Improved high-fat diet-induced glucose intolerance by an oral administration of phytosphingosine

The two-way immunotoxicity in native fish induced by exudates of Microcystis aeruginosa: Immunostimulation and immunosuppression

Secondary metabolites of cyanobacterial blooms have caused serious risks to aquatic animals. The immune system is an important barrier for fish against pollutants in aquatic systems. The immunetoxic mechanism of the exudates of Microcystis aeruginosa (MaE) on fish was lacking due to the complex components of MaE. In this project, Sinocyclocheilus grahami was used as the model to study the immunotoxic effects of MaE and PHS (one of the main components of the MaE) in fish. The immunosuppression effects of MaE are mainly in, decreased head-kindey index, damaged tissue structure of head-kidney and downregulated NF-κB, IL-1β. PHS induce immunostimulation via, increasing spleen index, apparently increasing leucocytes, increasing the IgM and lysozyme levels in serum and skin mucus, upregulating protease in skin mucus, increasing pro-immunologic factors (IL-1β, IL-6, IL-8, IL-10, TNF-α and NF-κB), probably activating the TLRs/NF-κB, MAPK, FoxO1 and PPARγ signaling pathways. Therefore, our research identified potential data gaps that how the exudates of cyanobacteria induces immunostimulation and immunosuppression from immune organs level to skin mucus to blood cells to inflammatory factors to potential molecular initiating event of MaE and PHS. Further research is needed to obtain a deeper view of the molecular mechanisms involved in MaE and PHS immunotoxicity and its consequences in long-time exposures.

Searching for the primary metabolic alterations of polycystic ovary syndrome by application of the untargeted metabolomics approach

Despite a large number of studies, the pathogenesis of polycystic ovary syndrome (PCOS) still remains unexplained. In light of ambiguous observations reported in metabolomics, there is a need to carry out studies focusing on confirming the discriminating power of the proposed metabolomics biomarkers. Our research aimed to perform a validation study of metabolites detected in our previous study from serum samples, on the new set of samples obtained from PCOS women and healthy controls to confirm previously selected compounds. Additionally, the second biological matrix - urine - was used to get a more comprehensive insight into metabolic alterations. We applied two analytical techniques - gas chromatography and liquid chromatography coupled with mass spectrometry to analyze both serum and urine samples obtained from 35 PCOS patients and 35 healthy women. Thank to our approach, we identified and described a comprehensive set of metabolites altered in PCOS patients. Results of our study indicate increased steroid hormone synthesis, alteration in sphingo- and phospholipids metabolism, and disturbed fatty acids metabolism. Moreover, the citric acid cycle, γ-glutamyl cycle, vitamin B metabolism, and a few primary amino acids like tryptophan, phenylalanine, histidine, and alanine are altered.

Phytosphingosine alleviates Staphylococcus aureus-induced mastitis by inhibiting inflammatory responses and improving the blood-milk barrier in mice

Mastitis is one of the common diseases in dairy cows which threatens the health of cows and impacts on economic benefits seriously. Recent studies have been showed that Subacute Ruminal Acidosis (SARA) increased the susceptibility of cow mastitis. SARA leads the disturbance of the rumen microbiota, and the rumen bacterial disordered community is an important endogenous factor of cow mastitis. That is to say, cows which suffer from SARA have a disordered rumen microbiota, a prolonged decline in ruminal PH and a high level of lipopolysaccharide (LPS) in the rumen, blood. Therefore, ruminal metabolism is closely related to the rumen microbiota. However, the specific mechanism of SARA and mastitis still not clear. We found an intestinal metabolite according to the metabonomics, which is correlated to inflammation. Phytophingosine (PS), a product from rumen fluid and milk of the cows which suffer from SARA and mastitis. It has the effect of killing bacteria and anti-inflammatory. Emerging evidences indicate that PS can alleviate inflammatory diseases. However, how PS affects mastitis is largely unknown. In this study, we explored the concrete role of PS on Staphylococcus aureus (S. aureus) -induced mastitis in mice. We found that PS obviously decreased the level of the proinflammatory cytokines. Meanwhile, PS also significantly relieved the mammary gland inflammation caused by S. aureus and restored the function of the blood-milk barrier. Here, we showed that PS increased the expression of the classic Tight-junctions (TJs) proteins including ZO-1, Occludin and Claudin-3. Moreover, PS improves S. aureus-induced mastitis by inhibiting the activation of the NF-κB and NLRP3 signaling pathways. These data indicated that PS relieved S. aureus-induced mastitis effectively. This also provides a reference for exploring the correlation between the intestinal metabolism and inflammation.

