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The disruption of mitochondria‐associated endoplasmic reticulum (ER) membranes (MAMs) plays a relevant role in Alzheimer's disease (AD). MAMs have been implicated in neuronal dysfunction and death since it is associated with impairment of functions regulated in this subcellular domain, including lipid synthesis and trafficking, mitochondria dysfunction, ER stress‐induced unfolded protein response (UPR), apoptosis, and inflammation. Since MAMs play an important role in lipid metabolism, in this study we characterized and investigated the lipidome alterations at MAMs in comparison with other subcellular fractions, namely microsomes and mitochondria, using an in vitro model of AD, namely the mouse neuroblastoma cell line (N2A) over‐expressing the APP familial Swedish mutation (APPswe) and the respective control (WT) cells. Phospholipids (PLs) and fatty acids (FAs) were isolated from the different subcellular fractions and analyzed by HILIC‐LC–MS/MS and GC–MS, respectively. In this in vitro AD model, we observed a down‐regulation in relative abundance of some phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and lysophosphatidylethanolamine (LPE) species with PUFA and few PC with saturated and long‐chain FA. We also found an up‐regulation of CL, and antioxidant alkyl acyl PL. Moreover, multivariate analysis indicated that each organelle has a specific lipid profile adaptation in N2A APPswe cells. In the FAs profile, we found an up‐regulation of C16:0 in all subcellular fractions, a decrease of C18:0 levels in total fraction (TF) and microsomes fraction, and a down‐regulation of 9‐C18:1 was also found in mitochondria fraction in the AD model. Together, these results suggest that the over‐expression of the familial APP Swedish mutation affects lipid homeostasis in MAMs and other subcellular fractions and supports the important role of lipids in AD physiopathology. [ABSTRACT FROM AUTHOR]

Several species of sacoglossan sea slugs are able to sequester chloroplasts from algae and incorporate them into their cells. However, the ability to maintain functional "stolen" plastids (kleptoplasts) can vary significantly within the Sacoglossa, giving species different capacities to withstand periods of food shortage. The present study provides an insight on the comparative shifts experienced by the lipidome of two sacoglossan sea slug species, Elysia viridis (long-term retention of functional chloroplasts) and Placida dendritica (retention of non-functional chloroplasts). A hydrophilic interaction liquid chromatography–mass spectrometry approach was employed to screen the lipidome of specimens from both species feeding on the macroalga Codium tomentosum and after 1-week of starvation. The lipidome of E. viridis was generally unaffected by the absence of food, while that of P. dendritica varied significantly. The retention of functional chloroplasts by E. viridis cells allows this species to endure periods of food shortage, while in P. dendritica a significant reduction in the amount of main lipids was the consequence of the consumption of its own mass to endure starvation. The large proportion of ether phospholipids (plasmalogens) in both sea slug species suggests that these compounds may play a key role in chloroplast incorporation in sea slug cells and/or be involved in the reduction of the oxidative stress resulting from the presence of kleptoplasts. [ABSTRACT FROM AUTHOR]

Cardiolipins (CL) are anionic dimeric phospholipids bearing four fatty acids, found in inner mitochondrial membrane as structural components and are involved in several processes as oxidative phosphorylation or apoptotic signalling. As other phospholipids, CL can be modified by reactive oxygen species (ROS) and reactive nitrogen species (RNS), which can modulate various cellular functions. Modifications of CL by RNS remain largely unstudied although other nitrated lipids are emerging as bioactive molecules. In this work, we developed a C30-LC-HRMS/MS methodology to identify the nitrated and nitroxidized tetralinoleoyl-cardiolipin (TLCL), using a biomimetic model of nitration, and to disclose specific fragmentation pathways under HCD MS/MS. Using this lipidomics approach, we were able to separate and identify nitro, nitroso, nitronitroso, and nitroxidized TLCL derivatives, comprising 11 different nitrated compounds. These products were identified using accurate mass measurements and the fragmentation pattern acquired in higher-energy collision dissociation (HCD)-tandem MS/MS experiments. These spectra showed classifying fragmentation pathways, yielding phosphatidic acid (PA−), lysophosphatidic acid (LPA−), and carboxylate fragment ions with the modifying moiety. Remarkably, the typical neutral losses associated with the added moieties were not observed. In conclusion, this work has developed a new method for the identification of nitroso, nitrated and nitroxidized cardiolipin products by using a C30LC-MS platform method, potentially allowing their detection in biological samples. Image 1 • C30 LC-MS allows to separate nitro-oxidation products of nitroxidized TLCL. • C30 LC-MS separated and identified 11 different nitrated compounds. • HCD-MS/MS showed classifying fragmentation pathways. • HCD-MS/MS fragmentation confirmed the identity of each isomer after LC separation. [ABSTRACT FROM AUTHOR]

Nitrated phospholipids have been recently identified in biological systems and showed to display anti-oxidant and anti-inflammatory potential in models of inflammation in vitro. Here, we have explored the effects of nitrated 1-palmitoyl-2-oleyl-phosphatidyl choline (NO 2 -POPC) in cellular models. We have observed that NO 2 -POPC, but not POPC, induces cellular changes consisting in cytoskeletal rearrangement and cell shrinking, and ultimately, loss of cell adhesion or impaired cell attachment. NO 2 -POPC releases NO in vitro and induces accumulation of NO in cells. Nevertheless, the effects of NO 2 -POPC are not superimposable with those of NO donors, which points to distinctive mechanisms of action. Notably, they show a stronger parallelism, although not complete overlap, with the effects of nitrated fatty acids. Interestingly, redistribution of vimentin by NO 2 -POPC is attenuated in a C328S mutant, thus indicating that this residue may be a target for direct or indirect modification in NO 2 -POPC-treated cells. Additionally, NO 2 -POPC interacts with several typical lipoxidation targets in vitro , including vimentin and PPARγ constructs, likely through cysteine residues. Therefore, nitrated phospholipids emerge as potential novel electrophilic lipid mediators with selective actions. Image 1 • Nitrated phospholipids induce concentration-dependent cytoskeletal rearrangements. • NO donors do not mimic the effects of nitrated phospholipids. • Nitrated fatty acids recapitulate some effects of nitrated phospholipids. • Nitrated phospholipids could act through electrophilic mechanisms. [ABSTRACT FROM AUTHOR]

The occurrence of protein synthesis errors (mistranslation) above the typical mean mistranslation level of 10−4 is mostly deleterious to yeast, zebrafish and mammal cells. Previous yeast studies have shown that mistranslation affects fitness and deregulates genes related to lipid metabolism, but there is no experimental proof that such errors alter yeast lipid profiles. We engineered yeast strains to misincorporate serine at alanine and glycine sites on a global scale and evaluated the putative effects on the lipidome. Lipids from whole cells were extracted and analysed by thin layer chromatography (TLC), liquid chromatography-mass spectrometry(LC-MS) and gas chromatography (GC). Oxidative damage, fatty acid desaturation and membrane fluidity changes were screened to identify putative alterations in lipid profiles in both logarithmic (fermentative) and post-diauxic shift (respiratory) phases. There were alterations in several lipid classes, namely lyso-phosphatidylcholine, phosphatidic acid, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and triglyceride, and in the fatty acid profiles, namely C16:1, C16:0, C18:1 and C18:0. Overall, the relative content of lipid species with saturated FA increased in detriment of those with unsaturated fatty acids. The expression of the OLE1 mRNA was deregulated, but phospholipid fluidity changes were not observed. These data expand current knowledge of mistranslation biology and highlight its putative roles in human diseases. [ABSTRACT FROM AUTHOR]

Under nitroxidative stress conditions, lipids are prone to be modified by reaction with reactive nitrogen species (RNS) and different modifications were reported to occur in fatty acids. However, in the case of phospholipids (PL) studied under nitroxidative stress conditions, only nitroalkene derivatives of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), were reported when using both in vitro biomimetic conditions and in vivo model system of type 1 diabetes mellitus. Therefore, in order to further explore other nitroxidative modifications of PL, a biomimetic model of nitroxidation combined with liquid chromatography mass spectrometry (MS) and MS/MS approaches were used to characterize the nitrated and nitroxidized derivatives of PCs and PEs. Single and multiple nitrated derivatives of phospholipids (PLs) such as nitroso and dinitroso, nitro, dinitro, and nitronitroso derivatives, together with nitroxidized derivatives were identified. Further, the specific MS/MS fragmentation pathways of these products were studied. Product ions arising from loss of HNO and HNO 2 , from the combined loss of HNO (or HNO 2 ) and polar head groups, [NO n -FA+O n +H] + and [NO n -FA+O n -H] − (n=1–2) product ions corresponding to the modified fatty acyl chains were observed, depending on each modification. The knowledge obtained from the study of the MS/MS fragmentation pattern has allowed us to identify nitrated PCs, including NO 2 -PC, (NO 2 ) 2 -PCs, (NO 2 )(NO)-PC, NO-PC; nitrated PEs, NO 2 -PEs; and nitroxidized PCs, (NO 2 )(2O)-PC in H9c2 cells under starvation, but not under ischemia or control conditions. The physiological relevance of this nitrated and nitroxidized PCs and PEs species observed exclusively in cardiomyoblast cells (H9c2) under starvation is still unknown but deserves to be explored. [ABSTRACT FROM AUTHOR]

