Neutral Lipid Classes Research Articles

Patterns of Variation in the Usage of Fatty Acid Chains among Classes of Ester and Ether Neutral Lipids and Phospholipids in the Queensland Fruit Fly.

Modern lipidomics has the power and sensitivity to elucidate the role of insects' lipidomes in their adaptations to the environment at a mechanistic molecular level. However, few lipidomic studies have yet been conducted on insects beyond model species such as Drosophila melanogaster. Here, we present the lipidome of adult males of another higher dipteran frugivore, Bactrocera tryoni. We describe 421 lipids across 15 classes of ester neutral lipids and phospholipids and ether neutral lipids and phospholipids. Most of the lipids are specified in terms of the carbon and double bond contents of each constituent hydrocarbon chain, and more ether lipids are specified to this degree than in any previous insect lipidomic analyses. Class-specific profiles of chain length and (un)saturation are broadly similar to those reported in D. melanogaster, although we found fewer medium-length chains in ether lipids. The high level of chain specification in our dataset also revealed widespread non-random combinations of different chain types in several ester lipid classes, including deficits of combinations involving chains of the same carbon and double bond contents among four phospholipid classes and excesses of combinations of dissimilar chains in several classes. Large differences were also found in the length and double bond profiles of the acyl vs. alkyl or alkenyl chains of the ether lipids. Work on other organisms suggests some of the differences observed will be functionally consequential and mediated, at least in part, by differences in substrate specificity among enzymes in lipid synthesis and remodelling pathways. Interrogation of the B. tryoni genome showed it has comparable levels of diversity overall in these enzymes but with some gene gain/loss differences and considerable sequence divergence from D. melanogaster.

Efficient in vitro digestion of lipids and proteins in bovine milk fat globule membrane ingredient (MFGMi) and whey-casein infant formula with added MFGMi

The relative immaturity of the infant digestive system has the potential to affect the bioavailability of dietary lipids, proteins, and their digested products. We performed a lipidomic analysis of a commercial bovine milk fat globule membrane ingredient (MFGMi) and determined the profile of lipids and proteins in the bioaccessible fraction after in vitro digestion of both the ingredient and whey-casein-based infant formula without and with MFGMi. Test materials were digested using a static 2-phase in vitro model, with conditions simulating those in the infant gut. The extent of digestion and the bioaccessibility of various classes of neutral and polar lipids were monitored by measuring a wide targeted lipid profile using direct infusion-mass spectrometry. Digestion of abundant proteins in the ingredient and whey-casein infant formula containing the ingredient was determined by denaturing PAGE with imaging of Coomassie Brilliant Blue stained bands. Cholesterol esters, diacylglycerides, triacylglycerides, phosphatidylcholines, and phosphatidylethanolamines in MFGMi were hydrolyzed readily during in vitro digestion, which resulted in marked increases in the amounts of free fatty acids and lyso-phospholipids in the bioaccessible fraction. In contrast, sphingomyelins, ceramides, and gangliosides were largely resistant to simulated digestion. Proteins in MFGMi and the infant formulas also were hydrolyzed efficiently. The results suggest that neutral lipids, cholesterol esters, phospholipids, and proteins in MFGMi are digested efficiently during conditions that simulate the prandial lumen of the stomach and small intestine of infants. Also, supplementation of whey-casein-based infant formula with MFGMi did not appear to alter the profiles of lipids and proteins in the bioaccessible fraction after digestion.

Effect of starvation and pesticide exposure on neutral lipid composition of the digestive gland of males of the apple snails Pomacea canaliculata

Pollutants as well as starvation usually modify homeostasis of neutral lipids in aquatic organisms. However, studies on the simultaneous effects of both stressors are scarce. The aim of this study was to evaluate the effect of toxicant exposure under starvation conditions on neutral lipids of the freshwater snail Pomacea canaliculata, selected as the model organism. Starved adult male snails were exposed to sublethal concentration of the pesticide cypermethrin (100 µg/L) during 4 and 10 days. Fed snails were sacrificed at the onset of the experiment (T0), along with starved snails exposed to the pesticide vehicle (ethanol) and another group without solvent served as controls. Total lipid content, neutral lipid classes, fatty acid composition, and pesticide accumulation were determined in the digestive gland of snails. The ethanol concentration used was not an additional stressful agent. As expected, starvation caused a decrease in neutral lipid content in the digestive gland of snails with respect to T0 snails. Pesticide exposure caused, on the other hand, an increase in triacylglycerol content compared to ethanol exposure at day 10 of the bioassay. This increment correlated with the bioconcentration of cypermethrin, which was 47% higher by day 10 than by day 4. The fatty acid profile of triacylglycerols in the digestive gland was significantly altered under starvation and pesticide exposure. Stressed male snails showed the ability to preserve polyunsaturated fatty acids, as evidenced by their significant increase with respect to T0 snails. These results suggest that the alteration of lipid homeostasis could be involved in an adaptive mechanism of aquatic organisms to lipophilic and obesogenic pollutants.

