Liposome Surface Research Articles

Ensembles of carboxymethyl cyclodextrins on cationic liposomes as highly efficient nanocontainers for the delivery of hydrophobic compounds

The increase of payload is one of the key tasks in creation of nanocontainers for the delivery of bioactive substances (BAS). In this work the adsorption of anionic carboxymethyl cyclodextrins (CMCDs) on the surface of cationic liposomes was studied as mechanism of formation of capacious nanocontainers for the encapsulation and delivery of hydrophobic BAS. The formation and physico-chemical characteristics of complexes were studied by means of laser microelectrophoresis, dynamic light-scattering, conductometry and atomic force microscopy (AFM). As a model, bioactive molecule hydrophobic curcumin was chosen for the investigation. The encapsulation of curcumin was controlled by UV–Vis spectrometry. Interaction of CMCDs/liposomes complexes with model cell membranes was visualized by fluorescent microscopy. Finally, cytotoxicity of nanocontainers was studied by MTT-test. It was estimated that colloid stable complexes with net positive charge could contain up to 2.5÷5 CMCD molecules per one cationic lipid. Incorporation of curcumin in CMCDs does not change the character of interaction of oligosaccharides with liposomal membranes of individual liposome. CMCDs/liposomes complexes adsorb on model cell membranes without significant loss of CMCD molecules. This fact in addition to low cytotoxicity of cationic CMCDs/liposomes complexes demonstrates potential of their application as nanovehicles for the delivery of BAS.

Abstract 2003: Evaluation of liposome encapsulated sunitinib efficacy and immune modulation on renal cell carcinoma

Abstract Renal cell carcinoma (RCC) is one of the deadliest malignant tumors worldwide. The RCC’s standard treatments are including surgery, radiation, and chemotherapy. SUTENT® (sunitinib) was approved by US Food and Drug Administration (FDA) in 2016 to treat advanced RCC. According to the results from the clinical trial, sunitinib is associated with a higher objective response rate and survival rate than IFN-α, which indicates that it is an effective multiple tyrosine kinase inhibitor (TKi) against advanced RCC. Meanwhile, recent studies demonstrated sunitinib could cause tumor immune surveillance by upregulated autophagy to inhibit tumor PD-L1 expression. However, sunitinib targets not only tumor tissue but also multiple organs in the human body, which causes many serious side effects and even leads to death. In order to reduce the toxicity of sunitinib, our group design a novel nanocarrier by PEGylated liposome to encapsulate sunitinib (lipo-sunitinib). The PEGylated liposome could passively target tumor tissue by extravasation of nanoparticles through increased permeability of the tumor vasculature (enhanced permeability and retention, EPR effect). Moreover, the PEGylation on the liposome surface could prolong liposome half-life in the body through increased particle size. Through the EPR effect and PEGylation of lipo-sunitinib to target tumor cells precisely, we successfully increased RCC orthotopic tumor inhibition in mouse models compared with vehicle and sunitinib groups. Furthermore, the RCC tumor immunofluorescence staining revealed lipo-sunitinib had higher activated effector T cells (CD8+IL-2+IFN-γ+) and type 1 dendritic cells (CD11c+CD24+MHCII+) infiltration and lower vessel formation than sunitinib group. The flow cytometry also demonstrated that lipo-sunitinib had increased anti-tumor immune cells and inhibited immune suppressors in the systemic system. More importantly, lipo-sunitinib showed lower toxicity in mouse livers, hearts, and kidneys compared to the sunitinib group. Our results suggested lipo-sunitinib could inhibit tumor growth and prolong survival rate by modulating a positive anti-tumor microenvironment and anti-angiogenesis effects. In sum, with the polish of the delivery system, our novel nanodrug lipo-sunitinib could be a potential new treatment strategy for RCC patients. Citation Format: Po-Fu Yueh, Yuan Chang, Keng-Li Lan, Fei-Ting Hsu. Evaluation of liposome encapsulated sunitinib efficacy and immune modulation on renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2003.

On-demand integrated nano-engager converting cold tumors to hot via increased DNA damage and dual immune checkpoint inhibition.

