Collective Total Synthesis of Ecklonialactones, Eiseniachlorides and Analogs.

Ecklonialactones, Eiseniachlorides, and Egregiachlorides are synthesized in living organisms via the lipoxygenase-mediated oxidation of polyunsaturated fatty acids. Originally isolated and identified from brown seaweed (Ecklonia stolonifera, Eisenia bicyclis, and Egregia menziesii), and later replicated on milligram scale through chemical synthesis, the full biological activities of these compounds remain to be elucidated. To bridge this gap in knowledge, we propose a unified methodology to synthesize the 14-membered macrocyclic structures of Ecklonialactones, Eiseniachlorides and analogs using a versatile and convergent approach. This study delineates the synthesis of Ecklonialactone A, B, C, D, and Eiseniachlorides A and B, as well as ent-Ecklonialactone B, 16-epi-Ecklonialactone B and 12,13-diepi-Ecklonialactone B.

Identification of bacterial lipopeptides as key players in IBS.

OBJECTIVES: Clinical studies revealed that early-life adverse events contribute to the development of IBS in adulthood. The aim of our study was to investigate the relationship between prenatal stress (PS), gut microbiota and visceral hypersensitivity with a focus on bacterial lipopeptides containing γ-aminobutyric acid (GABA). DESIGN: We developed a model of PS in mice and evaluated, in adult offspring, visceral hypersensitivity to colorectal distension (CRD), colon inflammation, barrier function and gut microbiota taxonomy. We quantified the production of lipopeptides containing GABA by mass spectrometry in a specific strain of bacteria decreased in PS, in PS mouse colons, and in faeces of patients with IBS and healthy volunteers (HVs). Finally, we assessed their effect on PS-induced visceral hypersensitivity. RESULTS: Prenatally stressed mice of both sexes presented visceral hypersensitivity, no overt colon inflammation or barrier dysfunction but a gut microbiota dysbiosis. The dysbiosis was distinguished by a decreased abundance of Ligilactobacillus murinus, in both sexes, inversely correlated with visceral hypersensitivity to CRD in mice. An isolate from this bacterial species produced several lipopeptides containing GABA including C14AsnGABA. Interestingly, intracolonic treatment with C14AsnGABA decreased the visceral sensitivity of PS mice to CRD. The concentration of C16LeuGABA, a lipopeptide which inhibited sensory neurons activation, was decreased in faeces of patients with IBS compared with HVs. CONCLUSION: PS impacts the gut microbiota composition and metabolic function in adulthood. The reduced capacity of the gut microbiota to produce GABA lipopeptides could be one of the mechanisms linking PS and visceral hypersensitivity in adulthood.

The effect of SARS-CoV-2 variants on the plasma oxylipins and PUFAs of COVID-19 patients.

Oxylipins are important signalling compounds that are significantly involved in the regulation of the immune system and the resolution of inflammation. Lipid metabolism is strongly activated upon SARS-CoV-2 infection, however the modulating effects of oxylipins induced by different variants remain unexplored. Here, we compare the plasma profiles of thirty-seven oxylipins and four PUFAs in subjects infected with Wild-type, Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (B.1.1.529) variants. The results suggest that oxidative stress and inflammation resulting from COVID-19 were highly dependent on the SARS-CoV-2 variant, and that the Wild-type elicited the strongest inflammatory storm. The Alpha and Delta variants induced a comparable lipid profile alteration upon infection, which differed significantly from Omicron. The latter variant increased the levels of pro-inflammatory mediators and decreased the levels of omega-3 PUFA in infected patients. We speculate that changes in therapeutics, vaccination, and prior infections may have a role in the alteration of the oxylipin profile besides viral mutations. The results shed new light on the evolution of the inflammatory response in COVID-19.

Oxidative stress mitigation in horticultural crops using foliar applications of Ilex paraguariensis extract: a dose-dependent study.

