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Leaf Huang - One of the best experts on this subject based on the ideXlab platform.

  • Efficient Cytoplasmic Delivery of a Fluorescent Dye by pH-sensitive Immunoliposomes
    2013
    Co-Authors: Jerome Connor, Leaf Huang
    Abstract:

    ABSTRACT We previously showed that liposomes composed of Dioleoylphosphatidylethanolamine and palmitoyl-homocysteine (8:2) are highly fusion competent when 'exposed to an acidic environment of pH <6.5. (Connor, J., M. B. Yatvin, and L. Huang, 1984, Proc. Natl. Acad. Sci. USA. 81:1715-1718). Palmitoyl anti-H2K k was incorporated into these pHsensitive liposomes by a modified reserve-phase evaporation method. Mouse L929 cells (k haplotype) treated with immunoliposomes composed of Dioleoylphosphatidylethanolamine/ palmitoyl-homocysteine (8:2) with an entrapped fluorescent dye, calcein, showed diffused fluorescence throughout the cytoplasm. Measurements by use of a microscope-associated photometer gave an approximate value of 50/~M for the cytoplasmic calcein concentration. This concentration represents an efficient delivery of the aqueous content of the immunoliposome. Cells treated with immunoliposomes composed of dioleoylphosphatidylcholine (pHinsensitive liposomes) showed only punctate fluorescence. The cytoplasmic delivery of calcein by the pH-sensitive immunoliposomes could be inhibited by chloroquine or by incubation at 20°C. These results suggest that the efficient cytoplasmic delivery involves the endocytic pathway, particularly the acidic organelles such as the endosomes and/or lysosomes. On

  • amphipathic poly ethylene glycol 5000 stabilized Dioleoylphosphatidylethanolamine liposomes accumulate in spleen
    Biochimica et Biophysica Acta, 1992
    Co-Authors: David C Litzinger, Leaf Huang
    Abstract:

    Relatively small liposomes (d < 200 nm) composed of Dioleoylphosphatidylethanolamine (DOPE) and cholesterol (Chol) and containing dioleoyl-N-(monomethoxypoly(ethylene glycol)phosphatidylethanolamine (PEG-PE), with PEG of Mr 5000 (PEG5000-PE), accumulate in the spleen (∼40% i.v. injected dose), unlike dioleoylphosphatidylcholine (DOPC)/Chol/PEG5000-PE liposomes of similar size, which show prolonged circulation in the blood. Spleen accumulation was dependent on the injection dose, PEG-PE concentration, and the PEG chain length. The DOPE/Chol/PEG5000-PE liposomes are plasma stable and morphologically indistinguishable from DOPC/Chol/PEG5000-PE liposomes. These results reveal the significance of the matrix lipid in determining the circulation time of PEG-PE-containing liposomes, and are relevant to the design of liposomes which avoid or accumulate in the spleen.

  • Some negatively charged phospholipid derivatives prolong the liposome circulation in vivo
    Biochimica et Biophysica Acta, 1992
    Co-Authors: Yong Serk Park, Kazuo Maruyama, Leaf Huang
    Abstract:

    Abstract A series of negatively charged phospholipid derivatives has been synthesized by coupling aliphatic dicar☐ylic acids, HOOC(CH 2 ) n COOH, to diolcoylphosphatidylethanolamine (DOPE). The individual derivatives were incorporated into egg phosphatidylcholine/cholesterol liposomes (2:1, molar ratio) and injected into mice to test its effect on liposome circulation in vivo. The effectiveness of DOPE derivatives was dependent on the hydrocarbon chain length between the terminal car☐yl group and the amide bond. N -Glutaryl DOPE and N -adipyl DOPE were effective in prolonging the circulation time of liposomes. On the other hand, liposome uptake by the liver and spleen was increased by the addition of N -malonyi DOPE or N -succinyl DOPE, while it was not changed by the addition of N -pimelyl DOPE and N -suberyl DOPE. Our observation suggested that not all negatively charged phospholipids enhance liposome uptake by RES, some even reduce the uptake.

