Enhanced gene expression in lung by a stabilized lipoplex using sodium chloride for complex formation

Navigating the intricate in-vivo journey of lipid nanoparticles tailored for the targeted delivery of RNA therapeutics: a quality-by-design approach

RNA therapeutics, such as mRNA, siRNA, and CRISPR-Cas9, present exciting avenues for treating diverse diseases. However, their potential is commonly hindered by vulnerability to degradation and poor cellular uptake, requiring effective delivery systems. Lipid nanoparticles (LNPs) have emerged as a leading choice for in vivo RNA delivery, offering protection against degradation, enhanced cellular uptake, and facilitation of endosomal escape. However, LNPs encounter numerous challenges for targeted RNA delivery in vivo, demanding advanced particle engineering, surface functionalization with targeting ligands, and a profound comprehension of the biological milieu in which they function. This review explores the structural and physicochemical characteristics of LNPs, in-vivo fate, and customization for RNA therapeutics. We highlight the quality-by-design (QbD) approach for targeted delivery beyond the liver, focusing on biodistribution, immunogenicity, and toxicity. In addition, we explored the current challenges and strategies associated with LNPs for in-vivo RNA delivery, such as ensuring repeated-dose efficacy, safety, and tissue-specific gene delivery. Furthermore, we provide insights into the current clinical applications in various classes of diseases and finally prospects of LNPs in RNA therapeutics.

Diffusion coefficient of cationic liposomes during lipoplex formation determines transfection efficiency in HepG2 cells

Cationic lipid-based lipoplexes are well-known for gene delivery. To determine the relationship between physicochemical characteristics and transfection efficiency, cationic liposomes of different sizes were prepared and incubated with plasmid DNA at different temperatures to form lipoplexes. We found that the liposome diffusion coefficient during lipoplex formation strongly correlated with the physicochemical characteristics of lipoplexes, accessibility of plasmid DNA in lipoplexes, and logarithm of gene expression per metabolic activity. Clathrin-mediated endocytosis was the major route for lipoplexes comprising 100 nm-liposomes, as reported previously. As liposome size increased, the major route shifted to lipid raft-mediated endocytosis. In addition, macropinocytosis was observed for all liposome sizes. The role of reactive oxygen species might depend on liposome size and endocytosis. Information from this study would be useful for understanding cationic lipoplex-mediated transfection.

Understanding In Vivo Fate of Nucleic Acid and Gene Medicines for the Rational Design of Drugs

Nucleic acid and genetic medicines are increasingly being developed, owing to their potential to treat a variety of intractable diseases. A comprehensive understanding of the in vivo fate of these agents is vital for the rational design, discovery, and fast and straightforward development of the drugs. In case of intravascular administration of nucleic acids and genetic medicines, interaction with blood components, especially plasma proteins, is unavoidable. However, on the flip side, such interaction can be utilized wisely to manipulate the pharmacokinetics of the agents. In other words, plasma protein binding can help in suppressing the elimination of nucleic acids from the blood stream and deliver naked oligonucleotides and gene carriers into target cells. To control the distribution of these agents in the body, the ligand conjugation method is widely applied. It is also important to understand intracellular localization. In this context, endocytosis pathway, endosomal escape, and nuclear transport should be considered and discussed. Encapsulated nucleic acids and genes must be dissociated from the carriers to exert their activity. In this review, we summarize the in vivo fate of nucleic acid and gene medicines and provide guidelines for the rational design of drugs.