Olive oil (OO), a key ingredient of the Mediterranean diet, is frequently subjected to adulteration. A lipidomic approach has been used to study the lipid composition of Portuguese commercial OOs, to find out differences in their profile or a unique fingerprint, namely in the polar lipid pool. Extra virgin (EVOO, n = 3) and virgin olive oils (VOO, n = 3) were analysed. The fatty acids (FA) were analysed by GC-MS and the triacylglycerols by MALDI-TOF-MS. The polar lipid fraction was obtained through solid phase extraction and analysed by hydrophilic interaction liquid chromatography-electrospray ionization-MS. The amount of FA C 16:0 and C 18:1 was significantly different between the EVOOs and the VOOs. Both categories of OO were discriminated by the FAs C 18:3 , C 18:2 and C 16:1 . Five classes of phospholipids were identified in the polar lipid fraction, with significant differences in phosphatidylcholines. Besides FA, it is important to study the polar lipidome to identify minor components that could help to reveal a fingerprint associated with each OO. [ABSTRACT FROM AUTHOR]

Cinnamylideneacetophenones (CA) are an important group of α,β,γ,δ-diunsaturated ketones that have been widely used in a variety of synthetic transformations. Biological studies concerning these compounds are scarce and refer mainly to antiviral and antibacterial evaluations. Curcumin ( CR ), a natural polyphenol, is a yellow pigment extracted from the plant Curcuma longa , which is one of the major spices used in the Indian culinary. It has been reported that CR has cancer chemopreventive properties in a range of animal models of chemical carcinogenesis, along with antioxidative and anti-inflammatory properties. Inspired by the biological activity shown by CR and their structural resemblance with CA, it was considered to study the ability of the latter molecules to inhibit lipid oxidation induced by the hydroxyl radical (Fenton reaction) by electrospray ionization (ESI) mass spectrometry (MS) using phosphatidylcholine (PC) liposomes as a model of cell membrane. Compound 4 , holding a methylated hydroxy group in the position R 2 , and CR showed similar effects in inhibiting lipid peroxidation. In the presence of 7 , the extension of oxidation was higher than the one verified in all other compounds. Other methodologies, namely DPPH radical scavenging and oxygen radical absorption capacity (ORAC) assays, were performed to complement and clarify the results attained by oxidation of PC monitored by ESI-MS and to evaluate the antioxidant profile of compounds. For both assays, compound 7 showed to be rather efficient due to its specific structure. This derivative can form a quite stable allylic radical by abstraction of a hydrogen atom which accounts for these results. [ABSTRACT FROM AUTHOR]

Myocardium infarction is one of the most deathly cardiovascular diseases. It is characterized by myocardium ischemia as a result of nutrients depletion and hypoxia. The cell can respond to this injury by autophagy or apoptosis, which determines the evolution and possible recovery of the myocardium infarction. Lipids play an important role in cardiovascular disease. However reports stating lipidome variations in cardiovascular disease are scarce and the role that lipids play in this pathological condition is not completely understood. The aim of this work was to identify changes in lipid profile of a myoblast H9c2 cell line under starvation and ischemia, to better understand and recognize new biomarkers for myocardial infarction. Lipidomic profile was evaluated by HILIC-LC-MS and GC-MS. Cardiac cells showed alterations in phosphatidylcholines PC (34:1) and PC (36:2), lysophosphatidylcholines lyso PC(16:0), lysoPC(18:1) and lysoPC(18:0), phosphatidylethanolamine PE (34:1), phosphatidylserine PS (36:1), phosphatidylinositol PI (36:2), PI (38:3) and PI (38:5), sphingomyelin SM (34:1) and cardiolipins CL(68:4), CL(72:5) and CL(74:7) in ischemia and/or starvation, in comparison with control. Specific differences observed only in starvation were decrease of SM (34:1) and FA (20:4), and increase of PS (36:1). Differences observed only in ischemia were decrease of PC (36:2), lyso PC (16:0) and FA (18:1) and simultaneous increase of FA (16:0), and FA (18:0). Interestingly, PC (34:1) increased in ischemia and decreased in starvation. In conclusion, our work suggests that lipids are potential markers for evaluation of cell fate, either cell death or recovery, which will be useful to improve diagnosis and prognostic of cardiovascular diseases. J. Cell. Physiol. 231: 2266-2274, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing interest in nitrofatty acids (NO2-FA) as signaling molecules formed under nitroxidative stress. NO2-FA were detected in vivo in a free form, although it is assumed that they may also be esterified to phospholipids (PL). Nevertheless, insufficient discussion about the nature, origin, or role of nitro phospholipids (NO2-PL) was reported up to now. The aim of this study was to develop a mass spectrometry (MS) based approach which allows identifying nitroalkenes derivatives of three major PL classes found in living systems: phosphatidylcholines (PCs), phosphatidylethanolamine (PEs), and phosphatidylserines (PSs). NO2-PLs were generated by NO2BF4 in hydrophobic environment, mimicking biological systems. The NO2-PLs were then detected by electrospray ionization (ESI-MS) and ESI-MS coupled to hydrophilic interaction liquid chromatography (HILIC). Identified NO2-PLs were further analyzed by tandem MS in positive (as [M + H]+ ions for all PL classes) and negative-ion mode (as [M - H]- ions for PEs and PSs and [M + OAc]- ions for PCs). Typical MS/MS fragmentation pattern of all NO2-PL included a neutral loss of HNO2, product ions arising from the combined loss of polar headgroup and HNO2, [NO2-FA + H]+ and [NO2-FA - H]- product ions, and cleavages on the fatty acid backbone near the nitro group, allowing its localization within the FA akyl chain. Developed MS method was used to identify NO2-PL in cardiac mitochondria from a well-characterized animal model of type 1 diabetes mellitus. We identified nine NO2-PCs and one NO2-PE species. The physiological relevance of these findings is still unknown. [ABSTRACT FROM AUTHOR]

Marine macroalgae are emerging as sustainable and healthy food, and a source of lipids with nutritional and bioactive properties. Nonetheless, the lipidome of macroalgae is little explored compared to other photosynthetic organisms. Most of the literature is devoted to the analysis of fatty acid (FA) from macroalgae, because of they are a source of long‐chain omega‐3 and omega‐6 polyunsaturated FA, which can be used as an alternative to fish oil. However, FA occurs mostly esterified in other lipids, such as polar lipids, that still overlooked. The data published on the study of polar lipids (phospholipids, glycolipids, betaine lipids) pinpoint their remarkable characteristics and bioactive properties which mainly remain unexplored. The lipidome of macroalgae seems to be species‐specific, while some lipid classes appear to be characteristic of phyla. Lipidome plasticity of macroalgae is verified to change under abiotic and biotic factors which may modulate the functionality and add‐value of the biomass. This biochemical plasticity represents an advantage to obtain ingredients for target applications and niche of markets. This review provides an overview on macroalgae lipidome characterization, addressing analysis workflow based on liquid chromatography coupled to mass spectrometry, and discussing the bioactive properties and biotechnological applications of macroalga lipids. Practical Applications: The current state of the art on marine macroalgae lipidomics is reviewed, including the lipid characterization using modern liquid chromatography‐mass spectrometry, the distribution of polar lipids by macroalgae species and phylum, their bioactive properties, and potential biotechnological applications. In a time of increasing awareness of sustainably produced marine resources, the lipids from macroalgae are still underexplored. This review provides information for smart valorization of macroalgae as source of add‐value lipids contributing to the development of blue bioeconomy. [ABSTRACT FROM AUTHOR]

• High-value polar lipids from C. vulgaris were obtained using EtOH with UAE. • UAE and DCM showed the highest lipid yields and purity and EtOH the lowest yields. • The polar lipidome of DCM and UAE extracts was similar, with minor differences. • EtOH had lower efficiency for extraction of anionic lipids such as PI, SQDG and PG. • UAE and EtOH lipid extracts revealed antioxidant activity comparable to DCM. Glycolipids and phospholipids are the main reservoirs of omega polyunsaturated fatty acids in microalgae. Their extraction for the food industry requires food grade solvents, however, the use of these solvents is generally associated with low extraction yields. In this study, we evaluated the lipid extraction efficiency of food-grade ethanol, ultrasound-assisted ethanol (UAE) and dichloromethane/methanol (DCM) from Chlorella vulgaris cultivated under autotrophic and heterotrophic conditions. Yields of lipids, fatty acids (FA), and complex lipid profiles were determined by gravimetry, GC–MS, and LC-MS/MS, respectively. UAE and DCM showed the highest lipid yields with similar purity. The FA profiles were identical for all extracts. The polar lipidome of the DCM and UAE extracts was comparable, while the EtOH extracts were significantly different. These results demonstrated the effectiveness of UAE extraction to obtain high yields of polar lipids and omega-3 and -6-rich extracts from C. vulgaris that can be used for food applications. [ABSTRACT FROM AUTHOR]

