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Kentaro Kogure

Publications and source records attributed to Kentaro Kogure.

At least 19 recordsLinked to original sources
PubMed2006

Cellular uptake and subsequent intracellular trafficking of R8-liposomes introduced at low temperature.

Intracellular trafficking is a determining factor in the transgene expression efficiency of gene vectors. In the present study, the mechanism of the cellular uptake of octaarginine (R8)-modified liposomes, when introduced at 37 degrees C and 4 degrees C, was investigated in living cells. Compared with 37 degrees C, the uptake of R8-liposomes was only slightly reduced at 4 degrees C. Dual imaging of liposomes and plasma membranes revealed that R8-liposomes were internalized by vesicular transport, and partially escaped to the cytosol at the perinuclear region at 37 degrees C. When introduced at 4 degrees C, intracellular liposomes were observed within a specific region close to the plasma membrane, and internalization of the plasma membrane was completely inhibited. Therefore, at 4 degrees C, R8-liposomes appear to enter cells via unique pathway, which is separate and distinct from energy-dependent vesicular transport. The subsequent nuclear delivery of encapsulated pDNA, when introduced at 4 degrees C, was less prominent compared with those introduced at 37 degrees C. Collectively, these findings demonstrate that a vesicular transport-independent pathway is responsible for the cellular uptake of liposomes. In addition, the uptake route is closely related to the subsequent nuclear delivery process; the operation of an endogenous vesicular sorting system is advantageous for the nuclear delivery of pDNA.

Base Sequence↗
PubMed2006

Biocleavable polyrotaxane-plasmid DNA polyplex for enhanced gene delivery.

A biocleavable polyrotaxane, having a necklace-like structure consisting of many cationic alpha-cyclodextrins (alpha-CDs) and a disulfide-introduced poly(ethylene glycol) (PEG), was synthesized and examined as a nonviral gene carrier. The polyrotaxane formed a stable polyplex having positively charged surface even at low charge ratio. This is likely to be due to structural factors of the polyrotaxane, such as the mobile motion of alpha-CDs in the necklace-like structure. Rapid endosomal escape was observed 90 min after transfection. The positively charged surface and the good buffering capacity are advantageous to show the proton sponge effect. The pDNA decondensation occurred through disulfide cleavage of the polyrotaxane and subsequent supramolecular dissociation of the noncovalent linkages between alpha-CDs and PEG. Transfection of the DMAE-SS-PRX polyplex is independent of the amount of free polycation. Those properties played a key role for delivery of pDNA clusters to the nucleus. Therefore, the polyplex nature and the supramolecular dissociation of the polyrotaxane contributed to the enhanced gene delivery.

Cell Nucleus↗
PubMed2006

Improved cell viability of linear polyethylenimine through gamma-cyclodextrin inclusion for effective gene delivery.

A polypseudorotaxane consisting of a linear polyethylenimine with Mn of 22,000 (LPEI22k) and gamma-cyclodextrins (gamma-CDs; LPEI22k/gamma-CD) has been examined as a gene carrier. The polyplex formation with luciferase-encoding plasmid DNA (pDNA), intracellular trafficking of polyplex, cytotoxicity, and transfection efficiency were evaluated by various characteristic methods. LPEI22k/gamma-CD formed a pDNA polyplex at higher N/P ratios than LPEI22k; this suggests that the gamma-CD threading sterically interfered with the polyplex formation. In addition, the zeta potentials of the polyplex significantly decreased due to the reduction in charge density of LPEI22k caused by gamma-CD threading. The cellular uptake of pDNA in the LPEI22k/gamma-CD polyplex was enhanced by free gamma-CDs released from the polyplex that might accelerate the cellular uptake through enhanced membrane affinity. LPEI22k/gamma-CD significantly increased cell viability even at high N/P ratios, and the polyplex showed high transfection efficacy. The low cytotoxicity and high gene expression of LPEI22k/gamma-CD are advantageous to polyplex administration in vivo.

Animals↗
PubMed2006

Evaluation of the nuclear delivery and intra-nuclear transcription of plasmid DNA condensed with micro (mu) and NLS-micro by cytoplasmic and nuclear microinjection: a comparative study with poly-L-lysine.