Efficient gene transfection to the brain with ultrasound irradiation in mice using stabilized bubble lipopolyplexes prepared by the surface charge regulation method

Introduction

We previously developed anionic ternary bubble lipopolyplexes, an ultrasound-responsive carrier, expecting safe and efficient gene transfection. However, bubble lipopolyplexes have a low capacity for echo gas (C₃F₈) encapsulation (EGE) in nonionic solution such as 5% glucose. On the other hand, we were able to prepare bubble lipopolyplexes by inserting phosphate-buffered saline before C₃F₈ encapsulation. Surface charge regulation (SCR) by electrolytes stabilizes liposome/plasmid DNA (pDNA) complexes by accelerated membrane fusion. Considering these facts, we hypothesized that SCR by electrolytes such as NaCl would promote C₃F₈ encapsulation in bubble lipopolyplexes mediated by accelerated membrane fusion. We defined this hypothesis as SCR-based EGE (SCR-EGE). Bubble lipopolyplexes prepared by the SCR-EGE method (SCR-EGE bubble lipopolyplexes) are expected to facilitate the gene transfection because of the high amount of C₃F₈. Therefore, we applied these methods for gene delivery to the brain and evaluated the characteristics of transgene expression in the brain.

Methods

First, we measured the encapsulation efficiency of C₃F₈ in SCR-EGE bubble lipopolyplexes. Next, we applied these bubble lipopolyplexes to the mouse brain; then, we evaluated the transfection efficiency. Furthermore, three-dimensional transgene distribution was observed using multicolor deep imaging.

Results

SCR-EGE bubble lipopolyplexes had a higher C₃F₈ content than conventional bubble lipopolyplexes. In terms of safety, SCR-EGE bubble lipopolyplexes possessed an anionic potential and showed no aggregation with erythrocytes. After applying SCR-EGE bubble lipopolyplexes to the brain, high transgene expression was observed by combining with ultrasound irradiation. As a result, transgene expression mediated by SCR-EGE bubble lipopolyplexes was observed mainly on blood vessels and partially outside of blood vessels.

Conclusion

The SCR-EGE method may promote C₃F₈ encapsulation in bubble lipopolyplexes, and SCR-EGE bubble lipopolyplexes may be potent carriers for efficient and safe gene transfection in the brain, especially to the blood vessels.

Small interfering RNA delivery into the liver by cationic cholesterol derivative-based liposomes

PURPOSE

Previously, we reported that the cationic liposomes composed of a cationic cholesterol derivative, cholesteryl (2-((2-hydroxyethyl)amino)ethyl)carbamate (OH-C-Chol) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) (termed LP-C), could deliver small interfering RNAs (siRNAs) with high transfection efficiency into tumor cells. In this study, to develop a liposomal vector for siRNA delivery in vivo, we prepared the poly(ethyleneglycol) (PEG)-modified cationic liposomes (LP-C-PEG) and evaluated their transfection efficiency in vitro and in vivo.

MATERIALS AND METHODS

We prepared LP-C-PEG/siRNA complexes (LP-C-PEG lipoplexes) formed in water or 50 mM NaCl solution, and evaluated their siRNA biodistribution and gene silencing effect in mice after intravenous injection.

RESULTS

LP-C-PEG lipoplexes strongly exhibited in vitro gene silencing effects in human breast tumor MCF-7 cells as well as LP-C lipoplexes. In particular, formation of LP-C and LP-C-PEG lipoplexes in the NaCl solution increased the cellular association. When LP-C-PEG lipoplexes with Cy5.5-labeled siRNA formed in water or NaCl solution were injected into mice, accumulation of the siRNA was observed in the liver. Furthermore, injection of LP-C-PEG lipoplexes with ApoB siRNA could suppress ApoB mRNA levels in the liver and reduce very-low-density lipoprotein/low-density lipoprotein levels in serum compared with that after Cont siRNA transfection, although the presence of NaCl solution in forming the lipoplexes did not affect gene silencing effects in vivo.

CONCLUSIONS

LP-C-PEG may have potential as a gene vector for siRNA delivery to the liver.