Highly reactive lipid peroxidation-derived carbonyls (oxoLPP) modify protein nucleophiles via Michael addition or Schiff base formation. Once formed, Michael adducts can be further stabilized via cyclic hemiacetals with or without loss of water. Depending on the mechanism of their formation, peptide-oxoLPP can carry aldehyde or keto groups and thus be a part of the total protein carbonylation level. If a carbonyl function is lost during consecutive reactions, the oxoLPP-peptide adducts will not be detected using the common carbonyl labeling protocols. Because of the differences in adduct stabilities, it is possible to address the heterogeneity of peptide/protein-oxoLPP adducts by careful evaluation of tandem mass spectra of modified peptides. Here, we used hydrophilic interaction liquid chromatography-tandem mass spectrometry analysis of lysine, cysteine and histidine containing model peptides co-incubated with oxidized 1-palmitoyl-2-linoleoyl- sn-glycerophosphatidylcholine to characterize the collision-induced dissociation behavior of peptide-carbonyl adducts. Numerous modifications were detected based on the analysis of tandem mass spectra, including Schiff bases on lysine (two), Michael adducts on lysine (six), cysteine (eleven) and histidine (two), as well as 4-hydroxy-2-aldehydes derived dehydrated cyclic hemiacetals on cysteine (five) and histidine (one). Additionally, cysteine and histidine side chains were modified by lipid-bound aldehydes as Michael adducts and dehydrated hemiacetals. The tandem mass spectra revealed collision-induced dissociation characteristics specific for each class of oxoLPP-peptide adducts. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Photodynamic inactivation (PDI) is a simple and controllable method to destroy microorganisms based on the production of reactive oxygen species (ROS) ( e.g. , free radicals and singlet oxygen), which irreversibly oxidize microorganism’s vital constituents resulting in lethal damage. This process requires the combined action of oxygen, light and a photosensitizer (PS), which absorbs and uses the energy from light to produce ROS. For a better understanding of the photoinactivation process, the knowledge on how some molecular targets are affected by PDI assumes great importance. The aim of this work was to study the relation between the number and position of positive charges on porphyrinic macrocycles and the changes observed on bacterial lipids. For that, five porphyrin derivatives, bearing one to four positive charges, already evaluated as PS on Escherichia coli inactivation , have been tested on lipid extracts from this bacterium, and also on a simple liposome model. The effects were evaluated by the quantification of lipid hydroperoxides and by analysis of the variation of fatty acyl profiles. E. coli suspensions and liposomes were irradiated with white light in the presence of each PS (5.0 μM). Afterwards, total E. coli lipids were extracted and quantified by phosphorus assay. Lipid oxidation on bacteria and on liposomes was quantified by ferrous oxidation in xylenol orange (FOX2 assay) and the analysis of the fatty acid profile was done by gas chromatography (GC). As previously observed for E. coli viability, an overall increase in the lipid hydroperoxides content, depending on the PS charge and on its distribution on the macrocycle, was observed. Analysis of the fatty acid profile has shown a decrease of the unsaturated fatty acids, corroborating the relation between lipid oxidation and PDI efficiency. Bacterial membrane phospholipids are important molecular targets of photoinactivation and the number of charges of the PS molecule, as well as their distribution, have a clear effect on the lipid oxidation and on the efficiency of PDI. The distinct extent of the formation of lipid hydroperoxy derivatives, depending on the PS used, is a good indicator of this process. The FOX2 assay allowed the detection of lipid peroxidation of E. coli membrane after PDI with all the five porphyrins, however, it was not the most appropriated method to quantify the relative lipid oxidation caused by PS with different efficiencies. The fatty acid analysis used to quantify the extent of lipid oxidation by the different PS provided better results. The same results were observed for the liposome model. Consequently, the model system based on liposomes is a fast and simple method that can be used for the screening of the efficiency of new PS, before proceeding with the more complex studies on bacterial models. [ABSTRACT FROM AUTHOR]

Photodynamic therapy combines visible light and a photosensitizer (PS) in the presence of molecular oxygen to generate reactive oxygen species able to modify biological structures such as phospholipids. Phosphatidylethanolamines (PEs), being major phospholipid constituents of mammalian cells and membranes of Gram-negative bacteria, are potential targets of photosensitization. In this work, the oxidative modifications induced by white light in combination with cationic porphyrins (Tri-Py+-Me-PF and Tetra-Py+-Me) were evaluated on PE standards. Electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS) were used to identify and characterize the oxidative modifications induced in PEs (POPE: PE 16:0/18:1, PLPE: PE 16:0/18:2, PAPE: PE 16:0/20:4). Photo-oxidation products of POPE, PLPE and PAPE as hydroxy, hydroperoxy and keteno derivatives and products due to oxidation in ethanolamine polar head were identified. Hydroperoxy-PEs were found to be the major photo-oxidation products. Quantification of hydroperoxides (PE-OOH) allowed differentiating the potential effect in photodamage of the two porphyrins. The highest amounts of PE-OOH were notorious in the presence of Tri-Py+-Me-PF, a highly efficient PS against bacteria. The identification of these modifications in PEs is an important key point in the understanding cell damage processes underlying photodynamic therapy approaches. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Phosphatidylethanolamines (PE) are one of the major components of cells membranes, namely in skin and in retina, that are continuously exposed to solar UV radiation being major targets of photooxidation damage. In addition, due to the presence of the free amine group, PE can also undergo glycation, in hyperglycemic conditions which may increase the susceptibility to oxidation. The aim of this study is to develop a model, based on mass spectrometry (MS) analysis, to identify photooxidative degradation of selected PE (POPE: PE 16:0/18:1, PLPE: PE 16:0/18:2, PAPE: PE 16:0/20:4) and glycated PEs due to UV irradiation. Photooxidation products were analysed by electrospray ionization MS (ESI-MS) and tandem MS (ESI-MS/MS) in positive and negative mode. Emphasis is placed in the influence of glycation in the generation of distinct photooxidation products. ESI-MS spectra of PE after UV photo-irradiation showed mainly hydroperoxy derivatives, due to oxidation of unsaturated fatty acyl chains. Glycated PE gave rise to several new photooxidation products formed due to oxidative cleavages of the glucose moiety, namely between C1 and C2, C2 and C3, and C5 and C6 of this sugar unit. These new products were identified by ESI-MS/MS in positive mode showing distinct neutral loss depending on the different structure of the polar head group. These new identified advanced glycated photooxidation products may have a deleterious role in the etiology of diabetic retinopathy and in diabetic retinal microvascular complications. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Sphingolipids are a class of lipids that play important cellular roles both as structural components of membranes and as signaling molecules. They have also an active participation in apoptosis and inflammation processes which are associated with oxidative stress conditions. However, no studies so far accomplished the oxidative modification of sphingolipids under oxidative stress conditions. In the present study, different sphingolipids, ((d18:1/16:0) sphingomyelin ( N-palmitoyl- D-erythro-sphingosylphosphorylcholine, SM), (d18:1) sphingosylphosphorylcholine (a lysosphingolipid, SPC), and (d18:1/18:0) ceramide (Cer)) were oxidized by the hydroxyl radical, generated under Fenton reaction conditions, and the oxidation reaction was monitored by ESI-MS in positive mode. No oxidation products were identified for Cer under the oxidative conditions used, while ESI-MS spectra of SPC and SM after oxidation show some oxidation products that were analyzed by ESI-MS/MS. This approach allowed identifying hydroxyl and keto derivatives of SPC and acetaldehydephosphorylcholine derivative ( m/ z 226). SM oxidation occurs exclusively in sphingosine backbone with formation of SPC, hydroxyl, and keto derivatives of SPC and the oxidation product at m/ z 226. This study may give new insight and could help to understanding the behavior and biological roles of the sphingolipids under oxidative stress conditions. [ABSTRACT FROM AUTHOR]

