Multifunctional Envelope-type Nano Device Research Articles

Hyaluronic acid controls the uptake pathway and intracellular trafficking of an octaarginine-modified gene vector in CD44 positive- and CD44 negative-cells

The cellular uptake pathway for a gene vector is an important factor in transgene expression. We previously constructed an original gene vector, multifunctional envelope-type nano device (MEND). The use of octaarginine (R8), a cell-penetrating peptide dramatically enhanced the transfection activity of the MEND since efficient cellular uptake via macropinocytosis, while the R8 should overcome its poor cell selectivity. Here we prepared an R8-MEND equipped with GALA (a peptide for endosomal escape) (R8/GALA-MEND) coated with hyaluronic acid (HA) (HA-R8/GALA-MEND), a natural ligand for cancer cells overexpressing CD44. We investigated the cellular uptake pathway of the HA-R8/GALA-MEND and the R8/GALA-MEND using HCT116 cells overexpressing CD44. Both carriers were taken up by cells mainly via macropinocytosis, whereas only the HA-R8/GALA-MEND was partially internalized into cells via a CD44-mediated pathway. Investigation of transgene expression showed that the HA-R8/GALA-MEND had a high transfection activity in HCT116 cells via both macropinocytotic and CD44-mediated pathways. On the other hand, the value for the HA-R8/GALA-MEND was significantly decreased compared with the value for the R8/GALA-MEND in NIH3T3 cells (CD44-negative cells). These findings indicate that the HA-coating controls the intracellular pathway for R8-modified nanocarriers, and that a CD44-mediated pathway is an important route for transgene expression.

A KALA-modified lipid nanoparticle containing CpG-free plasmid DNA as a potential DNA vaccine carrier for antigen presentation and as an immune-stimulative adjuvant.

Technologies that delivery antigen-encoded plasmid DNA (pDNA) to antigen presenting cell and their immune-activation are required for the success of DNA vaccines. Here we report on an artificial nanoparticle that can achieve these; a multifunctional envelope-type nanodevice modified with KALA, a peptide that forms α-helical structure at physiological pH (KALA-MEND). KALA modification and the removal of the CpG-motifs from the pDNA synergistically boosted transfection efficacy. In parallel, transfection with the KALA-MEND enhances the production of multiple cytokines and chemokines and co-stimulatory molecules via the Toll-like receptor 9-independent manner. Endosome-fusogenic lipid envelops and a long length of pDNA are essential for this immune stimulation. Furthermore, cytoplasmic dsDNA sensors that are related to the STING/TBK1 pathway and inflammasome are involved in IFN-β and IL-1β production, respectively. Consequently, the robust induction of antigen-specific cytotoxic T-lymphoma activity and the resulting prophylactic and therapeutic anti-tumor effect was observed in mice that had been immunized with bone marrow-derived dendritic cells ex vivo transfected with antigen-encoding pDNA. Collectively, the KALA-MEND possesses dual functions; gene transfection system and immune-stimulative adjuvant, those are both necessary for the successful DNA vaccine.

Efficient Packaging of Plasmid DNA Using a pH Sensitive Cationic Lipid for Delivery to Hepatocytes.

Plasmid DNA (pDNA) is expected to be a new class of medicine for treating currently incurable diseases. To deliver these nucleic acids, we developed a liposomal delivery system we have called a multifunctional envelope-type nano device (MEND). In this report, we demonstrate that a MEND containing a pH-sensitive cationic lipid, YSK05 (YSK-MEND), efficiently delivered pDNA via systemic injection, and that its expression was highly dependent on the encapsulation state of the pDNA. In the preparation, the pH, ionic strength, and sodium chloride (NaCl) concentration of the lipid/pDNA mixture strongly affected the encapsulation efficiency of pDNA. Additionally, the transgene expression of luciferase in the liver by the injected YSK-MEND was dependent on the encapsulation state of pDNA rather than the nature of the YSK-MEND. Confocal laser scanning microscopy findings revealed that injection of the YSK-MEND led to homogenous gene expression in the liver compared to injection via the hydrodynamic tail vein (HTV). Concerning the safety of the YSK-MEND, a transient increase in the activity of liver enzymes was observed. However, no significant adverse events were observed. Taken together, the YSK-MEND represents a potentially attractive therapy for the treatment of various hepatic diseases.

Application of apolipoprotein E-modified liposomal nanoparticles as a carrier for delivering DNA and nucleic acid in the brain.