Cancer immunotherapy has become a promising strategy. However, the effectiveness of immunotherapy is restricted in "cold tumors" characterized with insufficient T cells intratumoral infiltration and failed T cells priming. Herein, an on-demand integrated nano-engager (JOT-Lip) was developed to convert cold tumors to hot via "increased DNA damage and dual immune checkpoint inhibition" strategy. JOT-Lip was engineered by co-loading oxaliplatin (Oxa) and JQ1 into liposomes with T-cell immunoglobulin mucin-3 antibodies (Tim-3 mAb) coupled on the liposomal surface by metalloproteinase-2 (MMP-2)-sensitive linker. JQ1 inhibited DNA repair to increase DNA damage and immunogenic cell death (ICD) of Oxa, thus promoting T cells intratumoral infiltration. In addition, JQ1 inhibited PD-1/PD-L1 pathway, achieving dual immune checkpoint inhibition combining with Tim-3 mAb, thus effectively promoting T cells priming. It is demonstrated that JOT-Lip not only increased DNA damage and promoted the release of damage-associated molecular patterns (DAMPs), but also enhanced T cells intratumoral infiltration and promoted T cell priming, which successfully converted cold tumors to hot and showed significant anti-tumor and anti-metastasis effects. Collectively, our study provides a rational design of an effective combination regimen and an ideal co-delivery system to convert cold tumors to hot, which holds great potential in clinical cancer chemoimmunotherapy.

RSPO3 Furin domain-conjugated liposomes for selective drug delivery to LGR5-high cells.

The transmembrane receptor LGR5 potentiates Wnt/β-catenin signaling by binding both secreted R-spondin (RSPOs) and the Wnt tumor suppressors RNF43/ZNRF3, directing clearance of RNF43/ZNRF3 from the cell surface. Besides being widely used as a stem cell marker in various tissues, LGR5 is overexpressed in many types of malignancies, including colorectal cancer. Its expression characterizes a subpopulation of cancer cells that play a crucial role in tumor initiation, progression and cancer relapse, known as cancer stem cells (CSCs). For this reason, ongoing efforts are aimed at eradicating LGR5-positive CSCs. Here, we engineered liposomes decorated with different RSPO proteins to specifically detect and target LGR5-positive cells. Using fluorescence-loaded liposomes, we show that conjugation of full-length RSPO1 to the liposomal surface mediates aspecific, LGR5-independent cellular uptake, largely mediated by heparan sulfate proteoglycan binding. By contrast, liposomes decorated only with the Furin (FuFu) domains of RSPO3 are taken up by cells in a highly specific, LGR5-dependent manner. Moreover, encapsulating doxorubicin in FuFuRSPO3 liposomes allowed us to selectively inhibit the growth of LGR5-high cells. Thus, FuFuRSPO3-coated liposomes allow for the selective detection and ablation of LGR5-high cells, providing a potential drug delivery system for LGR5-targeted anti-cancer strategies.

Antibody induction in mice by liposome-displayed recombinant enterotoxigenic Escherichia coli (ETEC) colonization antigens

BackgroundEnterotoxigenic Escherichia coli (ETEC) strains cause infectious diarrhea and colonize host intestine epithelia via surface-expressed colonization factors. Colonization factor antigen I (CFA/I), a prevalent ETEC colonization factor, is a vaccine target since antibodies directed to this fimbria can block ETEC adherence and prevent diarrhea. MethodsTwo recombinant antigens derived from CFA/I were investigated with a vaccine adjuvant system that displays soluble antigens on the surface of immunogenic liposomes. The first antigen, CfaEB, is a chimeric fusion protein comprising the minor (CfaE) and major (CfaB) subunits of CFA/I. The second, CfaEad, is the adhesin domain of CfaE. ResultsOwing to their His-tag, recombinant CfaEB and CfaEad, spontaneously bound upon admixture with nanoliposomes containing cobalt-porphyrin phospholipid (CoPoP), as well as a synthetic monophosphoryl lipid A (PHAD) adjuvant. Intramuscular immunization of mice with sub-microgram doses CfaEB or CfaEad admixed with CoPoP/PHAD liposomes elicited serum IgG and intestinal IgA antibodies. The smaller CfaEad antigen benefitted more from liposome display. Serum and intestine antibodies from mice immunized with liposome-displayed CfaEB or CfaEad recognized native CFA/I fimbria as evidenced by immunofluorescence and hemagglutination inhibition assays using the CFA/I-expressing H10407 ETEC strain. ConclusionThese data show that colonization factor-derived recombinant ETEC antigens exhibit immunogenicity when delivered in immunogenic particle-based formulations.