Abiotic stress has been shown to induce the formation of reactive oxygen species (ROS) in plant cells. When the level of ROS surpasses the capacity of the endogenous defence mechanism, oxidative stress status is reached, leading to plant damage and a drop in crop productivity. Under oxidative stress conditions, ROS can react with polyunsaturated fatty acids to form oxidized derivatives called phytoprostanes (PhytoPs) and phytofurans (PhytoFs), which are recognized as biomarkers of oxidative damage advance. Modern agriculture proposes the use of biostimulants as a sustainable strategy to alleviate the negative effects of oxidative stress on plants. This work evaluates the dose effect of natural antioxidant extract to mitigate the oxidative-stress deleterious effects in melon and sweet pepper exposed to thermal stress. The plants were sprayed with Ilex paraguariensis (IP) aqueous extract in three different concentrations before exposure to abiotic stress. PhytoP and PhytoF levels were determined in the leaves of melon and pepper plants. IP1 and IP2 were effective against oxidative stress in both plants, with IP1 being the most protective one. IP1 decreased the levels of PhytoPs and PhytoFs by roughly 44% in both melon plants and pepper plants. The yield, with IP1, increased by 57 and 39% in stressed melon and pepper plants, respectively. IP3 foliar application in melon plants induced a pro-oxidant effect rather than the expected mitigating action. However, in sweet pepper plants, IP3 decreased the oxidative stress progress and increased the fruit yield.

Omega-3 to omega-6 fatty acid oxidation ratio as a novel inflammation resolution marker for metabolic complications in obesity.

BACKGROUND AND AIMS: The oxidative metabolism of polyunsaturated fatty acids (PUFAs) leads to bioactive isoprostanoids. The aim was to establish the associations of a complete urinary isoprostanoid profiling in a cohort study of carefully phenotyped obese subjects to determine possible potential differential implications for omega-6 PUFA- and omega-3 PUFA-derived isoprostanoids for obesity, metabolic indicators, and inflammation. METHODS AND RESULTS: PUFA peroxidation compounds were determined in urine samples from obese human subjects (n = 46) by liquid chromatography coupled to tandem mass spectrometry. Increased omega-6 arachidonic acid (AA) oxidation, mainly represented by 5-F2c isoprostane (5-F2c-IsoP) and metabolites of 15-F2t-IsoP, was associated with body mass index, glycated hemoglobin (HbA1c) and mean arterial blood pressure. In addition, we identified the omega-3 PUFA-derived urinary metabolites 14-F4t-NeuroP from docosahexaenoic acid (DHA) and 5-F3t-IsoP from eicosapentaenoic acid (EPA), which declined with age. The omega-3 to omega-6 oxidation ratio was a significant predictor of inflammation in obesity. CONCLUSION: The findings point to full urinary isoprostanoid profiling as a more sensitive measure of PUFA oxidative stress in obesity-induced metabolic complications compared with individual isoprostanoid measures. Furthermore, the results suggest the balance between the omega-3 and omega-6 PUFA oxidation as determinative for the consequences of oxidative stress on inflammation in obesity.

Bioactive Oxylipins Profile in Marine Microalgae.

Microalgae are photosynthetic microscopic organisms that serve as the primary food source in aquatic environments. Microalgae can synthesize a wide variety of molecules, such as polyunsaturated fatty acids (PUFAs) of the omega-3 and omega-6 series. Oxidative degradation of PUFA due to radical and/or enzymatic conversion leads to the formation of oxylipins, which are compounds known for their bioactive properties. In the present study, we aim to profile oxylipins from five microalgae species grown in 10-L photo-bioreactors under optimal conditions. During their exponential phase, microalgae were harvested, extracted and analyzed by LC-MS/MS to determine the qualitative and quantitative profile of oxylipins for each species. The five different selected microalgae revealed a high diversity of metabolites, up to 33 non-enzymatic and 24 enzymatic oxylipins present in different concentrations. Taken together, these findings highlight an interesting role of marine microalgae as a source of bioactive lipids mediators, which we hypothesize have an important function in preventive health measures such as amelioration of inflammation. The rich mixture of oxylipins may display advantages to biological organisms, especially by providing for human health benefits including antioxidant, anti-inflammatory, neuroprotective or immunomodulator activities. Some oxylipins are also well known for their cardiovascular properties.

