Interaction of a human plasma lipid transfer protein complex with lipid monolayers

Harmony, Judith A.K.; Jackson, Richard L.; Ihm, Jahei; Ellsworth, Jeff L.; Demel, R.A.

doi:10.1016/0005-2736(82)90325-x

Cited by 12 publications

(4 citation statements)

References 36 publications

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“…The isotherm of the neutral mixture and that of DOPC are quite similar throughout. The area measured for DOPC is in excellent agreement with previously published data. , …”

Section: Resultssupporting

confidence: 91%

Surface Properties of Dioleoyl-sn-glycerol-3-ethylphosphocholine, a Cationic Phosphatidylcholine Transfection Agent, Alone and in Combination with Lipids or DNA

et al. 2006

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Long-chain cationic amphipaths are routinely used for transfecting DNA into cells, although the mechanism of DNA delivery by these agents is poorly understood. Since their interfacial properties are undoubtedly involved at some stage in the process, a comprehensive study of the surface behavior of at least one of these compounds is highly desirable. Hence, the behavior of the cationic transfection agent EDOPC (dioleoyl-sn-glycerol-3-ethylphosphocholine or O-ethyldioleoylphosphatidylcholine), has been characterized at the air-water interface, by itself and in mixtures with other phospholipids. Surface pressure-molecular area isotherms obtained at the argon-buffer interface revealed that EDOPC is considerably (5-10 A(2)) more expanded than the parent phosphatidylcholine (DOPC) and even more expanded than the corresponding phosphatidylglycerol (DOPG), which has a similar charge density (of opposite polarity) as EDOPC. A 1:1 mixture of EDOPC and DOPG is very slightly condensed relative to DOPG and considerably condensed relative to EDOPC. The surface/dipole potential of this mixture is the mean of those of EDOPC and DOPG and is almost the same as that of DOPC. When the composition of EDOPC mixtures was varied, several surface parameters, including surface dipole moment, collapse pressure, and compressibility, exhibited discontinuities at a 1:1 mole ratio. EDOPC is unusually surface-active; the equilibrium surface tension of its dispersion was lower and the rate of fall of the surface tension (dynamic surface activity) of a dispersion with an initially clean surface was more than an order of magnitude greater than that for dispersions of DOPG. A 1:1 mixture of the cationic lipoid and phosphatidylglycerol had lower surface activity than DOPC in water but similar surface activity in 0.1 NaCl. Analysis, in terms of surface concentration, of the formation of EDOPC monolayers at the air interface of vesicle dispersions revealed a simple exponential rise to a maximum, at least for higher concentrations. Addition of a small proportion of DNA to EDOPC increased its dynamic surface activity even though DNA alone has no detectable surface activity at the concentrations used. This enhancement by DNA is presumably due to the disruption of the continuity of the bilayer and creation of defects from which lipoid spreads readily. The surface properties of this cationic compound, both alone and in combination with anionic lipids, provide insight into the previously described nonbilayer phase preferences of cationic-anionic lipid mixtures. In addition, they provide critical data (area condensation of mixed cationic-anionic monolayers) supporting a previously proposed mechanism of fusion of cationic bilayers with anionic bilayers. Such a process, involving anionic cellular membranes, is believed to be required for release of DNA from lipoplexes and is therefore a key stage of transfection.

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“…The isotherm of the neutral mixture and that of DOPC are quite similar throughout. The area measured for DOPC is in excellent agreement with previously published data. , …”

Section: Resultssupporting

confidence: 91%

Surface Properties of Dioleoyl-sn-glycerol-3-ethylphosphocholine, a Cationic Phosphatidylcholine Transfection Agent, Alone and in Combination with Lipids or DNA

et al. 2006

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“…Keto derivatives show, due to a lower polarity, a lower interracial stability and an increased molecular area [8]. Long chain cholesteryl ester derivatives as cholesteryl oleate from hardly monomolecular layers in a pure form [29]. These observations have led previously to the assumption that a 3fl-hydroxyl group is essential for membrane sterols [7].…”

