Alters Gut Microbiota and Metabolites of Weanling Piglets.

Maternal nutrition exerts a profound effect on the postnatal performance of offspring, especially during the weaning period. The multifunctional bioactive component magnolol (MAG) has shown promise as a dietary supplement. This study aimed to explore the effects of maternal MAG supplementation on the antioxidant capacity, gut health, gut microbiome, and metabolome composition of weanling piglets. Fifty pregnant sows were randomly divided into two equally sized groups, the control group and the group supplemented with 100 g/t MAG during the gestation and lactation periods, and 7 days postweaning, the pups were euthanized. The microbiome and metabolome features of weanling piglet colons were compared. Our results revealed that maternal MAG supplementation modified the serum redox status of weanling piglets by decreasing malondialdehyde concentration and increasing superoxide dismutase activity and total antioxidant capacity. Moreover, the decreased indicators of diarrhea were accompanied by improved gut barrier function, in which serum diamine oxidase concentration was decreased, and expressions of zona occludens-1, claudin-1, and intestinal alkaline phosphatase were increased in the colon of weanling piglets from sows supplemented with MAG. Further analysis of the gut microbiota indicated that maternal MAG supplementation significantly increased the relative abundance of beneficial bacteria in the colon of weanling piglets, including Faecalibacterium prausnitzii and Oscillospira. Metabolome analysis identified 540 differential metabolites in the colon of piglets from MAG-fed dams, of which glycerophospholipid classes were highly correlated with progeny gut health and key beneficial bacteria. Our findings indicated that maternal MAG supplementation can improve the oxidative status and gut health of weanling piglets, possibly due to alterations in the gut microbiota and metabolites.

Component and Content of Lipid Classes and Phospholipid Molecular Species of Eggs and Body of the Vietnamese Sea Urchin Tripneustes gratilla.

Sea urchins (Tripneustes gratilla) are among the most highly prized seafood products in Vietnam because of their nutritional value and medicinal properties. In this research, lipid classes and the phospholipid (PL) molecular species compositions from the body and eggs of T. gratilla collected in Hon Tam, Nha Trang, Khanh Hoa, Vietnam, were investigated. Hydrocarbon and wax (HW), triacylglycerol (TG), mono- and diacylglycerol (MDAG), free fatty acid (FFA), sterol (ST), polar lipid (PoL), and monoalkyl-diacylglycerol are the major lipid classes. In PL, five main glycerophospholipid classes have been identified, in which 137 PL molecular species were detected in the body and eggs of T. gratilla, including 20 inositol glycerophospholipids (PI), 11 serine glycerophospholipids (PS), 22 ethanolamine glycerophospholipids (PE), 11 phosphatidic acids (PA), and 73 choline glycerophospholipids (PC). PI 18:0/20:4, PS 20:1/20:1, PE 18:1e/20:4, PA 20:1/20:1, and PC 18:0e/20:4 are the most abundant species with the highest content values of 38.65-48.19%, 42.48-44.41%, 41.21-40.03%, 52.42-52.60%, and 7.77-7.18% in each class of the body-eggs, respectively. Interestingly, PL molecules predominant in the body sample were also found in the egg sample. The molecular species with the highest content account for more than 40% of the total species in each molecular class. However, in the PC class containing 73 molecular species, the highest content species amounted to only 7.77%. For both the body and egg TL samples of the sea urchin T. gratilla, a substantial portion of C20:4n polyunsaturated fatty acid was found in PI, PE, and PC, but C16, C18, C20, and C22 saturated fatty acids were reported at low levels. The most dominant polyunsaturated fatty acid in PI, PE, and PC was tetracosapolyenoic C20, while unsaturated fatty acid C20:1 was the most dominant in PS and PA. To our knowledge, this is the first time that the chemical properties of TL and phospholipid molecular species of the PoL of Vietnamese sea urchin (T. gratilla) have been studied.

