Epilipidomics platform for holistic profiling of oxidized complex lipids in blood plasma of obese individuals

Lipids are a structurally diverse class of biomolecules which can undergo a variety of chemical modifications. Among them, lipid (per)oxidation attracts most of the attention due to its significance in regulation of inflammation, cell proliferation and death programs. Despite their apparent regulatory significance, the molecular repertoire of oxidized lipids remains largely elusive as accurate annotation of lipid modifications is challenged by their low abundance and largely unknown, biological context-dependent structural diversity. Here we provide a holistic workflow based on the combination of bioinformatics and LC-MS/MS technologies to support identification and relative quantification of oxidized complex lipids in a modification type- and position-specific manner. The developed methodology was used to identify epilipidomics signatures of lean and obese individuals with and without type II diabetes. Characteristic signature of lipid modifications in lean individuals, dominated by the presence of modified octadecanoid acyl chains in phospho- and neutral lipids, was drastically shifted towards lipid peroxidation-driven accumulation of oxidized eicosanoids, suggesting significant alteration of endocrine signalling by oxidized lipids in metabolic disorders.

Bioactivities of Lipid Extracts and Complex Lipids from Seaweeds: Current Knowledge and Future Prospects

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.

Special Issue: Dynamics and Nano-Organization in Plasma Membranes

Cell membranes develop extraordinarily complex lipids and proteins geared to perform functions required by cells. [...]

Alterations in complex lipids in tumor tissue of patients with colorectal cancer

Background Accumulating evidence indicates alterations in lipid metabolism and lipid composition in neoplastic tissue. Earlier nuclear magnetic resonance studies showed that the contents of major lipid groups, such as triacylglycerols, phospholipids and cholesterol, are changed in colon cancer tissue. Methods In this study, a more detailed analysis of lipids in cancer and tumor adjacent tissues from colorectal cancer patients, using liquid chromatography–mass spectrometry, allowed for comparison of 199 different lipids between cancer tissue and tumor adjacent tissue using principal component analysis. Results Significant differences were found in 67 lipid compounds between the two types of tissue; many of these lipid compounds are bioactive lipids such as ceramides, lysophospholipids or sterols and can influence the development of cancer. Additionally, increased levels of phospholipids and sphingolipids were present, which are major components of the cell membrane, and increases in these lipids can lead to changes in cell membrane properties. Conclusions This study showed that many complex lipids are significantly increased or decreased in colon cancer tissue, reflecting significant alterations in lipid metabolism. This knowledge can be used for the selection of potential molecular targets of novel anticancer strategies based on the modulation of lipid metabolism and the composition of the cell membrane in colorectal cancer cells.

Sphingolipids of Asteroidea and Holothuroidea: Structures and Biological Activities

Sphingolipids are complex lipids widespread in nature as structural components of biomembranes. Commonly, the sphingolipids of marine organisms differ from those of terrestrial animals and plants. The gangliosides are the most complex sphingolipids characteristic of vertebrates that have been found in only the Echinodermata (echinoderms) phylum of invertebrates. Sphingolipids of the representatives of the Asteroidea and Holothuroidea classes are the most studied among all echinoderms. In this review, we have summarized the data on sphingolipids of these two classes of marine invertebrates over the past two decades. Recently established structures, properties, and peculiarities of biogenesis of ceramides, cerebrosides, and gangliosides from starfishes and holothurians are discussed. The purpose of this review is to provide the most complete information on the chemical structures, structural features, and biological activities of sphingolipids of the Asteroidea and Holothuroidea classes.

Involvement of lipids in immune system regulation: A mini-review

An immune system recognizes and responds to antigens entering the body. Maintaining these roles, components of the immune system need energy obtained from nutrients such as carbohydrates, proteins, and lipids. This study reviews and discusses roles of lipids, particularly fatty acids, in regulations of the immune system. This study was conducted by conducting a literature study on published research articles written in English. The articles were obtained from PubMed and Google Scholar by using search keywords: lipid, fatty acids, immune, regulation, inflammation, and response. Lipids are a group of biomolecule compounds composed of carbon, oxygen, and hydrogen, and they are classified into simple, compound and complex lipids. Fatty acids are compound lipids that act as a main fuel for metabolism, an essential component for all membranes, and a gene regulator. Fatty acids have a modulating effect on immune cells, such as: acting as a host defence, activating the immune system, interacting with nuclear transcription factors, playing roles in inflammatory responses, promoting apoptosis, as well as influencing lymphocyte proliferation, cytokine production, and Natural Killer (NK) cell activities. However, the modulation of the immune system by lipids is influenced by various factors such as concentration and types of fatty acids, types of immune cells, and species. This study is suggested to provide an overview of beneficial roles of lipids in maintaining immunity.

NMR Methods for Determining Lipid Turnover via Stable Isotope Resolved Metabolomics

Lipids comprise diverse classes of compounds that are important for the structure and properties of membranes, as high-energy fuel sources and as signaling molecules. Therefore, the turnover rates of these varied classes of lipids are fundamental to cellular function. However, their enormous chemical diversity and dynamic range in cells makes detailed analysis very complex. Furthermore, although stable isotope tracers enable the determination of synthesis and degradation of complex lipids, the numbers of distinguishable molecules increase enormously, which exacerbates the problem. Although LC-MS-MS (Liquid Chromatography-Tandem Mass Spectrometry) is the standard for lipidomics, NMR can add value in global lipid analysis and isotopomer distributions of intact lipids. Here, we describe new developments in NMR analysis for assessing global lipid content and isotopic enrichment of mixtures of complex lipids for two cell lines (PC3 and UMUC3) using both 13C6 glucose and 13C5 glutamine tracers.

Effect of Life Stress on Incidence of Fatty Liver Disease

We hear about fatty liver more and more often: at least one European adult in five suffers from it and pediatric cases are also on the rise, a consequence of childhood obesity of epidemic proportions in recent years. The cause is metabolic : liver cells normally combine free fatty acids in the blood - introduced with the diet and produced by metabolism - with sugars, giving rise to complex lipids such as triglycerides, which can be accumulated in the liver for storage and energy reserve and to be exploited if necessary. Overweight, dyslipidemia, diabetes, bowel disease or abuse of certain medications (like cortisones) can increase the workload on the liver which is thus storing more fat than necessary. Feeling nervous when stressed is completely natural. This is a short-term stress sign. Chronic stress, on the other hand, is characterized by prolonged symptoms, including breathing difficulties, dizziness, decreased desire, chest pains and fatigue. Many of these symptoms are immediately identifiable by the sufferer. However, the impact of stress is not only visible externally. Inside, our bodies desperately struggle to restore a natural balance. This chemical disruption caused by chronic stress affects many other biological features. This article highlights the effect of stress on fatty liver.