scholarly journals Lipotoxic stress alters the membrane lipid profile of extracellular vesicles released by Huh-7 hepatocarcinoma cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sandra Buratta ◽  
Y. Shimanaka ◽  
E. Costanzi ◽  
S. Ni ◽  
L. Urbanelli ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Cell Membrane ◽  
Er Stress ◽  
Extracellular Vesicles ◽  
Biological Properties ◽  
Membrane Lipid ◽  
Membrane Phospholipids ◽  
Δ9 Desaturase ◽  
Hepatocarcinoma Cells ◽  
Hepatic Lipotoxicity

AbstractExtracellular vesicles (EVs) are well-known mediators in intercellular communication playing pivotal roles in promoting liver inflammation and fibrosis, events associated to hepatic lipotoxicity caused by saturated free fatty acid overloading. However, despite the importance of lipids in EV membrane architecture which, in turn, affects EV biophysical and biological properties, little is known about the lipid asset of EVs released under these conditions. Here, we analyzed phospholipid profile alterations of EVs released by hepatocarcinoma Huh-7 cells under increased membrane lipid saturation induced by supplementation with saturated fatty acid palmitate or Δ9 desaturase inhibition, using oleate, a nontoxic monounsaturated fatty acid, as control. As an increase of membrane lipid saturation induces endoplasmic reticulum (ER) stress, we also analyzed phospholipid rearrangements in EVs released by Huh-7 cells treated with thapsigargin, a conventional ER stress inducer. Results demonstrate that lipotoxic and/or ER stress conditions induced rearrangements not only into cell membrane phospholipids but also into the released EVs. Thus, cell membrane saturation level and/or ER stress are crucial to determine which lipids are discarded via EVs and EV lipid cargos might be useful to discriminate hepatic lipid overloading and ER stress.

scholarly journals Haemophilus influenzae Rd Lacks a Stringently Conserved Fatty Acid Biosynthetic Enzyme and Thermal Control of Membrane Lipid Composition

2003 ◽  
Vol 185 (16) ◽  
pp. 4930-4937 ◽  
Author(s):  
Haihong Wang ◽  
John E. Cronan
Keyword(s):  
Fatty Acid ◽  
Haemophilus Influenzae ◽  
Growth Temperature ◽  
Acyl Carrier Protein ◽  
Thermal Control ◽  
Membrane Lipid ◽  
Membrane Phospholipids ◽  
E Coli ◽  
K 12

ABSTRACT The organization of the fatty acid synthetic genes of Haemophilus influenzae Rd is remarkably similar to that of the paradigm organism, Escherichia coli K-12, except that no homologue of the E. coli fabF gene is present. This finding is unexpected, since fabF is very widely distributed among bacteria and is thought to be the generic 3-ketoacyl-acyl carrier protein (ACP) synthase active on long-chain-length substrates. However, H. influenzae Rd contains a homologue of the E. coli fabB gene, which encodes a 3-ketoacyl-ACP synthase required for unsaturated fatty acid synthesis, and it seemed possible that the H. influenzae FabB homologue might have acquired the functions of FabF. E. coli mutants lacking fabF function are unable to regulate the compositions of membrane phospholipids in response to growth temperature. We report in vivo evidence that the enzyme encoded by the H. influenzae fabB gene has properties essentially identical to those of E. coli FabB and lacks FabF activity. Therefore, H. influenzae grows without FabF function. Moreover, as predicted from studies of the E. coli fabF mutants, H. influenzae is unable to change the fatty acid compositions of its membrane phospholipids with growth temperature. We also demonstrate that the fabB gene of Vibrio cholerae El Tor N16961 does not contain a frameshift mutation as was previously reported.

scholarly journals Polarization of Macrophages in Human Adipose Tissue is Related to the Fatty Acid Spectrum in Membrane Phospholipids

Nutrients ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 8 ◽  
Author(s):  
Rudolf Poledne ◽  
Hana Malinska ◽  
Hana Kubatova ◽  
Jiri Fronek ◽  
Filip Thieme ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Cell Membrane ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Human Adipose Tissue ◽  
Membrane Phospholipids ◽  
Anti Inflammatory ◽  
Inflammatory Macrophages

Residential macrophages in adipose tissue play a pivotal role in the development of inflammation not only within this tissue, but also affect the proinflammatory status of the whole body. Data on human adipose tissue inflammation and the role of macrophages are rather scarce. We previously documented that the proportion of proinflammatory macrophages in human adipose tissue correlates closely with non-HDL cholesterol concentrations. We hypothesized that this is due to the identical influence of diet on both parameters and decided to analyze the fatty acid spectrum in cell membrane phospholipids of the same individuals as a parameter of the diet consumed. Proinflammatory and anti-inflammatory macrophages were isolated from human adipose tissue (n = 43) and determined by flow cytometry as CD14+CD16+CD36high and CD14+CD16−CD163+, respectively. The spectrum of fatty acids in phospholipids in the cell membranes of specimens of the same adipose tissue was analyzed, and the proportion of proinflammatory macrophage increased with the proportions of palmitic and palmitoleic acids. Contrariwise, these macrophages decreased with increasing alpha-linolenic acid, total n-3 fatty acids, n-3/n-6 ratio, and eicosatetraenoic acid. A mirror picture was documented for the proportion of anti-inflammatory macrophages. The dietary score, obtained using a food frequency questionnaire, documented a positive relation to proinflammatory macrophages in individuals who consumed predominantly vegetable fat and fish, and individuals who consumed diets based on animal fat without fish and nut consumption. he present data support our hypothesis that macrophage polarization in human visceral adipose tissue is related to fatty acid metabolism, cell membrane composition, and diet consumed. It is suggested that fatty acid metabolism might participate also in inflammation and the risk of developing cardiovascular disease.