Molecular species of some glycerophospholipid classes of soft coral \(\textit{Sinularia leptoclados}\) collected in Nha Trang, Khanh Hoa

In the soft coral Sinularia leptoclados, 30 molecular species belonged to 4 glycerophospholipid classes, including 8 ethanolamine glycerophospholipid (PE), 13 choline glycerophospholipid (PC), 3 serine glycerophospholipid (PS) and 6 inositol glycerophospholipid (PI) molecular species were identified. PE 18:1e/20:4, PC 18:0e/20:4, PS 18:0e/24:5 and PI 18:0/24:5 are the most abundant species with value of 69.94%, 45.57%, 68.55% and 68.18%, respectively. The PE, PC, and PS classes are reported to contain alkylacylphospholipid; meanwhile, a considerable level of diacylphospholipid is found in PI. A large portion of C20:4n polyunsaturated fatty acid was found in PE and PC; meanwhile, C16, C18, C22, and C24 fatty acids were reported at a minor level. The most dominant polyunsaturated fatty acid in PI and PS is tetracosapolyenoic C24. In the presence of fatty acids specific for the biosynthesis of zooxanthellae18:4n and 22:6n, PC is the most influenced class by the lipid composition of symbiotic microalgae. The PC 16:0e/18:4 and PC 18:1e/22:6 molecular species with recorded content of 1.69% and 8.05% are the evidence for lipid transportation from zooxanthellae to host corals. The PE, PS, and PI classes exhibit the lipid composition of the host coral; also, they are less affected by zooxanthellae lipids.

Huangshan Maofeng Green Tea Extracts Prevent Obesity-Associated Metabolic Disorders by Maintaining Homeostasis of Gut Microbiota and Hepatic Lipid Classes in Leptin Receptor Knockout Rats.

Huangshan Maofeng green tea (HMGT) is one of the most well-known green teas consumed for a thousand years in China. Research has demonstrated that consumption of green tea effectively improves metabolic disorders. However, the underlying mechanisms of obesity prevention are still not well understood. This study investigated the preventive effect and mechanism of long-term intervention of Huangshan Maofeng green tea water extract (HTE) on obesity-associated metabolic disorders in leptin receptor knockout (Lepr−/−) rats by using gut microbiota and hepatic lipidomics data. The Lepr−/− rats were administered with 700 mg/kg HTE for 24 weeks. Our results showed that HTE supplementation remarkably reduced excessive fat accumulation, as well as ameliorated hyperlipidemia and hepatic steatosis in Lepr−/− rats. In addition, HTE increased gut microbiota diversity and restored the relative abundance of the microbiota responsible for producing short chain fatty acids, including Ruminococcaceae, Faecalibaculum, Veillonellaceae, etc. Hepatic lipidomics analysis found that HTE significantly recovered glycerolipid and glycerophospholipid classes in the liver of Lepr−/− rats. Furthermore, nineteen lipid species, mainly from phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), and triglycerides (TGs), were significantly restored increases, while nine lipid species from TGs and diglycerides (DGs) were remarkably recovered decreases by HTE in the liver of Lepr−/− rats. Our results indicated that prevention of obesity complication by HTE may be possible through maintaining homeostasis of gut microbiota and certain hepatic lipid classes.

Formation of N-acyl-phosphatidylethanolamines by cytosolic phospholipase A2ε in an ex vivo murine model of brain ischemia

N-Acyl-phosphatidylethanolamines (NAPEs), a minor class of membrane glycerophospholipids, accumulate along with their bioactive metabolites, N-acylethanolamines (NAEs) during ischemia. NAPEs can be formed through N-acylation of phosphatidylethanolamine by cytosolic phospholipase A2ε (cPLA2ε, also known as PLA2G4E) or members of the phospholipase A and acyltransferase (PLAAT) family. However, the enzyme responsible for the NAPE production in brain ischemia has not yet been clarified. Here, we investigated a possible role of cPLA2ε using cPLA2ε-deficient (Pla2g4e−/−) mice. As analyzed with brain homogenates of wild-type mice, the age dependency of Ca2+-dependent NAPE-forming activity showed a bell-shape pattern being the highest at the first week of postnatal life, and the activity was completely abolished in Pla2g4e−/− mice. However, liquid chromatography-tandem mass spectrometry revealed that the NAPE levels of normal brain were similar between wild-type and Pla2g4e−/− mice. In contrast, post-mortal accumulations of NAPEs and most species of NAEs were only observed in decapitated brains of wild-type mice. These results suggested that cPLA2ε is responsible for Ca2+-dependent formation of NAPEs in the brain as well as the accumulation of NAPEs and NAEs during ischemia, while other enzyme(s) appeared to be involved in the maintenance of basal NAPE levels.