DOPE/CHEMS-Based EGFR-Targeted Immunoliposomes for Docetaxel Delivery: Formulation Development, Physicochemical Characterization and Biological Evaluation on Prostate Cancer Cells

Docetaxel (DTX) is a non-selective antineoplastic agent with low solubility and a series of side effects. The technology of pH-sensitive and anti-epidermal growth factor receptor (anti-EGFR) immunoliposomes aims to increase the selective delivery of the drug in the acidic tumor environment to cells with EFGR overexpression. Thus, the study aimed to develop pH-sensitive liposomes based on DOPE (dioleoylphosphatidylethanolamine) and CHEMS (cholesteryl hemisuccinate), using a Box-Behnken factorial design. Furthermore, we aimed to conjugate the monoclonal antibody cetuximab onto liposomal surface, as well as to thoroughly characterize the nanosystems and evaluate them on prostate cancer cells. The liposomes prepared by hydration of the lipid film and optimized by the Box-Behnken factorial design showed a particle size of 107.2 ± 2.9 nm, a PDI of 0.213 ± 0.005, zeta potential of -21.9 ± 1.8 mV and an encapsulation efficiency of 88.65 ± 20.3%. Together, FTIR, DSC and DRX characterization demonstrated that the drug was properly encapsulated, with reduced drug crystallinity. Drug release was higher in acidic pH. The liposome conjugation with the anti-EGFR antibody cetuximab preserved the physicochemical characteristics and was successful. The liposome containing DTX reached an IC50 at a concentration of 65.74 nM in the PC3 cell line and 28.28 nM in the DU145 cell line. Immunoliposome, in turn, for PC3 cells reached an IC50 of 152.1 nM, and for the DU145 cell line, 12.60 nM, a considerable enhancement of cytotoxicity for the EGFR-positive cell line. Finally, the immunoliposome internalization was faster and greater than that of liposome in the DU145 cell line, with a higher EGFR overexpression. Thus, based on these results, it was possible to obtain a formulation with adequate characteristics of nanometric size, a high encapsulation of DTX and liposomes and particularly immunoliposomes containing DTX, which caused, as expected, a reduction in the viability of prostate cells, with high cellular internalization in EGFR overexpressing cells.

Doxorubicin-loaded liposomes surface engineered with the matrix metalloproteinase-2 cleavable polyethylene glycol conjugate for cancer therapy

BackgroundColorectal cancer is one of the prominent leading causes of fatality worldwide. Despite recent advancements within the field of cancer therapy, the cure rates and long-term survivals of patients suffering from colorectal cancer have changed little. The application of conventional chemotherapeutic agents like doxorubicin is limited by some drawbacks such as cardiotoxicity and hematotoxicity. Therefore, nanotechnology has been exploited as a promising solution to address these problems. In this study, we synthesized and compared the anticancer efficacy of doxorubicin-loaded liposomes that were surface engineered with the 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-matrix metalloproteinase-2 (MMP-2) cleavable peptide-polyethylene glycol (PEG) conjugate. The peptide linker was used to cleave in response to the upregulated MMP-2 in the tumor microenvironment, thus exposing a positive charge via PEG-deshielding and enhancing liposomal uptake by tumor cells/vasculature. Liposomal formulations were characterized in terms of size, surface charge and morphology, drug loading, release properties, cell binding and uptake, and cytotoxicity.ResultsThe formulations had particle sizes of ~ 100–170 nm, narrow distribution (PDI ˂ 0.2), and various surface charges (− 10.2 mV to + 17.6 mV). MMP-2 overexpression was shown in several cancer cell lines (C26, 4T1, and B16F10) as compared to the normal NIH-3T3 fibroblast cells by gelatin zymography and qRT-PCR. In vitro results demonstrated enhanced antitumor efficacy of the PEG-cleavable cationic liposomes (CLs) as compared to the commercial Caelyx® (up to fivefold) and the chick chorioallantoic membrane assay showed their great antiangiogenesis potential to target and suppress tumor neovascularization. The pharmacokinetics and efficacy studies also indicated higher tumor accumulation and extended survival rates in C26 tumor-bearing mice treated with the MMP-2 cleavable CLs as compared to the non-cleavable CLs with no remarkable sign of toxicity in healthy tissues.ConclusionAltogether, the MMP-2-cleavable CLs have great potency to improve tumor-targeted drug delivery and cellular/tumor-vasculature uptake which merits further investigation.

Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties.