  • biodistribution and immunotargetability of ganglioside stabilized Dioleoylphosphatidylethanolamine liposomes
    Biochimica et Biophysica Acta, 1992
    Co-Authors: David C Litzinger, Leaf Huang
    Abstract:

    The biodistribution and immunotargetability of liposomes composed primarily of Dioleoylphosphatidylethanolamine (DOPE) or dioleoylphosphatidylcholine (DOPC) in mice injected via the tail vein were examined and compared. The ganglioside GM1 (7 mol%) prolonged the circulation of DOPC but not DOPE liposomes. Gangliosides GD1a and GT1b (7 mol%) also increased the amount of DOPC liposomes remaining in circulation, and to a similar extent as GM1, at 15 min post injection. However, these liposomes were cleared from the circulation by 2.5 h. Monoclonal antibody 34A, which specifically binds to a surface glycoprotein (gp 112) of the pulmonary endothelial cell surface, was coupled with N-glutarylphosphatidylethanolamine and incorporated into liposomes by a dialysis procedure. These 34A-immunoliposomes, composed of DOPE and GM1 (7 mol%), but not the antibody-free liposomes, accumulated efficiently (approximately 24% of the injected dose) in the lungs. Inclusion of cholesterol (31 mol%) enhanced the lung accumulation of both DOPE/GM1 immunoliposomes and DOPC/GM1 immunoliposomes to 33% and 51% of the injected dose, respectively. The transient increase in DOPC liposome circulation provided by GD1a and GT1b was sufficient to enhance DOPC immunoliposome binding, where 44% and 43% of the injected dose of DOPC/Chol/GD1a and DOPC/Chol/GT1b immunoliposomes accumulated in lung at 15 min after injection, respectively. In general, cholesterol-containing DOPC liposomes were more targetable than DOPE liposomes, and the degree to which these liposomes avoid RES uptake influences their targetability. The results presented here are relevant to the design of targetable drug delivery vehicles.

  • A novel cationic liposome reagent for efficient transfection of mammalian cells
    Biochemical and Biophysical Research Communications, 1991
    Co-Authors: Xiang Gao, Leaf Huang
    Abstract:

    Abstract A novel cationic derivative of cholesterol, 3β[N-(N′,N′-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol), has been synthesized and used to prepare sonicated liposomes with Dioleoylphosphatidylethanolamine. This novel cationic liposome reagent facilitates efficient DNA mediated transfection in A431 human epidermoid carcinoma cells, A549 human lung carcinoma cells, L929 mouse fibroblast cells, and YPT minipig primary endothelial cells. The activity was greater than that of a commercial reagent, Lipofectin, and was approximately 4-fold less toxic than Lipofectin when assayed with A431 cells. The reagent is easy to synthesize and stable for at least 6 weeks.

Peter L Steponkus - One of the best experts on this subject based on the ideXlab platform.

  • phase behavior and glass transition of 1 2 Dioleoylphosphatidylethanolamine dope dehydrated in the presence of sucrose
    Biochimica et Biophysica Acta, 2001
    Co-Authors: Evgenyi Shalaev, Peter L Steponkus
    Abstract:

    The effect of sucrose on the phase behavior of 1,2-Dioleoylphosphatidylethanolamine (DOPE) as a function of hydration was studied using differential scanning calorimetry and X-ray diffraction. DOPE/sucrose/water dispersions were dehydrated at osmotic pressures (Pi) ranging from 2 to 300 MPa at 30 degrees C and 0 degrees C. The hexagonal II-to-lamellar gel (H(II)-->L(beta)) thermotropic phase transition was observed during cooling in mixtures dehydrated at Pi or=57 MPa, the H(II)-->L(beta) thermotropic phase transition was precluded when sucrose entered the rigid glassy state while the lipid was in the H(II) phase. Sucrose also hindered the H(II)-to-lamellar crystalline (L(c)), and H(II)-to-inverted ribbon (P(delta)) lyotropic phase transitions, which occurred in pure DOPE. Although the L(c) phase was observed in dehydrated 2:1 (mole ratio) DOPE/sucrose mixtures, it did not form in mixtures with higher sucrose contents (1:1 and 1:2 mixtures). The impact of sucrose on formation of the ordered phases (i.e., the L(c), L(beta), and P(delta) phases) of DOPE was explained as a trapping of DOPE in a metastable H(II) phase due to increased viscosity of the sucrose matrix. In addition, a glass transition of DOPE in the H(II) phase was observed, which we believe is the first report of a glass transition in phospholipids.