BACKGROUND: The efficient nuclear delivery of plasmid DNA (pDNA) is essential for the development of a promising non-viral gene vector. In an attempt to achieve nuclear delivery, NLS-mu, a novel pDNA condenser, was prepared. This consists of mu, a highly potent polypeptide for condensing the pDNA, and a SV40 T antigen-derived nuclear localization signal (NLS(SV40)). METHODS: The utility of NLS-mu was assessed in terms of green fluorescent protein (GFP) expression after cytoplasmic and nuclear microinjection of GFP-encoding pDNA along with the transfection, and compared with mu and poly-L-lysine (PLL). Trans-gene expression after cytoplasmic microinjection was affected by the efficiencies of nuclear transfer and following intra-nuclear transcription. To evaluate the nuclear transfer process separately, we introduced a parameter, a nuclear transfer score (NT score), which was calculated as the trans-gene expression after cytoplasmic microinjection divided by that after nuclear microinjection. RESULTS: As expected, the rank order of trans-gene expression after the transfection and cytoplasmic microinjection was NLS-mu > mu > PLL. However, the calculated NT scores were unexpectedly ranked as mu = NLS-mu > PLL, suggesting that mu, and not NLS(SV40), is responsible for the nuclear delivery of pDNA. In addition, confocal images of rhodamine-labeled pDNA indicated that pDNA condensed with mu and NLS-mu was delivered as a condensed form. In comparing the nuclear transcription, the rank order of trans-gene expression after nuclear microinjection was PLL = NLS-mu > mu, suggesting that intra-nuclear transcription is inhibited by efficient condensation by mu, and is avoided by the attachment of NLS(SV40). CONCLUSIONS: Collectively, NLS-mu, which consists of chimeric functions, is an excellent DNA condenser, and the process is based on mu-derived nuclear transfer and NLS(SV40)-derived efficient intra-nuclear transcription.

Cell Nucleus↗
PubMed2006

Uptake pathways and subsequent intracellular trafficking in nonviral gene delivery.

The successful delivery of therapeutic genes to the designated target cells and their availability at the intracellular site of action are crucial requirements for successful gene therapy. Nonviral gene delivery is currently a subject of increasing attention because of its relative safety and simplicity of use; however, its use is still far from being ideal because of its comparatively low efficiency. Most of the currently available nonviral gene vectors rely on two main components, cationic lipids and cationic polymers, and a variety of functional devices can be added to further optimize the systems. The design of these functional devices depends mainly on our understanding of the mechanisms involved in the cellular uptake and intracellular disposition of the therapeutic genes as well as their carriers. Macromolecules are internalized into cells by a variety of mechanisms, and their intracellular fate is usually linked to the entry mechanism. Therefore, the successful design of a nonviral gene delivery system requires a deep understanding of gene/carrier interactions as well as the mechanisms involved in the interaction of the systems with the target cells. In this article, we review the different uptake pathways that are involved in nonviral gene delivery from a gene delivery point of view. In addition, available knowledge concerning cellular entry and the intracellular trafficking of cationic lipid-DNA complexes (lipoplexes) and cationic polymer-DNA complexes (polyplexes) is summarized.

Animals↗
PubMed2006

Significant and prolonged antisense effect of a multifunctional envelope-type nano device encapsulating antisense oligodeoxynucleotide.

A multifunctional envelope-type nano device (MEND) was developed for use as an efficient non-viral system for the delivery of plasmid DNA (pDNA) using octaarginine (R8) as an internalizing ligand. Three types of R8-MENDs were prepared, co-encapsulating luciferase-encoding pDNA and anti-luciferase oligodeoxynucleotide (ODN) condensed by three polycations, stearyl octaarginine (STRR8), poly-L-lysine (PLL) and protamine, and the antisense effects of the ODN-encapsulated R8-MENDs (ODN-MEND) were analysed in-vitro. The ODN-MEND packaged using protamine as a condenser showed a 90% antisense effect 16 h after the transfection, and a persistent antisense effect of over 75% for up to 48 h, which was much more effective than that of LipofectAmine2000. On the other hand, the ODN-MENDs prepared using PLL and STR-R8 as condensers did not show any significant inhibition of luciferase activity. Although there was no specific relation between the physicochemical characteristics of the ODN-MENDs and their antisense effect, the pattern of the antisense effect among the ODN-MENDs was similar to that of the silencing effect of R8-MEND encapsulating plasmid DNA encoding siRNA. These results suggest that R8-MENDs are able to deliver encapsulated DNA to the cytosol as well as to the nucleus, and that protamine can also function as an efficient decondenser, not only in the nucleus but also in the cytosol. In conclusion, we successfully developed an ODN-MEND with a high antisense effect using protamine as a DNA condensing as well as a decondensing agent.

