Anionic Complex with Efficient Expression and Good Safety Profile for mRNA Delivery

We previously found that a complex comprising plasmid DNA (pDNA), polyethylenimine (PEI), and γ-polyglutamic acid (γ-PGA) had high transgene efficiency without cytotoxicity in vitro and in vivo. However, messenger RNA (mRNA) remains an attractive alternative to pDNA. In this study, we developed a safe and effective delivery system for mRNA to prevent its degradation and efficiently deliver it into target cells. Various cationic and anionic complexes were produced containing PEI, γ-PGA, and an mRNA encoding firefly luciferase. Their physicochemical properties and cytotoxicities were analyzed and the in vitro and in vivo protein expression were determined. The cationic mRNA/PEI complex showed high in vitro protein expression with strong cytotoxicity. The anionic complex was constructed as mRNA/PEI8/γ-PGA12 complex with a theoretical charge ratio of 1:8:12 based on the phosphate groups of the mRNA, nitrogen groups of PEI, and carboxylate groups of γ-PGA. It was stable and showed high in vitro protein expression without cytotoxicity. After intravenous administration of mRNA/PEI8/γ-PGA12 complex to mice, high protein expression was observed in the spleen and liver and slight expression was observed in the lung over 24 h. Thus, the newly constructed mRNA/PEI8/γ-PGA12 complex provides a safe and effective strategy for the delivery of mRNA

Delivery of pDNA to the Lung by Lipopolyplexes Using N-Lauroylsarcosine and Effect on the Pulmonary Fibrosis

In a previous study, we constructed a lung-targeting lipopolyplex containing polyethyleneimine (PEI), 1,2-di-O-octadecenyl-3-trimethylammonium propane (DOTMA), and N-lauroylsarcosine (LS). The lipopolyplex exhibited an extremely high gene expression in the lung after intravenous administration. Here, we optimized the lipopolyplex and used it to deliver a TGF-β1 shRNA to treat refractory pulmonary fibrosis. We constructed several lipopolyplexes with pDNA, various cationic polymers, cationic lipids, and LS to select the most effective formulation. Then, the pDNA encoding shRNA against mouse TGF-β1 was encapsulated in the lipopolyplex and injected into mice with bleomycin-induced pulmonary fibrosis. After optimizing the lipopolyplex, dendrigraft poly-L-lysine (DGL) and DOTMA were selected as the appropriate cationic polymer and lipid, respectively. The lipopolyplex was constructed with a pDNA, DGL, DOTMA, and LS charge ratio of 1:2:2:4 showed the highest gene expression. After intravenous administration of the lipopolyplex, the highest gene expression was observed in the lung. In the in vitro experiment, the lipopolyplex delivered pDNA into the cells via endocytosis. As a result, the lipopolyplex containing pDNA encoding TGF-β1 shRNA significantly decreased hydroxyproline in the pulmonary fibrosis model mice. We have successfully inhibited pulmonary fibrosis using a novel lung-targeting lipopolyplex

Highly stomach-selective gene transfer following gastric serosal surface instillation of naked plasmid DNA in rats.

BACKGROUND: The purpose of this study was to achieve stomach-selective gene transfer in rats by our simple and novel administration method, which is gastric serosal surface instillation of naked plasmid DNA (pDNA). METHODS: Naked pDNA encoding firefly luciferase as a reporter gene was instilled onto the gastric serosal surface in male Wistar rats. As controls, we performed intraperitoneal, intragastric and intravenous administration of naked pDNA. At appropriate time intervals, we measured luciferase activities in the stomach and other tissues. RESULTS: Gene expression in the stomach 6 h after gastric serosal surface instillation of naked pDNA (5 microg) was significantly higher than that after using other administration methods. The present study is the first report on stomach-selective gene transfer following instillation of naked pDNA onto the gastric serosal surface in rats. Also, the gene expression level in the stomach 6 h after gastric serosal surface instillation of naked pDNA was markedly higher than that in other tissues. In a dose-dependent study, the gene expression level was saturated over 5 microg. Gene expression in the stomach was detected 3 h after gastric serosal surface instillation of naked pDNA. The gene expression level peaked 12-24 h after instillation of naked pDNA, then decreased to a level similar to 3 h at 48 h. CONCLUSIONS: Gastric serosal surface in stillation of naked pDNA can be a highly stomach-selective gene transfer method in rats

Induction of mucosal immunity by pulmonary administration of a cell-targeting nanoparticle