Evaluation of New Fluorescent Lipophosphoramidates for Gene Transfer and Biodistribution Studies after Systemic Administration

The objective of lung gene therapy is to reach the respiratory epithelial cells in order to deliver a functional nucleic acid sequence. To improve the synthetic carrier's efficacy, knowledge of their biodistribution and elimination pathways, as well as cellular barriers faced, depending on the administration route, is necessary. Indeed, the in vivo fate guides the adaptation of their chemical structure and formulation to increase their transfection capacity while maintaining their tolerance. With this goal, lipidic fluorescent probes were synthesized and formulated with cationic lipophosphoramidate KLN47 (KLN: Karine Le Ny). We found that such formulations present constant compaction properties and similar transfection results without inducing additional cytotoxicity. Next, biodistribution profiles of pegylated and unpegylated lipoplexes were compared after systemic injection in mice. Pegylation of complexes led to a prolonged circulation in the bloodstream, whereas their in vivo bioluminescent expression profiles were similar. Moreover, systemic administration of pegylated lipoplexes resulted in a transient liver toxicity. These results indicate that these new fluorescent compounds could be added into lipoplexes in small amounts without perturbing the transfection capacities of the formulations. Such additional properties allow exploration of the in vivo biodistribution profiles of synthetic carriers as well as the expression intensity of the reporter gene.

Efficient in vivo transfection and safety profile of a CpG-free and codon optimized luciferase plasmid using a cationic lipophosphoramidate in a multiple intravenous administration procedure

As any drug, the success of gene therapy is largely dependent on the vehicle that has to selectively and efficiently deliver therapeutic nucleic acids into targeted cells with minimal side-effects. In the case of chronic diseases that require a life-long treatment, non-viral gene delivery vehicles are less likely to induce an immune response, thereby allowing for repeated administration. Beyond the gene delivery efficiency of a given vector, the nature of nucleic acid constructs also has a central importance in gene therapy protocols. Herein, we investigated the impact of two firefly luciferase encoding plasmids on the transgene expression profile following systemic delivery of lipoplexes in mice, as well as their potential to be safely and efficiently readministered. Whereas pTG11033 plasmid is driven by a strong ubiquitous cytomegalovirus promoter, pGM144 plasmid, which has been designed to avoid inflammation and provide sustained transgene expression in lungs, is CpG-free and is under control of the human elongation factor-1 alpha promoter. Combined to the efficient cationic lipophosphoramidate BSV4, bioluminescence data showed that both plasmids were mostly expressed in the lungs of mice following a primary injection of lipoplexes. However, mice transfected with pGM144 exhibited a higher and more sustained transgene expression than those treated with pTG11033. Repeated administration studies revealed that several injections of lipoplexes could lead to similar transgene expression profiles if an interval of several weeks between subsequent injections was respected. A transient hepatotoxicity and a partial inflammatory response were caused by lipoplex injection, irrespective of the plasmid used. Altogether, these results indicate that repeated systemic administration of lipophosphoramidate-based lipoplexes in mice conducts to an effective lung transfection without serious side effects, and highlight the need to use long-lasting expressing and well tolerated plasmids in order to efficiently renew transgene expression by the successive doses.

Genetically manipulated adult stem cells for wound healing

New knowledge of the signal controls and activities of adult stem cells (ASCs) involved in wound repair have led to extensive investigation of the topical delivery of biomacromolecules and multipotent stem cells to injured tissues for scar-less regeneration. The transplantation of genetically recombinant stem cells, which have roles as both therapeutics and carriers for gene delivery to wound sites, represents an attractive strategy for wound treatment. Here, we compare viral and non-viral vectors and three-dimensional scaffold-based transfection strategies in terms of their biosafety, recombinant efficiency and influence on the differentiation of ASCs, to indicate the future direction of the application of recombinant ASCs in wound treatment.