F4-Neuroprostane Effects on Human Sperm.

Swim-up selected human sperm were incubated with 7 ng F4-neuroprostanes (F4-NeuroPs) for 2 and 4 h. Sperm motility and membrane mitochondrial potential (MMP) were evaluated. The percentage of reacted acrosome was assessed by pisum sativum agglutinin (PSA). Chromatin integrity was detected using the acridine orange (AO) assay and localization of the ryanodine receptor was performed by immunofluorescence analysis. Sperm progressive motility (p = 0.02) and the percentage of sperm showing a strong MMP signal (p = 0.012) significantly increased after 2 h F4-NeuroP incubation compared to control samples. The AO assay did not show differences in the percentage of sperm with dsDNA between treated or control samples. Meanwhile, a significantly higher number of sperm with reacted acrosomes was highlighted by PSA localization after 4 h F4-NeuroP incubation. Finally, using an anti-ryanodine antibody, the immunofluorescence signal was differentially distributed at 2 and 4 h: a strong signal was evident in the midpiece and postacrosomal sheath (70% of sperm) at 2 h, whereas a dotted one appeared at 4 h (53% of sperm). A defined concentration of F4-NeuroPs in seminal fluid may induce sperm capacitation via channel ions present in sperm cells, representing an aid during in vitro sperm preparation that may increase the positive outcome of assisted fertilization.

A Phytoprostane from Gracilaria longissima Increases Platelet Activation, Platelet Adhesion to Leukocytes and Endothelial Cell Migration by Potential Binding to EP3 Prostaglandin Receptor.

Plant phytoprostanes (PhytoPs) are lipid oxidative stress mediators that share structural similarities with mammal prostaglandins (PGs). They have been demonstrated to modulate inflammatory processes mediated by prostaglandins. The present study aims to test the effects of the most abundant oxylipin from Gracilaria longissima, ent-9-D1t-Phytoprostane (9-D1t-PhytoP), on platelet activation and vascular cells as well as clarify possible interactions with platelets and the endothelial EP3 receptor Platelet and monocyte activation was assessed by flow cytometry in the presence of purified 9-D1t-PhytoP. Cell migration was studied using the human Ea.hy926 cell line by performing a scratch wound healing assay. The RNA expression of inflammatory markers was evaluated by RT-PCR under inflammatory conditions. Blind docking consensus was applied to the study of the interactions of selected ligands against the EP3 receptor protein. The 9D1t-PhytoP exerts several pharmacological effects; these include prothrombotic and wound-healing properties. In endothelial cells, 9D1t-PhytP mimics the migration stimulus of PGE2. Computational analysis revealed that 9D1t-PhytP forms a stable complex with the hydrophobic pocket of the EP3 receptor by interaction with the same residues as misoprostol and prostaglandin E2 (PGE2), thus supporting its potential as an EP3 agonist. The potential to form procoagulant platelets and the higher endothelial migration rate of the 9-D1t-PhytoP, together with its capability to interact with PGE2 main target receptor in platelets suggest herein that this oxylipin could be a strong candidate for pharmaceutical research from a multitarget perspective.

Twelve Weeks of High-Intensity Interval Training Alters Adipose Tissue Gene Expression but Not Oxylipin Levels in People with Non-Alcoholic Fatty Liver Disease.