Characterization and Comparison of Lipid Profiles of Selected Chicken Eggs Based on Lipidomics Approach

The present study aimed to analyze the lipid profiles of three selected chicken eggs (Nixi, silky fowl, and ordinary eggs) from the market of China by an UPLC-Q-Exactive-MS based untargeted lipidomics approach. In total, 11 classes and 285 lipid molecular species were identified from the egg yolks. Glycerophospholipids (GPLs, 6 classes, 168 lipid species) are the most abundant lipids groups, followed by sphingolipids (3 classes, 50 lipid species), and two neutral lipid classes (TG and DG). Notably, two ethersubclass of GPLs (PC-e and PE-p) and 12 species of cerebrosides were firstly detected from the chicken eggs. Furthermore, multivariate statistical analysis was performed and the lipids profiles of the three types of eggs were well discriminated from each other by 30 predominant lipids species. The characteristic lipid molecules of the different kind of eggs were also screened out. This study provides a novel insight for better understanding the lipid profiles and nutritional values of different chicken eggs.

Mitochondrial Fatty Acid β-Oxidation Disorders: From Disease to Lipidomic Studies-A Critical Review.

Fatty acid oxidation disorders (FAODs) are inborn errors of metabolism (IEMs) caused by defects in the fatty acid (FA) mitochondrial β-oxidation. The most common FAODs are characterized by the accumulation of medium-chain FAs and long-chain (3-hydroxy) FAs (and their carnitine derivatives), respectively. These deregulations are associated with lipotoxicity which affects several organs and potentially leads to life-threatening complications and comorbidities. Changes in the lipidome have been associated with several diseases, including some IEMs. In FAODs, the alteration of acylcarnitines (CARs) and FA profiles have been reported in patients and animal models, but changes in polar and neutral lipid profile are still scarcely studied. In this review, we present the main findings on FA and CAR profile changes associated with FAOD pathogenesis, their correlation with oxidative damage, and the consequent disturbance of mitochondrial homeostasis. Moreover, alterations in polar and neutral lipid classes and lipid species identified so far and their possible role in FAODs are discussed. We highlight the need of mass-spectrometry-based lipidomic studies to understand (epi)lipidome remodelling in FAODs, thus allowing to elucidate the pathophysiology and the identification of possible biomarkers for disease prognosis and an evaluation of therapeutic efficacy.

Mice with a deficiency in Peroxisomal Membrane Protein 4 (PXMP4) display mild changes in hepatic lipid metabolism

Peroxisomes play an important role in the metabolism of a variety of biomolecules, including lipids and bile acids. Peroxisomal Membrane Protein 4 (PXMP4) is a ubiquitously expressed peroxisomal membrane protein that is transcriptionally regulated by peroxisome proliferator-activated receptor α (PPARα), but its function is still unknown. To investigate the physiological function of PXMP4, we generated a Pxmp4 knockout (Pxmp4−/−) mouse model using CRISPR/Cas9-mediated gene editing. Peroxisome function was studied under standard chow-fed conditions and after stimulation of peroxisomal activity using the PPARα ligand fenofibrate or by using phytol, a metabolite of chlorophyll that undergoes peroxisomal oxidation. Pxmp4−/− mice were viable, fertile, and displayed no changes in peroxisome numbers or morphology under standard conditions. Also, no differences were observed in the plasma levels of products from major peroxisomal pathways, including very long-chain fatty acids (VLCFAs), bile acids (BAs), and BA intermediates di- and trihydroxycholestanoic acid. Although elevated levels of the phytol metabolites phytanic and pristanic acid in Pxmp4−/− mice pointed towards an impairment in peroxisomal α-oxidation capacity, treatment of Pxmp4−/− mice with a phytol-enriched diet did not further increase phytanic/pristanic acid levels. Finally, lipidomic analysis revealed that loss of Pxmp4 decreased hepatic levels of the alkyldiacylglycerol class of neutral ether lipids, particularly those containing polyunsaturated fatty acids. Together, our data show that while PXMP4 is not critical for overall peroxisome function under the conditions tested, it may have a role in the metabolism of (ether)lipids.

