Evidence for an Increase in Water Concentration in Bilayers after Oxidative Damage of Phospholipids Induced by Ionizing Radiation

Parasassi, Tiziana; Giusti, Anna Maria; Gratton, Enrico; Monaco, Edoardo; Raimondi, M.; Ravagnan, Giampietro; Sapora, O.

doi:10.1080/09553009414550391

Cited by 62 publications

(45 citation statements)

References 15 publications

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“…Thus, the GP values for each probe allow a quantitative estimation of local membrane polarity, related to local membrane fluidity. 18,24) As shown in Fig. 6A, the GP values for Prodan in the PEGmodified liposomes were significantly lower than those for unmodified liposomes at all temperatures, suggesting that the incorporation of PEG-lipids into the liposome membranes increases the membrane fluidity of the hydrophilic region in which Prodan is located.…”

Section: Effect Of Peg Modification On Prodan and Laurdan Fluorescencmentioning

confidence: 99%

Thermotropic Phase Behavior of Hydrogenated Soybean Phosphatidylcholine–Cholesterol Binary Liposome Membrane

et al. 2014

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By combination of differential scanning calorimetry (DSC) and fluorescence spectroscopy of 6-propionyl-2-(dimethylamino)naphthalene (Prodan), we elucidated the thermotropic phase behavior of hydrogenated soybean phosphatidylcholine (HSPC)-cholesterol binary liposome membrane which has similar lipid composition to Doxil ® , the widely used liposome product in treatment of various tumors. We found that the characteristic points at cholesterol mole fraction (X ch ) 0.023 and 0.077 correspond to the hexagonal lattice, in which cholesterol molecules are considered to be regularly distributed in all regions of HSPC lipid bilayer with 1 : 42 and 1 : 12 units, respectively, as static averaged structures. Apparent endothermic peak disappeared at X ch 0.40 in the DSC thermograms, indicating the existence of single liquid ordered phase at X ch >0.40. In addition, fluorescence measurements of Prodan and its lauroyl derivative in poly(ethylene glycol) (PEG)-modified liposomes indicated that PEG modification has a negligible effect on the phase behavior of HSPC-cholesterol binary liposome membrane. These results may provide useful information in developing novel liposome products whose stability and encapsulated drug release are controlled.Key words liposome; cholesterol; phase diagram; differential scanning calorimetry; Prodan Liposomes are used as drug delivery systems because of their high biocompatibility and ability to encapsulate a large amount of pharmaceuticals inside the vesicle.1) Thermodynamic states of liposome membrane are considered as an important factor in terms of particle stability and encapsulated drug release. Therefore, phase transition temperatures and phase states of lipid membranes are important physicochemical index in assessing the liposomal product.Liposomes are mainly composed of phospholipids in the lamellar phase such as dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC), and hydrogenated soybean phosphatidylcholine (HSPC). Because all these lipids have saturated fatty acids, they have relatively high phase transition temperatures 2) and therefore, are used in preparation of stable liposomes. The commercial liposomal products such as Doxil ® and AmBisome ® are composed of HSPC and cholesterol in which the incorporation of cholesterol into the lipid bilayer modulates the liposome membrane fluidity. 3,4)Poly(ethylene glycol) (PEG)-lipid is also a fundamental component in Doxil ® to extend the circulation time in plasma. In theory, HSPC and cholesterol can be either domain segregated, randomly distributed, or regularly distributed depending upon the energy function. 5) However, the relationship between the phase states of HSPC-cholesterol liposome membrane and lateral distribution of cholesterol in the membrane has not been fully elucidated. Optimal modulation of miscibility between lipid molecules is of fundamental importance to control drug release from liposomes. 6)The phase diagram for lipid mixtures shows several different regions of phase coexistence, 7) including lame...