Lifestyle modifications, including increased physical activity and exercise, are recommended for non-alcoholic fatty liver disease (NAFLD). Inflamed adipose tissue (AT) contributes to the progression and development of NAFLD and oxylipins such as hydroxyeicosatetraenoic acids (HETE), hydroxydocosahexanenoic acids (HDHA), prostaglandins (PEG2), and isoprostanoids (IsoP), which all may play a role in AT homeostasis and inflammation. To investigate the role of exercise without weight loss on AT and plasma oxylipin concentrations in NAFLD subjects, we conducted a 12-week randomized controlled exercise intervention. Plasma samples from 39 subjects and abdominal subcutaneous AT biopsy samples from 19 subjects were collected both at the beginning and the end of the exercise intervention. In the AT of women, a significant reduction of gene expression of hemoglobin subunits (HBB, HBA1, HBA2) was observed within the intervention group during the 12-week intervention. Their expression levels were negatively associated with VO2max and maxW. In addition, pathways involved in adipocyte morphology alterations significantly increased, whereas pathways in fat metabolism, branched-chain amino acids degradation, and oxidative phosphorylation were suppressed in the intervention group (p < 0.05). Compared to the control group, in the intervention group, the ribosome pathway was activated, but lysosome, oxidative phosphorylation, and pathways of AT modification were suppressed (p < 0.05). Most of the oxylipins (HETE, HDHA, PEG2, and IsoP) in plasma did not change during the intervention compared to the control group. 15-F2t-IsoP significantly increased in the intervention group compared to the control group (p = 0.014). However, this oxylipin could not be detected in all samples. Exercise intervention without weight loss may influence the AT morphology and fat metabolism at the gene expression level in female NAFLD subjects.

Wheat Oxylipins in Response to Aphids, CO2 and Nitrogen Regimes.

Wheat is critical for food security, and is challenged by biotic stresses, chiefly aphids and the viruses they transmit. The objective of this study was to determine whether aphids feeding on wheat could trigger a defensive plant reaction to oxidative stress that involved plant oxylipins. Plants were grown in chambers with a factorial combination of two nitrogen rates (100% N vs. 20% N in Hoagland solution), and two concentrations of CO2 (400 vs. 700 ppm). The seedlings were challenged with Rhopalosiphum padi or Sitobion avenae for 8 h. Wheat leaves produced phytoprostanes (PhytoPs) of the F1 series, and three types of phytofurans (PhytoFs): ent-16(RS)-13-epi-ST-Δ14-9-PhytoF, ent-16(RS)-9-epi-ST-Δ14-10-PhytoF and ent-9(RS)-12-epi-ST-Δ10-13-PhytoF. The oxylipin levels varied with aphids, but not with other experimental sources of variation. Both Rhopalosiphum padi and Sitobion avenae reduced the concentrations of ent-16(RS)-13-epi-ST-Δ14-9-PhytoF and ent-16(RS)-9-epi-ST-Δ14-10-PhytoF in relation to controls, but had little or no effect on PhytoPs. Our results are consistent with aphids affecting the levels of PUFAs (oxylipin precursors), which decreased the levels of PhytoFs in wheat leaves. Therefore, PhytoFs could be postulated as an early indicator of aphid hosting for this plant species. This is the first report on the quantification of non-enzymatic PhytoFs and PhytoPs in wheat leaves in response to aphids.

Development of a Chiral Supercritical Fluid Chromatography-Tandem Mass Spectrometry and Reversed-Phase Liquid Chromatography-Tandem Mass Spectrometry Platform for the Quantitative Metabolic Profiling of Octadecanoid Oxylipins.

Octadecanoids are broadly defined as oxylipins (i.e., lipid mediators) derived from 18-carbon fatty acids. In contrast to the well-studied eicosanoids, there is a lack of analytical methods for octadecanoids, hampering further investigations in the field. We developed an integrated workflow combining chiral separation by supercritical fluid chromatography (SFC) and reversed-phase liquid chromatography (LC) coupled to tandem mass spectrometry detection for quantification of a broad panel of octadecanoids. The platform includes 70 custom-synthesized analytical and internal standards to extend the coverage of the octadecanoid synthetic pathways. A total of 103 octadecanoids could be separated by chiral SFC and complex enantioseparations could be performed in <13 min, while the achiral LC method separated 67 octadecanoids in 13.5 min. The LC method provided a robust complementary approach with greater sensitivity relative to the SFC method. Both methods were validated in solvent and surrogate matrix in terms of linearity, lower limits of quantification (LLOQ), recovery, accuracy, precision, and matrix effects. Instrumental linearity was good for both methods (R2 > 0.995) and LLOQ ranged from 0.03 to 6.00 ng/mL for SFC and 0.01 to 1.25 ng/mL for LC. The average accuracy in the solvent and surrogate matrix ranged from 89 to 109% in SFC and from 106 to 220% in LC, whereas coefficients of variation (CV) were <14% (at medium and high concentrations) and 26% (at low concentrations). Validation in the surrogate matrix showed negligible matrix effects (<16% for all analytes), and average recoveries ranged from 71 to 83%. The combined methods provide a platform to investigate the biological activity of octadecanoids and expand our understanding of these little-studied compounds.