Incorporation of dietary lipids and fatty acids into red drum Sciaenops ocellatus eggs

Embryonic and early larval development and metabolism are fueled entirely by maternally derived nutritional resources (yolk and oil) before the onset of exogenous feeding. Composition of these maternally derived nutrients depends partly on maternal diet. Diet-egg relationships for fatty acids are well described for some species, but little is known about lipid transfer to eggs. To examine the effects of maternal diet on the egg composition, we fed adult red drum Sciaenops ocellatus six different diets, and measured lipid class and fatty acid composition of eggs they produced. Egg lipid class profiles remained relatively stable with only subtle differences in the concentrations of several lipid classes. Neutral lipid classes (wax ester/steryl ester (WE/SE), triglyceride (TG), sterol) varied more than polar lipid classes, with egg TG content being directly related to TG content of maternal diets. Dietary variations rapidly affected fatty acid composition of all major lipid classes in eggs (TG, WE/SE, phosphatidylcholine), with greater effects on neutral lipids than on the polar lipid. Results suggest a degree of maternal control over the provisioning of lipids as structural components (phospholipids) and energy substrates (neutral lipids), which may ensure proper development of larvae. But, egg fatty acid composition within lipid classes is more variable, and this may have consequences for larval survival and performance. This study also suggests that the pathways of maternal-offspring nutrient transfer are likely different for neutral and polar lipids.

TAMI-18. DIFFERENTIAL LIPID METABOLISM IN CANCER MICROENVIRONMENTS LEADS TO A REQUIREMENT FOR FATTY ACID DESATURASES FADS1 AND FADS2 IN GBM CANCER STEM CELL MAINTENANCE

Abstract Glioblastoma (GBM) is marked by cellular heterogeneity through microenvironments of a tumor, including metabolic heterogeneity. While altered cellular metabolism in cancer is well-known, how lipid metabolism is altered in different GBM microenvironmental conditions and cancer stem cell (CSC) states within a tumor remains an open question. We developed 3-dimensional GBM organoid models that mimic the transition zone between nutrient-rich cellular tumor and nutrient-poor psuedopalisading/perinecrotic tumor regions and performed spatially defined RNA-sequencing to investigate lipid metabolism. Spatial analysis revealed striking differences in metabolism between diverse cell populations from the same patient, with lipid enrichment in the hypoxic organoid cores and the pseudopalisading regions of patient tumors. This was accompanied by regionally restricted upregulation of lipid droplets and Hypoxia Inducible Lipid Droplet Associated gene expression in organoid cores and in the pseudopalisading regions of clinical GBM tumors. Using targeted lipidomic analysis, we assessed differences in acutely enriched CSC and non-CSCs from patient-derived models to explore the link between stem cell state and lipid metabolism. CSCs have low lipid droplet accumulation compared to non-CSCs in organoids and xenograft tumors, and prospectively sorted lipid-low GBM cells are functionally enriched for stem cell activity. This suggests lipid metabolism may not be simply a product of the microenvironment but also may be a reflection of cellular state. CSCs had decreased levels of major classes of neutral lipids compared to non-CSCs, but had significantly increased polyunsaturated fatty acid production due to increased expression of fatty acid desaturases FADS1 and FADS2. FADS1 and FADS2 expression are both essential to maintain CSC viability and self-renewal. Our data demonstrate that spatially and hierarchically distinct lipid metabolism phenotypes occur clinically in the majority of patients, can be recapitulated in laboratory models, and these altered lipid metabolic pathways may represent therapeutic targets for GBM.

α-Cyano-4-hydroxycinnamic Acid and Tri-Potassium Citrate Salt Pre-Coated Silicon Nanopost Array Provides Enhanced Lipid Detection for High Spatial Resolution MALDI Imaging Mass Spectrometry.

