Omega-3 polyunsaturated fatty acids do not fluidify bilayers in the liquid-crystalline state

Santis, Augusta De; Varela, Yaiza R.; Sot, Jesús; D’Errico, Gerardino; Goñi, Félix M.; Alonso, Alicia

doi:10.1038/s41598-018-34264-3

Cited by 21 publications

(18 citation statements)

References 31 publications

(47 reference statements)

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“…While this is often proposed as a mechanism for PUFA functions, it is rarely shown quantitatively that the gain of fluidity (here defined as the speed of molecules’ diffusion and rotation) by PUFAs (compared with MUFAs) is sufficient to explain a phenomenon. The role of PUFAs in fluidity regulation has even been questioned ( 84 ). A recent study combined theoretical and experimental approaches to demonstrate that bacterial respiration is a diffusion-limited process and that MUFAs have quantitatively enough impact on this process ( 85 ).…”

Section: Membrane Pufasmentioning

confidence: 99%

Roles of polyunsaturated fatty acids, from mediators to membranes

Harayama

Shiraishi

2020

Journal of Lipid Research

107

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Polyunsaturated fatty acids (PUFAs), such as arachidonic acid and docosahexaenoic acid, are recognized as important biomolecules, but understanding their precise roles and modes of action remains challenging. PUFAs are precursors for a plethora of signaling lipids, for which knowledge about synthetic pathways and receptors has accumulated. However, due to their extreme diversity and the ambiguity concerning the identity of their cognate receptors, the roles of PUFA-derived signaling lipids require more investigation. In addition, PUFA functions cannot be explained just as lipid mediator precursors, since they are also critical for the regulation of membrane biophysical properties. The presence of PUFAs in membrane lipids also affects the functions of transmembrane proteins and peripheral membrane proteins. Although the roles of PUFAs as membrane lipid building blocks were difficult to analyze, the discovery of lysophospholipid acyltransferases, which are critical for their incorporation, advanced our understanding. Recent studies unveiled how lysophospholipid acyltransferases affect PUFA levels in membrane lipids, and their genetic manipulation became an excellent strategy to study the roles of PUFA-containing lipids. In this review, we will provide an overview of metabolic pathways regulating PUFAs as lipid mediator precursors and membrane components, and update recent progress about their functions. Some issues to be solved for future research will also be discussed.

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Section: Membrane Pufasmentioning

confidence: 99%

Roles of polyunsaturated fatty acids, from mediators to membranes

Harayama

Shiraishi

2020

Journal of Lipid Research

107

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“…Sonicated SUV were obtained with a probe-type Soniprep 150 sonicator (MSK, London, UK). Fluorescence measurements were performed using a QuantaMaster 40 spectrofluorometer (Photon Technology International, Lawrenceville, NJ, USA) [33].…”

Section: Fluorescence Spectrometric Analysismentioning

confidence: 99%

Patches and Blebs: A Comparative Study of the Composition and Biophysical Properties of Two Plasma Membrane Preparations from CHO Cells

Monasterio

Jiménez‐Rojo

García-Arribas

et al. 2020

IJMS

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This study was aimed at preparing and characterizing plasma membranes (PM) from Chinese Hamster Ovary (CHO) cells. Two methods of PM preparation were applied, one based on adhering cells to a poly-lysine-coated surface, followed by hypotonic lysis and removal of intracellular components, so that PM patches remain adhered to each other, and a second one consisting of bleb induction in cells, followed by separation of giant plasma membrane vesicles (GPMV). Both methods gave rise to PM in sufficient amounts to allow biophysical and biochemical characterization. Laurdan generalized polarization was used to measure molecular order in membranes, PM preparations were clearly more ordered than the average cell membranes (GP ≈0.450 vs. ≈0.20 respectively). Atomic force microscopy was used in the force spectroscopy mode to measure breakthrough forces of PM, both PM preparations provided values in the 4–6 nN range, while the corresponding value for whole cell lipid extracts was ≈2 nN. Lipidomic analysis of the PM preparations revealed that, as compared to the average cell membranes, PM were enriched in phospholipids containing 30–32 C atoms in their acyl chains but were relatively poor in those containing 34–40 C atoms. PM contained more saturated and less polyunsaturated fatty acids than the average cell membranes. Blebs (GPMV) and patches were very similar in their lipid composition, except that blebs contained four-fold the amount of cholesterol of patches (≈23 vs. ≈6 mol% total membrane lipids) while the average cell lipids contained 3 mol%. The differences in lipid composition are in agreement with the observed variations in physical properties between PM and whole cell membranes.