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides. At pH2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH. This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

Application of two glycosylated Lactobacillus surface layer proteins in coating cationic liposomes

The ability of isolated surface layer proteins (SLPs) to reassemble on suitable surfaces enables the application of SLPs in various fields of nanotechnology. In this work, SLPs from Lactobacillus buchneri BNCC 187,964 and L. kefir BNCC 190,565 were extracted and verified as glycosylated proteins. They were applied to coat on the surface of cationic liposomes. The absorption of the two SLPs on liposomes induced the zeta potential reduction and particle size increase. The two kinds of SLP-coated liposomes demonstrated better thermal, light and pH stability than the control liposomes. And the L. kefir SLP showed better protective effects than the L. buchneri SLP. Moreover, both of the SLPs could endow liposomes with the function of binding ferritin as observed by transmission electron microscope. Fourier transform infrared spectroscopy illustrated that the interaction between the two SLPs and liposomes was similar. The recrystallization of the two SLPs on the liposomes might drive the lipid into a higher order state and hydrogen bonds were formed between the two SLPs and the liposomes. All the findings demonstrated that L. kefir SLP and L. buchneri SLP had great potential to be explored as effective coating agents to improve the stability and function of cationic liposomes.Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.Yes, all have been checked.

Multi-compartment containers from a mixture of natural and synthetic lipids

Small anionic liposomes were electrostatically adsorbed on the surface of larger cationic liposomes thus forming multi- compartment complexes composed exclusively of natural and synthetic lipids. The complexes contained two dozen anionic liposomes per a single cationic liposome and showed low cytotoxicity and ability to enzyme-induced bio-degradation. The liposomal multi-compartment complexes demonstrate great application potential as containers for drug encapsulation and delivery.

Effects of PEG-Linker Chain Length of Folate-Linked Liposomal Formulations on Targeting Ability and Antitumor Activity of Encapsulated Drug.

Ligand-conjugated liposomes are promising for the treatment of specific receptor-overexpressing cancers. However, previous studies have shown inconsistent results because of the varying properties of the ligand, presence of a polyethylene glycol (PEG) coating on the liposome, length of the linker, and density of the ligand. Here, we prepared PEGylated liposomes using PEG-linkers of various lengths conjugated with folate and evaluated the effect of the PEG-linker length on the nanoparticle distribution and pharmacological efficacy of the encapsulated drug both in vitro and in vivo. When folate was conjugated to the liposome surface, the cellular uptake efficiency in folate receptor overexpressed KB cells dramatically increased compared to that of the normal liposome. However, when comparing the effect of the PEG-linker length in vitro, no significant difference between the formulations was observed. In contrast, the level of tumor accumulation of particles in vivo significantly increased when the length of the PEG-linker was increased. The tumor size was reduced by >40% in the Dox/FL-10K-treated group compared to that in the Dox/FL-2K- or 5K-treated groups. Our study suggests that as the length of PEG-linker increases, the tumor-targeting ability can be enhanced under in vivo conditions, which can lead to an increase in the antitumor activity of the encapsulated drug.

Tailoring the Lamellarity of Liposomes Prepared by Dual Centrifugation.

Dual centrifugation (DC) is a new and versatile technique for the preparation of liposomes by in-vial homogenization of lipid-water mixtures. Size, size distribution, and entrapping efficiencies are strongly dependent on the lipid concentration during DC-homogenization. In this study, we investigated the detailed structure of DC-made liposomes. To do so, an assay to determine the ratio of inner to total membrane surfaces of liposomes (inaccessible surface) was developed based on either time-resolved or steady-state fluorescence spectroscopy. In addition, cryogenic electron microscopy (cryo-EM) was used to confirm the lamellarity results and learn more about liposome morphology. One striking result leads to the possibility of producing a novel type of liposome-small multilamellar vesicles (SMVs) with low PDI, sizes of the order of 100 nm, and almost completely filled with bilayers. A second particularly important finding is that VPGs can be prepared to contain open bilayer structures that will close spontaneously when, after storage, more aqueous phase is added and liposomes are formed. Through this process, a drug can effectively be entrapped immediately before application. In addition, dual centrifugation at lower lipid concentrations is found to produce predominantly unilamellar vesicles.

A Multifunctional Hybrid Nanocarrier for Non-Invasive siRNA Delivery to the Retina.

