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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]

Simple Summary: The aquaculture industry is expected to grow in the coming years, and this means more sustainable ways are urgently needed to feed cultured animals. Insects are a promising ingredient for fish and shrimp aquafeeds, as they can convert agricultural waste into nutritious biomass. However, insect species that are currently commercially available lack some essential nutrients, such as omega-3 fatty acids, necessary for suitably growing marine organisms. We have screened the native wild seaweed fly, Fucellia maritima, to increase current knowledge on the nutritional diversity that insects may add to aquafeeds and for the presence of pathogenic bacteria. We found that these flies have a good amount of healthy fats, including important fatty acids that are beneficial for marine fish. Additionally, they have an acceptable amount of Enterobacteriaceae for animal feed and no presence of Salmonella sp. This finding suggests that Fucellia maritima can be a valuable ingredient for aquafeed formulation, enhancing the growth and overall health of farmed marine animals. World aquaculture is expected to continue to grow over the next few decades, which amplifies the need for a higher production of sustainable feed ingredients for aquatic animals. Insects are considered good candidates for aquafeed ingredients because of their ability to convert food waste into highly nutritional biomass. However, commercially available terrestrial insect species lack n-3 long-chain polyunsaturated fatty acids (LC-PUFAs), which are essential biomolecules for marine cultured species. Nevertheless, several coastal insect species feature LC-PUFAs in their natural fatty acid (FA) profile. Here, we analysed the lipidic profile of wild-caught seaweed fly Fucellia maritima, with a focus on their FA profile, to evaluate its potential to be used as an aquafeed ingredient, as well as to screen for the presence of pathogenic bacteria. Results showed that the flies had a total lipid content of 13.2% of their total dry weight. The main classes of phospholipids (PLs) recorded were phosphatidylethanolamines (PEs) (60.8%), followed by phosphatidylcholine (PC) (17.1%). The most abundant FA was palmitoleic acid (C16:0) with 34.9% ± 4.3 of total FAs, followed by oleic acid (C18:1) with 30.4% ± 2.3. The FA composition of the flies included essential fatty acids (EFAs) for both freshwater fish, namely linoleic acid (C18:2 n-6) with 3.4% ± 1.3 and alpha-linoleic acid (C18:3 n-3) with 3.4% ± 1.9, and marine fish, namely arachidonic acid (C20:4 n-6) with 1.1% ± 0.3 and eicosapentaenoic acid (C20:5 n-3) with 6.1% ± 1.2. The microbiological analysis found 9.1 colony-forming units per gram (CFU/g) of Enterobacteriaceae and no presence of Salmonella sp. was detected in a sample of 25 g of fresh weight. These findings indicate that Fucellia maritima biomass holds the potential to be used as an additional aquafeed ingredient due to its FA profile and the low count of pathogenic bacteria, which can contribute to the optimal growth of fish and shrimp with a low risk of pathogen transfer during the feed production chain. [ABSTRACT FROM AUTHOR]

Salicornia ramosissima, commonly known as glasswort or sea asparagus, is a halophyte plant cultivated for human consumption that is often referred to as a sea vegetable rich in health-promoting n-3 fatty acids (FAs). Yet, the effect of abiotic conditions, such as salinity and temperature, on the FA profile of S. ramosissima remains largely unknown. These factors can potentially shape its nutritional composition and yield unique fatty acid signatures that can reveal its geographical origin. In this context, samples of S. ramosissima were collected from four different locations along the coastline of mainland Portugal and their FAs were profiled through gas chromatography–mass spectrometry. The lipid extracts displayed a high content of essential FAs, such as 18:2n-6 and 18:3n-3. In addition to an epoxide fatty acid exclusively identified in samples from the Mondego estuary, the relative abundance of FAs varied between origin sites, revealing that FA profiles can be used as site-specific lipid fingerprints. This study highlights the role of abiotic conditions on the nutritional profile of S. ramosissima and establishes FA profiling as a potential avenue to trace the geographic origin of this halophyte plant. Overall, the present approach can make origin certification possible, safeguard quality, and enhance consumers' trust in novel foods. [ABSTRACT FROM AUTHOR]