In Vitro, In Silico and Network Pharmacology Mechanistic Approach to Investigate the α-Glucosidase Inhibitors Identified by Q-ToF-LCMS from Phaleria macrocarpa Fruit Subcritical CO2 Extract

The fruit of Phaleria macrocarpa have been traditionally used as an antidiabetic remedy in Malaysia and neighbouring countries. Despite its potential for diabetes treatment, no scientific study has ever been conducted to predict the inhibitor interaction of the protein α-glucosidase identified in an extract prepared with a non-conventional extraction technique. Hence, the major aim of this research was to evaluate the in vitro antioxidant, the α-glucosidase inhibitors, and the molecular dynamic simulations of the α-glucosidase inhibitors identified by Quadrupole Time-of-Flight Liquid Chromatography Mass Spectrometry (Q-ToF-LCMS) analysis. Initially, dry fruit were processed using non-conventional and conventional extraction methods to obtain subcritical carbon dioxide extracts (SCE-1 and SCE-2) and heating under reflux extract (HRE), respectively. Subsequently, all extracts were evaluated for their in vitro antioxidative and α-glucosidase inhibitory potentials. Subsequently, the most bioactive extract (SCE-2) was subjected to Q-ToF-LCMS analysis to confirm the presence of α-glucosidase inhibitors, which were then analysed through molecular dynamic simulations and network pharmacology approaches to confirm their possible mechanism of action. The highest inhibitory effects of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and α-glucosidase on SCE-2 was found as 75.36 ± 0.82% and 81.79 ± 0.82%, respectively, compared to the SCE-1 and HRE samples. The Q-ToF-LCMS analysis tentatively identified 14 potent α-glucosidase inhibitors. Finally, five identified compounds, viz., lupenone, swertianolin, m-coumaric acid, pantothenic acid, and 8-C-glucopyranosyleriodictylol displayed significant stability, compactness, stronger protein-ligand interaction up to 100 ns further confirming their potential as α-glucosidase inhibitors. Consequently, it was concluded that the SCE-2 possesses a strong α-glucosidase inhibitory effect due to the presence of these compounds. The findings of this study might prove useful to develop these compounds as alternative safe α-glucosidase inhibitors to manage diabetes more effectively.

Implications of endocrine-disrupting chemicals on polycystic ovarian syndrome: A comprehensive review

Polycystic ovarian syndrome (PCOS) is a complex multifactorial disorder of unknown pathogenesis in which genetic and environmental factors contribute synergistically to its phenotypic expressions. Endocrine-disrupting chemicals (EDCs), a group of widespread pollutants freely available in the environment and consumer products, can interfere with normal endocrine signals. Extensive evidence has shown that EDCs, environmental contributors to PCOS, can frequently induce ovarian and metabolic abnormalities at low doses. The current research on environmental EDCs suggests that there may be link between EDC exposure and PCOS, which calls for more human bio-monitoring of EDCs using highly sophisticated analytical techniques for the identification and quantification and to discover the underlying pathophysiology of the disease. This review briefly elaborated on the general etiology of PCOS and listed various epidemiological and experimental data from human and animal studies correlating EDCs and PCOS. This review also provides insights into various analytical tools and sample preparation techniques for biomonitoring studies for PCOS risk assessment. Furthermore, we highlight the role of metabolomics in disease-specific biomarker discovery and its use in clinical practice. It also suggests the way forward to integrate biomonitoring studies and metabolomics to underpin the role of EDCs in PCOS pathophysiology.