We have developed a pre-coated substrate for matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) that enables high spatial resolution mapping of both phospholipids and neutral lipid classes in positive ion mode as metal cation adducts. The MALDI substrates are constructed by depositing a layer of α-cyano-4-hydroxycinnamic acid (CHCA) and potassium salts onto silicon nanopost arrays (NAPA) prior to tissue mounting. The matrix/salt pre-coated NAPA substrate significantly enhances all detected lipid signals allowing lipids to be detected at lower laser energies than bare NAPA. The improved sensitivity at lower laser energy enabled ion images to be generated at 10 μm spatial resolution from rat retinal tissue. Optimization of matrix pre-coated NAPA consisted of testing lithium, sodium, and potassium salts along with various matrices to investigate the increased sensitivity toward lipids for MALDI IMS experiments. It was determined that pre-coating NAPA with CHCA and potassium salts before thaw-mounting of tissue resulted in a signal intensity increase of at least 5.8 ± 0.1-fold for phospholipids and 2.0 ± 0.1-fold for neutral lipids compared to bare NAPA. Pre-coating NAPA with matrix and salt also reduced the necessary laser power to achieve desorption/ionization by ∼35%. This reduced the effective diameter of the ablation area from 13 ± 2 μm down to 8 ± 1 μm, enabling high spatial resolution MALDI IMS. Using pre-coated NAPA with CHCA and potassium salts offers a MALDI IMS substrate with broad molecular coverage of lipids in a single polarity that eliminates the need for extensive sample preparation after sectioning.

Molecular Mapping of Neutral Lipids Using Silicon Nanopost Arrays and TIMS Imaging Mass Spectrometry.

We demonstrate the utility of combining silicon nanopost arrays (NAPA) and trapped ion mobility imaging mass spectrometry (TIMS IMS) for high spatial resolution and specificity mapping of neutral lipid classes in tissue. Ionization of neutral lipid species such as triglycerides (TGs), cholestryl esters (CEs), and hexosylceramides (HexCers) from biological tissues has remained a challenge for imaging applications. NAPA, a matrix-free laser desorption ionization substrate, provides enhanced ionization efficiency for the above-mentioned neutral lipid species, providing complementary lipid coverage to matrix-assisted laser desorption ionization (MALDI). The combination of NAPA and TIMS IMS enables imaging of neutral lipid species at 20 μm spatial resolution while also increasing molecular coverage greater than 2-fold using gas-phase ion mobility separations. This is a significant improvement with respect to sensitivity, specificity, and spatial resolution compared to previously reported imaging studies using NAPA alone. Improved specificity for neutral lipid analysis using TIMS IMS was shown using rat kidney tissue to separate TGs, CEs, HexCers, and phospholipids into distinct ion mobility trendlines. Further, this technology allowed for the separation of isomeric species, including mobility resolved isomers of Cer(d42:2) (m/z 686.585) with distinct spatial localizations measured in rat kidney tissue section.

Altered lipid metabolism marks glioblastoma stem and non-stem cells in separate tumor niches

Glioblastoma (GBM) displays marked cellular and metabolic heterogeneity that varies among cellular microenvironments within a tumor. Metabolic targeting has long been advocated as a therapy against many tumors including GBM, but how lipid metabolism is altered to suit different microenvironmental conditions and whether cancer stem cells (CSCs) have altered lipid metabolism are outstanding questions in the field. We interrogated gene expression in separate microenvironments of GBM organoid models that mimic the transition between nutrient-rich and nutrient-poor pseudopalisading/perinecrotic tumor zones using spatial-capture RNA-sequencing. We revealed a striking difference in lipid processing gene expression and total lipid content between diverse cell populations from the same patient, with lipid enrichment in hypoxic organoid cores and also in perinecrotic and pseudopalisading regions of primary patient tumors. This was accompanied by regionally restricted upregulation of hypoxia-inducible lipid droplet-associated (HILPDA) gene expression in organoid cores and pseudopalisading regions of clinical GBM specimens, but not lower-grade brain tumors. CSCs have low lipid droplet accumulation compared to non-CSCs in organoid models and xenograft tumors, and prospectively sorted lipid-low GBM cells are functionally enriched for stem cell activity. Targeted lipidomic analysis of multiple patient-derived models revealed a significant shift in lipid metabolism between GBM CSCs and non-CSCs, suggesting that lipid levels may not be simply a product of the microenvironment but also may be a reflection of cellular state. CSCs had decreased levels of major classes of neutral lipids compared to non-CSCs, but had significantly increased polyunsaturated fatty acid production due to high fatty acid desaturase (FADS1/2) expression which was essential to maintain CSC viability and self-renewal. Our data demonstrate spatially and hierarchically distinct lipid metabolism phenotypes occur clinically in the majority of patients, can be recapitulated in laboratory models, and may represent therapeutic targets for GBM.