Ultraviolet B (UVB) radiation induces oxidative stress in skin cells, generating reactive oxygen species (ROS) and perturbing enzyme-mediated metabolism. This disruption is evidenced with elevated concentrations of metabolites that play important roles in the modulation of redox homeostasis and inflammatory responses. Thus, this research sought to determine the impacts of the lipid extract derived from the Nannochloropsis oceanica microalgae on phospholipid metabolic processes in keratinocytes subjected to UVB exposure. UVB-irradiated keratinocytes were treated with the microalgae extract. Subsequently, analyses were performed on cell lysates to ascertain the levels of phospholipid/free fatty acids (GC-FID), lipid peroxidation byproducts (GC-MS), and endocannabinoids/eicosanoids (LC-MS), as well as to measure the enzymatic activities linked with phospholipid metabolism, receptor expression, and total antioxidant status (spectrophotometric methods). The extract from N. oceanica microalgae, by diminishing the activities of enzymes involved in the synthesis of endocannabinoids and eicosanoids (PLA2/COX1/2/LOX), augmented the concentrations of anti-inflammatory and antioxidant polyunsaturated fatty acids (PUFAs), namely DHA and EPA. These concentrations are typically diminished due to UVB irradiation. As a consequence, there was a marked reduction in the levels of pro-inflammatory arachidonic acid (AA) and associated pro-inflammatory eicosanoids and endocannabinoids, as well as the expression of CB1/TRPV1 receptors. The microalgal extract also mitigated the increase in lipid peroxidation byproducts, specifically MDA in non-irradiated samples and 10-F4t-NeuroP in both control and post-UVB exposure. These findings indicate that the lipid extract derived from N. oceanica, by mitigating the deleterious impacts of UVB radiation on keratinocyte phospholipids, assumed a pivotal role in reinstating intracellular metabolic equilibrium. [ABSTRACT FROM AUTHOR]

Plant sterols (PS) are cholesterol-like terpenoids widely spread in the kingdom Plantae. Being the target of extensive research for more than a century, PS have topped with evidence of having beneficial effects in healthy subjects and applications in food, cosmetic and pharmaceutical industries. However, many gaps in several fields of PS's research still hinder their widespread practical applications. In fact, many of the mechanisms associated with PS supplementation and their health benefits are still not fully elucidated. Furthermore, compared to cholesterol data, many complex PS chemical structures still need to be fully characterized, especially in oxidized PS. On the other hand, PS molecules have also been the focus of structural modifications for applications in diverse areas, including not only the above-mentioned but also in e.g., drug delivery systems or alternative matrixes for functional foods and fats. All the identified drawbacks are also superimposed by the need of new PS sources and technologies for their isolation and purification, taking into account increased environmental and sustainability concerns. Accordingly, current and future trends in PS research warrant discussion. [ABSTRACT FROM AUTHOR]

The exposure of skin cells to UV radiation leads to redox imbalances and inflammation. The present study investigates a lipid extract obtained from the microalga Nannochloropsis oceanica as a potential protector against UVB-induced disturbances in human keratinocytes. The findings of this study show that the Nannochloropsis oceanica extract significantly inhibits UVB-induced cell death while concurrently decreasing the activity of pro-oxidative enzymes (xanthine and NADPH oxidase) and reducing the levels of ROS. Furthermore, the extract augments the activity of antioxidant enzymes (superoxide dismutases and catalase), as well as glutathione/thioredoxin-dependent systems in UVB-irradiated cells. The expression of Nrf2 factor activators (p62, KAP1, p38) was significantly elevated, while no impact was observed on Nrf2 inhibitors (Keap1, Bach1). The antioxidant activity of the extract was accompanied by the silencing of overexpressed membrane transporters caused by UVB radiation. Furthermore, the Nannochloropsis oceanica extract exhibited anti-inflammatory effects in UVB-irradiated keratinocytes by decreasing the levels of TNFα, 8-iso prostaglandin F2, and 4-HNE-protein adducts. In conclusion, the lipid components of Nannochloropsis oceanica extract effectively prevent the pro-oxidative and pro-inflammatory effects of UVB radiation in keratinocytes, thereby stabilizing the natural metabolism of skin cells. [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]

Marine environments occupy more than 70% of the earth's surface, integrating very diverse habitats with specific characteristics. This heterogeneity of environments is reflected in the biochemical composition of the organisms that inhabit them. Marine organisms are a source of bioactive compounds, being increasingly studied due to their health-beneficial properties, such as antioxidant, anti-inflammatory, antibacterial, antiviral, or anticancer. In the last decades, marine fungi have stood out for their potential to produce compounds with therapeutic properties. The objective of this study was to determine the fatty acid profile of isolates from the fungi Emericellopsis cladophorae and Zalerion maritima and assess the anti-inflammatory, antioxidant, and antibacterial potential of their lipid extracts. The analysis of the fatty acid profile, using GC-MS, showed that E. cladophorae and Z. maritima possess high contents of polyunsaturated fatty acids, 50% and 34%, respectively, including the omega-3 fatty acid 18:3 n-3. Emericellopsis cladophorae and Z. maritima lipid extracts showed anti-inflammatory activity expressed by the capacity of their COX-2 inhibition which was 92% and 88% of inhibition at 200 µg lipid mL−1, respectively. Emericellopsis cladophorae lipid extracts showed a high percentage of inhibition of COX -2 activity even at low concentrations of lipids (54% of inhibition using 20 µg lipid mL−1), while a dose-dependent behaviour was observed in Z. maritima. The antioxidant activity assays of total lipid extracts demonstrated that the lipid extract from E. cladophorae did not show antioxidant activity, while Z. maritima gave an IC20 value of 116.6 ± 6.2 µg mL−1 equivalent to 92.1 ± 4.8 µmol Trolox g−1 of lipid extract in the DPPH• assay, and 101.3 ± 14.4 µg mL−1 equivalent to 106.6 ± 14.8 µmol Trolox g−1 of lipid extract in the ABTS•+ assay. The lipid extract of both fungal species did not show antibacterial properties at the concentrations tested. This study is the first step in the biochemical characterization of these marine organisms and demonstrates the bioactive potential of lipid extracts from marine fungi for biotechnological applications. [ABSTRACT FROM AUTHOR]