Identification of bacterial lipo-amino acids: origin of regenerated fatty acid carboxylate from dissociation of lipo-glutamate anion.

The identification of bacterial metabolites produced by the microbiota is a key point to understand its role in human health. Among them, lipo-amino acids (LpAA), which are able to cross the epithelial barrier and to act on the host, are poorly identified. Structural elucidation of few of them was performed by high-resolution tandem mass spectrometry based on electrospray combined with selective ion dissociations reach by collision-induced dissociation (CID). The negative ions were used for their advantages of yielding only few fragment ions sufficient to specify each part of LpAA with sensitivity. To find specific processes that help structural assignment, the negative ion dissociations have been scrutinized for an LpAA: the N-palmitoyl acyl group linked to glutamic acid (C16Glu). The singular behavior of [C16Glu-H]¯ towards CID showed tenth product ions, eight were described by expected fragment ions. In contrast, instead of the expected product ions due to CONH-CH bond cleavage, an abundant complementary dehydrated glutamic acid and fatty acid anion pair were observed. Specific to glutamic moiety, they were formed by a stepwise dissociation via molecular isomerization through ion-dipole formation prior to dissociation. This complex dissociated by partner splitting either directly or after inter-partner proton transfer. By this pathway, surprising regeneration of deprotonated fatty acid takes place. Such regeneration is comparable to that occurred from dissociation to peptides containing acid amino-acid. Modeling allow to confirm the proposed mechanisms explaining the unexpected behavior of this glutamate conjugate.

First Total Synthesis of Phytoprostanes with Prostaglandin-Like Configuration, Evidence for Their Formation in Edible Vegetable Oils and Orienting Study of Their Biological Activity.

Phytoprostanes (PhytoP) are natural products, which form in plants under oxidative stress conditions from α-linolenic acid. However, their epimers with relative prostaglandin configuration termed phytoglandins (PhytoG) have never been detected in Nature, likely because of the lack of synthetic reference material. Here, the first asymmetric total synthesis of such compounds, namely of PhytoGF1α (9-epi-16-F1t -PhytoP) and its diastereomer ent-16-epi-PhytoGF1α (ent-9,16-diepi-16-F1t -PhytoP), has been accomplished. The synthetic strategy is based on radical anion oxidative cyclization, copper(I)-mediated alkyl-alkyl coupling and enantioselective reduction reactions. A UHPLC-MS/MS study using the synthesized compounds as standards indicates PhytoG formation at significant levels during autoxidation of α-linolenic acid in edible vegetable oils. Initial testing of synthetic PhytoGs together with F1 -PhytoP and 15-F2t -IsoP derivatives for potential interactions with the PGF2α (FP) receptor did not reveal significant activity. The notion that PUFA-derived oxidatively formed cyclic metabolites with prostaglandin configuration do not form to a significant extent in biological or food matrices has to be corrected. Strong evidence is provided that oxidatively formed PhytoG metabolites may be ingested with plant-derived food, which necessitates further investigation of their biological profile.

Circulating 4-F4t-Neuroprostane and 10-F4t-Neuroprostane Are Related to MECP2 Gene Mutation and Natural History in Rett Syndrome.