The molecular mechanism of phytosphingosine binding to FFAR4/GPR120 differs from that of other fatty acids

Free fatty acid receptor 4 (FFAR4)/GPR120 comprises a receptor for medium‐ and long‐chain fatty acids. We previously identified phytosphingosine (PHS) as a novel ligand of FFAR4. Although many natural FFAR4 ligands have carboxyl groups, PHS does not, thus suggesting that binding to FFAR4 is driven by a completely different mechanism than other natural ligands such as α‐linolenic acid (ALA). To test this hypothesis, we performed docking simulation analysis using a FFAR4 homology model based on a protein model derived from the crystal structure of activated turkey beta‐1 adrenoceptor. The docking simulation revealed that the probable hydrogen bonds to FFAR4 differ between various ligands. In particular, binding was predicted between R264 of the FFAR4 and the oxygen of the carboxylate group in ALA, as well as between E249 of the FFAR4 and the oxygen of the hydroxy group at the C4‐position in PHS. Alanine substitution at E249 (E249A) dramatically reduced PHS‐induced FFAR4 activation but demonstrated a weaker effect on ALA‐induced FFAR4 activation. Kinetic analysis and K_m values clearly demonstrated that the E249A substitution resulted in reduced affinity for PHS but not for ALA. Additionally, we observed that sphingosine, lacking a hydroxyl group at C4‐position, could not activate FFAR4. Our data show that E249 of the FFAR4 receptor is crucial for binding to the hydroxy group at the C4‐position in PHS, and this is a completely different molecular mechanism of binding from ALA. Because GPR120 agonists have attracted attention as treatments for type 2 diabetes, our findings may provide new insights into their development.

Drug-like sphingolipid SH-BC-893 opposes ceramide-induced mitochondrial fission and corrects diet-induced obesity

Ceramide-induced mitochondrial fission drives high-fat diet (HFD)-induced obesity. However, molecules targeting mitochondrial dynamics have shown limited benefits in murine obesity models. Here, we reveal that these compounds are either unable to block ceramide-induced mitochondrial fission or require extended incubation periods to be effective. In contrast, targeting endolysosomal trafficking events important for mitochondrial fission rapidly and robustly prevented ceramide-induced disruptions in mitochondrial form and function. By simultaneously inhibiting ARF6- and PIKfyve-dependent trafficking events, the synthetic sphingolipid SH-BC-893 blocked palmitate- and ceramide-induced mitochondrial fission, preserved mitochondrial function, and prevented ER stress in vitro. Similar benefits were observed in the tissues of HFD-fed mice. Within 4 h of oral administration, SH-BC-893 normalized mitochondrial morphology in the livers and brains of HFD-fed mice, improved mitochondrial function in white adipose tissue, and corrected aberrant plasma leptin and adiponectin levels. As an interventional agent, SH-BC-893 restored normal body weight, glucose disposal, and hepatic lipid levels in mice consuming a HFD. In sum, the sphingolipid analog SH-BC-893 robustly and acutely blocks ceramide-induced mitochondrial dysfunction, correcting diet-induced obesity and its metabolic sequelae.

Teadenol A in microbial fermented tea acts as a novel ligand on GPR120 to increase GLP-1 secretion

Post-fermented teas, produced by microbial fermentation, are attracting attention due to their health benefits that reduce the risk of hyperlipidemia and atherosclerosis. Although several novel polyphenols have been identified from post-fermented teas, their biological activities have not yet been fully elucidated. In this study, we found that teadenol A, a polyphenol recently isolated from Japanese post-fermented tea, acts as a novel ligand on a long-chain fatty acid receptor, GPR120. Teadenol A activated GPR120 was over-expressed in 293T cells, and this activation was inhibited by the GPR120 antagonist AH7614. Additionally, teadenol A induced Erk1/2 phosphorylation and increased the intracellular Ca²⁺ concentration in 293T cells, and these effects were completely dependent on GPR120 expression. Our results suggest that teadenol A binds and activates GPR120 directly. Furthermore, teadenol A enhanced the secretion of GLP-1 from intestinal endocrine STC-1 cells. GLP-1 suppresses appetite and increases insulin secretion, exhibiting anti-diabetic effects. GPR120/GLP-1 signaling is attracting attention as a potential target for pharmaceuticals against type 2 diabetes. Our results suggest that teadenol A is a key molecule in post-fermented tea responsible for beneficial effects on metabolic syndrome.