Comparison between a multifunctional envelope-type nano device and lipoplex for delivery to the liver

The utility of using a multifunctional envelope-type nano device (MEND) for delivering a gene to the liver was examined. Lipotrust, a commercially available transfection reagent whose lipid composition is DC6- 14 :DOPE: cholesterol=4 : 3 : 3, was used as a reference. When Lipotrust was administrated intravenously, luciferase activity of the lung was 25 times higher than that of the liver. The luciferase activity of the lung was greatly reduced when a MEND was administered, even though the lipid composition of the lipid envelope was the same in both devices. Furthermore, the luciferase activity of the liver was 5 times higher than that for lipotrust, suggesting that the encapsulation of plasmid DNA (pDNA) in liposomes is more advantageous for delivering pDNA to the liver than complex formation. The isolation of parenchymal cells (PCs) and non-parenchymal cells (NPCs) showed that the MEND system is capable of expressing the luciferase protein more preferentially in NPCs than the lipoplex system. In addition, when the surface was modified with a pH-sensitive fusogenic peptide (GALA) used as a device for endosomal escape, overall liver luciferase activity was greatly enhanced. This suggests that endosomal escape is a limiting step for the MEND system. In the case of the GALA-modified MEND, the luciferase activity of PCs and NPCs was 18 times and 11 times higher than MEND system, while the transfection efficiency of NPCs was significantly higher compared to that of PCs. Collectively, these data show that a GALA-modified MEND prepared with DC6-14 :DOPE: cholesterol represents a promising device for NPCtargeting gene delivery in vivo.

Polydispersity as a parameter for indicating the thermal stability of proteins by dynamic light scattering

A physical parameter for predicting the thermal stability of proteins was provided by a new approach using dynamic light scattering (DLS). The relationship between the melting point measured by differential scanning calorimetry (DSC) and the polydispersity of the hydrodynamic diameter determined by DLS analysis was examined. Calmodulin (CaM) and concanavalin A (ConA) were used as model proteins. The melting point measured by DSC, an indicator for thermal stability, increased and the polydispersity decreased on binding of the proteins to specific ligands, suggesting that the polydispersity could be used an indicator to predict thermal stability. In addition, the increase of thermal stability that resulted from forming a complex could be quantified by polydispersity analysis even when the melting point changed only slightly.

[Organ-, region- and cell-selective gene transfer using non-viral vectors]

Safety in gene therapy is an important issue since both viral and non-viral vectors have toxic side effects. Not only vectors themselves, but also distributions of produced proteins affect safety in gene therapy; thus, development of target-selective gene transfer methods is rational. We have developed organ-, region- and cell-selective gene transfer methods using non-viral vectors. To deliver foreign gene to liver parenchymal cells (hepatocytes), galactosylation of cationic liposome/plasmid DNA complex is useful strategy. Based on analyses for intrahepatic disposition characteristics and interaction with blood components, we formulated novel galactosylated lipoplex with regulated salt concentration to reduce particle size of lipoplex and to stabilize lipoplex simultaneously; as a consequence, we succeeded in improvement of hepatocyte-selective gene transfer after intraportal injection of the lipoplex in mice. On the other hand, administration routes are important for target-selective gene transfer. We discovered that simple instillation of naked plasmid DNA onto organ surface (the liver, kidney, spleen, stomach and lung) in mice and rats could result in effective and region-selective transgene expression. Neither physical force nor carriers are necessary for gene transfer onto organ surface mesothelial cells. To rationally improve transfection efficiency, mechanism of gene transfer should be elucidated. We clarified that Rac-mediated macropinocytosis was required for naked plasmid DNA transfer in gastric mesothelial cells.