Role of autophagy in lysophosphatidylcholine-induced apoptosis in mouse Leydig cells.

Lysophosphatidylcholine (LPC), a major class of glycerophospholipids ubiquitously present in most tissues, plays a dominant role in many diseases, while it is still unknown about the potential mechanism of LPC affecting the testicular Leydig cells. In the present study, mouse TM3 Leydig cells in vitro were treated with LPC for 48 h. LPC was found to significantly induce apoptosis and oxidative stress of mouse TM3 Leydig cells; while inhibition of oxidative stress by N-acetyl-L-cysteine, an inhibitor of oxidative stress, could rescue the induction of apoptosis, indicating that LPC induced apoptosis of mouse TM3 Leydig cells via oxidative stress. Interestingly, LPC was showed to inhibit autophagy; however, induction of autophagy by rapamycin significantly alleviated the induction of apoptosis by LPC. Taken together, oxidative stress was involved in LPC-induced apoptosis of mouse TM3 Leydig cells, and autophagy might play a protective role in LPC-induced apoptosis.

A Metabolomic Approach and Traditional Physical Assessments to Compare U22 Soccer Players According to Their Competitive Level.

Simple SummaryDifferent physical tests are applied in the sports context for athlete selection and training prescriptions. Recently, the metabolomics approach has been used to understand biological systems; it has shown high potential to answer integrated questions, including with regard to soccer. Our study is the first to combine traditional physical assessment protocols with metabolomics to detail and compare the physiological profiles of two soccer teams (under-22 soccer players) at different competitive levels. Using anthropometric measurements and the critical velocity model, no differences were observed between elite and non-elite soccer players. However, the metabolomic analysis was able to differentiate among the fasting serum metabolic profiles of athletes of different competitive levels. Our results suggest that the application of metabolomics combined with traditional physical assessment protocols can improve characterizations of athletes, strengthening the differentiation of the physiological profiles of soccer teams. Thus, the metabolomic approach can contribute by offering additional data in individual characterizations of athletes, improving training programs, and consequently, increasing the performance of players during competitions.The purpose of this study was to use traditional physical assessments combined with a metabolomic approach to compare the anthropometric, physical fitness level, and serum fasting metabolic profile among U22 soccer players at different competitive levels. In the experimental design, two teams of male U22 soccer were evaluated (non-elite = 20 athletes, competing in a regional division; elite = 16 athletes, competing in the first division of the national U22 youth league). Earlobe blood samples were collected, and metabolites were extracted after overnight fasting (12 h). Untargeted metabolomics through Liquid Chromatograph Mass Spectrometry (LC-MS) analysis and anthropometric evaluation were performed. Critical velocity was applied to determine aerobic (CV) and anaerobic (ARC) capacity. Height (non-elite = 174.4 ± 7.0 cm; elite = 176.5 ± 7.0 cm), body mass index (non-elite = 22.1 ± 2.4 kg/m2; elite = 21.9 ± 2.3 kg/m2), body mass (non-elite = 67.1 ± 8.8 kg; elite = 68.5 ± 10.1 kg), lean body mass (non-elite = 59.3 ± 7.1 kg; elite = 61.1 ± 7.9 kg), body fat (non-elite = 7.8 ± 2.4 kg; elite = 7.3 ± 2.4 kg), body fat percentage (non-elite = 11.4 ± 2.4%; elite = 10.5 ± 1.7%), hematocrit (non-elite = 50.2 ± 4.0%; elite = 51.0 ± 4.0%), CV (non-elite = 3.1 ± 0.4 m/s; elite = 3.0 ± 0.2 m/s), and ARC (non-elite = 129.6 ± 55.7 m; elite = 161.5 ± 61.0 m) showed no significant differences between the elite and non-elite teams, while the multivariate Partial Least Squares Discriminant Analysis (PLS-DA) model revealed a separation between the elite and non-elite athletes. Nineteen metabolites with importance for projection (VIP) >1.0 were annotated as belonging to the glycerolipid, sterol lipid, fatty acyl, flavonoid, and glycerophospholipid classes. Metabolites with a high relative abundance in the elite group were related in the literature to a better level of aerobic power, greater efficiency in the recovery process, and improvement of mood, immunity, decision making, and accuracy, in addition to acting in mitochondrial preservation and electron transport chain maintenance. In conclusion, although classical physical assessments were not able to distinguish the teams at different competitive levels, the metabolomics approach successfully indicated differences between the fasting metabolic profiles of elite and non-elite teams.