The application of metabolomics analysis in the research of gestational diabetes mellitus and preeclampsia

AIM

The aim of the study was to investigate the difference of the serum metabolic profile between gestational diabetes mellitus (GDM) patients and preeclampsia (PE) patients, to establish the disease differentiation model and to find characteristic metabolites, in order to provide a new idea for the occurrence, development and treatment of the disease.

METHODS

Twenty-nine patients with GDM group and 29 PE group who were examined in Tianjin No. 3 Central Hospital from March 2018 to August 2018 were enrolled as case group, and 29 normal pregnant women were selected as control group. All the serum samples were analyzed by using the ultra-performance liquid chromatography and mass spectrometry. Based on the multivariate statistical analysis method of pattern recognition, we screened out and identified the differential characteristic metabolites.

RESULTS

The serum metabolic profile model of GDM group and PE group was successfully constructed. A total of nine characteristic metabolites were screened and identified in this study, including LPC 18:0, LPC 22:6, LPC 16:0, (S)-14-methylhexadecanoic acid, behenic acid, palmitic acid, sphingosine, phytosphingosine and 1,25-dihydroxyvitamin D3-26,23-lactone. Among them, six characteristic metabolites which were LPC 18:0, LPC 22:6, behenic acid, palmitic acid, sphingosine and 1,25-dihydroxyvitamin D3-26,23-lactone all had a significant statistical difference among GDM, PE and normal pregnancy groups (P < 0.05).

CONCLUSION

The construction of metabolic profile discriminant model has a strong ability to differentiate GDM patients from PE pregnant women. The screened characteristic metabolites can early reflect the disorder of lipid, calcium and phosphorus metabolism of patients, and provide reference and help for the discussion of the occurrence, development and treatment of diseases.

Sphingolipids in food and their critical roles in human health

Sphingolipids (SLs) are ubiquitous structural components of cell membranes and are essential for cell functions under physiological conditions or during disease progression. Abundant evidence supports that SLs and their metabolites, including ceramide (Cer), ceramide-1-phosphate (C1P), sphingosine (So), sphingosine-1-phosphate (S1P), are signaling molecules that regulate a diverse range of cellular processes and human health. However, there are limited reviews on the emerging roles of exogenous dietary SLs in human health. In this review, we discuss the ubiquitous presence of dietary SLs, highlighting their structures and contents in foodstuffs, particularly in sea foods. The digestion and metabolism of dietary SLs is also discussed. Focus is given to the roles of SLs in both the etiology and prevention of diseases, including bacterial infection, cancers, neurogenesis and neurodegenerative diseases, skin integrity, and metabolic syndrome (MetS). We propose that dietary SLs represent a "functional" constituent as emerging strategies for improving human health. Gaps in research that could be of future interest are also discussed.

Serum and urine metabolomics based on UPLC-Q-TOF/MS reveals the antipyretic mechanism of Reduning injection in a rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Reduning injection (RDN), a patented traditional Chinese medicine, has the obvious antipyretic effect and has been widely used in China. Although some previous studies proved its antipyretic effect by animal efficacy experiment or clinical observation, its holistic mechanism in vivo was still unclear.

AIM OF THE STUDY

To comprehensively elucidate the antipyretic mechanism of RDN, the investigation of fever-related potential biomarkers and metabolic pathways in the rat fever model is described in this paper.

MATERIALS AND METHODS

Rat fever model was established by dry yeast. A large number of endogenous metabolites in serum and urine were detected by UPLC-Q-TOF/MS, and fever-related potential biomarkers were screened and identified by multivariate analysis and metabolite databases. The reliability and biological significance of the largely disturbed biomarkers was verified by the metabolic network and the correlation with pharmacodynamic indicators, which contained IL-1β, IL-6, TNF-α, PGE₂ and cAMP.