Brown macroalgae are an important source of polysaccharides, mainly fucose-containing sulphated polysaccharides (FCSPs), associated with several biological activities. However, the structural diversity and structure–function relationships for their bioactivities are still undisclosed. Thus, the aim of this work was to characterize the chemical structure of water-soluble Saccharina latissima polysaccharides and evaluate their immunostimulatory and hypocholesterolemic activities, helping to pinpoint a structure–activity relationship. Alginate, laminarans (F1, neutral glucose-rich polysaccharides), and two fractions (F2 and F3) of FCSPs (negatively charged) were studied. Whereas F2 is rich in uronic acids (45 mol%) and fucose (29 mol%), F3 is rich in fucose (59 mol%) and galactose (21 mol%). These two fractions of FCSPs showed immunostimulatory activity on B lymphocytes, which could be associated with the presence of sulphate groups. Only F2 exhibited a significant effect in reductions in in vitro cholesterol's bioaccessibility attributed to the sequestration of bile salts. Therefore, S. latissima FCSPs were shown to have potential as immunostimulatory and hypocholesterolemic functional ingredients, where their content in uronic acids and sulphation seem to be relevant for the bioactive and healthy properties. [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]

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]

Modulation of lipid metabolism is a well-established cancer hallmark, and SCD1 has been recognized as a key enzyme in promoting cancer cell growth, including in glioblastoma (GBM), the deadliest brain tumor and a paradigm of cancer resistance. The central goal of this work was to identify, by MS, the phospholipidome alterations resulting from the silencing of SCD1 in human GBM cells, in order to implement an innovative therapy to fight GBM cell resistance. With this purpose, RNAi technology was employed, and low serum-containing medium was used to mimic nutrient deficiency conditions, at which SCD1 is overexpressed. Besides the expected increase in the saturated to unsaturated fatty acid ratio in SCD1 silenced-GBM cells, a striking increase in polyunsaturated chains, particularly in phosphatidylethanolamine and cardiolipin species, was noticed and tentatively correlated with an increase in autophagy (evidenced by the increase in LC3BII/I ratio). The contribution of autophagy to mitigate the impact of SCD1 silencing on GBM cell viability and growth, whose modest inhibition could be correlated with the maintenance of energetically associated mitochondria, was evidenced by using autophagy inhibitors. In conclusion, SCD1 silencing could constitute an important tool to halt GBM resistance to the available treatments, especially when coupled with a mitochondria disrupter chemotherapeutic. [ABSTRACT FROM AUTHOR]

Halophytes have gradually been introduced in marine integrated multi-trophic aquaculture (IMTA) systems due to their capacity to bioremediate nutrient-rich marine effluents and their potential use for human consumption due to their content of omega-3 and omega-6 fatty acids (FA). To foster the valorization of halophytes produced using an IMTA framework for human consumption, it is important that culture conditions keep or enhance their FA profile, when compared to that displayed by conspecifics in the wild. The main objective of the present study was to compare the FA profiles of three halophyte species (Halimione portulacoides, Salicornia ramosissima and Sarcocornia perennis) cultured in aquaponics coupled to an IMTA system with that of wild conspecifics retrieved from donor sites. The FA profiles were compared considering different plant organs (edible parts and roots) and sampling dates (spring, summer and autumn). Results show that the FA profiles of specimens cultured in aquaponics were significantly different from that of wild conspecifics, displaying a high content of omega-3 FAs in edible parts, particularly during summer, and mostly in the form of α-linolenic acid (ALA, 18:3n-3). In more detail, for the specimens cultured in aquaponics, ALA concentration in the edible parts of each species ranged from 5.10 to 7.11 μg mg−1 DW in H. portulacoides, from 5.66 to 9.19 μg mg−1 DW in S. ramosissima and from 5.49 to 7.20 μg mg−1 DW in S. perennis. Concerning the omega-6 linoleic acid (LA, 18:2n-6) identified in edible parts, the concentrations ranged from 2.25 to 2.46 μg mg−1 DW in H. portulacoides, from 3.26 to 4.84 μg mg−1 DW in S. ramosissima, and from 2.17 to 3.06 μg mg−1 DW in S. perennis. The nutritional quality was assessed through the ratio of PUFA/SFA, for both wild and cultured plants, and revealed values well above the threshold (0.45), the threshold value indicative of good nutritional quality. Overall, the culture conditions tested in the present work reinforce the potential of aquaponics coupled to marine IMTA to produce high-quality halophytes suitable for human consumption. [ABSTRACT FROM AUTHOR]