The effects of salt on the physicochemical properties and immunogenicity of protein based vaccine formulated in cationic liposome

Recently, we have developed a simple and potent therapeutic cancer vaccine consisting of a cationic lipid and a peptide antigen. In this report, we expanded the utility of this formulation to protein based vaccines. First, we formulated the human papillomavirus (HPV) 16 E7 protein (E7) in different doses of DOTAP liposome. The results showed that these formulations failed to regress an established tumor. However, when sodium chloride (30 mM) was added to the DOTAP (100 nmol)/E7 (20 microg) formulation, anti-tumor activity was generated in the immunized mice. Correlatively, 30 mM NaCl in the DOTAP/E7 protein formulation increased the particle size from approximately 350 to 550 nm, decreased the protein loading capacity (from 95 to 90%), and finally increased the zeta potential (from 29 to 38 mV). Next, a model protein antigen ovalbumin (OVA) was formulated in different doses of DOTAP liposomes. Similarly, the results showed that 20 microg OVA formulated in 200 nmol DOTAP with 30 mM NaCl had the best OVA-specific antibody response, including both IgG(1) and IgG(2a), suggesting both Th1 and Th2 immune responses were generated by this formulation. In conclusion, we have expanded the application of cationic DOTAP liposome formulation to protein based vaccines and also identified that small amounts of salt could change the physicochemical properties of the vaccine formulation and enhance the activity of the DOTAP/protein based vaccine. The enhancement of immune responses by salt is possibly due to its interference of the electrostatic interaction between the cationic lipid and the protein antigen to facilitate the antigen release from the carrier and at the same time activate the antigen presenting cells.

Generation of highly potent nonviral gene vectors by complexation of lipoplexes and transferrin-bearing fusogenic polymer-modified liposomes in aqueous glucose solution

We reported previously that complexation of lipoplexes containing 3,5-dipentadecyloxybenzamidine (TRX-20) and transferrin-bearing succinylated poly(glycidol) (SucPG)-modified liposome, which becomes fusogenic under weakly acidic conditions, might produce gene carriers with high transfection activity. For the present study, we prepared the lipoplex-SucPG-modified liposome complexes by mixing them either in phosphate-buffered saline or in an aqueous 5% glucose solution. The complexes prepared in phosphate-buffered saline have large particles of more than 800 nm, whereas the complexes prepared in the glucose solution were remarkably small: 200-300 nm. The small complexes were taken up more effectively by HeLa cells, and their transfection was induced more efficiently than the large complexes'. In addition, the small complexes achieved cellular transfection more efficiently in the presence of serum than in the absence of serum, without marked cytotoxicity. Considering that their affinity to the cell is based on ligand-receptor interaction, the small complexes are highly promising as a safe vector with high transfection activity and high target cell specificity.

Non-viral gene transfection technologies for genetic engineering of stem cells

The recent rapid progress of molecular biology together with the steady progress of genome projects has given us some essential and revolutionary information about DNA and RNA to elucidate various biological phenomena at a genetic level. Under these circumstances, the technology and methodology of gene transfection have become more and more important to enhance the efficacy of gene therapy for several diseases. In addition, gene transfection is a fundamental technology indispensable to the further research development of basic biology and medicine regarding stem cells. Stem cells genetically manipulated will enhance the therapeutic efficacy of cell transplantation. In this paper, the carrier and technology of gene delivery are briefly overviewed while the applications to the basic researches of biology and medicine as well as regenerative medical therapy are introduced. A new non-viral carrier and the cell culture system are described to efficiently manipulate stem cells.

Targeted delivery systems of small interfering RNA by systemic administration

RNA interference (RNAi) is induced by 21-25 nucleotide, double-stranded small interfering RNA (siRNA), which is incorporated into the RNAi-induced silencing complex (RISC) and is a guide for cleavage of the complementary target mRNA in the cytoplasm. There are many obstacles to in vivo delivery of siRNAs, such as degradation by enzymes in blood, interaction with blood components and non-specific uptake by the cells, which govern biodistribution in the body. In order to achieve the knockdown by siRNAs in vivo, many delivery systems of siRNAs based on physical and pharmaceutical approaches have been proposed. In addition, the immune responses of siRNA must be taken into account when considering the application of siRNAs to in vivo therapy. This review focuses on recent reports about delivery systems and immune responses of siRNAs.

