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We previously reported that 6- O-α-(4- O-α- d-glucuronyl)- d-glucosyl-β-cyclodextrin (GUG-β-CyD) conjugate with polyamidoamine dendrimer (dendrimer, generation 2; G2) (GUG-β-CDE (G2)) is useful as a gene transfer carrier. In the present study, to investigate the potentials of GUG-β-CDE (G2) as a siRNA carrier, we evaluated the RNAi effect of its complex with siRNA against transthyretin (TTR) mRNA (siTTR) for the treatment of familial amyloidotic polyneuropathy (FAP). Among the various GUG-β-CDEs (G2) having the different degrees of substitution of GUG-β-CyD (degree of substation (DS) 1.8, 2.5, 3.0 and 5.0), GUG-β-CDE (G2, DS 1.8) showed the highest siTTR transfer activity. GUG-β-CDE (G2, DS 1.8)/siTTR complex showed no cytotoxicity in HepG2 cells. After intravenous administration of GUG-β-CDE (G2, DS 1.8)/siTTR complex to BALB/c mice, TTR mRNA expression was tended to reduce with negligible change of blood chemistry data. Particle size, ζ-potential and cellular association of the GUG-β-CDE (G2, DS 1.8) complex were almost the same as those of the other CDEs complexes. Meanwhile, GUG-β-CDE (G2, DS 1.8)/siTTR complex showed high endosomal escaping ability of siTTR in cytoplasm. These findings suggest the potential of GUG-β-CDE (G2, DS 1.8) as a siRNA carrier for the FAP treatment. [ABSTRACT FROM AUTHOR]

In this study, we newly synthesized the polyamidoamine STARBURST dendrimer (dendrimer, generation 3: G3) conjugates with 6- O-α-(4- O-α- d-glucuronyl)- d-glucosyl-β-cyclodextrin [GUG-β-CDE (G3)] having the various degrees of substitution (DS) of GUG-β-cyclodextrin of 1.6, 3.0, 3.7, 5.0 and 8.6, and evaluated them as a siRNA transfer carrier. GUG-β-CDEs (G3) formed the positively charged and nano-order complexes with siRNA. Of the siRNA complexes with five GUG-β-CDEs (G3), the complex with GUG-β-CDE (G3, DS 3.7) showed the highest RNAi effect and cellular uptake with negligible cytotoxicity in KB cells at a charge ratio of 20. In addition, the RNAi effect and cellular uptake of the complex with GUG-β-CDE (G3, DS 3.7) were higher than those of α-CDE (G3, DS 2.4) and comparable to those of Lipofectamine™ 2000. Furthermore, the complex with GUG-β-CDE (G3, DS 3.7) possessed the endosomal escaping ability, the releasing property of siRNA in the cytoplasm and serum resistance. These results suggest that GUG-β-CDE (G3, DS 3.7) has the potential as a novel siRNA carrier. [ABSTRACT FROM AUTHOR]

We have evaluated the potential use of various polyamidoamine (PAMAM) dendrimer [dendrimer, generation (G) 2-4] conjugates with cyclodextrins (CyDs) as novel DNA and RNA carriers. Among the various dendrimer conjugates with CyDs, the dendrimer (G3) conjugate with α-CyD having an average degree of substitution (DS) of 2.4 [α-CDE (G3, DS2)] displayed remarkable properties as DNA, shRNA and siRNA delivery carriers through the sensor function of α-CDEs toward nucleic acid drugs, cell surface and endosomal membranes. In an attempt to develop cell-specific gene transfer carriers, we prepared sugar-appended α-CDEs. Of the various sugar-appended α-CDEs prepared, galactose- or mannose-appended α-CDEs provided superior gene transfer activity to α-CDE in various cells, but not cell-specific gene delivery ability. However, lactose-appended α-CDE [Lac-α-CDE (G2)] was found to possess asialoglycoprotein receptor (AgpR)-mediated hepatocyte-selective gene transfer activity, both in vitro and in vivo. Most recently, we prepared folate-poly(ethylene glycol)-appended α-CDE [Fol-PαC (G3)] and revealed that Fol-P?C (G3) imparted folate receptor (FR)-mediated cancer cellselective gene transfer activity. Consequently, α-CDEs bearing integrated, multifunctional molecules may possess the potential to be novel carriers for DNA, shRNA and siRNA. [ABSTRACT FROM AUTHOR]