Evaluation of nuclear transfer and transcription of plasmid DNA condensed with protamine by microinjection: The use of a nuclear transfer score

AbstractIn the present study, the nuclear delivery of a green fluorescence protein (GFP)-encoding pDNA condensed by protamine was investigated in terms of trans-gene expression after cytoplasmic (E(cyt)) and nuclear (E(nuc)) microinjection. To compare the nuclear transfer process, a novel parameter; the nuclear transfer (NT) score was introduced. The E(cyt) value for protamine/pDNA particles increased in a charge ratio-dependent manner. The calculated NT score showed that this increase results from an enhancement in nuclear transfer efficiency, which was also quantitatively confirmed by a recently developed confocal image-assisted three-dimensionally integrated quantification (CIDIQ) method. Moreover, E(nuc) for protamine/pDNA particles was significantly higher than that for poly-l-lysine/pDNA particles, suggesting that pDNA, when condensed with protamine, is more accessible to intra-nuclear transcription. Collectively, protamine is an excellent DNA condenser, with bi-functional advantages: improvement in nuclear delivery and efficient intra-nuclear transcription

TARGETING DESIGN TO THE LUNGAND PULMONARY INTRACELLULAR STRUCTURE OF ENDOGENOUS GENE BY IRQ MODIFIED NANO CARRIER

TARGETING DESIGN TO THE LUNGAND PULMONARY INTRACELLULAR STRUCTURE OF ENDOGENOUS GENE BY IRQ MODIFIED NANO CARRIER. Inhibition of angiogenesis is a novel strategy for the treatment of lung cancer. For efficient therapy, vectors must firstly reach the target tissue and subsequently demonstrate an efficient intracellular targeting. In this study, we attempted to design a vector for in vivo pulmonary targeting which was able to deliver small interfering RibonucleicAcid (siRNA) for endogenous gene of angiogenesis in pulmonary endothelial cells. siRNA was condensed with polycation agent and encapsulated in lipidous nano carrier. To obtain high level of lung accumulation, we controlled the surface of nano-carrier by changing the length of Polyethylene glycol (PEG) moiety. These nano carriers showed prominent Ribonucleic acid interference (RNAi) effect, when luciferase gene was used as a target. In addition, an efficient transgene knockdown of Vascular Endothelial Growth Factor Receptor 1 (VEGFR1), a responsible gene of angiogenesis, can be obtained by the Instantaneous Respiratory Exchange Ratio (IRQ) modified nano carrier with the use of Stearyl-R8 (STR-R8) peptide, known as an endosomal membrane inducer. In conclusion, pulmonary targeting of nano carrier by encapsulating siRNA can be developed by controlling the PEG length and the structure of nano carrier for efficient intracellular targeting

Quantitative and mechanism-based investigation of post-nuclear delivery events between adenovirus and lipoplex

Quantitative and mechanism-based information on differences in transfection efficiency between viral and non-viral vectors would be highly useful for improving the effectiveness of non-viral vectors. A previous quantitative comparison of intracellular trafficking between adenovirus and LipofectAMINE PLUS (LFN) revealed that the three orders of magnitude lower transfection efficiency of LFN was dominantly rate limited by the post-nuclear delivery process. In the present study, the contribution of transcription and translation processes to the overall differences in the transgene expression efficiency of nucleus-delivered DNA was independently evaluated by quantifying mRNA. As a result, transcription efficiency (E(transcript)) of LFN, denoted as transgene expression divided by the amount of nuclear pDNA was about 16 times less than that for adenovirus. Furthermore, translation efficiency (E(translate)), denoted as transfection activity divided by mRNA expression was approximately 460 times less in LFN. Imaging of the decondensed form of DNA by in situ hybridization revealed that poor decondensation efficiency of LFN is involved in the inferior E(transcript). Moreover, the inferior translation efficiency (E(translate)) of LFN was mainly due to electrostatic interactions between LFN and mRNA. Collectively, an improvement in nuclear decondensation and the diminution of the interaction between vector and mRNA is essential for the development of new generations of non-viral vectors

Topology of octaarginines (R8) or IRQ ligand on liposomes affects the contribution of macropinocytosis- and caveolae-mediated cellular uptake