Plasma biochemical analysis remains one of the established ways of monitoring captive marine mammal health. More recently, complementary plasma lipidomic analysis has proven to be a valid tool in disease diagnosis and prevention, with the potential to validate and complement common biochemical analysis, providing a more integrative approach. In this study, we thoroughly characterized the plasma polar lipid content of Tursiops truncatus, the most common cetacean species held under human care. Our results showed that phosphatidylcholine, lysophosphatidylcholine, and sphingomyelins (CerPCho) are the most represented phospholipid classes in T. truncatus plasma. Palmitic, oleic, and stearic acids are the major fatty acid (FA) present esterified to the plasma polar lipids of this species, although some n‐3 species are also remarkably present, namely eicosapentaenoic and docosahexaenoic acids. The polar lipidome identified by HILIC LC–MS allowed identifying 304 different lipid species. These species belong to the phosphatidylcholine (103 lipid species), lysophosphatidylcholine (35), phosphatidylethanolamine (71), lysophosphatidylethanolamine (20), phosphatidylglycerol (13), lysophosphatidylglycerol (5), phosphatidylinositol (15), lysophosphatidylinositol (3), phosphatidylserine (6) lysophosphatidylserine (1), and sphimgomyelin (32) classes. This was the first time that the dolphin plasma phospholipid profile was characterized, providing a knowledge that will be important to further understand lipid metabolism and physiological regulation in small cetaceans. Furthermore, this study proved the practicability of the use of plasma lipid profiling for health assessment in marine mammals under human care. [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]

Abstract: Nitro‐fatty acids (NO2‐FA) have been widely studied with regard to their identification, structural characterization, and biological actions. NO2‐FA could also be present endogenously esterified to phospholipids (PL), and NO2‐PL were already detected in cardiac mitochondria from diabetic rats and cardiomyoblasts subjected to starvation. However, the biological actions of NO2‐PL have been overlooked. In this study, we evaluate the antioxidant and anti‐inflammatory potential of the nitrated 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) formed in vitro by incubation with NO2BF4, in a well‐recognized mimetic model of nitroxidative stress. Nitrated POPC showed anti‐radical ability to reduce both 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH•) (IC20 = 225 ± 4 μg/mL; Trolox equivalent (TE) = 86 ± 6 μmol Trolox/g lipid) and 2,2′‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid radical cation (ABTS•+) (IC50 = 124 ± 2 μg/mL; TE = 152 ± 9 μmol Trolox/g lipid). Also, higher lag times were achieved in oxygen radical absorbance capacity (ORAC) assay for nitrated POPC, indicating a faster reaction with oxygen‐derived radicals (TE = 1.03 ± 0.22 and TE = 1.30 ± 0.16 mmol Trolox/g lipid for nonmodified and nitrated POPC, respectively). Nitrated POPC showed the ability to inhibit lipid oxidation induced by the hydroxyl radical generated under Fenton reaction conditions, monitored by electrospray ionization (ESI) mass spectrometry (MS) using phosphatidylcholine (PtdCho) liposomes as a model of cell membrane. Nitrated POPC showed anti‐inflammatory potential, as assessed by the inhibition of inducible nitric oxide synthase (iNOS) expression in RAW 264.7 macrophages activated by the Toll‐like receptor 4 (TLR4) agonist lipopolysaccharide (LPS) in a well‐described in vitro model of inflammation. Altogether, this study provides new clues regarding the antioxidant and anti‐inflammatory potential of nitrated POPC, which should be explored in depth. [ABSTRACT FROM AUTHOR]

The lipidome of the red seaweed Gracilaria sp., cultivated on land-based integrated multitrophic aquaculture (IMTA) system, was assessed for the first time using hydrophilic interaction liquid chromatography-mass spectrometry and tandem mass spectrometry (HILIC--MS and MS/MS). One hundred and forty-seven molecular species were identified in the lipidome of the Gracilaria genus and distributed between the glycolipids classes monogalactosyl diacylglyceride (MGDG), digalactosyl diacylglyceride (DGDG), sulfoquinovosyl monoacylglyceride (SQMG), sulfoquinovosyl diacylglyceride (SQDG), the phospholipids phosphatidylcholine (PC), lyso-PC, phosphatidylglycerol (PG), lyso-PG, phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatic acid (PA), inositolphosphoceramide (IPC), and betaine lipids monoacylglyceryl- and diacylglyceryl-N,N,N-trimethyl homoserine (MGTS and DGTS). Antiproliferative and anti-inflammatory effects promoted by lipid extract of Gracilaria sp. were evaluated by monitoring cell viability in human cancer lines and by using murine macrophages, respectively. The lipid extract decreased cell viability of human T-47D breast cancer cells and of 5637 human bladder cancer cells (estimated half-maximal inhibitory concentration (IC50) of 12.2 µg/mL and 12.9 µg/mL, respectively) and inhibited the production of nitric oxide (NO) evoked by the Toll-like receptor 4 agonist lipopolysaccharide (LPS) on the macrophage cell line RAW 264.7 (35% inhibition at a concentration of 100 µg/mL). These findings contribute to increase the ranking in the value-chain of Gracilaria sp. biomass cultivated under controlled conditions on IMTA systems. [ABSTRACT FROM AUTHOR]