Overview of Lipidomic Analysis of Triglyceride Molecular Species in Biological Lipid Extracts.

Triglyceride (TG) is a class of neutral lipids, which functions as an energy storage depot and is important for cellular growth, metabolism, and function. The composition and content of TG molecular species are crucial factors for nutritional aspects in food chemistry and are directly associated with several diseases, including atherosclerosis, diabetes, obesity, stroke, etc. As a result of the complexities of aliphatic moieties and their different connections/locations to the glycerol backbone in TG molecules, accurate identification of individual TG molecular species and quantitative assessment of TG composition and content are particularly challenging, even at the current stage of lipidomics development. Herein, methods developed for analysis of TG species, such as liquid chromatography-mass spectrometry with a variety of columns and different mass spectrometric techniques, shotgun lipidomics approaches, and ion-mobility-based analysis, are reviewed. Moreover, the potential limitations of the methods are discussed. It is our sincere hope that the overviews and discussions can provide some insights for researchers to select an appropriate approach for TG analysis and can serve as the basis for those who would like to establish a methodology for TG analysis or develop a new method when novel tools become available. Biologically accurate analysis of TG species with an enabling method should lead us toward improving the nutritional quality, revealing the effects of TG on diseases, and uncovering the underlying biochemical mechanisms related to these diseases.

Lipid Fractions, Fatty Acid Profiles, and Bioactive Compounds of Lithospermum officinale L. Seeds

AbstractSeeds of Lithospermum officinale L. from different climatic zones were analyzed for new sources of γ‐linolenic acid (GLA, 18:3n‐6) and stearidonic acid (SDA, 18:4n‐3). Cultured Borago officinalis was also analyzed for comparative purposes. Analyses were conducted for fatty acid (FA) profiles of the glyceride oils from the seeds and in the neutral and polar lipids by gas chromatography (GC); lipid classes by open column chromatography and preparative thin layer chromatography (TLC); and tocopherols, sterols, and phenolic compounds by high‐performance liquid chromatography with diode array detection (HPLC‐DAD), and the later compounds were confirmed by liquid‐chromatography‐mass spectrometry (LC–MS). L. officinale from St. Petersburg Botanical Garden showed the highest percentage of GLA (17.9% of total FA), while wild‐growing L. officinale from the Rostov region contained the highest percentage of SDA (17.2% of total FA). Total FA content ranged from 11.3 to 20.8% of seed weight. Neutral and polar lipids accounted for ~98 and 2.27%, respectively, of total lipids. Five neutral lipid classes were identified (% of NL): triterpene esters (1.3), triacylglycerols (93.1), free FA (1.8), diacylglycerols (1.4), and monoacylglycerols (2.4). The highest tocopherol content was found in samples from Chechen Republic (35.7 mg/100 g), in which the δ isomer was the main component. Samples from the Rostov region had the highest amounts of sterols (83.8 mg/100 g), and Δ5‐avenasterol was the predominant compound in all samples. L. officinale seeds contain high amounts of phenolic compounds (389.9 mg/100 g as upper limit), in which rosmarinic acid is highlighted. Overall, all data suggest the possibility of using L. officinale seed oil in pharmaceutical and cosmetic formulae and as functional food.

The Fifth WS/DGAT Enzyme of the Bacterium Marinobacter aquaeoleiVT8.

