Influence of cholesterol on sphingomyelin metabolism and hemileaflet fluidity of rat liver plasma membranes

Nikolova‐Karakashian, Mariana; Petkova, Hristina; Koumanov, Kamen

doi:10.1016/0300-9084(92)90040-l

Cited by 16 publications

(6 citation statements)

References 43 publications

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“…Trinitrophenylation of plasma membranes was carried out as before (Nikolova‐Karakashian et al., 1992) by incubation with 2 mM TNBS in 0.8 M NaHCO 3 (pH 8.3) for 30 min on ice to label the amine moieties in the outer membrane monolayer. The reaction was terminated by the addition of HCl.…”

Section: Methodsmentioning

confidence: 99%

“…Individual leaflet fluidity measurement was based on the procedure of Schroeder (1985), with slight modifications (Nikolova‐Karakashian et al., 1992). The mechanism involves partitioning of the fluorescent probes (donor) into both leaflets of cellular plasma membranes linked to a quenching agent (acceptor) attached to only the outer membrane monolayer.…”

Section: Methodsmentioning

confidence: 99%

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Cell culturing in a three‐dimensional matrix affects the localization and properties of plasma membrane cholesterol

Stefanova

Staneva

Petkova

et al. 2009

Cell Biology International

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Most in vitro studies use 2-dimensional (2D) monolayer cultures, where cells are forced to adjust to unnatural substrates that differ significantly from the natural 3-dimensional (3D) extracellular matrix that surrounds cells in living organisms. Our analysis demonstrates significant differences in the cholesterol and sphingomyelin content, structural organization and cholesterol susceptibility to oxidation of plasma membranes isolated from cells cultured in 3D cultures compared with conventional 2D cultures. Differences occurred in the asymmetry of cholesterol molecules and the physico-chemical properties of the 2 separate leaflets of plasma membranes in 2D and 3D cultured fibroblasts. Transmembrane distribution of other membrane phospholipids was not different, implying that the cholesterol asymmetry could not be attributed to alterations in the scramblase transport system. Differences were also established in the chemical activity of cholesterol, assessed by its susceptibility to cholesterol oxidase in conventional and "matrix" cell cultures. The influence of plasma membrane sphingomyelin and phospholipid content on cholesterol susceptibility to oxidation in 2D and 3D cells was investigated with exogenous sphingomyelinase (SMase) and phospholipase C (PLC) treatment. Sphingomyelin was more effective than membrane phospholipids in protecting cholesterol from oxidation. We presume that the higher cholesterol/sphingomyelin molar ratio is the reason for the higher rate of cholesterol oxidation in plasma membranes of 3D cells.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cell culturing in a three‐dimensional matrix affects the localization and properties of plasma membrane cholesterol

Stefanova

Staneva

Petkova

et al. 2009

Cell Biology International

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“…Studies have often relied on RBCs, since they lack internal membranes, and exoplasmic quenchers or headgroup-specific chemistries to probe individual leaflets. However, even these seemingly simple methods yielded contradictory conclusions, with some studies inferring a more fluid inner PM leaflet 18,19 (18,19) and others a more fluid outer leaflet (20)(21)(22)(23)(24)(25). Ultimately, the presence and nature of biophysical asymmetry in mammalian membranes remains unresolved because of several limitations inherent to methodologies that rely on lipid-based probes and fluorescence quenchers (see Supplementary Text).…”

Section: Introductionmentioning

confidence: 99%

The mammalian plasma membrane is defined by transmembrane asymmetries in lipid unsaturation, leaflet packing, and protein shape

Lorent

Levental

Ganesan

et al. 2019

Preprint

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A fundamental feature of cellular plasma membranes (PM) is the asymmetric distribution of lipids between the bilayer leaflets. This asymmetry is central to cellular physiology, regulating signaling, apoptosis, coagulation, and cell-cell fusion. While the broad transbilayer distributions of some lipid types are well established, the detailed lipidomic asymmetry of the PM has not been characterized and thus the compositions of the individual leaflets remain poorly understood. Further, how these compositional differences contribute to structural asymmetries between PM leaflets in living cells is not defined. Here, we report the distinct lipidomes and biophysical properties of both monolayers in living mammalian PMs. Using mass spectrometry coupled to enzymatic digestion, we report the detailed compositions of PM leaflets of human erythrocytes. We find a dramatic asymmetry in phospholipid unsaturation, with the cytoplasmic leaflet being ~2-fold more unsaturated than the exoplasmic. Atomistic simulations of lipid mixtures compiled from the lipidomic observations suggested significant asymmetries in lipid order, packing, and dynamics between the two PM leaflets. These were probed directly in the PM of living cells by Fluorescence Lifetime Imaging Microscopy (FLIM) of leaflet-selective, environment-sensitive probes. The outer PM leaflet is highly packed and ordered, resembling a liquid ordered phase, whereas the inner leaflet is significantly more disordered. This biophysical asymmetry is maintained in the endocytic system. These observations reveal the detailed compositional and biophysical asymmetry of mammalian plasma membranes, elucidating fundamental design principles of living membranes. SIGNIFICANCE STATEMENT:The asymmetric distribution of lipids between the two bilayer leaflets is a fundamental feature of mammalian plasma membranes. Here, we quantify the comprehensive lipidomes of the two PM leaflets in living mammalian cells and examine their consequences on leaflet physical properties. Using computer simulations, we predict distinct biophysical features for the two leaflets and confirm these with a variety of spectroscopic and microscopic techniques. We find that the outer leaflet of the membrane contains many more fully saturated lipids, which endows it with higher lipid packing and lower diffusivity.

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“…At 90 th day of treatment no signifi cant changes in phospholipid and cholesterol content were observed. That might be a result of some compensatory processes which prevent further enhancement of cholesterol/phospholipid (CH/PL) ratio which is very important for the membrane function (34). The separate phospholipid species didn't undergo signifi cant changes during the time of experiment (data not shown) except the percent participation of phosphatidylserine (PS) in the total phospholipid content that increased about 1.7 fold compared to the control value.…”

Section: Resultsmentioning

confidence: 94%

Effect of 1,2 - Dymethylhydrazine on Sphingomyelin Metabolism and Protein Kinase Activities in Rat Liver

Petkova

2007

Biotechnology & Biotechnological Equipment

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Influence of cholesterol on sphingomyelin metabolism and hemileaflet fluidity of rat liver plasma membranes

Cited by 16 publications

References 43 publications

Cell culturing in a three‐dimensional matrix affects the localization and properties of plasma membrane cholesterol

Cell culturing in a three‐dimensional matrix affects the localization and properties of plasma membrane cholesterol

The mammalian plasma membrane is defined by transmembrane asymmetries in lipid unsaturation, leaflet packing, and protein shape

Effect of 1,2 - Dymethylhydrazine on Sphingomyelin Metabolism and Protein Kinase Activities in Rat Liver

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