Chlorococcum amblystomatis is a novel microalga with a high content of omega-3 fatty acids (FAs), with applications for food, feed, nutraceuticals, and biotechnology. These applications require the use of food-grade green solvents such as ethanol (EtOH) for lipid extraction, which can be associated with lower lipid recovery yields if not assisted with mechanical means. Ultrasonication can increase the recovery of lipids and omega-3 FAs, however, the impact on polar lipids remains poorly understood. In this study, we propose a comparative lipidomic analysis through liquid-chromatography mass spectrometry (LC–MS) of extracts obtained with EtOH combined with ultrasound-assisted extraction (UAE) and conventional extraction with dichloromethane:methanol (DCM) or EtOH. Extraction with UAE improved the recovery yield of EtOH alone from 2.3 ± 0.3 to 14.6 ± 0.6%, which is comparable to lipid recovery from DCM (16.7 ± 0.8%). The fatty acid profile of UAE extracts showed no differences in comparison with DCM. Lipidomic LC–MS/MS analysis showed that UAE allowed lipid extracts rich in polar lipids containing omega-3 PUFAs with lipid yield and lipid profile similar to DCM to be obtained. Taken together these results demonstrate the effectiveness of UAE in obtaining extracts rich in omega-3 glycolipids and phospholipids from C. amblystomatis for different biotechnological applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Dried blood spots (DBS) are being considered as an alternative sampling method of blood collection that can be used in combination with lipidomic and other omic analysis. DBS are successfully used in the clinical context to collect samples for newborn screening for the measurement of specific fatty acid derivatives, such as acylcarnitines, and lipids from whole blood for diagnostic purposes. However, DBS are scarcely used for lipidomic analysis and investigations. Lipidomic studies using DBS are starting to emerge as a powerful method for sampling and storage in clinical lipidomic analysis, but the major research work is being done in the pre- and analytical steps and procedures, and few in clinical applications. This review presents a description of the impact factors and variables that can affect DBS lipidomic analysis, such as the type of DBS card, haematocrit, homogeneity of the blood drop, matrix/chromatographic effects, and the chemical and physical properties of the analyte. Additionally, a brief overview of lipidomic studies using DBS to unveil their application in clinical scenarios is also presented, considering the studies of method development and validation and, to a less extent, for clinical diagnosis using clinical lipidomics. DBS combined with lipidomic approaches proved to be as effective as whole blood samples, achieving high levels of sensitivity and specificity during MS and MS/MS analysis, which could be a useful tool for biomarker identification. Lipidomic profiling using MS/MS platforms enables significant insights into physiological changes, which could be useful in precision medicine. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2012) 120, 993-1013. Abstract Tacrine is an acetylcholinesterase (AChE) inhibitor used as a cognitive enhancer in the treatment of Alzheimer's disease (AD). However, its low therapeutic efficiency and a high incidence of side effects have limited its clinical use. In this study, the molecular mechanisms underlying the impact on brain activity of tacrine and two novel tacrine analogues (T1, T2) were approached by focusing on three aspects: (i) their effects on brain cholinesterase activity; (ii) perturbations on electron transport chain enzymes activities of non-synaptic brain mitochondria; and (iii) the role of mitochondrial lipidome changes induced by these compounds on mitochondrial bioenergetics. Brain effects were evaluated 18 h after the administration of a single dose (75.6 μmol/kg) of tacrine or tacrine analogues. The three compounds promoted a significant reduction in brain AChE and butyrylcholinesterase (BuChE) activities. Additionally, tacrine was shown to be more efficient in brain AChE inhibition than T2 tacrine analogue and less active than T1 tacrine analogue, whereas BuChE inhibition followed the order: T1 > T2 > tacrine. The studies using non-synaptic brain mitochondria show that all the compounds studied disturbed brain mitochondrial bioenergetics mainly via the inhibition of complex I activity. Furthermore, the activity of complex IV is also affected by tacrine and T1 treatments while FoF1-ATPase is only affected by tacrine. Therefore, the compounds' toxicity as regards brain mitochondria, which follows the order: tacrine >> T1 > T2, does not correlate with their ability to inhibit brain cholinesterase enzymes. Lipidomics approaches show that phosphatidylethanolamine (PE) is the most abundant phospholipids (PL) class in non-synaptic brain mitochondria and cardiolipin (CL) present the greatest diversity of molecular species. Tacrine induced significant perturbations in the mitochondrial PL profile, which were detected by means of changes in the relative abundance of phosphatidylcholine (PC), PE, phosphatidylinositol (PI) and CL and by the presence of oxidized phosphatidylserines. Additionally, in both the T1 and T2 groups, the lipid content and molecular composition of brain mitochondria PL are perturbed to a lesser extent than in the tacrine group. Abnormalities in CL content and the amount of oxidized phosphatidylserines were associated with significant reductions in mitochondrial enzymes activities, mainly complex I. These results indicate that tacrine and its analogues impair mitochondrial function and bioenergetics, thus compromising the activity of brain cells. [ABSTRACT FROM AUTHOR]

Artificial intelligence (AI) models have received considerable attention in recent years for their ability to identify optical coherence tomography (OCT) biomarkers with clinical diagnostic potential and predict disease progression. This study aims to externally validate a deep learning (DL) algorithm by comparing its segmentation of retinal layers and fluid with a gold-standard method for manually adjusting the automatic segmentation of the Heidelberg Spectralis HRA + OCT software Version 6.16.8.0. A total of sixty OCT images of healthy subjects and patients with intermediate and exudative age-related macular degeneration (AMD) were included. A quantitative analysis of the retinal thickness and fluid area was performed, and the discrepancy between these methods was investigated. The results showed a moderate-to-strong correlation between the metrics extracted by both software types, in all the groups, and an overall near-perfect area overlap was observed, except for in the inner segment ellipsoid (ISE) layer. The DL system detected a significant difference in the outer retinal thickness across disease stages and accurately identified fluid in exudative cases. In more diseased eyes, there was significantly more disagreement between these methods. This DL system appears to be a reliable method for accessing important OCT biomarkers in AMD. However, further accuracy testing should be conducted to confirm its validity in real-world settings to ultimately aid ophthalmologists in OCT imaging management and guide timely treatment approaches. [ABSTRACT FROM AUTHOR]

Multiple sclerosis is a neurodegenerative disease causing disability in young adults. Alterations in metabolism and lipid profile have been associated with this disease. Several studies have reported changes in the metabolism of arachidonic acid and the profile of fatty acids, ceramides, phospholipids and lipid peroxidation products. Nevertheless, the understanding of the modulation of circulating lipids at the molecular level in multiple sclerosis remains unclear. In the present study, we sought to assess the existence of a distinctive lipid signature of multiple sclerosis using an untargeted lipidomics approach. It also aimed to assess the differences in lipid profile between disease status (relapse and remission). For this, we used hydrophilic interaction liquid chromatography coupled with mass spectrometry for phospholipidomic profiling of serum samples from patients with multiple sclerosis. Our results demonstrated that multiple sclerosis has a phospholipidomic signature different from that of healthy controls, especially the PE, PC, LPE, ether-linked PE and ether-linked PC species. Plasmalogen PC and PE species, which are natural endogenous antioxidants, as well as PC and PE polyunsaturated fatty acid esterified species showed significantly lower levels in patients with multiple sclerosis and patients in both remission and relapse of multiple sclerosis. Our results show for the first time that the serum phospholipidome of multiple sclerosis is significantly different from that of healthy controls and that few phospholipids, with the lowest p-value, such as PC(34:3), PC(36:6), PE(40:10) and PC(38:1) may be suitable as biomarkers for clinical applications in multiple sclerosis. [ABSTRACT FROM AUTHOR]

Cholesteryl esters (CE) are prone to oxidation under increased oxidative stress conditions, but little is known about oxidized CE species (oxCE). To date, only a few oxCE have been identified, however, mainly based on the detection of molecular ions by mass spectrometry (MS) or target approaches for specific oxCE. The study of oxCE occurring from radical oxidation is still scarcely addressed. In this work, we made a comprehensive assessment of oxCE derivatives and their specific fragmentation patterns to identify detailed structural features and isomer differentiation using high-resolution C18 HPLC–MS- and MS/MS-based lipidomic approaches. The LC–MS/MS analysis allowed us to pinpoint oxCE structural isomers of long-chain and short-chain species, eluting at different retention times (tR). Data analysis revealed that oxCE can be modified either in the fatty acyl moiety or in the cholesterol ring. The location of the hydroxy/hydroperoxy group originates characteristic fragment ions, namely the unmodified cholestenyl cation (m/z 369) for the isomer with oxidation in the fatty acyl chain or ions at m/z 367 and m/z 385 (369 + 16) when oxygenation occurs in the cholesterol ring. Additionally, we identified CE 18:2 and 20:4 aldehydic and carboxylic short-chain products that showed a clear fragmentation pattern that confirmed the modification in the fatty acyl chain. Specific fragmentation fingerprinting allowed discrimination of the isobaric short-chain species, namely carboxylic short-chain products, from hydroxy aldehyde short-chain products, with a hydroxycholesterol moiety. This new information is important to identify different oxCE in biological samples and will contribute to unraveling their role in biological conditions and diseases such as cardiovascular disease. [ABSTRACT FROM AUTHOR]

Polar lipids from microalgae have aroused greater interest as a natural source of omega-3 (n-3) polyunsaturated fatty acids (PUFA), an alternative to fish, but also as bioactive compounds with multiple applications. The present study aims to characterize the polar lipid profile of cultured microalga Emiliania huxleyi using hydrophilic interaction liquid chromatography coupled with high-resolution mass spectrometry (HILIC–MS) and fatty acids (FA) analysis by gas chromatography (GC–MS). The lipidome of E. huxleyi revealed the presence of distinct n-3 PUFA (40% of total FA), namely docosahexaenoic acid (22:6n-3) and stearidonic acid (18:4n-3), which give this microalga an increased commercial value as a source of n-3 PUFA present in the form of polar lipids. A total of 134 species of polar lipids were identified and some of these species, particularly glycolipids, have already been reported for their bioactive properties. Among betaine lipids, the diacylglyceryl carboxyhydroxymethylcholine (DGCC) class is the least reported in microalgae. For the first time, monomethylphosphatidylethanolamine (MMPE) has been found in the lipidome of E. huxleyi. Overall, this study highlights the potential of E. huxleyi as a sustainable source of high-value polar lipids that can be exploited for different applications, namely human and animal nutrition, cosmetics, and pharmaceuticals. [ABSTRACT FROM AUTHOR]