Occupational exposure to low molecular weight reactive chemicals often leads to development of allergic reactions such as allergic contact dermatitis and respiratory allergies. Further insights into the interaction of these chemicals with physiopathological relevant cellular models might provide the foundations for novel non-animal approaches to safety assessment. In this work we used the human THP-1 cell line to determine phospholipidome changes induced by the skin sensitizer 1-fluoro-2,4-dinitrobenzene (DNFB), the respiratory allergen hexamethylene diisocyanate (HDI), and the irritant methyl salicylate (MESA). We detected that these chemicals differently induce lipid peroxidation and modulate THP-1 IL-1β, IL-12B, IL-8, CD86, and HMOX1 transcription. Decreased phosphatidylethanolamine content was detected in cells exposed to MESA, while profound alterations in the relative abundance of cardiolipin species were observed in cells exposed to DNFB. All chemicals tested induced a decrease in the relative abundance of plasmanyl phosphatidylcholine species PC (O-16:0e/18:1) and phosphatidylinositol species PI (34:1), while increasing PI (38:4). An increased abundance of oleic acid was observed in the phospholipids of cells exposed to DNFB while a decreased abundance of palmitic acid was detected in cells treated with MESA or DNFB. We conclude that both specific and common alterations at phospholipidome levels are triggered by the different chemicals, while not allowing a complete distinction between them using a Canonical Analysis of Principal Coordinates (CAP). The common effects observed at phospholipids level with all the chemicals tested might be related to unspecific cell cytotoxic mechanisms that nevertheless may contribute to the elicitation of specific immune responses. J. Cell. Physiol. 231: 2639-2651, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The endoplasmic reticulum (ER) plays important roles in eukaryotic protein folding and lipid biosynthesis. Several exogenous and endogenous cellular sources of stress can perturb ER homeostasis leading to the accumulation of unfolded proteins in the lumen. Unfolded protein accumulation triggers a signal-transduction cascade known as the unfolded protein response (UPR), an adaptive mechanism which aims to protect cells from protein aggregates and to restore ER functions. Further to this protective mechanism, in immune cells, UPR molecular effectors have been shown to participate in a wide range of biological processes such as cell differentiation, survival and immunoglobulin and cytokine production. Recent findings also highlight the involvement of the UPR machinery in the maturational program and antigen presentation capacities of dendritic cells. UPR is therefore a key element in immune system homeostasis with direct implications on both adaptive and innate immune responses. The present review summarizes the knowledge on the emerging roles of UPR signaling cascades in mammalian immune cells as well as the consequences of their dysregulation in relation to the pathogenesis of several diseases. [ABSTRACT FROM AUTHOR]

In recent years, noteworthy research has been performed around lipids from microalgae. Among lipids, glycolipids (GLs) are quite abundant in microalgae and are considered an important source of fatty acids (FAs). GLs are rich in 16- and 18-carbon saturated and unsaturated fatty acids and often contain polyunsaturated fatty acids (PUFAs) like n-3 α-linolenic (ALA 18:3), eicosapentaenoic (EPA, 20:5) and docosahexaenoic (DHA, 22:6). GLs comprise three major classes: monogalactosyldiacyl glycerolipids (MGDGs), digalactosyl diacylglycerolipids (DGDGs) and sulfoquinovosyl diacylglycerolipids (SQDGs), whose composition in FA directly depends on the growth conditions. Some of these lipids are high value-added compounds with antitumoral, antimicrobial and anti-inflammatory activities and also with important nutritional significance. To fully explore GLs' bioactive properties it is necessary to fully characterize their structure and to understand the relation between the structure and their biological properties, which can be addressed using modern mass spectrometry (MS)-based lipidomic approaches. This review will focus on the up-to-date FA composition of GLs identified by MS-based lipidomics and their potential as phytochemicals. [ABSTRACT FROM AUTHOR]

The marine environment supports a remarkable diversity of organisms which are a potential source of natural products with biological activities. These organisms include a wide variety of marine plants (from micro- to macrophytes), which have been used in the food and pharmaceutical industry. However, the biochemistry and biological activities of many of these macrophytes (namely macroalgae and halophytes, including seagrasses) are still far from being fully explored. Most popular bioactive components include polysaccharides, peptides, phenolics and fatty acids (FAs). Polar lipids (glycolipids, phospholipids and betaine lipids) are emerging as novel value-added bioactive phytochemicals, rich in n-3 FA, with high nutritional value and health beneficial effects for the prevention of chronic diseases. Polar lipids account various combinations of polar groups, fatty acyl chains and backbone structures. The polar lipidome of macrophytes is remarkably diverse, and its screening represents a significant analytical challenge. Modern research platforms, particularly mass spectrometry (MS)-based lipidomic approaches, have been recently used to address this challenge and are here reviewed. The application of lipidomics to address lipid composition of marine macrophytes will contribute to the stimulation of further research on this group and foster the exploration of novel applications. [ABSTRACT FROM AUTHOR]