Wax esters (WE) belong to the class of neutral lipids. They are formed by an esterification of a fatty alcohol and an activated fatty acid. Dependent on the chain length and desaturation degree of the fatty acid and the fatty alcohol moiety, WE can have diverse physicochemical properties. WE derived from monounsaturated long-chain acyl moieties are of industrial interest due to their very good lubrication properties. Whereas WE were obtained in the past from spermaceti organs of the sperm whale, industrial WE are nowadays mostly produced chemically from fossil fuels. In order to produce WE more sustainably, attempts to produce industrial WE in transgenic plants are steadily increasing. To achieve this, different combinations of WE producing enzymes are expressed in developing Arabidopsis thaliana or Camelina sativa seeds. Here we report the identification and characterization of a fifth wax synthase from the organism Marinobacter aquaeolei VT8, MaWSD5. It belongs to the class of bifunctional wax synthase/acyl-CoA:diacylglycerol O-acyltransferases (WSD). The protein was purified to homogeneity. In vivo and in vitro substrate analyses revealed that MaWSD5 is able to synthesize WE but no triacylglycerols. The protein produces WE from saturated and monounsaturated mid- and long-chain substrates. Arabidopsis thaliana seeds expressing a fatty acid reductase from Marinobacter aquaeolei VT8 and MaWSD5 produce WE. Main WE synthesized are 20:1/18:1 and 20:1/20:1. This makes MaWSD5 a suitable candidate for industrial WE production in planta.

ER stress in antigen‐presenting cells promotes NKT cell activation through endogenous neutral lipids

CD1d‐restricted invariant natural killer T (iNKT) cells constitute a common glycolipid‐reactive innate‐like T‐cell subset with a broad impact on innate and adaptive immunity. While several microbial glycolipids are known to activate iNKT cells, the cellular mechanisms leading to endogenous CD1d‐dependent glycolipid responses remain largely unclear. Here, we show that endoplasmic reticulum (ER) stress in APCs is a potent inducer of CD1d‐dependent iNKT cell autoreactivity. This pathway relies on the presence of two transducers of the unfolded protein response: inositol‐requiring enzyme‐1a (IRE1α) and protein kinase R‐like ER kinase (PERK). Surprisingly, the neutral but not the polar lipids generated within APCs undergoing ER stress are capable of activating iNKT cells. These data reveal that ER stress is an important mechanism to elicit endogenous CD1d‐restricted iNKT cell responses through induction of distinct classes of neutral lipids.

Normal phase HPLC method for combined separation of both polar and neutral lipid classes with application to lipid metabolic flux

Three normal phase HPLC methods were produced to separate lipid classes on a PVA-Sil stationary phase including: 9 polar lipids (method 1); 13 combined polar and neutral lipids (method 2); and a combined method that further separates the neutral lipids into 2–4 subclasses based on the presence of fatty acids containing a polar functional group (e.g. hydroxyl) for a total of 20 lipid classes and subclasses separated in a single run (method 3). Polar lipids separated include: the phosphoglycerolipids PG, PE, PI, PS, PC and LPC; the galactoglycerolipids MGDG and DGDG; and a sulfoglycerolipid SQDG. Neutral lipids include TAG, DAG, and MAG classes and sub-classes containing 0–3, 0–2, and 0–1 hydroxy fatty acids, respectively. The hexane/isopropanol/methanol/aqueous system separates polar lipids without the use of chloroform such that it is suitable for radioactivity analysis by in-line flow scintillation counting. Each method was optimized using the natural lipid standards comprised of diverse molecular species that were detected by ELSD. All molecular species of each lipid class eluted together as single peak detected by ELSD. The methods were demonstrated to be suitable for resolving lipid extracts from animal, microbial, and plant sources as well as application to 14C based metabolic tracing of lipid metabolism in leaves and seeds.

Seed Lipids from Pulmonaria mollis Growing in Several RF Climate Zones

Lipids from seeds of Pulmonaria mollis (Boraginaceae) from two RF climate zones, i.e., Krasnodar Krai (I) and Republic of Bashkortostan (II), were characterized. The neutral lipid (NL) contents of I were greater than those of II (33.8 and 20.5%, respectively). The NL classes were characterized. A larger amount of polyunsaturated fatty acids (PUFAs) concentrated in NL and triacylglycerides (TAGs) from I and II [in NL (%, respectively): 65.6 and 65.0, including α-18:2, 28.8 and 31.9; γ-18:3, 18.5 and 14.5; α-18:3, 12.7 and 14.5; 18:4, 5.7 and 4.1; in TAG (%, respectively): 63.5 and 66.0, including α-18:2, 29.4 and 32.3; γ-18:3, 17.15 and 14.36; α-18:3, 12.5 and 14.6; 18:4, 4.5 and 4.7]. Fractions enriched in PUFAs γ-18:3 (47.1%) and 18:4 (21.2%) were obtained. The ω-6/ω-3 ratios in the lipid PUFAs were 2.7:1-2.2:1.