Marine edible macroalgae have functional proprieties that might improve human health and wellbeing. Lipids represent a minor fraction of macroalgae, yet with major interest as main carriers of omega 3 polyunsaturated fatty acids and intrinsic bioactive properties. In this study, we used lipid extracts from the green macroalgae Ulva rigida and Codium tomentosum; the red Gracilaria gracilis,Palmaria palmata and Porphyra dioica; and the brown Fucus vesiculosus, produced in a land-based integrated multitrophic aquaculture (IMTA) system. We determined the lipid quality indices based on their fatty acid profiles and their bioactivities as putative antioxidant, anti-inflammatory and antiproliferative agents. The results reveal to be species-specific, namely U. rigida displayed the lowest atherogenicity and thrombogenicity indices. Palmaria palmata and F. vesiculosus lipid extracts displayed the lowest inhibitory concentration in the free radical scavenging antioxidant assays. Ulva rigida, C. tomentosum, P. palmata and P. dioica inhibited COX-2 activity by up to 80%, while P. dioica and P. palmata extracts showed the highest cytotoxic potential in the MDA-MB-231 breast cancer cells. This work enhances the valorization of macroalgae as functional foods and promising ingredients for sustainable and healthy diets and fosters new applications of high-valued algal biomass, in a species-specific context. [ABSTRACT FROM AUTHOR]

Cancer associated body wasting is the cause of physical disability, reduced tolerance to anticancer therapy and reduced survival of cancer patients and, similarly to cancer, its incidence is increasing. There is no cure for this clinical condition, and the pathophysiological process involved is largely unknown. Exercise training appears as the gold standard non-pharmacological therapy for the management of this wasting syndrome. Herein we used a lipidomics approach based on liquid chromatography coupled with high-resolution mass spectrometry (LC-HR-MS) to study the effect of exercise in the modulation of phospholipids profile of mitochondria isolated from gastrocnemius muscle of a pre-clinical model of urothelial carcinoma-related body wasting (BBN induced), submitted to 13 weeks of treadmill exercise after diagnosis. Multivariate analysis showed a close relationship between the BBN exercise group and both control groups (control sedentary and control exercise), while the BBN sedentary group was significantly separated from the control groups and the BBN exercise group. Univariate statistical analysis revealed differences mainly in phosphatidylserine (PS) and cardiolipin (CL), although some differences were also observed in phosphatidylinositol (PI, LPI) and phosphatidylcholine (PC) phospholipids. PS with shorter fatty acyl chains were up-regulated in the BBN sedentary group, while the other species of PS with longer FA and a higher degree of unsaturation were down-regulated, but the BBN exercise group was mostly similar to control groups. Remarkably, exercise training prevented these alterations and had a positive impact on the ability of mitochondria to produce ATP, restoring the healthy phospholipid profile. The remodelling of mitochondria phospholipid profile in rats with urothelial carcinoma allowed confirming the importance of the lipid metabolism in mitochondria dysfunction in cancer-induced skeletal muscle remodelling. The regulation of phospholipid biosynthetic pathways observed in the BBN exercise group supported the current perspective that exercise is an adequate therapeutic approach for the management of cancer-related muscle remodeling. [ABSTRACT FROM AUTHOR]

Olives (Olea europaea L.) are classic ingredients in the Mediterranean diet with well-known health benefits, but their lipid composition has not been fully addressed. In this work, we characterised triacylglycerol (TAG) and polar lipid profiles of the olive pulp while using a complementary methodological approach that was based on solid-phase extraction to recover the neutral lipid (NL) and the polar lipid-rich fractions. The TAG profile was analysed in the NL-fraction by C30 reversed-phase liquid chromatography (LC) and the polar lipid profile by normal-phase hydrophilic interaction liquid chromatography (HILIC), with both being coupled to electrospray ionization-mass spectrometry (ESI-MS) and ESI-MS/MS. This approach identified 71 TAG ions that were attributed to more than 350 molecular species, with fatty acyl chain lengths from C11:0 to C26:0, including different polyunsaturated acyl chains. The polar lipids included 107 molecular species that belonged to 11 lipid classes that comprised phospholipids, glyceroglycolipids, glycosphingolipids, and betaine lipids. In addition to polyunsaturated fatty acids, some of the phospholipids, glycolipids, and glycosphingolipids that were identified in the olive pulp have been described as biologically active molecules. Lipidomic phenotyping of the olive pulp has led to the discovery of compounds that will allow for a better assessment of its nutritional value and new applications of bioactive lipid components in this functional food. [ABSTRACT FROM AUTHOR]

Lipids are well‐known targets of reactive nitrogen species and this reaction leads to the formation of nitrated lipids that have been associated with anti‐inflammatory and cytoprotective effects. Nitro‐fatty acids (NO2‐FA) are highly electrophilic compounds that can form covalent adducts with proteins, leading to the formation of lipoxidation adducts, which modulate the protein structure and function. Nitrated phospholipids (NO2‐PL) have been detected recently in biological samples, but their biological effects are unknown, although similarly to what has been described for nitrated lipids, it has been hypothesized that they may react with peptides and proteins. In this study, in vitro biomimetic assays are used to synthetize adducts of nitrated POPC (NO2POPC), already detected in biological samples, and GSH peptide. The formation of NO2POPC‐GSH adducts is studied by ESI‐MS and MS2, using both low and high energy CID in different MS platforms: a LXQ linear ion trap, a Q‐TOF 2, and a Q‐Exactive Hybrid Quadrupole‐Orbitrap. Typical product ions observed under MS2 conditions are modified b, y, and C ions bearing NO2POPC covalently linked that unequivocally confirms the presence of the lipid‐peptide adduct. Typical loss of HNO2 is only observed in the MS2 of the mono‐charged precursor ions, [M+H]+. Product ions at m/z 184 or neutral loss of 183 Da are assigned as typical fragmentations that confirm the presence of the phosphatidylcholine. In summary, the characterization of nitro PL‐peptide adducts by MS and MS2 allows the identification of the structure and specific MS2 reporter ions to be used to pinpoint these adductions in biological systems. Practical Applications: The covalent interaction between nitro phospholipids and peptides suggests a new pathway in cellular transduction of nitroxidative stress signal. This adduction can be considered a post‐translational modification (PTM) of lipoxidation type, similarly as it has been described for nitro‐fatty acids and with important physiological implications. The identification and characterization of the nitro phospholipids and peptides adducts are possible by MS and tandem MS. This analytical technique also represents a robust and sensitive approach for detection of nitro‐lipids adduction to peptides or proteins in biological samples, allowing to disclose their physiological and clinical implications. Tandem MS fingerprinting is an essential feature for this purpose, so in this work, the identification of the reporter ions typical for this type of lipoxidation adducts is provided. These reporter ions can be used to design target (NL, PIS, or MRM) approaches to detect these type of PTM in biological environments. Nitrated phospholipids can adduct covalently to nucleophilic peptide gluthathione, as demonstrated by characterization using tandem MS. Nitrated phospholipids can adduct covalently to nucleophilic peptide gluthathione, as demonstrated by characterization using tandem MS. [ABSTRACT FROM AUTHOR]

There is a growing trend to explore microalgae as an alternative resource for the food, feed, pharmaceutical, cosmetic and fuel industry. Moreover, the polar lipidome of microalgae is interesting because of the reports of bioactive polar lipids which could foster new applications for microalgae. In this work, we identified for the first time the Chlorococcum amblystomatis lipidome using hydrophilic interaction liquid chromatography-high resolution electrospray ionization- tandem mass spectrometry (HILIC–HR–ESI–MS/MS). The Chlorococcum amblystomatis strain had a lipid content of 20.77% and the fatty acid profile, determined by gas chromatography-mass spectrometry, has shown that this microalga contains high amounts of omega-3 polyunsaturated fatty acids (PUFAs). The lipidome identified included 245 molecular ions and 350 lipid species comprising 15 different classes of glycolipids (6), phospholipids (7) and betaine lipids (2). Of these, 157 lipid species and the main lipid species of each class were esterified with omega-3 PUFAs. The lipid extract has shown antioxidant activity and anti-inflammatory potential. Lipid extracts also had low values of atherogenic (0.54) and thrombogenic index (0.27). In conclusion, the lipid extracts of Chlorococcum amblystomatis have been found to be a source of lipids rich in omega-3 PUFAs for of great value for the food, feed, cosmetic, nutraceutical and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