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Section: Effect Of Peg Modification On Prodan and Laurdan Fluorescencmentioning

confidence: 99%

Thermotropic Phase Behavior of Hydrogenated Soybean Phosphatidylcholine–Cholesterol Binary Liposome Membrane

et al. 2014

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“…liquid crystalline phase) allows more water molecules to partition into the membrane core, thus shifting Laurdan's emission maximum further into the red (Lee et al, 2001;Parasassi et al, 1990). To quantify this shift, Gratton and co-workers (Parasassi et al, 1990) have defined the generalized polarization (GP) and applied it to phase transitions of different lipid systems (Parasassi et al, 1991;Parasassi et al, 1993;Parasassi et al, 1994) as well as natural membranes (Parasassi et al, 1992;Waschuk et al, 2001). A higher GP value indicates that the membrane becomes more gel-like, and a lower GP indicates that the membrane becomes more liquid crystalline-like.…”

Section: H 2 O 2 Stimulates P38 Mapk In Astrocytesmentioning

confidence: 99%

Hydrogen peroxide alters membrane and cytoskeleton properties and increases intercellular connections in astrocytes

Zhu

Tan

Zhang

et al. 2005

Journal of Cell Science

228

152

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Excess hydrogen peroxide (H2O2) is produced in the pathogenesis of brain injuries and neurodegenerative diseases. H2O2 may damage cells through direct oxidation of lipids, proteins and DNA or it can act as a signaling molecule to trigger intracellular pathways leading to cell death. In this study, H2O2 caused plasma membranes of primary astrocytes to become more gel-like, while artificial membranes of vesicles composed of rat brain lipid extract became more liquid crystalline-like. Besides the effects on membrane phase properties, H2O2 promoted actin polymerization, induced the formation of cell-to-cell tunneling nanotube (TNT)-like connections among astrocytes and increased the colocalization of myosin Va with F-actin. Myosin Va was also observed in the H2O2-induced F-actin-enriched TNT-like connections. Western blot analysis suggests that H2O2 triggered the phosphorylation of the p38 mitogen-activated protein kinase (MAPK), and that SB203580, a specific inhibitor of p38 MAPK, suppressed the changes in membrane phase properties and cytoskeleton resulting from H2O2 treatment. These results suggest that H2O2 alters astrocyte membranes and the cytoskeleton through activation of the p38 MAPK pathway.

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“…because of different configurations of protein and lipids and the resulting interactions. A model recently developed by Parasassi et al [13] suggests water penetration in the lipid bilayer as a consequence of oxidative damage. Membrane hydration also depends on the net surface charge density and thus on the membrane surface electrostatics and vice versa [14].…”

Section: Resultsmentioning

confidence: 99%

Effects of gamma-irradiation on the electrokinetic properties of purple membranes

Doltchinkova¹,

Stoilova²,

Baldjiiska³

1998

Radiation and Environmental Biophysics

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The effect of gamma-irradiation (5, 10 and 15 Gy) on the kinetic surface charge of purple membranes (PM) was followed by means of particle microelectrophoresis. The changes in electrophoretic mobility (EPM) were examined at 2, 5 and 26 h, respectively, following irradiation of native PM, and at 2, 26, 50 h and 5 days following irradiation of delipidated PM. It was concluded that the high inhomogeneity of the suspension, even after sonication, largely affects the measured zeta-potential. The 15-Gy treatment significantly increased the net negative surface charge density at 5 and 26 h after irradiation of native PM. However, the opposite effect of approximately twofold reduction of EPM values was derived from simultaneous studies concerning their delipidated form. Low irradiation doses clearly induced an enhancement of negative surface charge density at 2 h post-exposure as well as the formation of unstable structures of delipidated PM. The changes in electrokinetic properties might reflect the specific aggregate formation in both native and delipidated PM. It was suggested that the effect observed of both types of PM was mainly a structural phenomenon possibly related to the modification of functionally active residues.

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Evidence for an Increase in Water Concentration in Bilayers after Oxidative Damage of Phospholipids Induced by Ionizing Radiation

Cited by 62 publications

References 15 publications

Thermotropic Phase Behavior of Hydrogenated Soybean Phosphatidylcholine–Cholesterol Binary Liposome Membrane

Thermotropic Phase Behavior of Hydrogenated Soybean Phosphatidylcholine–Cholesterol Binary Liposome Membrane

Hydrogen peroxide alters membrane and cytoskeleton properties and increases intercellular connections in astrocytes

Effects of gamma-irradiation on the electrokinetic properties of purple membranes

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