It was recently reported that liposomes modified with octaarginine (R8) and its analogue peptide (IRQRRRR: IRQ) are taken into NIH3T3 cells by unique pathways, macropinocytosis and caveolae-mediated endocytosis, respectively. This study evaluated the topology of these peptides as it relates to the uptake routes of liposomes, where they are modified either directly on the surface, or on the edge of a polyethylene glycol (PEG) spacer. The uptake mechanism of peptide-modified liposomes and peptide-modified PEG-liposomes was investigated by confocal laser scanning microscopy. To determine the contribution of clathrin-mediated endocytosis, macropinocytosis and caveolar endocytosis to the uptake of liposomes, the uptake was evaluated in the presence of these specific inhibitors. The uptake pathway changed from macropinocytosis to clathrin-mediated endocytosis when R8 was modified on the edge of a PEG spacer, indicating that the flexible display of R8 impaired the induction of macropinocytosis. However, the contribution of caveolae-mediated endocytosis increased when IRQ was conjugated to the distal end of the PEG chain, suggesting that flexible surface display enhanced IRQ recognition by the specific molecules in the caveolae. The present results demonstrate that topology control of the ligand affects the contribution of the entry pathway, depending on the uptake mechanism

The Polyethyleneglycol Dilemma: Advantage and Disadvantage of PEGylation of Liposomes for Systemic Genes and Nucleic Acids Delivery to Tumors

Gene and nucleic acid therapy is expected to play a major role in the next generation of agents for cancer treatment. We have recently developed a multifunctional envelope-type nano device (MEND) for use as a novel nonviral gene delivery system. The modification of polyethyleneglycol (PEG), i.e., PEGylation, is a useful method for achieving a longer circulation time for the delivery of MEND to a tumor via the enhanced permeability and retention (EPR) effect. However, PEGylation strongly inhibits cellular uptake and endosomal escape, which results in significant loss of activity of the delivery system. For successful nucleic acid delivery for cancer treatment, the crucial problem associated with the use of PEG, i.e., the "PEG dilemma" must be resolved. In this review, we describe the development and applications of MEND and discuss various strategies for overcoming the PEG dilemma based on the manipulation of both pharmacokinetics and intracellular trafficking of cellular uptake and endosomal release. To increase cellular uptake, target ligands including proteins, peptides, antibodies and aptamers that recognize molecules specifically expressed on tumors are first introduced. Second, cleavable PEG systems are described. The cleavage of PEG from carriers was achieved in response to the intracellular environment as well as the tumor microenvironment, which improvs cellular uptake and endosomal escape. Then, endosomal fusogenic peptides are discussed. Finally, pH-sensitive liposomes using pH-sensitive lipids are described

Advantages of ethanol dilution method for preparing GALA-modified liposomal siRNA carriers on the in vivo gene knockdown efficiency in pulmonary endothelium

We previously reported that a multifunctional envelope-type nano device (MEND) modified with a GALA peptide (GALA/MEND) exerted dual functions; effective targeting the pulmonary endothelium and endosomal escape. The GALA/MEND containing encapsulated siRNA was originally prepared by the film coated hydration method (GALA/MENDHyd). However, an ethanol dilution method was found to be more appropriate for scaling up the preparation of this liposomal nanoparticle. In this study, we report on the preparation of a GALA/MEND based on the principal of the ethanol dilution (GALA/MENDEto). The gene knockdown efficiency of the MENDHyd and MENDEt0H without GALA-modification was equivalent regardless of the method used in the preparation. The GALA/MENDEt0H induced more efficient gene silencing in the pulmonary endothelium (ED50; approximately 0.17 mg siRNA/kg) compared to the GALA/ MENDHyd. The GALA/MENDEt0H escaped from endosomes more rapidly than GALA/MENDHyd, while the pharmacokinetics and lung accumulation of GALA/MENDEtcni and GALA/MENDHyd were comparable after i.v. administration. Collectively, the ethanol dilution method improves the function of the GALA/MEND as a lung-targeting siRNA carrier. (C) 2014 Elsevier B.V. All rights reserved