SETD7 (SET7/9, KMT7) is a lysine methyltransferase that targets master regulators of cell proliferation and differentiation. Here, the impact of inhibiting SETD7 catalytic activity on mammary epithelial cell differentiation was studied by focusing on genes associated with epithelial differentiation, lactogenesis, and lipid metabolism in HC11 and EpH4 cell lines. Setd7 mRNA and protein levels were induced upon lactogenic differentiation in both cell lines. Inhibition of SETD7 activity by the compound (R)‐PFI‐2 increased cell proliferation and downregulated E‐cadherin, beta‐catenin, lactoferrin, insulin‐like growth factor binding protein 5, and beta‐casein levels. In addition, inhibition of SETD7 activity affected the lipid profile and altered the mRNA expression of the phospholipid biosynthesis‐related genes choline phosphotransferase 1, and ethanolamine‐phosphate cytidylyltransferase. Altogether, the results suggest that inhibiting SETD7 catalytic activity impairs mammary epithelial and lactogenic differentiation. [ABSTRACT FROM AUTHOR]

Marine algae are one of the most important sources of high‐value compounds such as polar lipids, omega‐3 fatty acids, photosynthetic pigments, or secondary metabolites with interesting features for different niche markets. Acetabularia acetabulum is a macroscopic green single‐celled alga, with a single nucleus hosted in the rhizoid. This alga is one of the most studied dasycladalean species and represents an important model system in cell biology studies. However, its lipidome and pigment profile have been overlooked. Total lipid extracts were analyzed using hydrophilic interaction liquid chromatography‐high resolution mass spectrometry (HILIC‐HRMS), tandem mass spectrometry (MS/MS), and high‐performance liquid chromatography (HPLC). The antioxidant capacity of lipid extracts was tested using DPPH and ABTS assays. Lipidomics identified 16 polar lipid classes, corresponding to glycolipids, betaine lipids, phospholipids, and sphingolipids, with a total of 191 lipid species, some of them recognized by their bioactivities. The most abundant polar lipids were glycolipids. Lipid classes less studied in algae were identified, such as diacylglyceryl‐carboxyhydroxymethylcholine (DGCC) or hexosylceramide (HexCer). The pigment profile of A. acetabulum comprised carotenoids (17.19%), namely cis‐neoxanthin, violaxanthin, lutein and β,β‐carotene, and chlorophylls a and b (82.81%). A. acetabulum lipid extracts showed high antioxidant activity promoting a 50% inhibition (IC50) with concentrations of 57.91 ± 1.20 μg · mL−1 (438.18 ± 8.95 μmol Trolox · g−1 lipid) in DPPH and 20.55 ± 0.60 μg · mL−1 in ABTS assays (918.56 ± 27.55 μmol Trolox · g−1 lipid). This study demonstrates the potential of A. acetabulum as a source of natural bioactive molecules and antioxidant compounds. [ABSTRACT FROM AUTHOR]

Cyanobacteria are photosynthetic organisms that produce a variety of molecules with beneficial properties for applications in fields such as food and feed, pharmaceuticals, and industrial chemicals. In particular, polar lipids from algae are gaining interest because they have been associated with bioactive properties and health benefits. Cyanobacteria have been little studied, particularly in the case of Gloeothece sp. whose polar lipidome is unknown. We have used a high-resolution liquid chromatography mass spectrometry-based approach to identify the polar lipidome of Gloeothece sp. and have also evaluated their antioxidant and anti-inflammatory potential. Results obtained allowed the identification of 162 lipid molecular species from glycolipids, betaine lipids, and phospholipid categories. These molecular species were esterified to fatty acids (FA) with C16 and C18 chain length and with a degree of unsaturation (DoU) ranging between 0 and 4. Some of the lipid species identified in the lipidome are recognized for their bioactive properties. Therefore, the antioxidant capacity of the polar lipid extracts was evaluated against superoxide (O2·−) and nitric oxide (·NO) radicals and the anti-inflammatory capacity using the COX-2 Enzyme Activity Assay Kit. The lipid extracts displayed antioxidant capacity toward O2·− and ·NO radicals in a dose-dependent manner with IC50 of 939.8 ± 15.6 and 1033.7 ± 17.9 μg mL−1, respectively. The extracts showed anti-inflammatory activity by the inhibition of the conversion of arachidonic acid to prostaglandin H2 (PGH2) via inhibition of COX-2, with the lowest concentration tested of 10 μg mL−1 inhibiting the production of PGH2 by about 58%. Overall, these results suggest that the extracts from Gloeothece could be a source of natural product, fostering increasing interest of cyanobacterial exploitation to produce food and metabolites with potential bioactive properties useful for nutraceutical, cosmetics, and medicinal applications. [ABSTRACT FROM AUTHOR]

Oxidative stress and glucolipotoxicity have been associated with endothelial dysfunction, underlying the development of cardiovascular diseases (CVD), atherosclerosis and diabetes. Lipids are involved in cell signaling, proliferation, apoptosis and inflammation. Thus, analysis of lipid profiles in endothelial cells (EC) can reflect the molecular alterations occurring in endothelial dysfunction. In this study, we used hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) for the analysis of the phospholipids (PL) from bovine aortic EC exposed to oxidative (H 2 O 2 ), glycative (glucose), or lipoxidative (4-hydroxynonenal, HNE) stress. We observed a sharper adaptation of the PL profile after treatment with H 2 O 2 , compared with the shifts due to treatment with glucose or HNE. Unsaturated PL species were up-regulated by H 2 O 2, while an opposite trend was observed after treatment with glucose or HNE. Overall, distinct phospholipid signatures characterize EC in response to specific types of stress. Further studies are needed to validate the biological significance of these results. [ABSTRACT FROM AUTHOR]

Nitrated phospholipids (PL) were identified in biological samples using MS based lipidomics. This give new evidence of NO 2 -PL formation under nitroxidative stress conditions, similar to well-known NO 2 -FA. Their identification is based on the typical neutral loss of 47 Da (-HNO 2 ), fragmentation of polar head group and fatty acyl chains. However, the reporter ions formed by HNO 2 are dependent on the instrumental conditions, which make the identification of nitrated PL a challenge. Determination of the best parameters to obtain the most useful information is a key issue for their identification. We evaluated the influence of normalized collision energy (NCE) in a Q-Orbitrap on the abundance of reporter product ions formed by neutral loss of 47 Da (HNO 2 ), for nitrated phosphatidylcholines synthesized through in vitro mimetic nitration with NO 2 BF 4 . Results indicated that lower CID NCE allowed to see typical reporter ions, but they were absent when using higher NCE. Overall, the abundance of reporter ions of NO 2 -PL is significantly affected by the NCE, which in fact determines the observation of the ions and the successful detection of nitrated PL in biological samples. [ABSTRACT FROM AUTHOR]

Lipids are targets of reactive nitrogen species (RNS). Nitro-fatty acids (NO2-FA) are well-known products of RNS and have been associated with anti-inflammatory and cytoprotective effects. NO2-FAs play their biological actions mainly by covalent adduction to key peptides/proteins, modulating their roles. Nitroxidation of phospholipids (PL) has been recently detected in biological samples, but their biological effects were not addressed. We hypothesize that nitrated PL may react with peptide/proteins. We performed in vitro biomimetic assays to synthetize adducts of nitrated POPC (NO2-POPC), already detected in biological samples, and GSH. The formation of NO2-POPC-GSH adducts was studied by ESI-MS and MS2, and low and high energy CID using different MS platforms. Typical product ions observed under MS2 conditions are b, y and immonium ions bearing NO2-POPC covalently-linked that unequivocally confirmed the presence of the lipid-peptide adduct. In summary, the characterization of nitro PL-peptide adducts by MS and MS2 allowed the identification of specific reporter ions to be used to pinpoint these adductions in biological systems. [ABSTRACT FROM AUTHOR]

The aquaculture of macroalgae for human consumption and other high-end applications is experiencing unprecedented development in European countries, with the brown algae Saccharina latissima being the flag species. However, environmental conditions in open sea culture sites are often unique, which may impact the biochemical composition of cultured macroalgae. The present study compared the elemental compositions (CHNS), fatty acid profiles, and lipidomes of S. latissima originating from three distinct locations (France, Norway, and the United Kingdom). Significant differences were found in the elemental composition, with Norwegian samples displaying twice the lipid content of the others, and significantly less protein (2.6%, while French and UK samples contained 6.3% and 9.1%, respectively). The fatty acid profiles also differed considerably, with UK samples displaying a lower content of n-3 fatty acids (21.6%), resulting in a higher n-6/n-3 ratio. Regarding the lipidomic profile, samples from France were enriched in lyso lipids, while those from Norway displayed a particular signature of phosphatidylglycerol, phosphatidylinositol, and phosphatidylcholine. Samples from the UK featured higher levels of phosphatidylethanolamine and, in general, a lower content of galactolipids. These differences highlight the influence of site-specific environmental conditions in the shaping of macroalgae biochemical phenotypes and nutritional value. It is also important to highlight that differences recorded in the lipidome of S. latissima make it possible to pinpoint specific lipid species that are likely to represent origin biomarkers. This finding is relevant for future applications in the field of geographic origin traceability and food control. [ABSTRACT FROM AUTHOR]