Biotechnological applications of marine macroalgae have gained new interest due the added-value of their chemical constituents. This is the case of glycerolipids, phospholipids and glycolipids that display several commercial applications in food, pharmaceutical and cosmetic industries. This study is the first report on the isolation and characterization of the polar lipids of Codium tomentosum originating from a land-based integrated multi-trophic aquaculture (IMTA) using a lipidomic-based approach employing hydrophilic interaction liquid chromatography–electrospray ionization mass spectrometry (HILIC–ESI-MS). The polar lipid profile of C. tomentosum revealed the presence of over two hundred species, corresponding to glycolipids (sulfoquinovosyldiacylglycerols, sulfoquinovosylmonoacylglycerols, di- and monogalactosyldiacylglycerols), glycerophospholipids (lyso- and phosphatidylcholines, phosphatidylinositols, phosphatidic acids, lyso- and phosphatidylglycerols), and di- and monoacyl betaine lipids. Phosphatidylinositols, sulfoquinovosylmonoacylglycerols and some species of monoacyl betaine lipids were reported for the first time in green algae. Some of these polar lipids contain polyunsaturated fatty acids (PUFAs), namely 20:5 and 22:6 species, revealing the ability of C. tomentosum to synthesize larger PUFAs. Also hydroxy-PUFAs of DGDG species were identified, inferring the occurrence of oxylipins. As several of the lipids identified have been reported to have nutritional and health benefits, the present study unravels the potential of C. tomentosum from IMTA to a range of new applications. [ABSTRACT FROM AUTHOR]

Marine macroalgae, or seaweeds, have been used for direct human consumption, as additives in the food industry, and as fertilizers in agriculture. The fatty acid composition of several species of macroalgae has been extensively studied, considering their nutritional value and for phylogenetic characterization. However, the polar lipid components of macroalgae, which include compounds with important nutraceutical and bioactive properties, are still very poorly studied at the molecular level. Herein, it is reported, for the first time, a lipidomic study on the red seaweed Chondrus crispus , namely its fatty acid and polar lipid composition through hydrophilic interaction liquid chromatography — electrospray ionization mass spectrometry (HILIC–ESI–MS), as an approach to better understand its valuable properties provided from lipidic components. The main polar lipid groups identified include glycolipids (sulfoquinovosyldiacylglycerols and digalactosyldiacylglycerols), glycosphingolipids bearing ceramide backbones (galactosylceramides), inositolphosphoceramides, glycerophospholipids (phosphatidylcholines, lyso-phosphatidylcholines, phosphatidic acids, phosphatidylglycerols and lyso-phosphatidylglycerols), and betaine lipids, as well as some phytyl derivatives, as chlorophylls and pheophytins. This lipidomic-based approach is envisaged as very promising in the study of algae lipid fingerprint, required to understand algae metabolism, their dependence of environmental conditions, and also for the valorization of macroalgae as edible products and a source of bioactive compounds. [ABSTRACT FROM AUTHOR]

Microalgae are known as a producer of proteins and lipids, but also of valuable compounds for human health benefits (e.g., polyunsaturated fatty acids (PUFAs); minerals, vitamins, or other compounds). The overall objective of this research was to prospect novel products, such as nutraceuticals from microalgae, for application in human health, particularly for metabolic diseases. Chlorella vulgaris and Chlorococcum amblystomatis were grown autotrophically, and C. vulgaris was additionally grown heterotrophically. Microalgae biomass was extracted using organic solvents (dichloromethane, ethanol, ethanol with ultrasound-assisted extraction). Those extracts were evaluated for their bioactivities, toxicity, and metabolite profile. Some of the extracts reduced the neutral lipid content using the zebrafish larvae fat metabolism assay, reduced lipid accumulation in fatty-acid-overloaded HepG2 liver cells, or decreased the LPS-induced inflammation reaction in RAW264.7 macrophages. Toxicity was not observed in the MTT assay in vitro or by the appearance of lethality or malformations in zebrafish larvae in vivo. Differences in metabolite profiles of microalgae extracts obtained by UPLC-LC-MS/MS and GNPS analyses revealed unique compounds in the active extracts, whose majority did not have a match in mass spectrometry databases and could be potentially novel compounds. In conclusion, microalgae extracts demonstrated anti-obesity, anti-steatosis, and anti-inflammatory activities and could be valuable resources for developing future nutraceuticals. In particular, the ultrasound-assisted ethanolic extract of the heterotrophic C. vulgaris significantly enhanced the anti-obesity activity and demonstrated that the alteration of culture conditions is a valuable approach to increase the production of high-value compounds. [ABSTRACT FROM AUTHOR]