A normal phase high performance liquid chromatography method for the separation of hydroxy and non-hydroxy neutral lipid classes compatible with ultraviolet and in-line liquid scintillation detection of radioisotopes

In this paper, we report a method for the separation of hydroxy fatty acid and non-hydroxy fatty acid containing neutral lipid classes via normal phase HPLC with UV detection on a PVA-Sil column. The hexane/isopropanol/methanol/water based method separates all the neutral lipids in 21 min, and subsequently flushes through the polar lipids by 27 min such that prefractionation of neutral and polar lipids are not required, and the column is re-equilibrated for the next run in 15 min, for a total run time of 45 min per sample. The separation was demonstrated at both 1.0 mL/min and 1.5 mL/min for added applicability for fraction collection or inline analysis. Separation of various hydroxy fatty acid containing lipids was demonstrated from three different plant species Ricinus communis, Physaria fendleri, and engineered Arabidopsis thaliana. Additionally, we have combined this method with an in-line liquid scintillation counter for the separation and quantification of 14C labeled lipids obtained from in vivo metabolic flux experiments conducted in the developing seeds of Arabidopsis thaliana.

Lipid profiling of pre-treatment plasma reveals biomarker candidates associated with response rates and hand-foot skin reactions in sorafenib-treated patients.

Sorafenib is a multi-kinase inhibitor for treatment of advanced hepatocellular carcinoma (HCC). Beyond its clinical benefit against advanced HCC, the efficacy and safety of sorafenib chemotherapy are critical concerns. In this study, we addressed the lipid profiles associated with the efficacy and safety of sorafenib chemotherapy. Plasma samples from HCC patients before sorafenib chemotherapy (N = 44) were collected and subjected to lipidomic analysis. We measured the levels of 176 lipids belonging to 8 classes of phosphoglycerolipids, 2 classes of sphingolipids, 3 classes of neutral lipids, and 4 other classes of lipids. To characterize lipids associated with efficacy, we compared the responder group (N = 21; partial response and stable disease) with non-responder group (N = 22; progressive disease). To characterize lipids associated with hand-foot skin reaction (HFSR), we compared the susceptible group (N = 12; grade 2 and 3) with non-susceptible group (N = 32; grade 0 and 1). The levels of 8 lipids, including phosphatidylcholine (PC)[34:2], PC[34:3]a, PC[35:2], PC[36:4]a, PC[34:3e], acylcarnitine (Car)[18:0], cholesterol ester[20:2], and diacylglycerol (DG)[34:2], were significantly lower in the responder group, and 6 out of 8 these lipids contained FA(18:2). In addition, the levels of 7 lipids (Car[12:0], Car[18:0], Car[18:1], Car[20:1]and fatty acid amides (FAA[16:0], FAA[18:0], and FAA[18:1]b)) were significantly lower in the group susceptible to HFSR. Our comprehensive lipidomics study using samples from sorafenib-treated patients with HCC revealed that significant differences in the lipid profiles of pre-treatment plasma were associated with sorafenib efficacy and sorafenib-induced HFSR. Validation using another set of patient plasma samples and elucidating the molecular basis of these changes will lead to better treatment with sorafenib chemotherapy.

Lipid composition of the spores of zygomycetous and ascomycetous fungi during cessation of the exogenous dormancy state

The composition of lipids and fatty acids was studied in the spores of exogenously dormant (spores 0) and germinating (spores G) spores in distilled water for sporangiospores of zygomycetous fungi Cunninghamella echinulata VKM F-663 and Umbelopsis ramanniana VKM F-582 and for conidia of ascomycetous fungi Aspergillus tamarii VKM F-64 and A. sydowii VKM F-441. Compared to spores 0, the lipids of spores G contained higher shares of unsaturated fatty acids, lower levels of massive phospholipids (phosphatidylcholine and phosphatidylethanolamine), and elevated levels of phosphatidylglycerol and phosphatidic acid. The level of cardiolipin, the main phospholipid of the mitochondrial membranes, increased when the spores of both zygomycetes exited from the dormant state. While a certain increase in the content of free and esterified sterols in the neutral lipids of the slowly germinating U. ramanniana G spores was observed, germination of sporangiospores and conidia of the studied fungi generally did not result in significant changes in the composition of the neutral lipid classes, which may be due to the fact that they are not the major reserve mobilized at the stage of exit from the dormant state.