• Systemic Lupus Erythematosus is an inflammatory chronic disease that lacks tools for prognostics. • Lipids and oxidized lipids have important role in inflammation and disease progression in SLE. • Lipidomics as tool to identify new lipid biomarkers of SLE relapsing episodes. • Lipidomics to identify lipid biomarkers to ensure better patient care and personalized medicine. Autoimmune diseases (AID) are a heterogeneous group of disorders that have in common a chronic inflammation and dysregulation of the immune system. Systemic lupus erythematosus (SLE) is one of the most frequent systemic autoimmune diseases characterized by autoimmune phenomena in multiple organs. The tests used for evolution and prognosis assessment are either non-specific or non-sensitive, impairing an adequate therapeutics. To face this drawback, lipidomics is being used to provide more knowledge and insights regarding autoimmune disorders. Through lipidomic approaches using MS, it is possible to identify and quantify the level of lipid molecular species in the biological system and this could be useful to identify biomarkers and to better understand the pathophysiology of autoimmune diseases. There are some evidence that lipids and oxidized lipids can play a key role in AID pathogenesis. Although this field has been scarcely explored, there are some studies that reported variations on the lipid profile at a molecular level using lipidomic approaches based on MS in SLE. The results gathered herein showed changes mainly in the level of phospholipids, with decrease of some plasmenyl lipids, fatty acids, with reduction of PUFA, and sphingolipids, with changes in fatty acyl chain composition. These changes may be the result of lipids' modifications due to oxidation and increase of ROS. Some alterations can be associated with changes in membrane of lymphocytes and with the deregulation of the immune system. Thus, exploring the knowledge from modern lipidomic approaches in the study of the role of lipids and oxidized lipids, in oxidative stress and in inflammatory diseases, could contribute for the identification of new lipid biomarkers. Lipid biomarkers are promising tools to prognosis and treatment monitoring, tailored for the best therapeutic response and highest safety to ensure better patient care and to be used for personalized medicine. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) (exossomes, microvesicles and apoptotic bodies) have been well acknowledged as mediators of intercellular communications in prokaryotes and eukaryotes. Lipids are essential molecular components of EVs but at the moment the knowledge about the lipid composition and the function of lipids in EVs is limited and as for now none lipidomic studies in Giardia EVs was described. Therefore, the focus of the current study was to conduct, for the first time, the characterization of the polar lipidome, namely phospholipid and sphingolipid profiles of G. lamblia trophozoites, microvesicles (MVs) and exosomes, using C18—Liquid Chromatography—Mass Spectrometry (C18-LC-MS) and Tandem Mass Spectrometry (MS/MS). A total of 162 lipid species were identified and semi-quantified, in the trophozoites, or in the MVs and exosomes belonging to 8 lipid classes, including the phospholipid classes phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI), cardiolipins (CL), the sphingolipid classes sphingomyelin (SM) and ceramides (Cer), and cholesterol (ST), and 3 lipid subclasses that include lyso PC (LPC), lyso PE (LPE) and lyso PG (LPG), but showing different abundances. This work also identified, for the first time, in G. lamblia trophozoites, the lipid classes CL, Cer and ST and subclasses of LPC, LPE and LPG. Univariate and multivariate analysis showed clear discrimination of lipid profiles between trophozoite, exosomes and MVs. The principal component analysis (PCA) plot of the lipidomics dataset showed clear discrimination between the three groups. Future studies focused on the composition and functional properties of Giardia EVs may prove crucial to understand the role of lipids in host-parasite communication, and to identify new targets that could be exploited to develop novel classes of drugs to treat giardiasis. [ABSTRACT FROM AUTHOR]

Phosphatidylinositols (PIs) are complex lipids that play a key role in cell signaling. Like other phospholipids, they are esterified with unsaturated fatty acyl residues (FAs), making them susceptible to modification by reactive oxygen and nitrogen species (RNS). Recent studies using mass spectrometry (MS)-based lipidomics approaches have revealed that lipid nitration results in a plethora of structurally and chemically modified lipids (epilipids), including nitrated and nitroxidized derivatives of phosphatidylcholines, phosphatidylethanolamines, phosphatidylserines, and cardiolipins. However, there is a notable lack of knowledge regarding the characterization of RNS-modified PI derivatives. In this study, we used C18 high-resolution liquid chromatography–tandem MS approaches to describe the fragmentation signature of nitrated and nitroxidized PIs, bearing different fatty acyl chains. Using this approach and accurate mass measurements, we were able to identify nitro- PI derivatives, dinitro- and nitrohydroxy- derivatives for a few PI species. The data showed the typical neutral loss of nitrous acid (HNO2) as well as the fragmentation patterns corresponding to modified fatty acyl chains (such as NOx-RCOO–, [M – NOx-RCOOH – H]− and [M – NOx-RCOOH – C6H10O5 – H]−), making it possible to identify these epilipids. The susceptibility of PIs to nitration was also investigated, revealing that it depends exclusively on the chains of unsaturated FAs esterified in PI, showing a higher conversion rate for those with C18:1. Overall, the knowledge gathered in this study will contribute to the precise characterization of these epilipids in complex biological samples, offering new opportunities to unveil the pathophysiological roles of nitrated and nitroxidized PI derivatives at the cellular and tissue levels. [ABSTRACT FROM AUTHOR]

Abstract Aminophospholipids (APL), phosphatidylethanolamine (PE) and phosphatidylserine (PS), can be oxidized upon oxidative stress. Oxidized PE and PS have been detected in clinical samples of different pathologies and may act as modulators of the inflammatory response. However, few studies have focused on the effects of oxidized APL (ox-APL) esterified with arachidonic acid, even though a considerable number of studies have assessed the modulation of the immune system by oxidized 1-palmitoyl-2-arachidonoyl- sn -3-glycerophosphocholine (OxPAPC). In the present study, we have used flow cytometry to evaluate the ability of oxidized PAPE (OxPAPE) and PAPS (OxPAPS) to promote or suppress an inflammatory phenotype on monocytes subsets and myeloid dendritic cells (mDCs). The results indicate that OxPAPE increases the frequency of all monocyte subpopulations expressing TNF-α, which promotes an inflammatory response. However, immune cell stimulation with OxPAPE in the presence of LPS results in a decrease of TNF-α expressed by classical monocytes. Incubation with OxPAPS and LPS induces a decrease in TNF-α produced by monocytes, and a significant decrease in IL-1β expressed by monocytes and mDCs, indicating that OxPAPS reduces the LPS-induced pro-inflammatory expression in these populations. These results show the importance of OxPAPE and OxPAPS as modulators of the inflammatory response and demonstrate their possible contribution to the onset and resolution of human diseases related to oxidative stress and inflammation. Highlights • OxPAPE increases frequencies of monocytes expressing TNF-α, promoting inflammation. • Incubation with OxPAPE and LPS decreases production of TNF-α in classical monocytes. • Incubation with OxPAPS and LPS downregulates TNF-α and IL-1β in monocytes and mDC. • OxPAPS does not show any pro-inflammatory effect in any of the tested populations. [ABSTRACT FROM AUTHOR]

Porphyra dioica is a commercial seaweed consumed all over the world, mostly in the shape of nori sheets used for "sushi" preparation. It is a well-known part of the Asian diet with health benefits, which have been associated, among others, to the high levels of n-3 and n-6 fatty acids in this red alga. However, other highly valued lipids of Porphyra are polar lipids that remain largely undescribed and can have both nutritional value and bioactivity, thus could contribute to the valorization of this seaweed. In this context, the present work aims to identify the lipidome of two life cycle stages of the Atlantic species Porphyra dioica: the early life stage conchocelis produced in an indoor-nursery, and young blades produced outdoors using an integratedmultitrophic aquaculture (IMTA) framework. Both the blades (gametophyte) and conchocelis (sporophyte) are commercialized in the food and cosmetics sectors. Liquid chromatography coupled to Q-Exactive high resolution-mass spectrometry (MS) platform was used to gain insight into the lipidome of these species. Our results allowed the identification of 110 and 100 lipid molecular species in the lipidome of the blade and conchocelis, respectively. These lipid molecular species were distributed as follows (blade/conchocelis): 14/15 glycolipids (GLs), 93/79 phospholipids (PLs), and 3/6 betaine lipids. Both life stages displayed a similar profile of GLs and comprised 20:4(n-6) and 20:5(n-3) fatty acids that contribute to n-3 and n-6 fatty acid pool recorded and rank among the molecular species with higher potential bioactivity. PLs' profile was different between the two life stages surveyed, mainly due to the number and relative abundance of molecular species. This finding suggests that differences between both life stages were more likely related with shifts in the lipids of extraplastidial membranes rather than in plastidial membranes. PLs contained n-6 and n-3 precursors and in both life stages of Porphyra dioica the n-6/n-3 ratio recorded was less than 2, highlighting the potential benefits of using these life stages in human diet to prevent chronic diseases. Atherogenic and thrombogenic indexes of blades (0.85 and 0.49, respectively) and conchocelis (0.34 and 0.30, respectively) are much lower than those reported for other Rhodophyta, which highlights their potential application as food or as functional ingredients. Overall, MS-based platforms represent a powerful tool to characterize lipid metabolism and target lipids along different life stages of algal species displaying complex life cycles (such as Porphyra dioica), contributing to their biotechnological application. [ABSTRACT FROM AUTHOR]