Isomeric lipid signatures reveal compartmentalized fatty acid metabolism in cancer

The cellular energy and biomass demands of cancer drive a complex dynamic between uptake of extracellular FAs and their de novo synthesis. Given that oxidation of de novo synthesized FAs for energy would result in net-energy loss, there is an implication that FAs from these two sources must have distinct metabolic fates; however, hitherto, all FAs have been considered part of a common pool. To probe potential metabolic partitioning of cellular FAs, cancer cells were supplemented with stable isotope-labeled FAs. Structural analysis of the resulting glycerophospholipids revealed that labeled FAs from uptake were largely incorporated to canonical (sn-) positions on the glycerol backbone. Surprisingly, labeled FA uptake also disrupted canonical isomer patterns of the unlabeled lipidome and induced repartitioning of n-3 and n-6 PUFAs into glycerophospholipid classes. These structural changes support the existence of differences in the metabolic fates of FAs derived from uptake or de novo sources and demonstrate unique signaling and remodeling behaviors usually hidden from conventional lipidomics.

Essential role of a conserved aspartate for the enzymatic activity of plasmanylethanolamine desaturase

Plasmalogens are an abundant class of glycerophospholipids in the mammalian body, with special occurrence in the brain and in immune cell membranes. Plasmanylethanolamine desaturase (PEDS1) is the final enzyme of plasmalogen biosynthesis, which introduces the characteristic 1-O-alk-1′-enyl double bond. The recent sequence identification of PEDS1 as transmembrane protein 189 showed that its protein sequence is related to a special class of plant desaturases (FAD4), with whom it shares a motif of 8 conserved histidines, which are essential for the enzymatic activity. In the present work, we wanted to gain more insight into the sequence–function relationship of this enzyme and mutated to alanine additional 28 amino acid residues of murine plasmanylethanolamine desaturase including those 20 residues, which are also totally conserved—in addition to the eight-histidine-motif—among the animal PEDS1 and plant FAD4 plant desaturases. We measured the enzymatic activity by transient transfection of tagged murine PEDS1 expression clones to a PEDS1-deficient human HAP1 cell line by monitoring of labeled plasmalogens formed from supplemented 1-O-pyrenedecyl-sn-glycerol in relation to recombinant protein expression. Surprisingly, only a single mutation, namely aspartate 100, led to a total loss of PEDS1 activity. The second strongest impact on enzymatic activity had mutation of phenylalanine 118, leaving only 6% residual activity. A structural model obtained by homology modelling to available structures of stearoyl-CoA reductase predicted that this aspartate 100 residue interacts with histidine 96, and phenylalanine 118 interacts with histidine 187, both being essential histidines assumed to be involved in the coordination of the di-metal center of the enzyme.