scholarly journals Effects of Glucomannan-Enriched, Aronia Juice-Based Supplement on Cellular Antioxidant Enzymes and Membrane Lipid Status in Subjects with Abdominal Obesity

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Nevena Kardum ◽  
Gordana Petrović-Oggiano ◽  
Marija Takic ◽  
Natalija Glibetić ◽  
Manja Zec ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Fatty Acids ◽  
Antioxidant Enzymes ◽  
Fatty Acid ◽  
Waist Circumference ◽  
Abdominal Obesity ◽  
Positive Impact ◽  
Membrane Lipid ◽  
Membrane Phospholipids ◽  
Anthropometric Parameters

The aim of this study was to analyze the effects of a 4-week-long consumption of glucomannan-enriched, aronia juice-based supplement on anthropometric parameters, membrane fatty acid profile, and status of antioxidant enzymes in erythrocytes obtained from postmenopausal women with abdominal obesity. Twenty women aged 45–65 with a mean body mass index (BMI) of 36.1 ± 4.4 kg/m2and waist circumference of 104.8 ± 10.1 cm were enrolled. Participants were instructed to consume 100 mL of supplement per day as part of their regular diet. A significant increase in the content of n-3 (P<0.05) polyunsaturated fatty acids in membrane phospholipids was observed, with a marked increase in the level of docosahexaenoic fatty acid (P<0.05). Accordingly, a decrease in the n-6 and n-3 fatty acids ratio was observed (P<0.05). The observed effects were accompanied with an increase in glutathione peroxidase activity (P<0.05). Values for BMI (P<0.001), waist circumference (P<0.001), and systolic blood pressure (P<0.05) were significantly lower after the intervention. The obtained results indicate a positive impact of tested supplement on cellular oxidative damage, blood pressure, and anthropometric indices of obesity.

Surface exposure of phosphatidylserine increases calcium oxalate crystal attachment to IMCD cells

1997 ◽  
Vol 272 (1) ◽  
pp. F55-F62 ◽  
Author(s):  
M. W. Bigelow ◽  
J. H. Wiessner ◽  
J. G. Kleinman ◽  
N. S. Mandel
Keyword(s):  
Cell Membrane ◽  
Calcium Oxalate ◽  
Specific Binding ◽  
Collecting Duct ◽  
Phospholipid Composition ◽  
Annexin V ◽  
Membrane Lipid ◽  
Critical Event ◽  
Membrane Composition ◽  
Membrane Phospholipids

The development of urolithiasis is a multifaceted process, starting at urine supersaturation and ending with the formation of mature renal calculi. The retention of microcrystals by the urothelial cell membrane is a critical event in the process. The current study examines calcium oxalate monohydrate (COM) crystal attachment to inner medullary collecting duct (IMCD) cells following selective changes in cell membrane phospholipid composition. Both primary culture of IMCD cells and a continuous IMCD cell line were used for these studies. Cell membrane composition was selectively altered by either exogenous addition of membrane phospholipids or using membrane lipid scrambling agents. Enrichment with anionic phospholipids was found to greatly increase attachment of crystals to the cells. This increased attachment correlated with the exposure of phosphatidylserine (PS) on the exofacial leaflet of the cell membrane as demonstrated by the use of the membrane scrambling agent A-23187. Furthermore, the increased COM attachment following PS exposure could be blocked by incubating the cells with the PS-specific binding protein, annexin V. These results support the hypothesis that exposure of PS head groups on the papillary epithelial cell surface may mediate stone crystal attachment to the kidney tubule cell epithelium in the renal papilla, possibly as an initiating event in urolithiasis.

scholarly journals A Brief Introduction to Some Aspects of the Fluid–Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 947
Author(s):  
Garth L. Nicolson ◽  
Gonzalo Ferreira de Mattos
Keyword(s):  
Membrane Proteins ◽  
Cell Membrane ◽  
Lipid Bilayers ◽  
Membrane Structure ◽  
Membrane Lipid ◽  
Membrane Domains ◽  
Membrane Phospholipids ◽  
Membrane Asymmetry ◽  
Extracellular Matrix Components ◽  
Membrane Components

