Ternary complex of plasmid DNA electrostatically assembled with polyamidoamine dendrimer and chondroitin sulfate for effective and secure gene delivery.

The purpose of this study was to develop a ternary complex of plasmid DNA (pDNA) electrostatically assembled with polyamidoamine (PAMAM) dendrimer and chondroitin sulfate (CS) for effective and secure gene delivery. PAMAM dendrimers are new cationic polymers that are expected to be used as gene delivery vectors. However, cationic non-viral gene vectors showed cytotoxicity by binding to negative cellular membranes. We therefore prepared a ternary complex by adding CS, an anionic polymer, and examined its usefulness. The pDNA/PAMAM dendrimer complex (PAMAM dendriplex) and the PAMAM dendriplex coated by CS (CS complex) showed nanoparticles with positive ζ-potential and negative ζ-potential, respectively. The CS complex had no cytotoxicity against B16-F10 cells and no agglutination activity, although severe cytotoxicity and high agglutination were observed in the PAMAM dendriplex. As a result of an in vitro gene expression study of B16-F10 cells, not only the PAMAM dendriplex but also the CS complex showed high transfection efficiency. The transfection efficiency of the CS complex was significantly inhibited by clathrin-mediated endocytosis inhibitor (chlorpromazine), caveolae-mediated endocytosis inhibitor (genistein), and hypothermia. Tail-vein injection of the CS complex into mice led to significantly higher gene expression in the spleen than the PAMAM dendriplex. Thus, the ternary complex of pDNA electrostatically assembled with PAMAM denriplex and CS showed safe high gene expression in the spleen. This vector is expected to be useful for useful gene delivery.

Ternary complex of plasmid DNA with protamine and γ-polyglutamic acid for biocompatible gene delivery system.

The purpose of the present study was to investigate the usefulness of the ternary complex with protamine and γ-polyglutamic acid (γ-PGA), which are biodegradable materials for foods and medical products, as a safe gene delivery vector. We formed cationic binary complexes (plasmid DNA (pDNA)/protamine complexes) with high transfection efficiency. The binary complex showed slight toxicity probably related to its total cationic charge. Then, we formed ternary complexes (pDNA/protamine/γ-PGA complexes) by addition of anionic polymer, γ-PGA, and they showed no cytotoxicity. The transfection efficiency of the pDNA/protamine/γ-PGA complexes was as high as that of the pDNA/protamine complexes, although their zeta potentials were different. Inhibition study of the gene expressions in B16-F10 cells suggested that pDNA/protamine complexes were taken up by caveolae-mediated endocytosis and macropinocytosis. On the other hand, pDNA/protamine/γ-PGA complexes were taken up by clathrin-mediated endocytosis and macropinocytosis. Thus, we succeeded in developing the ternary complex as a safe gene delivery vector with biocompatible materials.

Effect of imatinib mesilate on the disposition kinetics of ciclosporin in rats.

The purpose of this study was to investigate the effect of imatinib mesilate on the disposition kinetics of ciclosporin in rats. The blood concentration-time course and pharmacokinetic parameters of ciclosporin did not significantly change after intravenous injection of ciclosporin (10 mg kg(-1)) in rats treated with imatinib mesilate (50 mg kg(-1)) as compared with a control. When ciclosporin (10 mg kg(-1)) was orally administered, the time course, area under the curve, bioavailability and peak blood concentration of ciclosporin were significantly increased in rats that had been treated with imatinib mesilate 2 h before ciclosporin administration as compared with the control. Because both drugs are transported via P-glycoprotein and breast cancer resistance protein and metabolized by cytochrome P450 3A2, the interaction of imatinib mesilate with these proteins may be responsible for the increased intestinal absorption of ciclosporin in rats. These results indicate that imatinib mesilate enhanced the intestinal absorption of ciclosporin in rats with only the oral administration of ciclosporin, suggesting that our results support clinical data. In addition, imatinib mesilate may increase the pharmacological effects and possibly toxicity of ciclosporin.