Drug therapy for retinal diseases (e.g., age-related macular degeneration, the leading cause of blindness) is generally performed by invasive intravitreal injection because of poor drug delivery caused by the blood-retinal barrier (BRB). This study aimed to develop a nanocarrier for the non-invasive delivery of small interfering RNA (siRNA) to the posterior segment of the eye (i.e., the retina) by eyedrops. To this end, we prepared a hybrid nanocarrier based on a multifunctional peptide and liposomes, and the composition was optimized. A cytoplasm-responsive stearylated peptide (STR-CH2R4H2C) was used as the multifunctional peptide because of its superior ability to enhance the complexation, cell permeation, and intracellular dynamics of siRNA. By adding STR-CH2R4H2C to the surface of liposomes, intracellular uptake increased regardless of the liposome surface charge. The STR-CH2R4H2C-modified cationic nanocarrier demonstrated significant siRNA transfection efficiency with no cytotoxicity, enhanced siRNA release from endosomes, and effectively suppressed vascular endothelial growth factor expression in rat retinal pigment epithelium cells. The 2.0 mol% STR-CH2R4H2C-modified cationic nanocarrier enhanced intraocular migration into the retina after instillation into rat eyes.

Liposomal Doxorubicin: the Sphingomyelin/Cholesterol System Significantly Enhances the Antitumor Efficacy of Doxorubicin

Doxorubicin (DOX) has a cytotoxic effect on many tumor cells; however, its clinical application is limited owing to its strong side effects. Although Doxil® reduces the cardiotoxicity of free DOX, it has also introduced a new dose-limiting toxicity. In a previous study, a sialic acid-cholesterol conjugate (SA-CH) was synthesized and modified onto the surface of DOX-loaded liposomes to target tumor-associated macrophages (TAMs), further improving the efficacy of DOX-loaded liposomes over that of Doxil®. Meanwhile, the good retention characteristics and promising antitumor ability of sphingomyelin/cholesterol (SM/CH) system for water-soluble drugs have attracted wide attention. Therefore, we aimed to use SA-CH as the target and hydrogenated soybean phosphatidylcholine (HSPC) or egg sphingomyelin (ESM) as the membrane material to develop a more stable DOX-loaded liposome with stronger antitumor activity. The liposomes were evaluated for particle size, polydispersity index, zeta potential, entrapment efficiency, in vitro release, long-term storage, cytotoxicity, cellular uptake, pharmacokinetics, tumor targetability, and in vivo antitumor activity. In the liposomes prepared using HSPC/CH, sialic acid (SA) modification considerably increased the accumulation of DOX-loaded liposomes in the tumor, thus exerting a better antitumor effect. However, SA modification in DOX-ESL (SA-CH-modified DOX-loaded liposomes prepared by ESM/CH) destroyed the strong retention effect of the ESM/CH system on DOX, resulting in a reduced antitumor effect. Notably, DOX-ECL (DOX-loaded liposome prepared by ESM/CH) had the optimal storage stability, lowest toxicity, and optimal antitumor effect due to better drug retention properties. Thus, the ESM/CH liposome of DOX is a potential drug delivery system. Sketch of the effect of two DOX-loaded liposomes with hydrogenated soybean phospholipid (HSPC) and egg sphingomyelin (ESM) as lipid membrane material and surface-modified SA derivative on tumor growth inhibition.

Complexes of Cationic Pyridylphenylene Dendrimers with Anionic Liposomes: The Role of Dendrimer Composition in Membrane Structural Changes.

In the last decades, dendrimers have received attention in biomedicine that requires detailed study on the mechanism of their interaction with cell membranes. In this article, we report on the role of dendrimer structure in their interaction with liposomes. Here, the interactions between cationic pyridylphenylene dendrimers of the first, second, and third generations with mixed or completely charged pyridyl periphery (D16+, D215+, D229+, and D350+) with cholesterol-containing (CL/Chol/DOPC) anionic liposomes were investigated by microelectrophoresis, dynamic light scattering, fluorescence spectroscopy, and conductometry. It was found that the architecture of the dendrimer, namely the generation, the amount of charged pyridynium groups, the hydrophobic phenylene units, and the rigidity of the spatial structure, determined the special features of the dendrimer-liposome interactions. The binding of D350+ and D229+ with almost fully charged peripheries to liposomes was due to electrostatic forces: the dendrimer molecules could be removed from the liposomal surfaces by NaCl addition. D350+ and D229+ did not display a disruptive effect toward membranes, did not penetrate into the hydrophobic lipid bilayer, and were able to migrate between liposomes. For D215+, a dendrimer with a mixed periphery, hydrophobic interactions of phenylene units with the hydrocarbon tails of lipids were observed, along with electrostatic complexation with liposomes. As a result, defects were formed in the bilayer, which led to irreversible interactions with lipid membranes wherein there was no migration of D215+ between liposomes. A first-generation dendrimer, D16+, which was characterized by small size, a high degree of hydrophobicity, and a rigid structure, when interacting with liposomes caused significant destruction of liposomal membranes. Evidently, this interaction was irreversible: the addition of salt did not lead to the dissociation of the complex.

