Nanopolymeric micelle effect on the transdermal permeability, the bioavailability and gene expression of plasmid.

This study attempts to investigate the transdermal permeability, the bioavailability and gene expression of plasmid formulated with nonionic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) polymeric micelles (PM). Dynamic light scattering (DLS) and atomic force microscopy (AFM) were used to analyze the PM formulated pCMV-Lac Z (P/PM) containing the gene for ß-galactosidase (ß-Gal) driven by cytomegalovirus early promoter. Franz diffusion cell was used for in vitro transdermal permeability analysis. Real-time PCR was used to quantify the permeated plasmid in vitro and in vivo. ß-Gal activity assay was performed to evaluate transgene expression in vivo. The size of P/PM was ~50 nm with round shape. PM significantly enhanced the in vitro transdermal permeability of plasmid in a direction- and temperature-dependent manner. Following transdermal application of P/PM, higher area under the curve (AUC(P/PM): 98.34 h·ng/mL) and longer half-life of plasmid were detected compared with that of plasmid alone (AUC(P): 10.12 h·ng/mL). Additionally, the ß-Gal activity was significantly increased in skin, stomach, brain and spinal cord at both 48 and 72 h after P/PM application and in testis and spleen at 72 h postapplication. In conclusion, PM formulation enhanced the permeation of plasmid through skin into blood circulation, increasing its absorption and the transgene expression in various tissues.

Polymeric micelle gene delivery of bcl-xL via eye drop reduced corneal apoptosis following epithelial debridement.

Stromal keratocyte apoptosis triggered by epithelial injury is one mechanism of corneal disorders. A model of epithelial injury by epithelial debridement is established, and keratocyte apoptosis is evidenced by DNA fragmentation and cellular morphological changes in the anterior stroma underlying the injured epithelium. Delivery of plasmid (pCMV-bcl-x(L)-eGFP) encoding an anti-apoptotic gene, the bcl-x(L) with a nano-carrier, polymeric micelles (PM) via eye drop to cornea after epithelial debridement, the mRNA level of bcl-x(L) was significantly increased (2.2-fold, P<0.05) at 48 h and the eGFP mRNA was detected (4571.7 ± 1194.5 copies/µg total RNA). The bcl-x(L)-eGFP fusion protein was also detected in wounded cornea at 48 h after delivery, accompanying with decreased DNA fragmentation and lower caspase-3 activity (P<0.05). In conclusion, eye drop of pCMV-bcl-x(L)-eGFP/PM reduced corneal apoptosis following epithelial debridement.

Eye drop delivery of nano-polymeric micelle formulated genes with cornea-specific promoters.

BACKGROUND: This study evaluates the eye drop delivery of genes with cornea-specific promoters, i.e., keratin 12 (K12) and keratocan (Kera3.2) promoters, by non-ionic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) polymeric micelles (PM) to mouse and rabbit eyes, and investigates the underlying mechanisms. METHODS: Three PM-formulated plasmids (pCMV-Lac Z, pK12-Lac Z and pKera3.2-Lac Z) containing the Lac Z gene for beta-galactosidase (beta-Gal) whose expression was driven by the promoter of either the cytomegalovirus early gene, the keratin 12 gene or the keratocan gene, were characterized by critical micelle concentration (CMC), dynamic light scattering (DLS), and atomic force microscopy (AFM). Transgene expression in ocular tissue after gene delivery was analyzed by 5-bromo-4-chloro-3-indolyl-beta-D-galactoside (X-Gal) color staining, 1,2-dioxetane beta-Gal enzymatic activity measurement, and real-time polymerase chain reaction (PCR) analysis. The delivery mechanisms of plasmid-PM on mouse and rabbit corneas were evaluated by EDTA and RGD (arginine-glycine-aspartic acid) peptide. RESULTS: The sizes of the three plasmid-PM complexes were around 150-200 nm with unimodal distribution. Enhanced stability was found for three plasmid-PM formulations after DNase I treatment. After six doses of eye drop delivery of pK12-Lac Z-PM three times a day, beta-Gal activity was significantly increased in both mouse and rabbit corneas. Stroma-specific Lac Z expression was only found in pKera3.2-Lac Z-PM-treated animals with pretreatment by 5 mM EDTA, an opener of junctions. Lac Z gene expression in both pK12-Lac Z-PM and pKera3.2-Lac Z-PM delivery groups was decreased by RGD peptide pretreatment. CONCLUSIONS: Cornea epithelium- and stroma-specific gene expression could be achieved using cornea-specific promoters of keratin 12 and keratocan genes, and the gene was delivered with PM formulation through non-invasive, eye drop in mice and rabbits. The transfection mechanism of plasmid-PM may involve endocytosis and particle size dependent paracellular transport.

Nonionic polymeric micelles for oral gene delivery in vivo.

The main aim of this study was to investigate the feasibility of using nonionic polymeric micelles of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) as a carrier for oral DNA delivery in vivo. The size and appearance of DNA/PEO-PPO-PEO polymeric micelles were examined, respectively, by dynamic light scattering and atomic force microscopy, and their zeta potential was measured. Expression of the delivered lacZ gene in various tissues of nude mice was assessed qualitatively by 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining of sections and quantitatively by measuring enzyme activity in tissue extracts, using the substrate of beta-galactosidase, chlorophenol red-beta-D-galactopyranoside. In addition, the types of cells expressing the lacZ gene in the duodenum were identified by histological analysis. DNA/PEO-PPO-PEO polymeric micelles are a single population of rounded micelles with a mean diameter of 170 nm and a zeta potential of -4.3 mV. Duodenal penetration of DNA/PEO-PPO-PEO polymeric micelles was evaluated in vitro by calculating the apparent permeability coefficient. The results showed a dose-independent penetration rate of (5.75 +/- 0.37) x 10(-5) cm/sec at low DNA concentrations (0.026-0.26 microg/microl), but a decrease to (2.89 +/- 0.37) x 10(-5) cm/sec at a concentration of 1.3 microg/microl. Furthermore, when 10 mM RGD peptide or 10 mM EDTA was administered before and concurrent with the administration of DNA/PEO-PPO-PEO polymeric micelles, transport was inhibited ([0.95 +/- 0.57] x 10(-5) cm/sec) by blocking endocytosis or enhanced ([29.8 +/- 5.7] x 10(-5) cm/sec) by opening tight junctions, respectively. After oral administration of six doses at 8-hr intervals, the highest expression of transferred gene lacZ was seen 48 hr after administration of the first dose, with gene expression detected in the villi, crypts, and goblet cells of the duodenum and in the crypt cells of the stomach. Reporter gene activity was seen in the duodenum, stomach, and liver. Activity was also seen in the brain and testis when mice were administered 10 mM EDTA before and concurrent with DNA/PEO-PPO-PEO polymeric micelle administration. lacZ mRNA was detected in these five organs and in the blood by reverse transcription-polymerase chain reaction. Taken together, these results show efficient, stable gene transfer can be achieved in mice by oral delivery of PEO-PPO-PEO polymeric micelles.