Intracellular trafficking is the important process that determines the optimal charge ratio on transfection by galactosylated lipoplex in HEPG2 cells

The purpose of the present study was to gain insight into the major factors affecting transfection efficiency with galactosylated lipoplex in HepG2 cells. In this study, lipoplex and galactosylated lipoplex were examined at different charge ratios (- : +): 1.0 : 1.2, 1.0 : 2.3, 1.0 : 3.1, 1.0 : 4.7, and 1.0 : 7.0. The particle size and zeta potential of the both lipoplexes was dependent on the charge ratio. Cellular uptake was evaluated by using [(32)P]-labeled pCMV-Luc and this showed that the cellular uptake of galactosylated lipoplex was significantly higher than that of lipoplex at a charge ratio ranging from 1.0 : 2.3 to 1.0 : 7.0. As the charge ratio increased in both lipoplexes, the apparent cellular uptake increased. Transfection activity by galactosylated lipoplex was significantly higher than that by lipoplex except at a charge ratio of 1.0 : 7.0. The optimal charge ratio for transfection efficacy was 1.0 : 2.3 and transfection was reduced at higher charge ratios. Both lipoplexes exhibited no significant cytotoxicity at any charge ratio. In conclusion, it is suggested that intracellular trafficking, rather than the degree of uptake and cytotoxicity, is the important process that determines the optimal charge ratio of galactosylated lipoplex in HepG2 cells.

Enhanced DNA vaccine potency by mannosylated lipoplex after intraperitoneal administration

BACKGROUND

Here we describe a novel DNA vaccine formulation that can enhance cytotoxic T lymphocyte (CTL) activity through efficient gene delivery to dendritic cells (DCs) by mannose receptor-mediated endocytosis.

METHODS

Ovalbumin (OVA) was selected as a model antigen for vaccination; accordingly, OVA-encoding pDNA (pCMV-OVA) was constructed to evaluate DNA vaccination. Mannosylated cationic liposomes (Man-liposomes) were prepared using cholesten-5-yloxy-N-{4-[(1-imino-2-D-thiomannosylethyl)amino]butyl}formamide (Man-C4-Chol) with cationic lipid. The potency of the mannosylated liposome/pCMV-OVA complex (Man-lipoplex) was evaluated by measuring OVA mRNA in CD11c+ cells, CTL activity, and the OVA-specific anti-tumor effect after in vivo administration.

RESULTS

An in vitro study using DC2.4 cells demonstrated that Man-liposomes could transfect pCMV-OVA more efficiently than cationic liposomes via mannose receptor-mediated endocytosis. In vivo studies revealed that the Man-lipoplex exhibited higher OVA mRNA expression in CD11c+ cells in the spleen and peritoneal cavity and provided a stronger OVA-specific CTL response than intraperitoneal (i.p.) administration of the conventional lipoplex and intramuscular (i.m.) administration of naked pCMV-OVA, the standard protocol for DNA vaccination. Pre-immunization with the Man-lipoplex provided much better OVA-specific anti-tumor effect than naked pCMV-OVA via the i.m. route.

CONCLUSIONS

These results suggested that in vivo active targeting of DNA vaccine to DCs with Man-lipoplex might prove useful for the rational design of DNA vaccine.

Effect of the particle size of galactosylated lipoplex on hepatocyte-selective gene transfection after intraportal administration

The purpose of this study was to examine the effect of the size of galactosylated cationic liposome (Gal-liposome)/plasmid DNA complex (Gal-lipoplex) on hepatocyte-selective gene transfection after intraportal administration. pCMV-Luc was selected as a model plasmid DNA. After intraportal administration of Gal-lipoplex to mice, the hepatic and intrahepatic gene expression was evaluated. To evaluate the effect of size, three different sizes of Gal-liposome were prepared. The mean particle sizes of Gal-lipoplex were about 141, 179, and 235 nm, respectively. The hepatic transfection efficacy was significantly enhanced by increasing the size of Gal-lipoplex. However, the gene expression in liver parenchymal cells (PC) of Gal-lipoplex of about 141 nm in size was significantly higher than that in liver non-parenchymal cells (NPC). In contrast, gene expression in PC of Gal-lipoplex of about 235 nm in size was significantly lower than that in NPC. These results highlight the importance of the Gal-lipoplex size for hepatocyte-selective gene transfer in vivo. The information in this study will be valuable for the future use, design, and development of Gal-lipoplex for in vivo applications.