RESULTS

The established UPLC-Q-TOF/MS analytical method afforded satisfactory results in terms of precision, repeatability and stability, which met the requirements of biological sample determination. A total of 32 potential biomarkers associated with fever were screened and identified, among which 22 species could be adjusted by RDN. The metabolism pathway analysis revealed that valine, leucine and isoleucine biosynthesis, and sphingolipid metabolism were greatly disturbed. Their biomarkers involved L-leucine, L-valine, sphinganine and phytosphingosine, all of which showed a callback trend after RDN was given. These 4 biomarkers had a certain correlation with some known fever-related small molecules and pharmacodynamic indicators, which indicated that the selected fever-related biomarkers had certain reliability and biological significance.

CONCLUSIONS

RDN has a good regulation of the metabolic disorder of endogenous components in dry yeast-induced fever rats. Its antipyretic mechanism is mainly related to the regulation of amino acid, lipid and energy metabolism. The study is useful to better understand and analyze the pharmacodynamic mechanism of complex systems, such as traditional Chinese medicine.

Intestinal Availability and Metabolic Effects of Dietary Camelina Sphingolipids during the Metabolic Syndrome Onset in Mice

Sphingolipids appear as a promising class of components susceptible to prevent the onset of the metabolic syndrome (MetS). Gut availability and effects of Camelina sativa sphingolipids were investigated in a mouse model of dietary-induced MetS. Seed meals from two Camelina sativa lines enriched, respectively, in C24- and C16-NH_2^- glycosyl-inositol-phosphoryl-ceramides (NH₂GIPC) were used in hypercaloric diets. After 5 weeks on these two hypercaloric diets, two markers of the MetS were alleviated (adiposity and insulin resistance) as well as inflammation markers and colon barrier dysfunction. A more pronounced effect was observed with the C16-NH₂GIPC-enriched HC diet, in particular for colon barrier function. Despite a lower digestibility, C16-NH₂GIPC were more prevalent in the intestine wall. Sphingolipids provided as camelina meal can therefore counteract some deleterious effects of a hypercaloric diet in mice at the intestinal and systemic levels. Interestingly, these beneficial effects seem partly dependent on sphingolipid acyl chain length.

Mammalian sphingoid bases: Biophysical, physiological and pathological properties

Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.

Mammalian sphingoid bases: Biophysical, physiological and pathological properties

Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules, and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.

Koji glycosylceramide commonly contained in Japanese traditional fermented foods alters cholesterol metabolism in obese mice

Koji, which is manufactured by proliferating non-pathogenic fungus Aspergillus oryzae on steamed rice, is the base for Japanese traditional fermented foods. We have revealed that koji and related Japanese fermented foods and drinks such as amazake, shio-koji, unfiltered sake and miso contain abundant glycosylceramide. Here, we report that feeding of koji glycosylceramide to obese mice alters the cholesterol metabolism . Liver cholesterol was significantly decreased in obese mice fed with koji glycosylceramide. We hypothesized that their liver cholesterol was decreased because it was converted to bile acids. Consistent with the hypothesis, many bile acids were increased in the cecum and feces of obese mice fed with koji glycosylceramide. Expressions of CYP7A1 and ABCG8 involved in the metabolism of cholesterol were significantly increased in the liver of mice fed with koji glycosylceramide. Therefore, it was considered that koji glycosylceramide affects the cholesterol metabolism in obese mice.