Metabolomic analysis reveals potential biomarkers and the underlying pathogenesis involved in Mycoplasma pneumoniae pneumonia

ABSTRACT Although previous studies have reported the use of metabolomics for infectious diseases, little is known about the potential function of plasma metabolites in children infected with Mycoplasma pneumoniae (MP). Here, a combination of liquid chromatography-quadrupole time-of-flight mass spectrometry and random forest-based classification model was used to provide a broader range of applications in MP diagnosis. In the training cohort, plasma from 63 MP pneumonia children (MPPs), 37 healthy controls (HC) and 29 infectious disease controls (IDC) was collected. After multivariate analyses, 357 metabolites were identified to be differentially expressed among MPP, HC and IDC groups, and 3 metabolites (568.5661, 459.3493 and 411.3208) had high diagnostic values. In an independent cohort with 57 blinded subjects, samples were successfully classified into different groups, demonstrating the reliability of these biomarkers for distinguishing MPPs from controls. A metabolomic signature analysis identified major classes of glycerophospholipids, sphingolipids and fatty acyls were increased in MPPs. These markedly altered metabolites are mainly involved in glycerophospholipid and sphingolipid metabolism. As the ubiquitous building blocks of eukaryotic cell membranes, dysregulated lipid metabolism indicates damage of the cellular membrane and the activation of immunity in MPPs. Moreover, lipid metabolites, differentially expressed between severe and mild MPPs, were correlated with the markers of extrapulmonary complications, suggesting that they may be involved in MPP disease severity. These findings may offer new insights into biomarker selection and the pathogenesis of MPP in children.

Glycerophospholipidomics of Five Edible Oleaginous Microgreens.

Microgreens are a special type of vegetal product, born as a culinary novelty (traditionally used to garnish gourmet dishes) and then progressively studied for their potentially high content in nutraceuticals, like polyphenolic compounds, carotenoids, and glucosinolates, also in the perspective of implementing their cultivation in space stations/colonies. Among further potential nutraceuticals of microgreens, lipids have received very limited attention so far. Here, glycerophospholipids contained in microgreens of typical oleaginous plants, namely, soybean, chia, flax, sunflower, and rapeseed, were studied using hydrophilic interaction liquid chromatography (HILIC), coupled to high-resolution Fourier transform mass spectrometry (FTMS) or low-resolution collisionally induced dissociation tandem mass spectrometry (CID-MS2) with electrospray ionization (ESI). Specifically, this approach was employed to obtain qualitative and quantitative profiling of the four main classes of glycerophospholipids (GPL) found in the five microgreens, i.e., phosphatidylcholines (PC), phosphatidylethanolamines (PE), phosphatidylglycerols (PG), and phosphatidylinositols (PI). Saturated chains with 16 and 18 carbon atoms and unsaturated 18:X (with X = 1-3) chains emerged as the most common fatty acyl substituents of those GPL; a characteristic 16:1 chain (including a C═C bond between carbon atoms 3 and 4) was also found in some PG species. Among polyunsaturated acyl chains, the 18:3 one, likely referred mainly to α-linolenic acid, exhibited a relevant incidence, with the highest estimated amount (corresponding to 160 mg per 100 g of lyophilized vegetal tissue) found for chia. This outcome opens interesting perspectives for the use of oleaginous microgreens as additional sources of essential fatty acids, especially in vegetarian/vegan diets.

Enhanced Characterization of Cardiolipins via Hybrid 193 nm Ultraviolet Photodissociation Mass Spectrometry.

Cardiolipins (CLs) constitute a structurally complex class of glycerophospholipids with a unique tetraacylated structure accompanied by distinctive functional roles. Aberrations in the composition of this lipid class have been associated with disease states, spurring interest in the development of new approaches to differentiate the structures of diverse CLs in complex mixtures. The structural characterization of these complex lipids using conventional methods, however, suffers from limited resolution and frequently proves unable to discern subtle yet biologically significant features such as unsaturation sites or acyl chain position assignments. Here, we describe the synergistic use of chemical derivatization and hybrid dissociation techniques to characterize CL from complex biological mixtures with both double bond and sn positional isomer resolution in a shotgun mass spectrometry strategy. Utilizing (trimethylsilyl)diazomethane (TMSD), CL phosphate groups were methylated to promote positive-mode ionization by the production of metal-cationized lipids, enabling structural interrogation via hybrid higher-energy collisional activation/ultraviolet photodissociation (HCD/UVPD). This combination of TMSD derivatization and HCD/UVPD fragmentation results in diagnostic product ions that permit distinction and relative quantitation of sn-stereoisomers and the localization of double bonds. Applying this strategy to a total lipid extract from a thyroid carcinoma revealed a previously unreported 18:2/18:1 motif, elucidating a structural feature unique to the lipid class.