The common octopus, Octopus vulgaris , is one of the most important cephalopod fisheries in the world. In Mediterranean cuisine, the common octopus is perceived as an ingredient highly valued for its palatability and nutritional value (source of omega-3 fatty acids). However, the polar lipids of this species are still poorly understood. The present study performed the first fingerprinting of the polar lipidome of the arm muscle of O. vulgaris using a high-resolution mass spectrometry HILIC-LC-MS lipidomics approach. Samples of common octopus were sourced from specimens landed in Santa Luzia (Tavira, Algarve, Portugal), the most important octopus mono-specific fishing harbour in mainland Portugal. Nearly 400 lipid species have been identified from 13 classes of polar lipids. Phosphatidylcholine and phosphatidylethanolamine were the main phospholipids recorded, while the phosphonolipid CAEP and ceramides were the main sphingolipids identified. The structural characterization recognised a high proportion of essential fatty acids, such as EPA, DHA and several other very-long-chain fatty acids (24:5, 24:6) esterified in the polar lipids. The present study provides an unprecedented elucidation of the polar lipidome of O. vulgaris that can be used as a reference for future studies on nutritional value, ecology and traceability of geographic origin. • The polar lipidome of Octopus vulgaris was determined by using untargeted lipidomics. • 398 molecular species of lipids were identified from 13 classes of polar lipids. • CAEP and N -CH 3 -CAEP phospholipid molecular species were identified. • Esterified fatty acids (DHA and EPA) were detected on the main polar lipid molecules. • Molecular lipid species with bioactive potential were identified. [ABSTRACT FROM AUTHOR]

Macro- and microalgae are currently recognized sources of lipids with great nutritional quality and attractive bioactivities for human health promotion and disease prevention. Due to the lipidomic diversity observed among algae species, giving rise to different nutritional and functional characteristics, the mixture of macro- and microalgae has the potential to present important synergistic effects resulting from the complementarity among algae. The aim of this work was to characterize for the first time the lipidome of a blend of macro- and microalgae and evaluate the antioxidant capacity of its lipid fraction. Fatty acids were profiled by GC-MS, the polar lipidome was identified by high resolution LC-MS, and ABTS+• and DPPH• assays were used to assess the antioxidant potential. The most abundant fatty acids were oleic (18:1 n-9), α-linolenic (18:3 n-3), and linoleic (18:2 n-6) acids. The lipid extract presented a beneficial n-6/n-3 ratio (0.98) and low values of atherogenic (0.41) and thrombogenic indices (0.27). The polar lipidome revealed 462 lipid species distributed by glycolipids, phospholipids, and betaine lipids, including some species bearing PUFA and a few with reported bioactivities. The lipid extract also showed antioxidant activity. Overall, the results are promising for the valorization of this blend for food, nutraceutical, and biotechnological applications. [ABSTRACT FROM AUTHOR]

Gangliosides are acidic glycosphingolipids that are present in cell membranes and lipid raft domains, being particularly abundant in central nervous systems. They participate in modulating cell membrane properties, cell-cell recognition, cell regulation, and signaling. Disturbance in ganglioside metabolism has been correlated with the development of diseases, such as neurodegenerative diseases, and in inflammation. Both conditions are associated with an increased production of reactive oxidation species (ROS) that can induce changes in the structure of biomolecules, including lipids, leading to the loss or modification of their function. Oxidized phospholipids are usually involved in chronic diseases and inflammation. However, knowledge regarding oxidation of gangliosides is scarce. In order to evaluate the effect of ROS in gangliosides, an in vitro biomimetic model system was used to study the susceptibility of GM1 (Neu5Ac α2-3(Gal β1-3GalNAc β1-4)Gal β1-4Glc β1Cer) to undergo oxidative modifications. Oxidation of GM1 under Fenton reaction conditions was monitored using high resolution electrospray ionization-mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Upon oxidation, GM1 underwent oxidative cleavages in the carbohydrate chain, leading to the formation of other gangliosides GM2 (GalNAcβ1-4Gal(Neu5Acα2-3)1-4Glcβ1Cer), GM3 (Neu5Acα2-3Galβ1-4Glcβ1Cer), asialo-GM1 (Gal β1-3GalNAc β1-4Gal β1-4Glc β1Cer), asialo-GM2 (GalNAc β1-4Gal β1-4Glc β1Cer), of the small glycolipids lactosylceramide (LacCer), glucosylceramide (GlcCer), and of ceramide (Cer). In addition, oxygenated GM1 and GM2 (as keto and hydroxy derivatives), glycans, oxidized glycans, and oxidized ceramides were also identified. Nonenzymatic oxidation of GM1 under oxidative stress contributes to the generation of other gangliosides that may participate in the imbalance of gangliosides metabolism in vivo, through uncontrolled enzymatic pathways and, consequently, play some role in neurodegenerative processes. [ABSTRACT FROM AUTHOR]

The growing resistance from pathogens against antibiotics has increased the research for new compounds and strategies with antibacterial potential. Lipids from algae are emerging as natural and potent bioactive molecules with interesting results regarding the inactivation of bacteria, viruses, and fungi. The combination of algae lipids with innovative strategies, such as antibacterial photodynamic therapy (aPDT) can enhance their antimicrobial potential. In this work, we aimed to evaluate the antibacterial potential in aPDT of total lipid extracts and polar lipid fractions from the green macroalga, Codium tomentosum , and the green microalga, Chlorella vulgaris on a Gram-positive bacteria Staphylococcus aureus. Total lipid extracts and polar lipid fractions were characterized by LC-MS. The results revealed that the total extracts of algae promote S. aureus inhibition after light irradiation, with a decrease of ca. 6 log 10 (CFU/mL) after 15 min of treatment with both extracts of algae. The polar lipid fractions, composed by phospholipids, glycolipids and betaine lipids, from C. tomentosum and C. vulgaris also revealed antibacterial potential in combination with aPDT, but a decrease of ca. 6 log 10 (CFU/mL) was reached at 60 min of treatment, later than with the total extracts. These results unveil algae lipids as antibacterial compounds in combination with aPDT displaying an alternative from natural origin to tackle pathogen resistance. • Algae total extracts are effective photosensitizers when used with aPDT. • Lipids from C. tomentosum and C. vulgaris reduce the viability of S. aureus in aPDT. • Algae polar lipids are effective photosensitizers when used with aPDT. • Algae polar lipids combined with aPDT can enhance their antimicrobial potential. [ABSTRACT FROM AUTHOR]

Male and female offspring of obese mothers are known to differ extensively in their metabolic adaptation and later development of complications. We investigate the sex-dependent responses in obese offspring mice with maternal obesity, focusing on changes in liver glucose and lipid metabolism. Here we show that maternal obesity prior to and during gestation leads to hepatic steatosis and inflammation in male offspring, while female offspring are protected. Females from obese mothers display important changes in hepatic transcriptional activity and triglycerides profile which may prevent the damaging effects of maternal obesity compared to males. These differences are sustained later in life, resulting in a better metabolic balance in female offspring. In conclusion, sex and maternal obesity drive differently transcriptional and posttranscriptional regulation of major metabolic processes in offspring liver, explaining the sexual dimorphism in obesity-associated metabolic risk.Sex and maternal obesity drive differently transcriptional and posttranscriptional regulation of major metabolic processes in the livers of female and male offspring, contributing to the sexual dimorphism in obesity-associated metabolic risk. [ABSTRACT FROM AUTHOR]

Prostate cancer (PCa) is one of the most lethal diseases in men, which justifies the search for new diagnostic tools. The aim of the present study was to gain new insights into the progression of prostate carcinogenesis by analyzing the urine proteome. To this end, urine from healthy animals and animals with prostate adenocarcinoma was analyzed at two time points: 27 and 54 weeks. After 54 weeks, the incidence of pre-neoplastic and neoplastic lesions in the PCa animals was 100%. GeLC-MS/MS and subsequent bioinformatics analyses revealed several proteins involved in prostate carcinogenesis. Increased levels of retinol-binding protein 4 and decreased levels of cadherin-2 appear to be characteristic of early stages of the disease, whereas increased levels of enolase-1 and T-kininogen 2 and decreased levels of isocitrate dehydrogenase 2 describe more advanced stages. With increasing age, urinary levels of clusterin and corticosteroid-binding globulin increased and neprilysin levels decreased, all of which appear to play a role in prostate hyperplasia or carcinogenesis. The present exploratory analysis can be considered as a starting point for studies targeting specific human urine proteins for early detection of age-related maladaptive changes in the prostate that may lead to cancer. [ABSTRACT FROM AUTHOR]