Oxygen supplementation liposomes for rheumatoid arthritis treatment via synergistic phototherapy and repolarization of M1-to-M2 macrophages

Rheumatoid arthritis (RA) is one of the most common systemic autoimmune diseases, with no current, clinically effective treatment. Activation of pro-inflammatory M1 macrophages is known to play a vital role in the pathogenesis of RA. Accumulating evidence suggests that phototherapy, especially photodynamic therapy (PDT), could apply as a new therapeutic method for the treatment of RA. However, due to the anoxic environment of RA synovial tissues and the oxygen consumption required for PDT process, the phototherapy efficiency was always reduced. Moreover, surviving and newly invading macrophages will be induced to polarize towards the pro-inflammatory M1-type, resulting in a relapse of the disease. To compensate for these deficits, we designed and developed novel phototherapeutic liposomal nanoparticles (CyI&Hb/FA-LPs) by incorporating heavy atom modified, cyanine dyes (CyI) as photosensitizers, and loading hemoglobin (Hb) into the inner core for relieving the hypoxic microenvironments and repolarizing M1-to-M2 macrophages. Meanwhile, folic acid was attached to the liposome surface to achieve active targeting of M1 macrophages. In vitro and in vivo studies demonstrate that near infrared light irradiation of CyI&Hb/FA-LPs reduces M1 macrophage populations and reduces the expression of hypoxia-inducible factor-1α that drives the remaining M1 macrophages to transition to the anti-inflammatory M2 phenotype. Moreover, intra-articular treatment of CyI&Hb/FA-LPs in a RA mouse model inhibited synovial cell infiltration, and alleviated inflammation and pathological features in the affected joint. This study highlights the potential of CyI-based oxygenated liposomes as a new and versatile strategy for implementing RA targeting phototherapy and M1-to-M2 repolarization. The dual mode phototherapy and O2 supplementation agent appears to function synergistically by reducing M1 macrophage populations through direct killing and induced apoptosis, as well as by inducing M2 phenotype proliferation.

Cationic liposomes bearing Bet v 1 by coiled coil-formation are hypo-allergenic and induce strong immunogenicity in mice.

Although aluminum hydroxide (alum) is widely accepted and used as safe vaccine adjuvant, there is some concern about possible toxicity upon long-lasting repeated exposure during subcutaneous allergen immunotherapy (SCIT). Our objective was to evaluate allergen-bearing liposomes as possible alternative for alum-adsorption in SCIT. A self-assembling, coiled-coil forming peptide pair was used to anchor the major birch pollen allergen Bet v 1 to the surface of cationic liposomes. The resulting nanoparticulate liposomes were characterized with respect to their physicochemical, allergenic and immunological properties. Allergenicity was studied by ImmunoCAP inhibition and rat basophil leukemia (RBL) cell assays. Immunogenicity (immunoglobulin responses) and immune skewing (cytokine responses) were evaluated upon immunization of naïve mice, and compared to alum-adsorbed Bet v 1. Bet v 1-bearing cationic liposomes with a diameter of ∼200 nm showed a positive zeta potential. The coiled-coil conjugation of Bet v 1 to the surface of liposomes resulted in about a 15-fold lower allergenicity than soluble Bet v 1 as judged by RBL assays. Moreover, the nanoparticles induced Bet v 1-specific IgG1/IgG2a responses in mice that were several orders of magnitude higher than those induced by alum-adsorbed Bet v 1. This strong humoral response was accompanied by a relatively strong IL-10 induction upon PBMC stimulation with Bet v 1. In conclusion, their hypo-allergenic properties, combined with their capacity to induce a strong humoral immune response and a relatively strong IL-10 production, makes these allergen-covered cationic liposomes a promising alternative for aluminum salt-adsorption of allergen currently used in SCIT.

Structural Insights Uncover the Specific Phosphoinositide Recognition by the PH1 Domain of Arap3.