Interactions between gastric microbiota and metabolites in gastric cancer

The development and progression of gastric cancer (GC) is greatly influenced by gastric microbiota and their metabolites. Here, we characterized the gastric microbiome and metabolome profiles of 37 GC tumor tissues and matched non-tumor tissues using 16s rRNA gene sequencing and ultrahigh performance liquid chromatography tandem mass spectrometry, respectively. Microbial diversity and richness were higher in GC tumor tissues than in non-tumor tissues. The abundance of Helicobacter was increased in non-tumor tissues, while the abundance of Lactobacillus, Streptococcus, Bacteroides, Prevotella, and 6 additional genera was increased in the tumor tissues. The untargeted metabolome analysis revealed 150 discriminative metabolites, among which the relative abundance of the amino acids, carbohydrates and carbohydrate conjugates, glycerophospholipids, and nucleosides was higher in tumor tissues compared to non-tumor tissues. The targeted metabolome analysis further demonstrated that the combination of 1-methylnicotinamide and N-acetyl-D-glucosamine-6-phosphate could serve as a robust biomarker for distinction between GC tumors and non-tumor tissues. Correlation analysis revealed that Helicobacter and Lactobacillus were negatively and positively correlated with the majority of differential metabolites in the classes of amino acids, carbohydrates, nucleosides, nucleotides, and glycerophospholipids, respectively, suggesting that Helicobacter and Lactobacillus might play a role in degradation and synthesis of the majority of differential metabolites in these classes, respectively. Acinetobacter, Comamonas, Faecalibacterium, Sphingomonas, and Streptococcus were also significantly correlated with many differential amino acids, carbohydrates, nucleosides, nucleotides, and glycerophospholipids. In conclusion, the differences in metabolome profiles between GC tumor and matched non-tumor tissues may be partly due to the collective activities of Helicobacter, Lactobacillus, and other bacteria, which eventually affects GC carcinogenesis and progression.

Lipidomic Analysis of Archival Pathology Specimens Identifies Altered Lipid Signatures in Ovarian Clear Cell Carcinoma

Cancer metabolism is associated with the enhanced lipogenesis required for rapid growth and proliferation. However, the magnitude of dysregulation of diverse lipid species still requires significant characterization, particularly in ovarian clear cell carcinoma (OCCC). Here, we have implemented a robust sample preparation workflow together with targeted LC-MS/MS to identify the lipidomic changes in formalin-fixed paraffin-embedded specimens from OCCC compared to tumor-free ovarian tissue. We quantitated 340 lipid species, representing 28 lipid classes. We observed differential regulation of diverse lipid species belonging to several glycerophospholipid classes and trihexosylceramide. A number of unsaturated lipid species were increased in OCCC, whereas saturated lipid species showed a decrease in OCCC compared to the controls. We also carried out total fatty acid analysis and observed an increase in the levels of several unsaturated fatty acids with a concomitant increase in the index of stearoyl-CoA desaturase (SCD) in OCCC. We confirmed the upregulation of SCD (the rate-limiting enzyme for the synthesis of monounsaturated fatty acids) by immunohistochemistry (IHC) assays. Hence, by carrying out a mass spectrometry analysis of archival tissue samples, we were able to provide insights into lipidomic alterations in OCCC.

Changes in lipidomic profile by anti-retroviral treatment regimen: An ACTG 5257 ancillary study.