Amino Acid Sequence↗
PubMed2006

Delivery of condensed DNA by liposomal non-viral gene delivery system into nucleus of dendritic cells.

In this study, we developed novel double-membranous non-viral gene delivery system modified with SV-40 T antigen-derived nuclear localization signal (NLS-DMEND) for delivery of luciferase plasmid DNA to nucleus of non-dividing mouse bone marrow-derived dendritic cells (BMDC). Intracellular trafficking and gene expression of NLS-DMEND in the BMDC were evaluated. Condensed DNA was observed in the nucleus by confocal laser scanning microscopy, and the NLS-DMEND induced significant luciferase activity in the BMDC. It was suggested that the condensed DNA particle transferred into nucleus via energy dependent manner, since the nuclear transfer was inhibited by metabolic inhibitors. In conclusion, condensed plasmid DNA was delivered into the nucleus of non-dividing BMDC by NLS-DMEND.

Animals↗
PubMed2006

[Envelope-type nano device for gene delivery].

We introduced a new concept "Programmed Packaging" for the rational development of non viral gene delivery system. There are many non-viral gene delivery system, however, their utility is limited in the in vitro experiments. The major reason is considered that it is difficult to package many functional devices into a nanoparticle. The new concept which we introduce here is named as Programmed Packaging, which is composed of the strategy to targeting, molecular design of functional devices to overcome barriers, and assembly technique to package them into a nanoparticle. In this article, we explain this concept and provide newly developed gene delivery systems based on this concept.

Gene Transfer Techniques↗
PubMed2005

Non-linear pharmacodynamics in a non-viral gene delivery system: positive non-linear relationship between dose and transfection efficiency.

A remarkable non-linearity was found between dose and transfection activities of non-viral gene delivery systems, such as a Lipofectamine/DNA complex and an octaarginine-modified multifunctional envelope-type nano device (R8-MEND). We measured the nuclear delivery of pDNA to distinguish the non-linearity in intracellular pharmacokinetics or pharmacodynamics after transfection with R8-MEND at different doses. A remarkable positive non-linearity was found in the pharmacodynamics when the dose was increased. Even dummy pDNA enhanced the efficiency of transcription and/or translation per pDNA in the nucleus, but empty liposomes did not. These results suggest the importance of controlled pharmacodynamics as well as the importance of intracellular pharmacokinetics for the rational design of non-viral gene delivery systems.

Animals↗
PubMed2005

High density of octaarginine stimulates macropinocytosis leading to efficient intracellular trafficking for gene expression.

The mechanism of the arginine-rich peptide-mediated cellular uptake is currently a controversial issue. Several factors, including the type of peptide, the nature of the cargo, and the linker between them, appear to affect uptake. One of the less studied factors, which may affect the uptake mechanism, is the effect of peptide density on the surface of the cargo. Here, we examined the mechanism of cellular uptake and intracellular trafficking of liposomes modified with different densities of the octaarginine (R8) peptide. Liposomes modified with a low R8 density were taken up mainly through clathrin-mediated endocytosis, leading to extensive lysosomal degradation, whereas those modified with a high R8 density were taken up mainly through macropinocytosis and were less subject to lysosomal degradation. Furthermore, the high density R8-liposomes were able to stimulate the macropinocytosis-mediated uptake of other particles. When plasmid DNA was condensed and encapsulated in R8-liposomes, the levels of gene expression were three orders of magnitude higher for the high density liposomes. The enhanced gene expression by the high density R8-liposomes was highly impaired by blocking uptake through macropinocytosis. The different extents of gene expression from different densities of the R8 peptide on the liposomes could be explained principally by the existence of an intracellular trafficking route, but not by the uptake amount, of internalized liposomes. These results show that the density of the R8 peptide on liposomes determines the uptake mechanism and that this is directly linked to intracellular trafficking, resulting in different levels of gene expression.

Animals↗
PubMed2005

A multifunctional envelope-type nano device for novel gene delivery of siRNA plasmids.

