scholarly journals Effect of membrane cholesterol on dynamical properties of solvent molecules

2021 ◽  
Author(s):  
Hadi Rahmaninejad ◽  
Darin D. Vaughan
Keyword(s):  
Cell Function ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Membrane Cholesterol ◽  
Concentration Gradients ◽  
Critical Feature ◽  
Membrane Lipid Composition ◽  
Close Proximity ◽  
Dynamical Properties ◽  
Solvent Molecules

AbstractMembrane lipid composition is a critical feature of cell function, where cholesterol is a major lipid sterol component that influences the membranes physical and electrical properties. The effects of cholesterol on transport properties between adjacent to the cells, especially in junctions formed between cells is not completely understood. These junctions where substances transport and signaling is critical may be affected by modifying the cholesterol composition of the membrane in these junctional regions. Here we show how the cholesterol content in a membrane can regulate these phenomena by changing their effect on transport into and through regions between cell membranes in close proximity. Through geometric and electrostatic effects interaction with substrates, the properties of the fluid between membranes are shown to potentially enforce concentration gradients of dissolved compounds that may be biologically significant.

Relationship between body size, Na+-K+-ATPase activity, and membrane lipid composition in mammal and bird kidney

2005 ◽  
Vol 288 (1) ◽  
pp. R301-R310 ◽  
Author(s):  
Nigel Turner ◽  
Kurt L. Haga ◽  
A. J. Hulbert ◽  
Paul L. Else
Keyword(s):  
Body Size ◽  
Atpase Activity ◽  
Lipid Composition ◽  
Unsaturated Fatty Acids ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Enzyme Concentration ◽  
Membrane Lipid Composition ◽  
Mass Scaling ◽  
Metabolic Intensity

We investigated the relationship between body size, Na+-K+-ATPase molecular activity, and membrane lipid composition in the kidney of five mammalian and eight avian species ranging from 30-g mice to 280-kg cattle and 13-g zebra finches to 35-kg emus, respectively. Na+-K+-ATPase activity was found to be higher in the smaller species of both groups. In small mammals, the higher Na+-K+-ATPase activity was primarily the result of an increase in the molecular activity (turnover rate) of individual enzymes, whereas in small birds the higher Na+-K+-ATPase activity was the result of an increased enzyme concentration. Phospholipids from both mammals and birds contained a relatively constant percentage of unsaturated fatty acids; however, phospholipids from the smaller species were generally more polyunsaturated, and a complementary significant allometric increase in monounsaturate content was observed in the larger species. In particular, the relative content of the highly polyunsaturated docosahexaenoic acid [22:6( n-3)] displayed the greatest variation with body mass, scaling with allometric exponents of −0.21 and −0.26 in the mammals and birds, respectively. This allometric variation in fatty acid composition was correlated with Na+-K+-ATPase molecular activity in mammals, whereas in birds molecular activity only correlated with membrane cholesterol content. These relationships are discussed with respect to the metabolic intensity of different-sized animals.

Mitochondrial cholesterol content and membrane properties in porcine myocardial ischemia

1982 ◽  
Vol 242 (2) ◽  
pp. H254-H259 ◽  
Author(s):  
W. Rouslin ◽  
J. MacGee ◽  
S. Gupte ◽  
A. Wesselman ◽  
D. E. Epps
Keyword(s):  
Myocardial Ischemia ◽  
Mitochondrial Membrane ◽  
Total Phospholipid ◽  
Membrane Damage ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Membrane Properties ◽  
Phospholipid Content ◽  
Membrane Cholesterol ◽  
Membrane Microviscosity

Regional myocardial ischemia was produced in anesthetized pigs by occluding the left anterior descending coronary artery. Mitochondria were prepared from both normally perfused and ischemic myocardium after 2 h of occlusion. Mitochondria from the ischemic area exhibited an 89% increase in cholesterol content from 32.7 +/- 1.9 (control) to 62.0 +/- 0.47 (ischemic) nmol/mg protein with no change in either total phospholipid content or in membrane fatty acid composition. This increase in mitochondrial membrane cholesterol was accompanied by an increase in membrane microviscosity as indicated by increased fluorescence polarization using the fluorescent membrane probe, 1,6-diphenyl-1,3,5-hexatriene. In these same experiments the Arrhenius plot discontinuity temperature of oligomycin-sensitive adenosinetriphosphatase (ATPase) activity fell from 20.0 to 14.2 degrees C. Our results suggest that, during the myocardial ischemic process in pigs, there is an intracellular redistribution of free cholesterol that produces a marked increase in mitochondrial membrane cholesterol content. This appears to produce an altered mitochondrial membrane lipid bilayer packing, resulting in increased membrane microviscosity and, possibly, altered inner membrane ATPase function. Intracellular cholesterol redistribution may thus contribute to the cell membrane damage that occurs during the myocardial ischemic process.

Inhibition of Platelet Aggregation by Ethanol in Vitro Shows Specificity for Aggregating Agent Used and Is Influenced by Platelet Lipid Composition

1982 ◽  
Vol 48 (01) ◽  
pp. 049-053 ◽  
Author(s):  
C G Fenn ◽  
J M Littleton
Keyword(s):  
Platelet Aggregation ◽  
Lipid Composition ◽  
Saturated Fatty Acids ◽  
Calcium Ionophore ◽  
Cholesterol Content ◽  
Membrane Lipid ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Increased Sensitivity

SummaryEthanol at physiologically tolerable concentrations inhibited platelet aggregation in vitro in a relatively specific way, which may be influenced by platelet membrane lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin (low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses were little affected, and aggregation to exogenous arachidonic acid was actually potentiated by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol in platelets enriched with saturated fatty acids than in those enriched with unsaturated fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate and adrenaline but this increase in cholesterol content did not appear to influence the inhibition by ethanol of platelet responses. The results suggest that ethanol may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization resulting in decreased activity of a membrane-bound phospholipase.

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