  • phase diagram of 1 2 Dioleoylphosphatidylethanolamine dope water system at subzero temperatures and at low water contents
    Biochimica et Biophysica Acta, 1999
    Co-Authors: Evgenyi Shalaev, Peter L Steponkus
    Abstract:

    The phase behavior of partially hydrated 1,2-Dioleoylphosphatidylethanolamine (DOPE) has been studied using differential scanning calorimetry and X-ray diffraction methods together with water sorption isotherms. DOPE liposomes were dehydrated in the HII phase at 29‡C and in the LK phase at 0‡C by vapor phase equilibration over saturated salt solutions. Other samples were prepared by hydration of dried DOPE by vapor phase equilibration at 29‡C and 0‡C. Five lipid phases (lamellar liquid crystalline, LK ; lamellar gel, LL ; inverted hexagonal, HII ; inverted ribbon, PN ; and lamellar crystalline, Lc) and the ice phase were observed depending on the water content and temperature. The ice phase did not form in DOPE suspensions containing 6 9 wt% water. The Lc phase was observed in samples with a water content of 2^6 wt% that were annealed at 0‡C for 2 or more days. The Lc phase melted at 5^20‡C producing the HII phase. The PN phase was observed at water contents of 6 0.5 wt%. The phase diagram, which includes five lipid phases and two water phases (ice and liquid water), has been constructed. The freeze-induced dehydration of DOPE has been described with the aid of the phase diagram. fl 1999 Elsevier Science B.V. All rights reserved.

  • mode of action of the cor15a gene on the freezing tolerance of arabidopsis thaliana
    Proceedings of the National Academy of Sciences of the United States of America, 1998
    Co-Authors: Peter L Steponkus, Matsuo Uemura, Raymond A Joseph, Sarah J Gilmour, Michael F Thomashow
    Abstract:

    Constitutive expression of the cold-regulated COR15a gene of Arabidopsis thaliana results in a significant increase in the survival of isolated protoplasts frozen over the range of −4.5 to −7°C. The increased freezing tolerance is the result of a decreased incidence of freeze-induced lamellar-to-hexagonal II phase transitions that occur in regions where the plasma membrane is brought into close apposition with the chloroplast envelope as a result of freeze-induced dehydration. Moreover, the mature polypeptide encoded by this gene, COR15am, increases the lamellar-to-hexagonal II phase transition temperature of Dioleoylphosphatidylethanolamine and promotes formation of the lamellar phase in a lipid mixture composed of the major lipid species that comprise the chloroplast envelope. We propose that COR15am, which is located in the chloroplast stroma, defers freeze-induced formation of the hexagonal II phase to lower temperatures (lower hydrations) by altering the intrinsic curvature of the inner membrane of the chloroplast envelope.

David C Litzinger - One of the best experts on this subject based on the ideXlab platform.

  • amphipathic poly ethylene glycol 5000 stabilized Dioleoylphosphatidylethanolamine liposomes accumulate in spleen
    Biochimica et Biophysica Acta, 1992
    Co-Authors: David C Litzinger, Leaf Huang
    Abstract:

    Relatively small liposomes (d < 200 nm) composed of Dioleoylphosphatidylethanolamine (DOPE) and cholesterol (Chol) and containing dioleoyl-N-(monomethoxypoly(ethylene glycol)phosphatidylethanolamine (PEG-PE), with PEG of Mr 5000 (PEG5000-PE), accumulate in the spleen (∼40% i.v. injected dose), unlike dioleoylphosphatidylcholine (DOPC)/Chol/PEG5000-PE liposomes of similar size, which show prolonged circulation in the blood. Spleen accumulation was dependent on the injection dose, PEG-PE concentration, and the PEG chain length. The DOPE/Chol/PEG5000-PE liposomes are plasma stable and morphologically indistinguishable from DOPC/Chol/PEG5000-PE liposomes. These results reveal the significance of the matrix lipid in determining the circulation time of PEG-PE-containing liposomes, and are relevant to the design of liposomes which avoid or accumulate in the spleen.

  • biodistribution and immunotargetability of ganglioside stabilized Dioleoylphosphatidylethanolamine liposomes
    Biochimica et Biophysica Acta, 1992
    Co-Authors: David C Litzinger, Leaf Huang
    Abstract:

    The biodistribution and immunotargetability of liposomes composed primarily of Dioleoylphosphatidylethanolamine (DOPE) or dioleoylphosphatidylcholine (DOPC) in mice injected via the tail vein were examined and compared. The ganglioside GM1 (7 mol%) prolonged the circulation of DOPC but not DOPE liposomes. Gangliosides GD1a and GT1b (7 mol%) also increased the amount of DOPC liposomes remaining in circulation, and to a similar extent as GM1, at 15 min post injection. However, these liposomes were cleared from the circulation by 2.5 h. Monoclonal antibody 34A, which specifically binds to a surface glycoprotein (gp 112) of the pulmonary endothelial cell surface, was coupled with N-glutarylphosphatidylethanolamine and incorporated into liposomes by a dialysis procedure. These 34A-immunoliposomes, composed of DOPE and GM1 (7 mol%), but not the antibody-free liposomes, accumulated efficiently (approximately 24% of the injected dose) in the lungs. Inclusion of cholesterol (31 mol%) enhanced the lung accumulation of both DOPE/GM1 immunoliposomes and DOPC/GM1 immunoliposomes to 33% and 51% of the injected dose, respectively. The transient increase in DOPC liposome circulation provided by GD1a and GT1b was sufficient to enhance DOPC immunoliposome binding, where 44% and 43% of the injected dose of DOPC/Chol/GD1a and DOPC/Chol/GT1b immunoliposomes accumulated in lung at 15 min after injection, respectively. In general, cholesterol-containing DOPC liposomes were more targetable than DOPE liposomes, and the degree to which these liposomes avoid RES uptake influences their targetability. The results presented here are relevant to the design of targetable drug delivery vehicles.

Giulio Caracciolo - One of the best experts on this subject based on the ideXlab platform.

  • The Open-Access Journal for the Basic Principles of Diffusion Theory, Experiment and Application Intracellular trafficking of lipoplexes: A particle image correlation spectroscopy (PICS) study
    2014
    Co-Authors: Daniela Pozzi, Giulio Caracciolo, Thomas Schmidt, D. Pozzi, Eloro De Sanctis, M. A. Digman, E. Gratton, Caracciolo G. Quantitative
    Abstract:

    Particle image correlation spectroscopy (PICS) is a powerful and robust analysis technique to investigate the dynamics of molecules with nanometer and millisecond spatio-temporal resolution [1]. This tool allows one to identify and categorize populations within an ensemble of particles, without any a priori knowledge about the dynamics. PICS is here applied to investigate the intracellular trafficking of lipoplexes in CHO living cells. We measured diffusion coefficients and velocities for DOTAP–DOPC/DNA (DOTAP: 1,2-dioleoyl-3-trimethylammonium-propane; DOPC: dioleoylphosphocholine) and DC-Chol–DOPE/DNA (DC-Chol: 3β-[N-(N,N-dimethylaminoethane)-carbamoyl] cholesterol; DOPE: Dioleoylphosphatidylethanolamine) lipoplexes. The results corroborate findings from previous experiments using single particle tracking and spatio-temporal image correlation spectroscopy [2, 3]. PICS allowed us to construct the displacement distributions that displayed clear non-homogeneous behavior. Detailed analyses showed for the first time a strong evidence of lipoplex transitions between active transport (mostly along microtubules) and free Brownian motion in the cytosol. For this latter finding a full theoretical description of intermittent diffusion was developed. References [1] S. Semrau, T. Schmidt: Particle image correlation spectroscopy (PICS): Retrieving nanometerscal

  • time evolution of nanoparticle protein corona in human plasma relevance for targeted drug delivery
    Langmuir, 2013
    Co-Authors: Ana L Barranberdon, Daniela Pozzi, Giulio Caracciolo, Anna Laura Capriotti, Giuseppe Caruso, Chiara Cavaliere, Anna Riccioli, Sara Palchetti, Aldo Lagana
    Abstract:

    When nanoparticles (NPs) enter a biological fluid (e.g., human plasma (HP)), proteins and other biomolecules adsorb on the surface leading to formation of a rich protein shell, referred to as “protein corona”. This corona is dynamic in nature and its composition varies over time due to continuous protein association and dissociation events. Understanding the time evolution of the protein corona on the time-scales of a particle’s lifetime in blood is fundamental to predict its fate in vivo. In this study, we used lipid NPs, the cationic lipid 3β-[N-(N′,N′-dimethylaminoethane)-carbamoyl] (DC-Chol) and the zwitterionic lipid Dioleoylphosphatidylethanolamine (DOPE), that are among the most promising nanocarriers both in vitro and in vivo. Here, we investigated the time evolution of DC-Chol–DOPE NPs upon exposure to HP. On time scales between 1 and 60 minutes, nanoliquid tandem mass spectrometry revealed that the protein corona of DC-Chol–DOPE NPs is mainly constituted of apolipoproteins (Apo A-I, Apo C–II, Ap...