Facile determination of sphingolipids under alkali condition using metal-free column by LC-MS/MS

Extraction and analysis of sphingolipids from biological samples is a critical step in lipidomics, especially for minor species such as sphingoid bases and sphingosine-1-phosphate. Although several liquid chromatography-mass spectrometry methods enabling the determination of sphingolipid molecular species have been reported, they were limited in analytical sensitivity and reproducibility by causing significant peak tailing, especially by the presence of phosphate groups, and most of the extraction techniques are laborious and do not cover a broad range of sphingolipid metabolites. In this study, we developed a rapid single-phase extraction and highly sensitive analytical method for the detection and quantification of sphingolipids (including phosphates) comprehensively using liquid chromatography-triple quadruple mass spectrometry. After validating the reliability of the method, we analyzed the intestinal tissue sphingolipids of germ-free (GF) and specific pathogen-free (SPF) mice and found significantly higher levels of free sphingoid bases and sphingosine-1-phosphate in the GF condition as compared to the SPF condition. This method enables a rapid extraction and highly sensitive determination of sphingolipids comprehensively at low femtomolar ranges. Graphical abstract Diagrammatic comparision of sphingolipid (phosphates) analysis between conventional and this method.

Facile Chemoselective Strategy toward Capturing Sphingoid Bases by a Unique Glutaraldehyde-Functionalized Resin

Sphingoid bases, which have a 2-amino-1,3-diol common functional group, are the structural backbone units of all sphingolipids. Recently, much attention has been focused on sphingoid bases because of their potentially beneficial bioactivities toward various cancer cells as well as their dietary interest. However, low abundance and the handling complexity caused by their amphiphilic character led to very limited research on them. Glutaraldehyde has two aldehyde groups, and it reacts rapidly with the 2-amino-1,3-diol functional group of sphingosine to give a tricyclic product. Immobilization of glutaraldehyde on a resin was successfully performed by organic synthesis, starting from trans-p-coumaric acid via eight steps. This approach suppresses the self-polymerization of glutaraldehyde, and addition of water to the developed resin causes the formation of cyclic double hemiacetal function, which avoids oxidation like a reducing sugar in nature and makes it stable even for up to 1 year incubation. The resin was applied to the solid-phase extracting experiment of free sphingosine from human serum at a concentration of 280 nM. Another extraction study of edible golden oyster mushrooms showed that the sphingoid base was selectively captured from complex natural extracts. These results demonstrate that the developed glutaraldehyde resin method is a highly selective method, and hence, the combination of it with the o-phthaldialdehyde HPLC method was confirmed as an efficient and sensitive method for analysis of sphingoid bases in biological samples.

Dietary sphingolipids: potential for management of dyslipidemia and nonalcoholic fatty liver disease

The development of therapeutic approaches aimed at reducing inflammation, improving lipid metabolism, and preventing nonalcoholic fatty liver disease holds significant potential in the management of obesity-associated disease. In this review, the recent basic science and clinical research examining dietary sphingolipid intake and the prevention of dyslipidemia and nonalcoholic fatty liver disease is summarized. Dietary sphingolipids have been shown to dose-dependently reduce the acute intestinal absorption of cholesterol, triglycerides, and fatty acids in rodents. Overall, studies feeding dietary sphingolipids to rodents typically show reductions in serum lipids. Furthermore, these hypolipidemic effects are also observed in most human studies, although the magnitude of such effects is typically smaller. Dietary sphingolipids also appear useful in preventing hepatic lipid uptake and accumulation and have shown benefits in preventing hepatic steatosis in rodent models. Dietary sphingolipids may affect the gut-liver axis by preventing the translocation of gut bacteria-derived lipopolysaccharide and/or inhibiting its proinflammatory effects. Current evidence from preclinical studies indicates that dietary sphingolipids have lipid-lowering and anti-inflammatory properties, although their potential to prevent human chronic disease has not been fully explored. It will be important to determine if such effects seen in cell and animal models translate to humans. More research is warranted to define how dietary sphingolipids influence lipid metabolism and inflammation.