While complex lipids of seaweeds are known to display important phytochemical properties, their full potential is yet to be explored. This review summarizes the findings of a systematic survey of scientific publications spanning over the years 2000 to January 2021 retrieved from Web of Science (WoS) and Scopus databases to map the state of the art and identify knowledge gaps on the relationship between the complex lipids of seaweeds and their reported bioactivities. Eligible publications (270 in total) were classified in five categories according to the type of studies using seaweeds as raw biomass (category 1); studies using organic extracts (category 2); studies using organic extracts with identified complex lipids (category 3); studies of extracts enriched in isolated groups or classes of complex lipids (category 4); and studies of isolated complex lipids molecular species (category 5), organized by seaweed phyla and reported bioactivities. Studies that identified the molecular composition of these bioactive compounds in detail (29 in total) were selected and described according to their bioactivities (antitumor, anti-inflammatory, antimicrobial, and others). Overall, to date, the value for seaweeds in terms of health and wellness effects were found to be mostly based on empirical knowledge. Although lipids from seaweeds are little explored, the published work showed the potential of lipid extracts, fractions, and complex lipids from seaweeds as functional ingredients for the food and feed, cosmeceutical, and pharmaceutical industries. This knowledge will boost the use of the chemical diversity of seaweeds for innovative value-added products and new biotechnological applications. [ABSTRACT FROM AUTHOR]

Seaweeds are considered healthy and sustainable food. Although their consumption is modest in Western countries, the demand for seaweed in food markets is increasing in Europe. Each seaweed species has unique nutritional and functional features. The preparation of blends, obtained by mixing several seaweeds species, allows the obtaining of maximum benefits and ingredients with single characteristics. In this work, five seaweed blends, commercially available and produced under organic conditions in Europe, were characterized. The proximal composition included contents of ash (20.28–28.68% DW), proteins (17.79–26.61% DW), lipids (0.55–1.50% DW), and total carbohydrates (39.47–47.37% DW). Fatty acid profiles were determined by gas chromatography–mass spectrometry (GC–MS), allowing quantification of healthy fatty acids, namely n-3 and n-6 polyunsaturated fatty acids (PUFA), and calculation of lipid quality indices. Each blend showed a characteristic PUFA content in the lipid pool (35.77–49.43% of total fatty acids) and the content in essential and healthy n-3 PUFA is highlighted. The atherogenicity (0.54–0.72) and thrombogenicity (0.23–0.45) indices evidenced a good nutritional value of lipid fractions. As nutritional and environmentally attractive products, the consumption of the studied seaweed blends can contribute to a healthy lifestyle. [ABSTRACT FROM AUTHOR]

Simple Summary: Some species of sacoglossan sea slugs are able to steal chloroplasts from the algae they feed on and maintain them functional for several months, a process termed "kleptoplasty". One of these photosynthetic slugs is Elysia crispata, found in coral reefs of the Gulf of Mexico. This sacoglossan inhabits different depths (0–25 m), being exposed to different food sources and contrasting light conditions. In this work, we characterized the pigment and fatty acid (FA) profiles, and quantified the total lipid, glycolipid and phospholipid contents of E. crispata from shallow (0–4 m) and deeper (8–12 m) waters, after a month of starvation to determine the longest and more stable retention of chloroplasts and its relation to habitat depth. Biochemical analyses allowed the identification of 12 photosynthetic pigments and 27 FAs. Heterogeneity in the composition of pigments confirmed the long-term retention of functional chloroplasts ingested from different algae. However, the differences found in pigment profile, total lipid content, and FA composition on individuals of E. crispata were not related to habitat depth. High amounts of glycolipids, exclusive chloroplast lipids, suggest a good condition of these photosynthetic organelles in animal cells. These results contribute baseline physiological data that may help explain evolutionary associations such as endosymbiosis. Long-term retention of functional chloroplasts in animal cells occurs only in sacoglossan sea slugs. Analysis of molecules related to the maintenance of these organelles can provide valuable information on this trait (kleptoplasty). The goal of our research was to characterize the pigment and fatty acid (FA) composition of the sea slug Elysia crispata and their associated chloroplasts that are kept functional for a long time, and to quantify total lipid, glycolipid and phospholipid contents, identifying differences between habitats: shallow (0–4 m) and deeper (8–12 m) waters. Specimens were sampled and analyzed after a month of food deprivation, through HPLC, GC-MS and colorimetric methods, to ensure an assessment of long-term kleptoplasty in relation to depth. Pigment signatures indicate that individuals retain chloroplasts from different macroalgal sources. FA classes, phospholipid and glycolipid contents displayed dissimilarities between depths. However, heterogeneities in pigment and FA profiles, as well as total lipid, glycolipid and phospholipid amounts in E. crispata were not related to habitat depth. The high content of chloroplast origin molecules, such as Chl a and glycolipids after a month of starvation, confirms that E. crispata retains chloroplasts in good biochemical condition. This characterization fills a knowledge gap of an animal model commonly employed to study kleptoplasty. [ABSTRACT FROM AUTHOR]