Section: Discussionmentioning

confidence: 99%

The effect of the sterol oxygen function on the interaction with phospholipids

Demel

Lala

Kumari

et al. 1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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The effect of cholesteryi ethers (namely cholesteryl methyl ether, cholesteryi ethyl ether, cholesteryl n-propyl ether, cholesteryi isopropyl ether, cholesteryi butyl ether, cholesteryl methoxymethyl ether, cholesteryl (2'-hydroxy)-3-ethyl ether) and cholesteryl ester (namely cholesteryi acetate) is tested on the interaction with phosphatidylcholines in liquid-crystalline and crystalline state. The interfacial properties of sterols are tested at the air-water interface. The cholesteryl ethers show a reduced interracial stability with increasing hydrophobicity of the ether-linked moiety. The interaction between the sterol derivatives and phospholipids in mixed monolayers is indicated by measuring the deviation from the simple addivity rule (condensing effect). An interaction is found only for cholesteryl (2'-hydroxy)-3-ethyl ether, cholesteryl methyl ether and cholesteryl ethyl ether. These sterols also reduce the glucose permeability of liposomal membranes in this order. In this respect cholesteryl (2'-hydroxy)-3-ethyl ether is as effective as cholesterol. Cholesteryl methyl ether and cholesteryl ethyl ether show 62 and 33 percent of the effect observed with cholesterol. The effect of the sterol derivatives on the gel-to-liquid-crystalline phase transition of dipalmitoylphosphatidylcholine is measured by differential scanning calorimetry. Cholesteryl methyl ether, cholesteryl ethyl ether, and cholesteryl (2'-hydroxy)-3-ethyl ether reduce the energy content of the phase transition nearly as effective as cholesterol, cholesteryl n-propyl ether has only a small effect. Although cholesteryl acetate, and cholesteryl methoxymethyl ether have no condensing or permeability-reducing effect, they have a considerable effect on the gel-to-liquid-crystalline phase transition. Cholesteryi isopropyl ether and cholesteryl butyl ether have no effect. It is concluded that a free 30-hydroxy group is not a prerequisite to observe a sterol-like effect in membranes. However, the interfacial stability and the orientation of the sterol and oxygen moiety at the sterol 3-position are important.

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“…The area of 0.315 nm2 was used for phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. For sphingomyelin an area of 0.24 nm2 was assumed (Harmony et al, 1981). In the presence of cholesterol in the bilayer the effective area per lipid-P; was increased by an amount of 0.18 nm2 per cholesterol molecule (Demel et al, 1972).…”

Section: Methodsmentioning

confidence: 99%

Transport Studies of Doxorubicin in Model Membranes Indicate a Difference in Passive Diffusion across and Binding at the Outer and Inner Leaflet of the Plasma Membrane

Speelmans¹,

Staffhorst²,

Kruijff³

et al. 1994

Biochemistry

108

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The kinetics of passive transport of the anticancer drug doxorubicin were analyzed in relation to membrane composition in large unilamellar vesicles in which DNA was enclosed. Special attention was paid to lipids that are typical for the inner and outer leaflet of the plasma membrane of mammalian cells: Phosphatidylethanolamine and anionic phosphatidylserine versus phosphatidylcholine, sphingomyelin, and cholesterol, respectively. The presence of anionic phospholipids results in a highly efficient incorporation of the drug into biological and model membranes [de Wolf, F. A., et al. (1993) Biochemistry 32, 6688-6695]. Therefore, the effect of drug binding on the amount of free, transportable drug was explicitly taken into account. However, even after correction for binding the permeability coefficient was about 35% lower in membranes containing 50 mol % of the anionic phosphatidylserine than in membranes consisting only of zwitterionic phospholipids (0.71-0.79 versus 1.18-1.25 microns s-1). This shows that drug binding and insertion also affect the intrinsic transport characteristics of the membranes. As compared to pure phosphatidylcholine, binding was not influenced by the incorporation of sphingomyelin or cholesterol, but equimolar amounts of sphingomyelin and cholesterol in phosphatidylcholine membranes decreased the rate of doxorubicin transport by 60% and 80%, respectively. The inhibitory effect of these two lipids is probably due to a closer packing of the membranes. In accordance, after the acyl chain order was decreased by adding the anaesthetic-like phenethyl alcohol (0.5% v/v), transport was stimulated more than 4-fold. The implications of our findings for the functioning and rate of drug pumping by the multidrug resistance-conferring P-glycoprotein in cancer cells are discussed.

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Interaction of a human plasma lipid transfer protein complex with lipid monolayers

Cited by 12 publications

References 36 publications

Surface Properties of Dioleoyl-sn-glycerol-3-ethylphosphocholine, a Cationic Phosphatidylcholine Transfection Agent, Alone and in Combination with Lipids or DNA

Surface Properties of Dioleoyl-sn-glycerol-3-ethylphosphocholine, a Cationic Phosphatidylcholine Transfection Agent, Alone and in Combination with Lipids or DNA

The effect of the sterol oxygen function on the interaction with phospholipids

Transport Studies of Doxorubicin in Model Membranes Indicate a Difference in Passive Diffusion across and Binding at the Outer and Inner Leaflet of the Plasma Membrane

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