We previously found that a nanoparticle constructed with an antigen, benzalkonium chloride (BK) and γ-polyglutamic acid (γ-PGA) showed high Th1 and Th2-type immune induction after subcutaneous administration. For prophylaxis of respiratory infections, however, mucosal immunity should be induced. In this study, we investigated the effect of pulmonary administration of a nanoparticle comprising ovalbumin (OVA) as a model antigen, BK, and γ-PGA on induction of mucosal immunity in the lungs and serum. The complex was strongly taken up by RAW264.7 and DC2.4cells. After pulmonary administration, lung retention was longer for the OVA/BK/γ-PGA complex than for OVA alone. OVA-specific serum immunoglobulin (Ig)G was highly induced by the complex. High IgG and IgA levels were also induced in the bronchoalveolar lavage fluid, and in vivo toxicities were not observed. In conclusion, we effectively and safely induced mucosal immunity by pulmonary administration of an OVA/BK/γ-PGA complex

Gamma-polyglutamic acid-coated vectors for effective and safe gene therapy.

In the present study, we developed some novel gene delivery vectors, coated cationic complexes with gamma-polyglutamic acid (gamma-PGA) for effective and safe gene therapy. Cationic complexes were constructed with pDNA and cationic vectors, such as poly-L-arginine hydrochloride (PLA), poly-L-lysine hydrobromide (PLL), N-[1-(2, 3-dioleyloxy) propyl]-N, N, N-trimethylammonium chloride (DOTMA)-cholesterol (Chol) liposomes, and DOTMA-dioleylphosphatidylethanolamine (DOPE) liposomes. The cationic complexes showed high gene expression with strong cytotoxicity in melanoma B16-F10 cells. The cationic complexes were also strongly toxic to erythrocytes. On the other hand, the gamma-PGA was able to coat all cationic complexes and form stable nano-sized particles with negative charges. These gamma-PGA-coated complexes had high gene expression without cytotoxicity and toxicities to the erythrocytes. In in vivo transfection experiments, polyplexes showed high transfection efficiency over 10(5) RLU/g in the lung tissue after intravenous injection, although gamma-PGA-coated polyplexes showed a high value in the spleen. High transfection efficiency in lipoplexes and gamma-PGA-coated lipoplexes was observed in the spleen and lung. Thus, gamma-PGA-coated vectors are useful for clinical gene therapy

Mesenchymal stem cell-derived extracellular vesicles as probable triggers of radiation-induced heart disease

Background: Radiation-induced heart disease has been reported, but the underlying mechanisms remain unclear. Mesenchymal stem cells (MSCs), also residing in the heart, are highly susceptible to radiation. We examined the hypothesis that the altered secretion of extracellular vesicles (EVs) from MSCs is the trigger of radiation-induced heart disease.Methods: By exposing human placental tissue-derived MSCs to 5 Gy γ-rays, we then isolated EVs from the culture medium 48 h later and evaluated the changes in quantity and quality of EVs from MSCs after radiation exposure. The biological effects of EVs from irradiated MSCs on HUVECs and H9c2 cells were also examined.Results: Although the amount and size distribution of EVs did not differ between the nonirradiated and irradiated MSCs, miRNA sequences indicated many upregulated or downregulated miRNAs in irradiated MSCs EVs. In vitro experiments using HUVEC and H9c2 cells showed that irradiated MSC-EVs decreased cell proliferation (P < 0.01), but increased cell apoptosis and DNA damage. Moreover, irradiated MSC-EVs impaired the HUVEC tube formation and induced calcium overload in H9c2 cells.Conclusions: EVs released from irradiated MSCs show altered miRNA profiles and harmful effects on heart cells, which provides new insight into the mechanism of radiation-related heart disease risks

Gene-Activated Matrix with Self-Assembly Anionic Nano-Device Containing Plasmid DNAs for Rat Cranial Bone Augmentation

We have developed nanoballs, a biocompatible self-assembly nano-vector based on electrostatic interactions that arrange anionic macromolecules to polymeric nanomaterials to create nucleic acid carriers. Nanoballs exhibit low cytotoxicity and high transfection efficiently in vivo. This study investigated whether a gene-activated matrix (GAM) composed of nanoballs containing plasmid (p) DNAs encoding bone morphogenetic protein 4 (pBMP4) could promote bone augmentation with a small amount of DNA compared to that composed of naked pDNAs. We prepared nanoballs (BMP4-nanoballs) constructed with pBMP4 and dendrigraft poly-L-lysine (DGL, a cationic polymer) coated by γ-polyglutamic acid (γ-PGA; an anionic polymer), and determined their biological functions in vitro and in vivo. Next, GAMs were manufactured by mixing nanoballs with 2% atelocollagen and β-tricalcium phosphate (β-TCP) granules and lyophilizing them for bone augmentation. The GAMs were then transplanted to rat cranial bone surfaces under the periosteum. From the initial stage, infiltrated macrophages and mesenchymal progenitor cells took up the nanoballs, and their anti-inflammatory and osteoblastic differentiations were promoted over time. Subsequently, bone augmentation was clearly recognized for up to 8 weeks in transplanted GAMs containing BMP4-nanoballs. Notably, only 1 μg of BMP4-nanoballs induced a sufficient volume of new bone, while 1000 μg of naked pDNAs were required to induce the same level of bone augmentation. These data suggest that applying this anionic vector to the appropriate matrices can facilitate GAM-based bone engineering

