Solute distributions and trapping efficiencies observed in freeze-thawed multilamellar vesicles

Mayer, Lawrence D.; Hope, Michael J.; Cullis, Pieter R.; Janoff, Andrew S.

doi:10.1016/0005-2736(85)90084-7

Cited by 435 publications

(240 citation statements)

References 4 publications

Supporting

Mentioning

226

Contrasting

Unclassified

Order By: Relevance

“…The chloroform solutions where dried to lipid films under dry N 2 pressure, and trace amounts of chloroform were removed by subjecting the samples to vacuum for at least 2 h. Buffer was then added, and samples were vortexed and allowed to hydrate overnight at room temperature. For liposome preparation, the solutions were subjected to seven freeze-thaw cycles using liquid N 2 and a water bath (42). Finally, the hydrated multilamellar structures were extruded using a Mini-Extruder (Avanti Polar Lipids, Inc.) which was assembled using two Millipore filters of 100-nm pore size.…”

Section: Methodsmentioning

confidence: 99%

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

Halskau

Ying

Baumann

et al. 2009

Journal of Biological Chemistry

View full text Add to dashboard Cite

Tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of catecholamines, is activated by phosphorylationdependent binding to 14-3-3 proteins. The N-terminal domain of TH is also involved in interaction with lipid membranes. We investigated the binding of the N-terminal domain to its different partners, both in the unphosphorylated (TH-(1-43)) and Ser 19 -phosphorylated (THp-(1-43)) states by surface plasmon resonance. THp-(1-43) showed high affinity for 14-3-3 proteins (K d ϳ 0.5 M for 14-3-3␥ and -and 7 M for 14-3-3 ). The domains also bind to negatively charged membranes with intermediate affinity (concentration at half-maximal binding S 0.5 ‫؍‬ 25-58 M (TH-(1-43)) and S 0.5 ‫؍‬ 135-475 M (THp-(1-43)), depending on phospholipid composition) and concomitant formation of helical structure. 14-3-3␥ showed a preferential binding to membranes, compared with 14-3-3 , both in chromaffin granules and with liposomes at neutral pH. The affinity of 14-3-3␥ for negatively charged membranes (S 0.5 ‫؍‬ 1-9 M) is much higher than the affinity of TH for the same membranes, compatible with the formation of a ternary complex between Ser 19 -phosphorylated TH, 14-3-3␥, and membranes. Our results shed light on interaction mechanisms that might be relevant for the modulation of the distribution of TH in the cytoplasm and membrane fractions and regulation of L-DOPA and dopamine synthesis.

show abstract

Section: Methodsmentioning

confidence: 99%

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

Halskau

Ying

Baumann

et al. 2009

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…In this regard, the measurement of the trapped volume of liposomes usually employs a radiolabeled membrane-impermeable marker, such as inulin or sucrose. 21,22 Before using sucrose to measure the trapped volume of SPLP, it was important to show that sucrose would not leak out during the time required to isolate the particles. The release rate of 14 Csucrose from LUV with the same lipid composition as the SPLP was therefore measured as indicated in Materials and methods.…”

Section: Splp Contain a Trapped Aqueous Volumementioning

confidence: 99%

“…21,22 A first step was to examine sucrose retention in vesicles with the SPLP lipid composition. This study employed 100 nm diameter LUV prepared by the freeze-thaw extrusion method.…”

Section: Trapped Volume Measurementsmentioning

confidence: 99%

Stabilized plasmid-lipid particles for regional gene therapy: formulation and transfection properties

et al. 1999

View full text Add to dashboard Cite

Previous work (Wheeler et al, Gene Therapy 1999; 6: 271-be generated. The SPLP produced could be isolated from 281) has shown that plasmid DNA can be entrapped in empty vesicles by sucrose density gradient centrifugation, 'stabilized plasmid-lipid particles' (SPLP) containing the and exhibited a narrow size distribution (62 ± 8 nm, as fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), determined by freeze-fracture electron microscopy) and a low levels (5-10 mol%) of cationic lipid, and stabilized by high plasmid-to-lipid ratio of 65 g/ mol (corresponding to a polyethyleneglycol (PEG) coating. The PEG moieties are one plasmid per particle) regardless of the DODAC conattached to a ceramide anchor containing an arachidoyl tent. It was found that isolated SPLP containing 20-acyl group (PEG-CerC 20 ). These SPLP exhibit low trans-24 mol% DODAC resulted in optimum transfection of COSfection potencies in vitro, due in part to the long residence 7 and HepG2 cells in vitro, with luciferase expression levels time of the PEG-CerC 20 on the SPLP surface. In this work comparable to those achieved for plasmid DNA-cationic we employed SPLP stabilized by PEG attached to ceralipid complexes. In vivo studies employing an intraperimide containing an octanoyl acyl group (PEG-CerC 8 ), toneal B16 tumor model and intraperitoneal administration which is able to quickly exchange out of the SPLP, to of SPLP also demonstrated maximum luciferase develop systems that give rise to optimized in vitro and in expression for DODAC contents of 20-24 mol% and sigvivo (regional) transfection. A particular objective was to nificantly improved gene expression in tumor tissue as achieve cationic lipid contents that give rise to maximum compared with complexes. We conclude that SPLP stabiltransfection levels. It is shown that by performing the dialyized by PEG-CerC 8 and containing 20-24 mol% cationic sis procedure in the presence of increasing concentrations lipid are attractive alternatives to plasmid DNA-cationic of citrate, SPLP containing up to 30 mol% of the cationic lipid complexes for regional gene therapy applications. lipid dioleoydimethylammonium chloride (DODAC) could

show abstract

“…The assay was performed by QELLS [14], using a BI 90 particle sizer (Brookhaven Instrument Co, Holtsville, NY), equipped with a laser source at an excitation wavelength of 632.8 nm. The fluctuation in scattered light intensity generated by vesicle diffusion in solution was analysed by digital autocorrelation technique.…”

Section: Liposome Size Distribution Analysismentioning

confidence: 99%

Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes

et al. 1996

View full text Add to dashboard Cite

Heparin (HE) exhibited a protective effect on liposome peroxidation induced by Fe 2+ and Cu 2+, decreasing the formation of both conjugated dienes and thiobarbituric acid reactive substances (TBARS) in a dose-dependent manner. The antioxidant activity was more relevant in the oxidizing system employing Fe 2+ and H202 and generating the highly reactive "OH radical. The analysis of liposome size distribution by quasielastic laser light scattering showed that: (1) the native structure of the particles was completely lost after exposure to Fenton reagent; (2) the presence of HE in the reaction mixture completely prevented the peroxidative damage on liposomes. Thus, HE acts as an antioxidant factor on membrane lipid bllayer. This suggests that HE, released from mast-cell granules during inflammatory processes, might locally protect the cell membrane from the oxidative injuries.

show abstract

Solute distributions and trapping efficiencies observed in freeze-thawed multilamellar vesicles

Cited by 435 publications

References 4 publications

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

Stabilized plasmid-lipid particles for regional gene therapy: formulation and transfection properties

Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes

Contact Info

Product

Resources

About

Solute distributions and trapping efficiencies observed in freeze-thawed multilamellar vesicles

Cited by 435 publications

References 4 publications

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

Stabilized plasmid-lipid particles for regional gene therapy: formulation and transfection properties

Heparin protection against Fe2+‐and Cu2+‐mediated oxidation of liposomes

Contact Info

Product

Resources

About

Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes