colfosceril-palmitate and 1-2-dipalmitoylphosphatidylglycerol

The purpose of this study was to inspect the interactions between an anti-breast cancer, TAM, with model of lipid membranes composed of either zwitterionic DPPC LUVs or anionic DPPG LUVs and how they depend on ionic strength and cholesterol.. The K. Ionic strength and cholesterol play a noteworthy role in regulation of TAM partitioning into lipid membranes as they could obstruct or promote such action.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Cell Membrane; Cholesterol; Membrane Lipids; Molecular Structure; Osmolar Concentration; Phosphatidylglycerols; Tamoxifen

We studied the effect of zoledronic acid encapsulated into liposomes (L-ZOL) on tumorassociated macrophages in the stroma of hepatocellular carcinoma xenograft. Liposomes were prepared from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dipalmitoyl-snglycero-3-phospho-sn-1-glycerol, and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000] using thin film method and loaded with zoledronic acid. It was shown that L-ZOL promoted apoptosis of RAW264.7 cells, eliminate much more protumoral M2 macrophages than antitumoral M1 macrophages in the tumor xenograft, and did not significantly reduce the size of xenograft in 6 days. Thus, the effect of treatment depends on the ratio between antitumoral M1 and protumoral M2 polarized macrophages in the tumor.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Hepatocellular; Cell Differentiation; Cell Line, Tumor; Cell Lineage; Drug Compounding; Female; Humans; Liposomes; Liver Neoplasms; Mice; Mice, Inbred BALB C; Phosphatidylethanolamines; Phosphatidylglycerols; Polyethylene Glycols; RAW 264.7 Cells; Tumor Burden; Tumor Microenvironment; Tumor-Associated Macrophages; Xenograft Model Antitumor Assays; Zoledronic Acid

Lung surfactant (LS) occurs at the air-water interface in the alveoli. Its main function is to reduce the work needed to expand the alveoli during inhalation and prevent the alveolar collapse during exhalation. Disturbance of this complex interfacial system by the uptake of pollutant molecules can lead to changes in fluidity, permeability, phase separation and domain formation, which in turn can lead to serious impairment in lung function. Knowledge of the LS-pollutant interaction is essential for understanding the mechanism of this process. In this study, we investigate the interaction of LS models with benzo[a]pyrene (BaP). Dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG) sodium salt, and their 4 : 1 mixture are used as LS models. Surface pressure-area isotherms and molecular dynamics simulations are employed to study the properties of LS monolayers. It was found that the addition of BaP has a destabilizing effect on the mixed DPPC/DPPG monolayer, manifested by the decrease in surface pressure. Compression of a monolayer during a respiratory cycle may expel BaP to the bulk solution. It was demonstrated that DPPG is an active component that prevents the BaP molecule from entering the water subphase; as a minor component of LS it can effectively reduce this process. In addition, the presence of BaP in LS models induces the reduction of monolayer hydration in the hydrophilic region and the increase in chain ordering in the hydrophobic region. The observed changes in monolayer fluidity and phase behavior can be a source of various lung function disorders.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Air Pollutants; Benzo(a)pyrene; Computational Biology; Hydrophobic and Hydrophilic Interactions; Models, Biological; Molecular Dynamics Simulation; Phosphatidylglycerols; Pulmonary Alveoli; Pulmonary Surfactants

Poor aqueous solubility, chemical instability, and indiscriminate cytotoxicity have limited clinical development of camptothecin (CPT) as potent anticancer therapeutic. This research aimed at fabricating thermoresponsive nanocomposites that enhance solubility and stability of CPT in aqueous milieu and enable stimulus-induced drug release using magnetic hyperthermia. 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and l-α-dipalmitoylphosphatidyl glycerol (DPPG) (1:1, mol/mol) were immobilized on the surface of superparamagnetic Fe

Topics: 1,2-Dipalmitoylphosphatidylcholine; Cell Survival; Drug Liberation; Humans; Hyperthermia, Induced; Jurkat Cells; Magnetite Nanoparticles; Neoplasms; Phosphatidylglycerols

Non-fluidic bio-layer interferometry (BLI) has rapidly become a standard tool for monitoring almost all biomolecular interactions in a label-free, real-time and high-throughput manner. High-efficiency screening methods which measure the kinetics of liposomes with a variety of compounds require the immobilization of liposomes. In this work, a method is described for immobilizing liposomes for interaction studies, based on the biophysical principles of this biosensor platform. The immobilization approach includes the loading of DSPE-PEG

Topics: 1,2-Dipalmitoylphosphatidylcholine; Adsorption; Biosensing Techniques; Biotin; Cardiolipins; Cytochromes c; Drosophila Proteins; Fluoresceins; Fluorescent Dyes; High-Throughput Screening Assays; Hydrophobic and Hydrophilic Interactions; Interferometry; Kinetics; Liposomes; Micelles; Microscopy, Fluorescence; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylglycerols; Polyethylene Glycols; Protein Phosphatase 1; Reproducibility of Results

The interaction between a drug molecule and lipid bilayers is highly important regarding the pharmaceutical activity of the drug. In this study, the interaction of fluoxetine, a well-known selective serotonin reuptake inhibitor antidepressant and lipid bilayers composed of 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was studied from the aspect of electrostatics using second derivative spectrophotometry and Fourier transform infrared spectroscopy (FTIR) in order to provide insights into the drug behavior. Changing pH from 7.4 to 9.5 to increases the neutral state of fluoxetine, the partitioning of fluoxetine into the zwitterionic DPPC large unilamellar vesicles (LUVs) was increased whereas it was reduced into the negatively charged DPPG LUVs. Fluoxetine was found to exhibit a disordering effect on the acyl chains of DPPC and DPPG bilayers upon its partitioning. In addition, increasing concentration of NaCl lessened the binding of fluoxetine into DPPG bilayers due to the reduction in electrostatic attraction between positively charged fluoxetine and negatively charged DPPG LUVs. In addition, the FTIR study revealed that increasing the NaCl concentration could trigger the shift to higher frequency of the CH

Topics: 1,2-Dipalmitoylphosphatidylcholine; Fluoxetine; Hydrogen-Ion Concentration; Kinetics; Lipid Bilayers; Phosphatidylglycerols; Sodium Chloride; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Static Electricity; Unilamellar Liposomes

The endomembrane system, including the endoplasmic reticulum, Golgi apparatus, lysosomes, and endosomes, is located in the crowded intracellular environment. An understanding of the cellular structure and functions requires knowledge of how macromolecular crowding and confinement affect the activity of membrane and its proteins. Using negatively charged liposome and the peptide K3L8K3 as a model system, we studied the aggregation behavior of liposome in a matrix of polyacrylamide and hyaluronic acid. Without matrix, the liposomes form spherical aggregates in the presence of K3L8K3. However, they orient in one dimension and fuse into a tube up to 40 μm long in the matrix. The growth of the tube is via end-to-end connection. This anisotropic growth is mainly due to the macromolecular confinement provided by the polymer network. The study of the interactions between liposome and peptide in the crowded environment helps to reveal the mechanism of membrane-related processes in vivo.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Acrylic Resins; Anisotropy; Hyaluronic Acid; Liposomes; Peptides; Phosphatidylglycerols; Static Electricity

Dimethyl sulfoxide (DMSO) has been broadly used in biology as a cosolvent, a cryoprotectant, and an enhancer of membrane permeability, leading to the general assumption that DMSO-induced structural changes in cell membranes and their hydration water play important functional roles. Although the effects of DMSO on the membrane structure and the headgroup dehydration have been extensively studied, the mechanism by which DMSO invokes its effect on lipid membranes and the direct role of water in this process are unresolved. By directly probing the translational water diffusivity near unconfined lipid vesicle surfaces, the lipid headgroup mobility, and the repeat distances in multilamellar vesicles, we found that DMSO exclusively weakens the surface water network near the lipid membrane at a bulk DMSO mole fraction (XDMSO) of <0.1, regardless of the lipid composition and the lipid phase. Specifically, DMSO was found to effectively destabilize the hydration water structure at the lipid membrane surface at XDMSO <0.1, lower the energetic barrier to dehydrate this surface water, whose displacement otherwise requires a higher activation energy, consequently yielding compressed interbilayer distances in multilamellar vesicles at equilibrium with unaltered bilayer thicknesses. At XDMSO >0.1, DMSO enters the lipid interface and restricts the lipid headgroup motion. We postulate that DMSO acts as an efficient cryoprotectant even at low concentrations by exclusively disrupting the water network near the lipid membrane surface, weakening the cohesion between water and adhesion of water to the lipid headgroups, and so mitigating the stress induced by the volume change of water during freeze-thaw.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Diffusion; Dimethyl Sulfoxide; Fatty Acids, Monounsaturated; Magnetic Resonance Spectroscopy; Membranes, Artificial; Phosphatidylcholines; Phosphatidylglycerols; Quaternary Ammonium Compounds; Scattering, Small Angle; Water; X-Ray Diffraction

Photodynamic therapy (PDT) is based on the delivery of photocytotoxic agents to a target tissue, followed by irradiation. In order to increase the efficiency of PDT in oesophageal cancer therapy, polyethylene glycol (PEG)-grafted, transferrin (Tf)-conjugated liposome formulations of 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (Foscan), a second-generation photosensitiser, were prepared. Expression of transferrin receptors (CD71) in the oesophageal cancer cell line, OE21, was confirmed by immunoblot and confocal laser scanning microscopy. The anti-proliferative effect of Foscan liposomes was evaluated and compared with plain formulations (i.e., without Tf) as well as with free drug. In addition, the intracellular accumulation was studied using high content analysis. Surprisingly, delivering Foscan by transferrin-conjugated PEG-liposomes to oesophageal cancer cells did not improve the photocytotoxicity or the intracellular accumulation of Foscan when compared to unmodified liposomes or indeed free photosensitiser. Tf-targeted drugs and drug delivery systems have shown improved the therapy of many cancers. Our study, however, did not corroborate these findings. If this is due to the tumour type, the choice of in vitro model or the delivery systems remains to be confirmed.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Antigens, CD; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Esophageal Neoplasms; Humans; Liposomes; Mesoporphyrins; Phosphatidylglycerols; Photochemotherapy; Photosensitizing Agents; Polyethylene Glycols; Receptors, Transferrin; Transferrin

Thermosensitive liposomes (TSL) with encapsulated magnetic resonance imaging (MRI) longitudinal relaxation time (T(1)) contrast agents (CAs) have been proposed for MRI assisted interventional thermotherapy in solid tumors. Here the feasibility of 6 clinically approved CAs (Gd-DTPA, Gd-BOPTA, Gd-DOTA, Gd-BT-DO3A, Gd-DTPA-BMA, and Gd-HP-DO3A) for formulation into TSL was investigated. CAs were passively encapsulated with 323 mOs kg(-1) into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-distearoyl-sn-glycero-3-phosphocholine/1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol 50/20/30 (mol/mol) TSL (DPPG(2)-TSL) to obtain stable formulations. T(1) relaxivity (r(1)) and diffusive permeability to water (P(d)) across the membrane were determined. Shelf life at 4°C was investigated by determining lysolipid content up to 10 weeks after preparation. All preparations were monodispersed with comparable small vesicle sizes (~135 nm). Neither zeta potential nor phase transition temperature (T(m)) was affected by the CA. The formulations showed an increase in r(1) in the temperature range between 38 and 44°C. This correlated with the phase transition. Change in r(1) (Δr(1)=r(1)(45.3°C)-r(1)(37.6°C)) and r(1) (T

Topics: 1,2-Dipalmitoylphosphatidylcholine; Contrast Media; Drug Carriers; Drug Compounding; Gadolinium DTPA; Liposomes; Magnetic Resonance Imaging; Particle Size; Phosphatidylcholines; Phosphatidylglycerols; Surface Properties; Transition Temperature

Cell selective, naturally occurring, host defence cationic peptides present a good template for the design of novel peptides with the aim of achieving a short length with improved antimicrobial potency and selectivity. A novel, short peptide CS-1a (14 residues) was derived using a sequence hybridization approach on sarcotoxin I (39 residues) and cecropin B (35 residues). The sequence of CS-1a was rearranged to enhance amphipathicity with the help of a Schiffer-Edmundson diagram to obtain CS-2a. Both peptides showed good antibacterial activity in the concentration range 4-16 μg·mL(-1) against susceptible as well as drug-resistant bacterial strains, including the clinically relevant pathogens Acenatobacter sp. and methicillin-resistant Staphylococcus aureus. The major thrust of these peptides is their nonhaemolytic activity against human red blood cells up to a high concentration of 512 μg·mL(-1). Compared to CS-1a, amphipathic peptide CS-2a showed a more pronounced α-helical conformation, along with a better membrane insertion depth in bacterial mimic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) small unilamellar vesicles. With equivalent lipid-binding affinity, the two peptides assumed different pathways of membrane disruption, as demonstrated by calcein leakage and the results of transmission electron microscopy on model bacterial mimic large unilamellar vesicles. Extending the work from model membranes to intact Escherichia coli cells, differences in membrane perturbation were visible in microscopic images of peptide-treated E. coli. The present study describes two novel short peptides with potent activity, cell selectivity and divergent modes of action that will aid in the future design of peptides with better therapeutic potential.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Amino Acid Sequence; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Bacteria; Circular Dichroism; Escherichia coli; Hemolysis; Humans; Insect Proteins; Lipid Bilayers; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Molecular Sequence Data; Moraxellaceae; Peptides; Phosphatidylglycerols; Protein Binding; Protein Structure, Secondary; Unilamellar Liposomes