Inhibition of pulmonary metastasis in mice by all-trans retinoic acid incorporated in cationic liposomes

The purpose of this study was to investigate whether all-trans retinoic acid (ATRA), an active metabolite of retinal, incorporated in cationic liposomes composed of 1,2 dioleoyl-3-trimethylammonium propane (DOTAP)/cholesterol could inhibit established metastatic lung tumors by delivery to the pulmonary tumor site after intravenous injection. After intravenous injection in mice, the highest lung accumulation of [(3)H]ATRA was observed by the DOTAP/cholesterol liposomes formulation, while other formulations including [(3)H]ATRA dissolved in serum or [(3)H]ATRA incorporated in distearoyl-l-phosphatidylcholine (DSPC)/cholesterol liposomes produced little accumulation in the lung. In mice used as a model of lung cancer metastasis, ATRA incorporated in DOTAP/cholesterol liposomes, injected intravenously, reduced the number of tumor nodules compared with free ATRA or ATRA incorporated in DSPC/cholesterol liposomes. These results suggest that ATRA incorporated in cationic liposomes would be an effective strategy for differentiation therapy of lung cancer metastasis.

Efficient gene transfer into macrophages and dendritic cells by in vivo gene delivery with mannosylated lipoplex via the intraperitoneal route

In this study, we developed an antigen-presenting cell (APC)-selective intraperitoneal (i.p.) gene delivery system with mannosylated cationic liposomes (Man-liposomes)/plasmid DNA complex (Man-lipoplex). An in vitro study using cultured peritoneal macrophages demonstrated that Man-liposomes could transfect luciferase-encoding plasmid DNA (pCMV-Luc) more efficiently than cationic liposomes via a mannose receptor-mediated mechanism. In vivo gene transfection studies revealed that Man-lipoplex showed a higher gene expression in the liver, spleen, peritoneal exuded cells, and mesenteric lymph nodes than cationic liposomes/plasmid DNA complex (lipoplex) or naked pCMV-Luc after i.p. administration, and this gene expression lasted for at least 24 h. The transfection activity of Man-lipoplex after i.p. administration was significantly higher than that after i.v. gene delivery with the Man-liposomes we developed previously, indicating that gene delivery via the i.p. route seems to be an efficient approach for in vivo gene delivery to APCs. Furthermore, it was demonstrated that Man-lipoplex could enhance gene expression in both F4/80+ and CD11c+ cells in the spleen. These results show that gene delivery with Man-liposomes via the i.p. route could be an effective approach for APC-selective gene transfection.

Intravenous administration of mannosylated cationic liposome/NFκB decoy complexes effectively prevent LPS-induced cytokine production in a murine liver failure model

The purpose of this study was to inhibit endotoxin induced cytokines production and liver injury by liver non-parenchymal cell (NPC) selective delivery of nuclear factor kappaB (NFkappaB) decoy using mannosylated cationic liposomes (Man-liposomes). In this study, we examined the distribution, inhibitory effect on cytokines production and ALT/AST of intravenously injected Man-liposome/NFkappaB decoy complex. Man-liposome/[(32)P] NFkappaB decoy complexes mostly accumulated in the liver, preferentially in NPC. In a murine lipopolysaccharide-induced liver failure model, the production of tumor necrosis factor-alpha (TNFalpha), IFNgamma, IL1-beta, ALT and AST were effectively reduced by Man-liposome complexes. However, cationic or galactosylated cationic liposome complexes could not inhibit TNFalpha production.