Synthesis and degradation of long-chain base phosphates affect fumonisin B1-induced cell death in Arabidopsis thaliana

Fumonisin B₁ (FB₁), an inducer of cell death, disrupts sphingolipid metabolism; large accumulations of de novo synthesized free long-chain bases (LCBs) are observed. However, it remains unclear whether tolerance to FB₁ toxicity in plants is connected with preventing the accumulation of free LCBs through their phosphorylation. Here a workflow for the extraction, detection and quantification of LCB phosphates (LCBPs) in Arabidopsis thaliana was developed. We studied the effect of expression of genes for three enzymes involved in the synthesis and degradation of LCBPs, LCB kinase (LCBK1), LCBP phosphatase (SPP1) and lyase (DPL1) on FB₁-induced cell death. As expected, large accumulations of saturated free LCBs, dihydrosphingosine and phytosphingosine, were observed in the FB₁-treated leaves. On the other hand, a high level of sphingenine phosphate was found in the FB₁-treated leaves even though free sphingenine was found in low amounts in these leaves. In comparison of WT and spp1 plants, the LCBP/LCB ratio is likely to be correlated with the degree of FB₁-induced cell death determined by trypan blue staining. The FB₁-treated leaves in dpl1 plants showed severe cell death and the elevation of free LCBs and LCBPs. LCBK1-OX and -KD plants showed resistance and sensitivity to FB₁, respectively, whereas free LCB and LCBP levels in FB₁-treated LCBK1-OX and -KD plants were moderately different to those in FB₁-treated WT plants. Overall, the findings described here suggest that LCBP/LCB homeostasis is an important topic that participates in the tolerance of plant cells to FB₁.

Analytical methods in sphingolipidomics: Quantitative and profiling approaches in food analysis

In recent years, sphingolipidomics has emerged as an interesting omic science that encompasses the study of the full sphingolipidome characterization, content, structure and activity in cells, tissues or organisms. Like other omics, it has the potential to impact biomarker discovery, drug development and systems biology knowledge. Concretely, dietary food sphingolipids have gained considerable importance due to their extensively reported bioactivity. Because of the complexity of this lipid family and their diversity among foods, powerful analytical methodologies are needed for their study. The analytical tools developed in the past have been improved with the enormous advances made in recent years in mass spectrometry (MS) and chromatography, which allow the convenient and sensitive identification and quantitation of sphingolipid classes and form the basis of current sphingolipidomics methodologies. In addition, novel hyphenated nuclear magnetic resonance (NMR) strategies, new ionization strategies, and MS imaging are outlined as promising technologies to shape the future of sphingolipid analyses. This review traces the analytical methods of sphingolipidomics in food analysis concerning sample extraction, chromatographic separation, the identification and quantification of sphingolipids by MS and their structural elucidation by NMR.

DEGS2 polymorphism associated with cognition in schizophrenia is associated with gene expression in brain

A genome-wide association study of cognitive deficits in patients with schizophrenia in Japan found association with a missense genetic variant (rs7157599, Asn8Ser) in the delta(4)-desaturase, sphingolipid 2 (DEGS2) gene. A replication analysis using Caucasian samples showed a directionally consistent trend for cognitive association of a proxy single-nucleotide polymorphism (SNP), rs3783332. Although the DEGS2 gene is expressed in human brain, it is unknown how DEGS2 expression varies during human life and whether it is affected by psychiatric disorders and genetic variants. To address these questions, we examined DEGS2 messenger RNA using next-generation sequencing in postmortem dorsolateral prefrontal cortical tissue from a total of 418 Caucasian samples including patients with schizophrenia, bipolar disorder and major depressive disorder. DEGS2 is expressed at very low levels prenatally and increases gradually from birth to adolescence and consistently expressed across adulthood. Rs3783332 genotype was significantly associated with the expression across all subjects (F3,348=10.79, P=1.12 × 10(-)(3)), particularly in control subjects (F1,87=13.14, P=4.86 × 10(-4)). Similar results were found with rs715799 genotype. The carriers of the risk-associated minor allele at both loci showed significantly lower expression compared with subjects homozygous for the non-risk major allele and this was a consistent finding across all diagnostic groups. DEGS2 expression showed no association with diagnostic status after correcting for multiple testing (P>0.05). Our findings demonstrate that a SNP showing genome-wide association study significant association with cognition in schizophrenia is also associated with regulation of DEGS2 expression, implicating a molecular mechanism for the clinical association.