Early cell membrane models placed most proteins external to lipid bilayers in trimolecular structures or as modular lipoprotein units. These thermodynamically untenable structures did not allow lipid lateral movements independent of membrane proteins. The Fluid–Mosaic Membrane Model accounted for these and other properties, such as membrane asymmetry, variable lateral mobilities of membrane components and their associations with dynamic complexes. Integral membrane proteins can transform into globular structures that are intercalated to various degrees into a heterogeneous lipid bilayer matrix. This simplified version of cell membrane structure was never proposed as the ultimate biomembrane description, but it provided a basic nanometer scale framework for membrane organization. Subsequently, the structures associated with membranes were considered, including peripheral membrane proteins, and cytoskeletal and extracellular matrix components that restricted lateral mobility. In addition, lipid–lipid and lipid–protein membrane domains, essential for cellular signaling, were proposed and eventually discovered. The presence of specialized membrane domains significantly reduced the extent of the fluid lipid matrix, so membranes have become more mosaic with some fluid areas over time. However, the fluid regions of membranes are very important in lipid transport and exchange. Various lipid globules, droplets, vesicles and other membranes can fuse to incorporate new lipids or expel damaged lipids from membranes, or they can be internalized in endosomes that eventually fuse with other internal vesicles and membranes. They can also be externalized in a reverse process and released as extracellular vesicles and exosomes. In this Special Issue, the use of membrane phospholipids to modify cellular membranes in order to modulate clinically relevant host properties is considered.

scholarly journals Absence of allergenic reactions to soy lecithin phospholipids used in Membrane Lipid Replacement studies

2021 ◽  
Vol 4 (1) ◽  
pp. 9
Author(s):  
Garth Nicolson
Keyword(s):  
Clinical Trials ◽  
Cell Membrane ◽  
Adverse Reactions ◽  
Control Strategies ◽  
Membrane Lipid ◽  
Food Allergens ◽  
Membrane Phospholipids ◽  
Positive Health ◽  
Soy Lecithin ◽  
Good Manufacturing Practices

Membrane Lipid Replacement (MLR) is the functional use of dietary supplements containing cell membrane glycerolphospholipids and antioxidants to safely replace and remove damaged membrane phospholipids that accumulate during various chronic and acute illnesses and during aging.  Some products used in MLR are obtained from soy lecithin extracts that contain cell membrane glycerolphospholipids.  Thus the soybean source has been questioned because of concerns related to genetic engineering (GMO) and the potential presence of hormone-like components or soy allergens. There is a complete lack of proteins or glycoproteins in soy lecithins and MLR supplements that could be allergenic.  One lecithin product that contains purified membrane phospholipids (NTFactor Lipids®) has been shown to produce significant positive health benefits in clinical trials. NTFactor Lipids® are fractionated and purified from non-GMO soy lecithin, and this formulation does not contain detectable amounts of protein or glycoprotein allergens or other components that could elicit allergic or non-allergic adverse reactions.  In addition, allergic and non-allergic reactions have not been found in multiple clinical trials and studies that have utilized this dietary supplement.  NTFactor Lipids® are manufactured in certified Good Manufacturing Practices (cGMP) facilities using established allergen-control strategies to minimize any cross-contact with food allergens. Keywords: Phospholipids, Clinical trials, Allergies, Cellular membranes

Repetitive amiodarone administration causes liver damage via adipose tissue ER-stress dependent lipolysis, leading to hepatotoxic free fatty acid accumulation

2021 ◽  
Author(s):  
Einav Hubel ◽  
Sigal Fishman ◽  
Minna Holopainen ◽  
Reijo Käkelä ◽  
Ortal Schaffer ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Er Stress ◽  
Liver Damage ◽  
De Novo ◽  
Drug Induced ◽  
Protein Levels ◽  
Hepatic Lipotoxicity ◽  
Stress Dependent

Drug-induced liver injury is an emerging form of acute and chronic liver disease that may manifest as fatty liver. Amiodarone (AMD), a widely used anti-arrhythmic drug, can cause hepatic injury and steatosis by a variety of mechanisms, not all completely understood. We hypothesized that repetitive AMD administration may induce hepatic lipotoxicity not only via effects on the liver, but also via effects on adipose tissue. Indeed, repetitive AMD administration induced endoplasmic reticulum (ER) stress in both liver and adipose tissue. In adipose tissue, AMD reduced lipogenesis and increased lipolysis. Moreover, AMD treatment induced ER stress and ER stress-dependent lipolysis in 3T3L1 adipocytes in vitro. In the liver, AMD caused increased expression of genes encoding proteins involved in fatty acid (FA) uptake and transfer (Cd36, Fabp1 and Fabp4) and resulted in increased hepatic accumulation of free FAs, but not of triacylglycerols. In line with this, there was increased expression of hepatic de novo FA synthesis genes. However, AMD significantly reduced the expression of the desaturase Scd1 and elongase Elovl6, detected at mRNA and protein levels. Accordingly, the FA profile of hepatic total lipids revealed increased accumulation of palmitate, a SCD1 and ELOVL6 substrate, and reduced levels of palmitoleate and cis-vaccenate, products of the enzymes. In addition, AMD-treated mice displayed increased hepatic apoptosis. The studies show that repetitive AMD induces ER stress and aggravates lipolysis in adipose tissue, while inducing a lipotoxic hepatic lipid environment, suggesting that AMD-induced liver damage is due to compound insult to liver and adipose tissue.

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