A multifunctional envelope-type nano device (MEND) for use in the delivery of siRNA expression plasmids is described. The plasmid DNA encoding anti-luciferase short interfering RNA (siRNA) was condensed by poly-L-lysine (PLL) and packaged into the MEND. The silencing effect of the MEND(PLL) showed a 96% inhibition of luciferase activities in a co-transfection study. The silencing effect was maintained at more than 60%, even under the 100-fold diluted conditions. In the luciferase transformed cells, however, the MEND(PLL) showed no significant silencing effect (10%), indicating heterogeneity in transfection by the MEND(PLL). To solve this problem, the DNA condensing agents were optimized by comparing PLL, stearyl octaarginine (STR-R8) and protamine (Prot). No difference in silencing effect (95-97%) was found among these MENDs in a co-transfection study. However, the MEND(Prot) showed a 70% silencing effect in the transformed cells. These results suggest that the MEND(Prot) has less heterogeneity in transfection, while the MEND(PLL) and the MEND(STR-R8) have large heterogeneities. These results demonstrate that MEND(Prot) is a promising gene delivery system for siRNA expression plasmids with less heterogeneity associated with the transfection.

Animals↗
PubMed2005

Construction of a multifunctional envelope-type nano device by a SUV*-fusion method.

A novel assembly method "SUV*-fusion method" was developed for the construction of a small and homogenous multifunctional envelope-type nano device (MEND) by utilizing a detergent-rich small unilamellar vesicle (SUV*). The method consists of three steps: (1) DNA condensation with a polycation, (2) electrostatic interaction of the SUV* with the DNA/polycation complex (DPC) and (3) lipid coating of DPC by SUV* fusion via removal of the detergent. We confirmed the construction of the MEND by sucrose density gradient centrifugation, and isolated the MEND only from the boundary between 25% and 40% sucrose. The isolated MEND had a small diameter (155 nm), was negatively charged (-24 mV), and encapsulated 30% of the total DNA. The MEND was formed by only SUV*, not by a lipid/detergent micelle. This confirms that a small and homogenous MEND can be constructed by the SUV*-fusion method. Furthermore, we confirmed that a transferrin-modified MEND could deliver a gene into a cell through receptor-mediated endocytosis. Consequently, we report on the successful construction of a small and homogenous MEND by a novel SUV*-fusion method.

Cell Line, Tumor↗
PubMed2005

Antioxidant effect of bovine serum albumin on membrane lipid peroxidation induced by iron chelate and superoxide.

Albumin is supposed to be the major antioxidant circulating in blood. This study examined the prevention of membrane lipid peroxidation by bovine serum albumin (BSA). Lipid peroxidation was induced by the exposing of enzymatically generated superoxide radicals to egg yolk phosphatidylcholine liposomes incorporating lipids with different charges in the presence of chelated iron catalysts. We used three kinds of Fe3+-chelates, which initiated reactions that were dependent on membrane charge: Fe3+-EDTA and Fe3+-EGTA catalyzed peroxidation in positively and negatively charged liposomes, respectively, and Fe3+-NTA, a renal carcinogen, catalyzed the reaction in liposomes of either charge. Fe3+-chelates initiated more lipid peroxidation in liposomes with increased zeta potentials, followed by an increase of their availability for the initiation of the reaction at the membrane surface. BSA inhibits lipid peroxidation by preventing the interaction of iron chelate with membranes, followed by a decrease of its availability in a charge-dependent manner depending on the iron-chelate concentration: one is accompanied and the other is unaccompanied by a change in the membrane charge. The inhibitory effect of BSA in the former at high concentrations of iron chelate would be attributed to its electrostatic binding with oppositely charged membranes. The inhibitory effect in the latter at low concentrations of iron chelate would be caused by BSA binding with iron chelates and keeping them away from membrane surface where lipid peroxidation is initiated. Although these results warrant further in vivo investigation, it was concluded that BSA inhibits membrane lipid peroxidation by decreasing the availability of iron for the initiation of membrane lipid peroxidation, in addition to trapping active oxygens and free radicals.

Animals↗
PubMed2005

Unique features of a pH-sensitive fusogenic peptide that improves the transfection efficiency of cationic liposomes.