Neuroprostanes, a family of non-enzymatic metabolites of the docosahexaenoic acid, have been suggested as potential biomarkers for neurological diseases. Objective biological markers are strongly needed in Rett syndrome (RTT), which is a progressive X-linked neurodevelopmental disorder that is mainly caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene with a predominant multisystemic phenotype. The aim of the study is to assess a possible association between MECP2 mutations or RTT disease progression and plasma levels of 4(RS)-4-F4t-neuroprostane (4-F4t-NeuroP) and 10(RS)-10-F4t-neuroprostane (10-F4t-NeuroP) in typical RTT patients with proven MECP2 gene mutation. Clinical severity and disease progression were assessed using the Rett clinical severity scale (RCSS) in n = 77 RTT patients. The 4-F4t-NeuroP and 10-F4t-NeuroP molecules were totally synthesized and used to identify the contents of the plasma of the patients. Neuroprostane levels were related to MECP2 mutation category (i.e., early truncating, gene deletion, late truncating, and missense), specific hotspot mutations (i.e., R106W, R133C, R168X, R255X, R270X, R294X, R306C, and T158M), and disease stage (II through IV). Circulating 4-F4t-NeuroP and 10-F4t-NeuroP were significantly related to (i) the type of MECP2 mutations where higher levels were associated to gene deletions (p ≤ 0.001); (ii) severity of common hotspot MECP2 mutation (large deletions, R168X, R255X, and R270X); (iii) disease stage, where higher concentrations were observed at stage II (p ≤ 0.002); and (iv) deficiency in walking (p ≤ 0.0003). This study indicates the biological significance of 4-F4t-NeuroP and 10-F4t-NeuroP as promising molecules to mark the disease progression and potentially gauge genotype-phenotype associations in RTT.

First Total Syntheses of Novel Non-Enzymatic Polyunsaturated Fatty Acid Metabolites and Their Identification in Edible Oils.

Oxidative stress (OS) is an in vivo process leading to free radical overproduction, which triggers polyunsaturated fatty acid (PUFA) peroxidation resulting in the formation of racemic non-enzymatic oxygenated metabolites. As potential biomarkers of OS, their in vivo quantification is of great interest. However, since a large number of isomeric metabolites is formed in parallel, their quantification remains difficult without primary standards. Three new PUFA-metabolites, namely 18-F3t -isoprostane (IsoP) from eicosapentaenoic acid (EPA), 20-F4t -neuroprostane (NeuroP) from docosahexaenoic acid (DHA) and 20-F3t -NeuroP from docosapentaenoic acid (DPAn-3 ) were synthesized by two complementary synthetic strategies. The first one relied on a racemic approach to 18(RS)-18-F3t -IsoP using an oxidative radical anion cyclization as a key step, whereas the second used an enzymatic deracemization of a bicyclo[3.3.0]octene intermediate obtained from cyclooctadiene to pursue an asymmetric synthesis. The synthesized metabolites were applied in targeted lipidomics to prove lipid peroxidation in edible oils of commercial nutraceuticals.

Combination of Lutein and Zeaxanthin, and DHA Regulated Polyunsaturated Fatty Acid Oxidation in H2O2-Stressed Retinal Cells.

Photochemical and oxidative damages in retinal pigment epithelial (RPE) cells are key events in the pathogenesis of age-related macular degeneration. Polyunsaturated fatty acids (PUFA) and carotenoids are rich in retinal cells, and under oxidative stress leads to oxidation and release lipid mediators. We evaluated the impact of carotenoids (lutein, zeaxanthin) and docosahexaenoic acid (DHA) supplementation on RPE cells under oxidative stress. ARPE-19 cells were exposed to H2O2 after pre-treatment with lutein, zeaxanthin, DHA, lutein + zeaxanthin or lutein + zeaxanthin with DHA. The data showed H2O2 reduced cell viability and DHA content, while promoted catalase activity and certain oxidized PUFA products. Treatment with DHA enhanced omega-3 PUFA enzymatic oxidation namely, anti-inflammatory mediators such as hydroxy-DHA, resolvins and neuroprotection compared to control; the effects were not influenced by the carotenoids. Omega-6 PUFA oxidation, namely pro-inflammatory HETE (5-, 9-, 12 and 20-HETE), and isoprostanes (5- and 15-F2t-IsoP and 4-F3t-IsoP) were reduced by lutein + zeaxanthin while the addition of DHA did not further reduce these effects. We observed transcriptional regulation of 5-lipoxygenase by DHA and GPx1 and NEFEL2 by the carotenoids that potentially resulted in decreased HETEs and glutathione respectively. 4-HNE was not affected by the treatments but 4-HHE was reduced by lutein + zeaxanthin with and without DHA. To conclude, carotenoids and DHA appeared to regulate inflammatory lipid mediators while the carotenoids also showed benefits in reducing non-enzymatic oxidation of omega-6 PUFA.