Arap3, a dual GTPase-activating protein (GAP) for the small GTPases Arf6 and RhoA, plays key roles in regulating a wide range of biological processes, including cancer cell invasion and metastasis. It is known that Arap3 is a PI3K effector that can bind directly to PI(3,4,5)P3, and the PI(3,4,5)P3-mediated plasma membrane recruitment is crucial for its function. However, the molecular mechanism of how the protein recognizes PI(3,4,5)P3 remains unclear. Here, using liposome pull-down and surface plasmon resonance (SPR) analysis, we found that the N-terminal first pleckstrin homology (PH) domain (Arap3-PH1) can interact with PI(3,4,5)P3 and, with lower affinity, with PI(4,5)P2. To understand how Arap3-PH1 and phosphoinositide (PIP) lipids interact, we solved the crystal structure of the Arap3-PH1 in the apo form and complex with diC4-PI(3,4,5)P3. We also characterized the interactions of Arap3-PH1 with diC4-PI(3,4,5)P3 and diC4-PI(4,5)P2 in solution by nuclear magnetic resonance (NMR) spectroscopy. Furthermore, we found overexpression of Arap3 could inhibit breast cancer cell invasion in vitro, and the PIPs-binding ability of the PH1 domain is essential for this function.

Use of different ligand modification liposomes to evaluate the anti-liver tumor activity of cantharidin

In this study, cantharidin(CTD), a bioactive terpenoid in traditional Chinese medicine cantharidin, was selected as a model component to construct novel nano liposome delivery systems for hepatocellular carcinoma therapy. Previous studies have shown that although cantharidin has definite curative effects on primary liver cancer, it is associated with numerous toxic and side effects. Therefore, based on the glycyrrhetinic acid (GA) binding site and the asialoglycoprotein receptor (ASGPR) on the hepatocyte membrane, the surface of CTD liposomes was modified with stearyl alcohol galactoside (SA-Gal) or/and the newly synthesized 3-succinic-30-stearyl deoxyglycyrrhetinic acid (11-DGA-Suc) ligands, and the physicochemical properties, pharmacokinetics, in vivo and in vitro anti-liver tumor activity and its mechanism of modified liposomes were investigated. Compared to CTD-lip, SA-Gal-CTD-lip, and 11-DGA-Suc + SA-Gal-CTD-lip, 11-DGA-Suc-CTD-lip showed stronger cytotoxicity and increased inhibition of HepG2 cell migration had the highest apoptosis rate. The cell cycle results indicated that HepG2 cells was arrested mainly at G0/G1phase and G2/M phase. The results of in vivo pharmacokinetic experiments revealed that the distribution of modified liposomes in the liver was significantly increased compared with that of unmodified liposome. In vivo tumor inhibition experiment showed that 11-DGA-Suc-CTD-lip had excellent tumor inhibition, and the tumor inhibition rates was 80.96%. The 11-DGA-Suc-CTD-lip group also displayed the strongest proliferation inhibition with the lowest proliferation index of 7% in PCNA assay and the highest apoptotic index of 49% in TUNEL assay. Taken together, our findings provide a promising solution for improving the targeting of nano liposomes and further demonstrates the encouraging potential of poor solubility and high toxicity drugs applicable to tumor therapy.

Click Chemistry for Liposome Surface Modification.

Click chemistry, and particularly azide-alkyne cycloaddition, represents one of the principal bioconjugation strategies that can be used to conveniently attach various ligands to the surface of preformed liposomes. This efficient and chemoselective reaction involves a Cu(I)-catalyzed azide-alkyne cycloaddition which can be performed under mild experimental conditions in aqueous media. Here we describe the application of a model click reaction to the conjugation, in a single step, of unprotected α-1-thiomannosyl ligands, functionalized with an azide group, to liposomes containing a terminal alkyne-functionalized lipid anchor. Excellent coupling yields were obtained in the presence of bathophenanthrolinedisulphonate, a water-soluble copper-ion chelator, acting as catalyst. No vesicle leakage was triggered by this conjugation reaction, and the coupled mannose ligands were exposed at the surface of the liposomes. The major limitation of Cu(I)-catalyzed click reactions is that this type of conjugation is restricted to liposomes made of saturated (phospho)lipids. To circumvent this constraint, an example of alternate copper-free azide-alkyne click reaction has been developed, and it was applied to the anchoring of a biotin moiety that was fully functional and could be therefore quantified. Molecular tools and results are presented here.