BACKGROUND: One of the critical steps in intracellular gene delivery using cationic liposomes is the endosomal escape of the plasmid/liposome complexes to the cytosol. The addition of GALA, a pH-sensitive fusogenic peptide, is a promising method to accelerate this step in order to enhance the expression of the desired proteins. Detailed studies on the methods of enhancement would broaden the horizon of its application. METHODS: Using representative commercially available cationic liposomes (Lipofectin, Lipofectamine, and Lipofectamine 2000), the effects of GALA on transfection efficiency were studied by luciferase assay and confocal microscopic observations. RESULTS: A concentration-dependent increase in the transfection efficiency was observed for GALA. Addition of 0.1 microM GALA to the plasmid/liposome complex significantly increased the transfection efficiency, especially in the case of Lipofectin, but higher concentration of GALA decreased transfection efficiency. Successful reduction in the liposomal dosage was attained by employing GALA while maintaining a high transfection efficiency. Interestingly, although the transfection efficiency was higher in the presence of GALA, a lower amount of the plasmid DNA was taken up by the cells. Confocal microscopic observations of the rhodamine-labeled plasmid did not show a significant difference in the cellular localization among cells incubated in the presence or absence of GALA, suggesting that a slight increase in GALA-induced release of the plasmid to the cytosol may cause a significant change in the transfection efficiency. CONCLUSION: The unique features of GALA to mediate improved transfection efficiencies were identified.

Animals↗
PubMed2005

Development of efficient packaging method of oligodeoxynucleotides by a condensed nano particle in lipid envelope structure.

An efficient delivery system is required if antisense oligodeoxynucleotides (ODN) are to be utilized for gene therapy. We report herein on the development of a novel ODN delivery system, ODN-encapsulated nano particles (ODN-ENP) using an efficient and simple packaging method. The ODN-ENP consists of a condensed ODN particle and a lipid envelope, which can be equipped with various functional devices for the efficient delivery of ODN with a small diameter (150 nm). The encapsulation efficiency and ODN recovery of ODN-ENP were significantly higher than those of other packaging methods, such as a stabilized antisense-lipid particles method or a freeze-thaw method. Furthermore, the time required for the preparation of the ODN-ENP was shorter than the other methods. The method developed in this study is a simple and efficient packaging method for ODN with a condensed nano particle in lipid-envelope structure.

Base Sequence↗
PubMed2005

Cytotoxicity of alpha-tocopheryl succinate, malonate and oxalate in normal and cancer cells in vitro and their anti-cancer effects on mouse melanoma in vivo.

alpha-Tocopheryl succinate (TS), which is known to induce apoptosis selectively in cancer cells, has attracted attention as a chemotherapeutic agent. Recently, we found that alpha-tocopheryl malonate (TM) and alpha-tocopheryl oxalate (TO), among the alpha-tocopheryl esters tested, have high apoptogenic activity as well as TS. In this study, we investigated the characteristics of their cytotoxicity on normal cells and cancer cells in vitro, and their anti-cancer effects on mice inoculated with melanoma B16-F1 cells in vivo. The order of in vitro cytotoxicity was TO > or = TM >> TS in all cell lines examined. Addition of exogenous superoxide dismutase (SOD) and the antioxidant N-acetyl cysteine (NAC) inhibited TS- and TM- but not TO-induced cell deaths. A selective cytotoxic effect on cancer cells was observed with TS but not with TM or TO. c-Jun N-terminal kinase (JNK) inhibitor II prevented cell death induced by TS but did not prevent cell deaths induced either by TM or TO. Intravenous administration of vesiculated TS and TM to mice inoculated with melanoma B16-F1 cells prevented tumor growth and enhanced the mean survival time, but TO administration killed the mice due to its acute high toxicity. From these results, we discussed the characteristics of their selective cytotoxicity toward tumor cells in vitro and anti-cancer effects in vivo.

Acetylcysteine↗
PubMed2004

Development of a non-viral multifunctional envelope-type nano device by a novel lipid film hydration method.

The development of a multifunctional envelope-type nano device (MEND) for use in a non-viral gene delivery system using a novel lipid film hydration method is described. This packaging method involves three steps: (i) DNA condensation with a polycation, (ii) lipid film hydration for the electrostatic binding of the condensed DNA, and (iii) sonication to package the condensed DNA with lipids. For DNA condensation, the optimum ratio of DNA to poly-L-lysine (PLL) was determined by titrating DNA and PLL. The condensed DNA/PLL complex (DPC) was coated with a lipid bilayer by lipid film hydration followed by sonication, which was confirmed by sucrose density gradient centrifugation. Packaging of DPC with lipids increased the transfection activity 10-fold over that of DPC. MEND, having octaarginine on the envelope as a device for membrane penetration to enhance cellular uptake, showed a 1000-fold higher transfection activity than DPC. The MEND developed in this study represents a promising non-viral gene delivery system.

Animals↗