Dietary omega-3 PUFA improved tubular function after ischemia induced acute kidney injury in mice but did not attenuate impairment of renal function.

BACKGROUND: Acute kidney injury (AKI) is an important complication after major surgery and solid organ transplantation. Here, we present a dietary omega-3 polyunsaturated fatty acid (n3-PUFA) supplementation study to investigate whether pre-treatment can reduce ischemia induced AKI in mice. METHODS: Male 12-14 week old C57BL/6 J mice received a linoleic acid rich sunflower oil based standard diet containing 10 % fat (STD) or the same diet enriched with n3-PUFA (containing 1 % EPA and 1 % DHA) (STD + n3). After 14 days of feeding bilateral 30 min renal ischemia reperfusion injury (IRI) was conducted to induce AKI and mice were sacrificed at 24 h. Serum creatinine and blood urea nitrogen (BUN) as well as liver enzyme elevation were measured. Kidney damage was analyzed by histology and immunohistochemistry. Furthermore, pro-inflammatory cytokines (IL-6, MCP-1) were determined by qPCR. FA and oxylipin pattern were quantified in blood and kidneys by GC-FID and LC-MS/MS, respectively. RESULTS: n3-PUFA supplementation prior to renal IRI increased systemic and renal levels of n3-PUFA. Consistently, eicosanoids and other oxylipins derived from n3-PUFA including precursors of specialized pro-resolving mediators were elevated while n6-PUFA derived mediators such as pro-inflammatory prostaglandins were decreased. Feeding of n3-PUFA did not attenuate renal function impairment, morphological renal damage and inflammation characterized by IL-6 and MCP-1 elevation or neutrophil infiltration. However, the tubular transport marker alpha-1 microglobulin (A1M) was significantly higher expressed in proximal tubular epithelial cells of STD + n3 compared to STD fed mice. This indicates a better integrity of proximal tubular epithelial cells and thus significant protection of tubular function. In addition, heme oxygenase-1 (HO-1) which protects tubular function was also up-regulated in the treatment group receiving n3-PUFA supplemented chow. DISCUSSION: We showed that n3-PUFA pre-treatment did not affect overall renal function or renal inflammation in a mouse model of moderate ischemia induced AKI, but tubular transport was improved. In conclusion, dietary n3-PUFA supplementation altered the oxylipin levels significantly but did not protect from renal function deterioration or attenuate ischemia induced renal inflammation.

Non-Enzymatic Synthesis of Bioactive Isoprostanoids in the Diatom Phaeodactylum following Oxidative Stress.

The ecological success of diatoms requires a remarkable ability to survive many types of stress, including variations in temperature, light, salinity, and nutrient availability. On exposure to these stresses, diatoms exhibit common responses, including growth arrest, impairment of photosynthesis, production of reactive oxygen species, and accumulation of triacylglycerol (TAG). We studied the production of cyclopentane oxylipins derived from fatty acids in the diatom Phaeodactylum tricornutum in response to oxidative stress. P. tricornutum lacks the enzymatic pathway for producing cyclopentane-oxylipins, such as jasmonate, prostaglandins, or thromboxanes. In cells subjected to increasing doses of hydrogen peroxide (H2O2), we detected nonenzymatic production of isoprostanoids, including six phytoprostanes, three F2t-isoprostanes, two F3t-isoprostanes, and three F4t-neuroprostanes, by radical peroxidation of α-linolenic, arachidonic, eicosapentaenoic, and docosahexanoic acids, respectively. H2O2 also triggered photosynthesis impairment and TAG accumulation. F1t-phytoprostanes constitute the major class detected (300 pmol per 1 million cells; intracellular concentration, ∼4 µm). Only two glycerolipids, phosphatidylcholine and diacylglycerylhydroxymethyl-trimethyl-alanine, could provide all substrates for these isoprostanoids. Treatment of P. tricornutum with nine synthetic isoprostanoids produced an effect in the micromolar range, marked by the accumulation of TAG and reduced growth, without affecting photosynthesis. Therefore, the emission of H2O2 and free radicals upon exposure to stresses can lead to glycerolipid peroxidation and nonenzymatic synthesis of isoprostanoids, inhibiting growth and contributing to the induction of TAG accumulation via unknown processes. This characterization of nonenzymatic oxylipins in P. tricornutum opens a field of research on the study of processes controlled by isoprostanoid signaling in various physiological and environmental contexts in diatoms.