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“…Then, the sample was kept under vacuum for 2 h to remove solvent traces and the lipids were swollen in buffer (NaCl 150 mM, Hepes 25 mM, pH 7.4). Sonicated SUV were obtained as described above and fluorescence measurements were performed using a QuantaMaster 40 spectrofluorometer (Photon Technology International, Lawrenceville, NJ) 52 .…”

Section: Image Acquisition and Analysismentioning

confidence: 99%

CHO/LY-B cell growth under limiting sphingolipid supply: correlation between lipid composition and biophysical properties of sphingolipid-restricted cell membranes⁺

Monasterio

Jiménez‐Rojo

García-Arribas

et al. 2020

Preprint

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ABSTRACTSphingolipids (SL) are ubiquitous in mammalian cell membranes, yet there is little data on the behavior of cells under SL-restriction conditions. LY-B cells derive from a CHO line in which serine palmitoyl transferase (SPT), thus de novo SL synthesis, is suppressed, while maintaining the capacity of taking up and metabolizing exogenous sphingoid bases from the culture medium. In the present study LY-B cells were adapted to grow in a fetal bovine serum (FBS)-deficient medium to avoid external uptake of lipids. The lowest FBS concentration that allowed LY-B cell growth, though at a slow rate, under our conditions was 0.04%, i.e. 250-fold less than the standard (10%) concentration. Cells grown under limiting SL concentrations remained viable for at least 72 h. Enriching with sphingomyelin the SL-deficient medium allowed the recovery of control LY-B cell growth rates. Studies including whole cells, plasma membrane preparations, and derived lipid vesicles were carried out. Laurdan fluorescence was recorded to measure membrane molecular order, showing a significant decrease in the rigidity of LY-B cells, not only in plasma membrane but also in whole cell lipid extract, as a result of SL limitation in the growth medium. Plasma membrane preparations and whole cell lipid extracts were also studied using atomic force microscopy in the force spectroscopy mode. Force measurements demonstrated that lower breakthrough forces were required to penetrate samples obtained from SL-poor LY-B cells than those obtained from control cells. Mass-spectroscopic analysis was also a helpful tool to understand the rearrangement undergone by the LY-B cell lipid metabolism. The most abundant SL in LY-B cells, sphingomyelin, decreased by about 85% as a result of SL limitation in the medium, the bioactive lipid ceramide and the ganglioside precursor hexosylceramide decreased similarly, together with cholesterol. Quantitative SL analysis showed that a 250-fold reduction in sphingolipid supply to LY-B cells led to a 6-fold decrease in membrane sphingolipids, underlining the resistance to changes in composition of these cells. Plasma membrane compositions exhibited similar changes, at least qualitatively, as the whole cells with SL restriction. A linear correlation was observed between the sphingomyelin concentration in the membranes, the degree of lipid order as measured by laurdan fluorescence, and membrane breakthrough forces assessed by atomic force microscopy. Concomitant changes were detected in glycerophospholipids under SL-restriction conditions.

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Omega-3 polyunsaturated fatty acids do not fluidify bilayers in the liquid-crystalline state

Cited by 21 publications

References 31 publications

Roles of polyunsaturated fatty acids, from mediators to membranes

Roles of polyunsaturated fatty acids, from mediators to membranes

Patches and Blebs: A Comparative Study of the Composition and Biophysical Properties of Two Plasma Membrane Preparations from CHO Cells

CHO/LY-B cell growth under limiting sphingolipid supply: correlation between lipid composition and biophysical properties of sphingolipid-restricted cell membranes⁺

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Omega-3 polyunsaturated fatty acids do not fluidify bilayers in the liquid-crystalline state

Cited by 21 publications

References 31 publications

Roles of polyunsaturated fatty acids, from mediators to membranes

Roles of polyunsaturated fatty acids, from mediators to membranes

Patches and Blebs: A Comparative Study of the Composition and Biophysical Properties of Two Plasma Membrane Preparations from CHO Cells

CHO/LY-B cell growth under limiting sphingolipid supply: correlation between lipid composition and biophysical properties of sphingolipid-restricted cell membranes+

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CHO/LY-B cell growth under limiting sphingolipid supply: correlation between lipid composition and biophysical properties of sphingolipid-restricted cell membranes⁺