The present study aimed to contrast the fatty acid (FA) profile of ascidians (Ascidiacea) and seaweeds (sea lettuce, Ulva spp. and bladderwrack, Fucus sp.) occurring in a coastal lagoon with versus without the influence of organic-rich effluents from fish farming activities. Our results revealed that ascidians and seaweeds from these contrasting environments displayed significant differences in their FA profiles. The n-3/n-6 ratio of Ascidiacea was lower under the influence of fish farming conditions, likely a consequence of the growing level of terrestrial-based ingredients rich on n-6 FA used in the formulation of aquafeeds. Unsurprisingly, these specimens also displayed significantly higher levels of 18:1(n-7+n-9) and 18:2n-6, as these combined accounted for more than 50% of the total pool of FAs present in formulated aquafeeds. The dissimilarities recorded in the FAs of seaweeds from these different environments were less marked (≈5%), with these being more pronounced in the FA classes of the brown seaweed Fucus sp. (namely PUFA). Overall, even under the influence of organic-rich effluents from fish farming activities, ascidians and seaweeds are a valuable source of health-promoting FAs, which confirms their potential for sustainable farming practices, such as integrated multi-trophic aquaculture. [ABSTRACT FROM AUTHOR]

Grateloupia turuturu Yamada, 1941, is a red seaweed widely used for food in Japan and Korea which was recorded on the Atlantic Coast of Europe about twenty years ago. This seaweed presents eicosapentaenoic acid (EPA) and other polyunsaturated fatty acids (PUFAs) in its lipid fraction, a feature that sparked the interest on its potential applications. In seaweeds, PUFAs are mostly esterified to polar lipids, emerging as healthy phytochemicals. However, to date, these biomolecules are still unknown for G. turuturu. The present work aimed to identify the polar lipid profile of G. turuturu, using modern lipidomics approaches based on high performance liquid chromatography coupled to high resolution mass spectrometry (LC–MS) and gas chromatography coupled to mass spectrometry (GC–MS). The health benefits of polar lipids were identified by health lipid indices and the assessment of antioxidant and anti-inflammatory activities. The polar lipids profile identified from G. turuturu included 205 lipid species distributed over glycolipids, phospholipids, betaine lipids and phosphosphingolipids, which featured a high number of lipid species with EPA and PUFAs. The nutritional value of G. turuturu has been shown by its protein content, fatty acyl composition and health lipid indices, thus confirming G. turuturu as an alternative source of protein and lipids. Some of the lipid species assigned were associated to biological activity, as polar lipid extracts showed antioxidant activity evidenced by free radical scavenging potential for the 2,2′-azino-bis-3-ethyl benzothiazoline-6-sulfonic acid (ABTS●+) radical (IC50 ca. 130.4 μg mL−1) and for the 2,2-diphenyl-1-picrylhydrazyl (DPPH●) radical (IC25 ca. 129.1 μg mL−1) and anti-inflammatory activity by inhibition of the COX-2 enzyme (IC50 ca. 33 µg mL−1). Both antioxidant and anti-inflammatory activities were detected using a low concentration of extracts. This integrative approach contributes to increase the knowledge of G. turuturu as a species capable of providing nutrients and bioactive molecules with potential applications in the nutraceutical, pharmaceutical and cosmeceutical industries. [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]

Brown seaweeds are known to present components with appealing bioactive properties eliciting great interest for industrial applications. However, their lipid content is generally disregarded beyond their fatty acid (FA) composition. This study thoroughly characterized the lipid profile of two brown seaweeds collected from Portuguese coast, the native Bifurcaria bifurcata and the invasive Sargassum muticum species, and bioprospecting for antioxidant activity. An integrated state-of-the-art approach including gas chromatography-mass spectrometry (GC–MS) and liquid chromatography-mass spectrometry (HILIC–ESI-MS/MS), allowed a comprehensive picture of FA and polar lipid content. Polar lipid profile of B. bifurcata and S. muticum included 143 and 217 lipid species respectively, distributed between glycolipids, phospholipids, and betaine lipids. Some of the lipid species found have been assigned biological activity and contain of n-3 and n-6 FA. Sargassum muticum presented the highest n-3 FA content. Low concentrations of extracts of both seaweeds displayed antioxidant activity, with S. muticum presenting more promising results. These findings contribute to the nutritional and industrial exploitation of both seaweeds, highlighting their relevance as viable sources of bioactive and added-value compounds. Sargassum muticum presented interesting lipid composition and bioactivity, which may represent an accessible opportunity for the exploitation of this invasive seaweed, especially taking advantage of Sargassum blooms. [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]

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]