Formation of trans-epoxy fatty acids correlates with formation of isoprostanes and could serve as biomarker of oxidative stress.

In mammals, epoxy-polyunsaturated fatty acids (epoxy-PUFA) are enzymatically formed from naturally occurring all-cis PUFA by cytochrome P450 monooxygenases leading to the generation of cis-epoxy-PUFA (mixture of R,S- and S,R-enantiomers). In addition, also non-enzymatic chemical peroxidation gives rise to epoxy-PUFA leading to both, cis- and trans-epoxy-PUFA (mixture of R,R- and S,S-enantiomers). Here, we investigated for the first time trans-epoxy-PUFA and the trans/cis-epoxy-PUFA ratio as potential new biomarker of lipid peroxidation. Their formation was analyzed in correlation with the formation of isoprostanes (IsoP), which are commonly used as biomarkers of oxidative stress. Five oxidative stress models were investigated including incubations of three human cell lines as well as the in vivo model Caenorhabditis elegans with tert-butyl hydroperoxide (t-BOOH) and analysis of murine kidney tissue after renal ischemia reperfusion injury (IRI). A comprehensive set of IsoP and epoxy-PUFA derived from biologically relevant PUFA (ARA, EPA and DHA) was simultaneously quantified by LC-ESI(-)-MS/MS. Following renal IRI only a moderate increase in the kidney levels of IsoP and no relevant change in the trans/cis-epoxy-PUFA ratio was observed. In all investigated cell lines (HCT-116, HepG2 and Caki-2) as well as C. elegans a dose dependent increase of both, IsoP and the trans/cis-epoxy-PUFA ratio in response to the applied t-BOOH was observed. The different cell lines showed a distinct time dependent pattern consistent for both classes of autoxidatively formed oxylipins. Clear and highly significant correlations of the trans/cis-epoxy-PUFA ratios with the IsoP levels were found in all investigated cell lines and C. elegans. Based on this, we suggest the trans/cis-epoxy-PUFA ratio as potential new biomarker of oxidative stress, which warrants further investigation.

Potential of Physalis peruviana calyces as a low-cost valuable resource of phytoprostanes and phenolic compounds.

BACKGROUND: In Colombia, agro-industrial residues represent an enormous economic and environmental problem, which could be reduced if different techniques for the addition of value to such residues were implemented by this industrial sector. One of the fruits with the highest export rates is Physalis peruviana (goldenberry); however, this fruit is generally marketed without its calyx, generating a large amount of residues. To develop a strategy to add value to these residues, it is essential to know their chemical composition. RESULTS: In the present work, phytoprostanes (PhytoPs) - new active oxylipins - have been detected for the first time in Physalis peruviana calyces by ultra-high performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS), F1t -phytoprostanes and D1t -phytoprostanes being the predominant and minor classes, respectively. In addition, we were able to characterize the phenolic compounds profile of this matrix using LC-IT-DAD-MS/MS, describing six phenolic derivatives for the first time therein. CONCLUSIONS: This study increases our knowledge of the chemical composition of the calyces of this fruit and thereby supports the recycling of this class of residue. Consequently, goldenberry calyces could be used as phytotherapeutic, nutraceutic, or cosmetic ingredients for the development of diverse natural products. © 2018 Society of Chemical Industry.