High cardiovascular disease risk in people living with HIV is partly attributed to antiretroviral therapy (ART). Lipid response to ART has been extensively studied, yet, little is known how small molecule lipids respond to Integrase inhibitor-based (INSTI-based) compared to Protease inhibitor-based (PI-based) ART regimens.Ancillary study to a phase 3, randomized, open-label trial [AIDS Clinical Trial Group A5257 Study] in treatment-naive HIV-infected patients randomized in a 1:1:1 ratio to receive ritonavir-boosted atazanavir (ATV/r), ritonavir-boosted darunavir (DRV/r) (both PI-based), or raltegravir with Tenofovir Disoproxil Fumarate-TDF plus emtricitabine (RAL, INSTI-based).We examined small molecule lipid response in a subcohort of 75 participants. Lipidomic assays of plasma samples collected pre- and post-ART treatment (48 weeks) were conducted using ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry. The effect of ART regimens was regressed on lipid species response adjusting for the baseline covariates (lipids, age, sex, race, CD4 level, BMI, and smoking). Results were validated in the Centers for AIDS Research Network of Integrated Clinical Systems study (N = 16).Out of 417 annotated lipids, glycerophospholipids (P = .007) and sphingolipids (P = .028) had a higher response to ATV/r and DRV/r compared to RAL. The lysophosphatidylcholine (LPCs(16:1),(17:1),(20:3)) and phosphophatidylcholine species (PCs(40:7),(38:4)) had an opposite response to RAL versus ATV/r in the discovery and validation cohort. The INSTI-based regimen had an opposite response of ceramide species ((d38:1), (d42:2)), PCs((35:2), (38:4)), phosphatidylethanolamines (PEs(38:4), (38:6)), and sphingomyelin(SMd38:1) species compared with the PI-based regimens. There were no differences observed between 2 PI-based regimens.We observed differences in response of small molecule lipid species by ART regimens in treatment-naive people living with HIV.

Phospholipid and n-alkane composition, anti-α-glucosidase and anti-cyclooxygenase activities of milk thistle oil

Although milk thistle oil has been authorized as a new edible oil in many countries, there is a lack of information about its chemical and biological properties. Thus, this study aimed to characterize the phospholipid and n-alkane composition as well as the α-glucosidase and cyclooxygenase inhibitory effects of milk thistle oil. The phospholipid composition of milk thistle seed oil was determined by liquid chromatography coupled to mass spectrometry HPLC–ESI–MS method and five glycerophospholipid classes were detected: phosphatidylinositol (35.8 ± 2.31%), phosphatidylcholine (29.2 ± 1.43%), phosphatidylethanolamine (15.7 ± 1.75%), phosphatidylglycerol (12.4 ± 1.61%) and phosphatidic acid (6.9 ± 0.82%). Twenty-three phospholipid molecular species were characterized, containing mainly palmitic, oleic and linoleic acids. Using gas chromatography coupled to mass spectrometry, seventeen n-alkanes were detected ranging from C14 to C35 carbon atoms. Nonacosane (13.79 ± 1.15%) was the predominant compound followed by heptacosane (9.52 ± 0.87%) and hexacosane (9.33 ± 1.21%). The carbon preference index of long-chain n-alkanes (CPI25–35) exhibited mainly odd/even predominance. The phospholipid and n-alkane composition of milk thistle oil is quite different from that of other oilseeds, indicating the possible use of those compounds as a means of determining oil authenticity. The total phenolic content of the tested oil was 10.28 ± 1.2 mg GAE/ g of oil. Furthermore, the tested oil showed moderate anti-cyclooxygenase1 capacity (IC50 = 42.3 ± 0.8 μg/mL) in comparison with the positive control aspirin. However, the inhibitory effect of milk thistle oil against α-glucosidase (IC50 = 28.4 ± 0.54 μg/mL) was similar to that of the positive control acarbose, which reveals the tested oil as a promising source of natural α-glucosidase inhibitors, proves protection against type 2 diabetes. Milk thistle oil has an excellent potential for application in the food and pharmaceutical industries.