Secure and effective gene delivery system of plasmid DNA coated by polynucleotide

Polynucleotides are anionic macromolecules which are expected to transfer into the targeted cells through specific uptake mechanisms. So, we developed polynucleotides coating complexes of plasmid DNA (pDNA) and polyethylenimine (PEI) for a secure and efficient gene delivery system and evaluated their usefulness. Polyadenylic acid (polyA), polyuridylic acid (polyU), polycytidylic acid (polyC), and polyguanylic acid (polyG) were examined as the coating materials. pDNA/PEI/polyA, pDNA/PEI/polyU, and pDNA/PEI/polyC complexes formed nanoparticles with a negative surface charge although pDNA/PEI/polyG was aggregated. The pDNA/PEI/polyC complex showed high transgene efficiency in B16-F10 cells although there was little efficiency in pDNA/PEI/polyA and pDNA/PEI/polyU complexes. An inhibition study strongly indicated the specific uptake mechanism of pDNA/PEI/polyC complex. Polynucleotide coating complexes had lower cytotoxicity than pDNA/PEI complex. The pDNA/PEI/polyC complex showed high gene expression selectively in the spleen after intravenous injection into mice. The pDNA/PEI/polyC complex showed no agglutination with erythrocytes and no acute toxicity although these were observed in pDNA/PEI complex. Thus, we developed polynucleotide coating complexes as novel vectors for clinical gene therapy, and the pDNA/PEI/polyC complex as a useful candidate for a gene delivery system

Biodegradable nanoparticles composed of dendrigraft poly-l-lysine for gene delivery

We developed novel gene vectors composed of dendrigraft poly-l-lysine (DGL). The transgene expression efficiency of the pDNA/DGL complexes (DGL complexes) was markedly higher than that of the control pDNA/poly-l-lysine complex. However, the DGL complexes caused cytotoxicity and erythrocyte agglutination at high doses. Therefore, γ-polyglutamic acid (γ-PGA), which is a biodegradable anionic polymer, was added to the DGL complexes to decrease their toxicity. The resultant ternary complexes (DGL/γ-PGA complexes) were shown to be stable nanoparticles, and those with γ-PGA to pDNA charge ratios of >8 had anionic surface charges. The transgene expression efficiency of the DGL/γ-PGA complexes was similar to that of the DGL complexes; however, they exhibited lower cytotoxicity and did not induce erythrocyte agglutination at high doses. After being intravenously administered to mice, the DGL6 complex demonstrated high transfection efficiency in the liver, lungs, and spleen, whereas the DGL6/γ-PGA8 complex only displayed high transfection efficiency in the spleen. Future studies should examine the utility of DGL and DGL/γ-PGA complexes for clinical gene therapy

Regional delivery of model compounds and 5-Fluorouracil to the liver by their application to the liver surface in rats: its implication for clinical use

PURPOSE: The purpose of this study was to examine drug distribution in the liver after drug application to the rat liver surface. METHODS: Phenolsulfonphthalein (PSP) and fluorescein isothiocyanate dextran (MW 4400, FD-4) as model compounds or 5-fluorouracil (5-FU) was applied to the rat liver surface by employing a cylindrical diffusion cell (i.d. 9 mm, 0.64 cm2). Then, blood and the remaining solution in the diffusion cell were collected at selected times, followed by excision of the liver. The excised liver was divided into three sites: the region under the diffusion cell attachment site (site 1), the applied lobe except for site 1 (site 2), and non-applied lobes (site 3). RESULTS: In the case of i.v. administration, there were no differences in PSP concentrations among the three sites of the rat liver, and the concentrations rapidly decreased. On the other hand, the PSP concentration in site 1 after application to the rat liver surface was considerably higher than in site 2 and site 3. In addition, the area under the curve (AUC) value (AUCsite1), calculated from the PSP concentration profile in site 1, was about 10 times larger than that in site 3. A similar trend of regional delivery advantage by liver surface application was observed in the case of the macromolecule model FD-4, with a marked AUCsite1 of about 5 times larger than the other two sites. Moreover, we clarified that the anticancer drug 5-FU preferentially distributed in site 1 after application to the rat liver surface. CONCLUSION: These results demonstrate the possibility of regional delivery of drugs to the liver by application to the liver surface