  • Effect of DOPE and cholesterol on the protein adsorption onto lipid nanoparticles
    'Springer Science and Business Media LLC', 2013
    Co-Authors: Giulio Caracciolo, Daniela Pozzi, Anna Laura Capriotti, Chiara Cavaliere, Aldo Lagana
    Abstract:

    Upon administration, nanoparticles (NPs) are exposed to biological fluids from which they adsorb proteins and other biomolecules to form a "protein corona". NP-protein interactions are still poorly understood and quantitative studies to characterize them remain scarce. Here, we have investigated the effect of neutral Dioleoylphosphatidylethanolamine (DOPE) and cholesterol on the adsorption of human plasma proteins onto the surface of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-based cationic liposomes of 100 nm in diameter. Quantitative analysis of the protein corona revealed that replacing cationic DOTAP lipids with neutral lipids, being indifferently DOPE or cholesterol, reduces the affinity of fibrinogen, prothrombin, vitamin K, and vitronectin for the lipid surface. On the other side, DOPE specifically promotes the adsorption of apolipoproteins and serum albumin, while cholesterol induces the preferential binding of immunoglobulins and complement proteins. The results of this study will help to explain why NPs of different lipid compositions have a dramatic difference in their in vivo transfection efficiency and will be useful for design of lipid NPs with optimal circulation profiles. © 2013 Springer Science+Business Media Dordrecht

  • Cholesterol-Dependent Macropinocytosis and Endosomal Escape Control the Transfection Efficiency of Lipoplexes in CHO Living Cells
    2012
    Co-Authors: Francesco Cardarelli, Daniela Pozzi, Cristina Marchini, Angelo Bifone, Giulio Caracciolo
    Abstract:

    Here we investigate the cellular uptake mechanism and final intracellular fate of two cationic liposome formulations characterized by similar physicochemical properties but very different lipid composition and efficiency for intracellular delivery of DNA. The first formulation is made of cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and the zwitterionic helper dioleoylphosphocholine (DOPC), while the second one is made of the cationic 3β-[N-(N,N-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and the zwitterionic lipid Dioleoylphosphatidylethanolamine (DOPE). Combining pharmacological and imaging approaches we show that both DOTAP-DOPC/DNA and DC-Chol-DOPE/DNA lipoplexes are taken up in Chinese hamster ovary (CHO) living cells mainly through fluid-phase macropinocytosis. Our results also indicate that lipoplex macropinocytosis is a cholesterol-sensitive uptake mechanism. On the other side, both clathrin-mediated and caveolae-mediated endocytosis play a minor role, if any, in the cell uptake. Colocalization of fluorescently tagged lipoplexes and Lysosensor, a primary lysosome marker, reveals that poorly efficient DOTAP-DOPC/DNA lipoplexes are largely degraded in the lysosomes, while efficient DC-Chol-DOPE/DNA systems can efficiently escape from endosomal compartments

  • phase diagram of 3β n n n dimethylaminoethane carbamoyl cholesterol Dioleoylphosphatidylethanolamine dna complexes suggests strategies for efficient lipoplex transfection
    Applied Physics Letters, 2010
    Co-Authors: Daniela Pozzi, Heinz Amenitsch, Cristina Marchini, Giulio Caracciolo
    Abstract:

    Synchrotron small angle x-ray scattering and electrophoresis on agarose gels have been applied to construct the phase diagram of the ternary complex made up of the cationic lipid 3β-[N-(N,N-dimethylaminoethane)-carbamoyl]-cholesterol, the neutral lipid Dioleoylphosphatidylethanolamine and DNA. We show that nominally charge-neutral complexes coexist with free DNA, while excess cationic charge is necessary to protect all the genetic cargo. Such an extra-charge requirement diminishes as the molar fraction of neutral lipid in the bilayer increases. Furthermore, complexes with very different membrane composition and charge ratio exhibit the very same DNA protection ability. The relevance of results for transfection studies is discussed.

Sigrid L Fossheim - One of the best experts on this subject based on the ideXlab platform.