An innovative drug delivery technology is urgently needed to satisfy unmet medical needs in treating various brain disorders. As a fundamental carrier for plasmid DNA or nucleic acids, we developed a liposomal nanoparticle (multifunctional envelope-type nano device [MEND]) containing a proton-ionizable amino lipid (YSK-MEND). Here we report on the impact of apolipoprotein E (ApoE) modification on the function of YSK-MEND in terms of targeting brain cells. The cellular uptake and function of YSK-MEND encapsulating short interference RNA or plasmid DNA were significantly improved as a result of ApoE modification in mouse neuron-derived cell lines (Neuro-2a and CAD). Intracerebroventricular administration of ApoE-modified YSK-MEND (ApoE/YSK-MEND) encapsulating plasmid DNA also resulted in higher transgene expression in comparison with YSK-MEND that was not modified with ApoE. Moreover, observation of fluorescence-labeled ApoE/YSK-MEND and expression of mCherry (fluorescence protein) derived from plasmid DNA indicated that this carrier might be useful for delivering and conferring transgene expression in neural stem cells and/or neural progenitor cells. Thus, this system may be a useful tool for the treatment of neurodegenerative disease.

Mono-cationic detergents play a critical role in the development of liposome-based gene vector via controlling its lamellarity

Controlling the number of lipid bilayers, the lamellarity, in a liposome is a major factor in the in vivo/in vitro pharmacokinetics of drug delivery using liposome-based nanocarriers. Findings reported in a previous study indicated that a mono-cationic detergent (MCD) could be useful in controlling liposomal size via interaction with the lipid envelope. Here, we investigated controlling the lamellarity of the liposomal gene vector by MCD, using a multifunctional envelope-type nano device (MEND). The MEND consisted of a condensed plasmid DNA core and lipid envelopes. The size of the MCD-contained MEND (MCD-MEND) decreased as a function of the amount of MCD, indicating that MCD can be used to control the number of the lipid bilayers. We also developed a triple-layered MEND (TL-MEND) by packaging a di-lamellar MEND into an MCD-containing lipid bilayer. We hypothesized that the TL-MEND would efficiently deliver a gene to the nucleus, when the outer single bilayer fused with the plasma membrane and the inner double membranes then fused with the nuclear double membranes. Transfection assays showed that the TL-MEND had a high transfection activity in JAWS II cells, non-dividing cells. These results indicate that MCD has the potential for enhancing the gene delivery by controlling liposomal lamellarity.

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/MENDEtOH). The gene knockdown efficiency of the MENDHyd and MENDEtOH without GALA-modification was equivalent regardless of the method used in the preparation. The GALA/MENDEtOH induced more efficient gene silencing in the pulmonary endothelium (ED50; approximately 0.17mg siRNA/kg) compared to the GALA/MENDHyd. The GALA/MENDEtOH escaped from endosomes more rapidly than GALA/MENDHyd, while the pharmacokinetics and lung accumulation of GALA/MENDEtOH 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.

Preparation and evaluation of multifunctional envelope-type nano device loading siRNA

We prepared multifunctional envelope-type nano device (MEND) loading siRNA through lipid film hydration method; the qualities of MEND were characterized by the shape, particle size, and evaluated by the encapsulation efficiency (EE), plasma stability, and transfection efficiency. The formulated MEND was found to be relatively uniform in size with a positive zeta potential. The average siRNA entrapment efficiency was 86.4%. After 48 h exposure in 50% (v/v) serum at 37°C, the siRNA in MEND had no significant degradation. When the concentration of siRNA in 24-well plates was 500 nM, the MEND had high transfection efficiency, almost 100%.

Improvement of doxorubicin efficacy using liposomal anti-polo-like kinase 1 siRNA in human renal cell carcinomas.

It is well-known that renal cell carcinomas (RCCs) are resistant to classical cytotoxic anticancer drugs. Therefore, facilitating the impact of anticancer drugs by altering the cell phenotype should be a useful strategy for circumventing this. We developed a multifunctional envelope-type nanodevice (MEND) as an in vivo carrier of siRNA to tumor tissues. We previously reported that a MEND containing YSK05 (YSK-MEND) efficiently delivered siRNA in RCC-bearing mice. We herein report on a combination therapy involving the use of siRNA-mediated specific gene knockdown and cytotoxic drug doxorubicin (DOX), and an advantage of YSK-MEND as an investigation tool for in vivo function of a gene. si-PLK1 encapsulated within YSK-MEND was prepared using the tertiary butanol dilution method. The in vitro cellular viability under the exposure of DOX was compared between OS-RC-2 cells with and without si-PLK1 transfection. In an in vivo study, tumor-bearing mice were systemically injected with YSK-MEND and DOX-loaded liposomes. The combination of DOX and si-PLK1 drastically reduced tumor growth rate, and apoptotic cells were observed. In an in vitro study, PLK1 knockdown increased G2/M cell population and reduced the expression of cyclin B1 (CCNB1) mRNA. CCNB1 suppression by si-PLK1 encapsulated in YSK-MEND was also observed in the in vivo experiments. A combination of DOX and anti-polo-like kinase 1 siRNA (si-PLK1) resulted in a measurable delay in OS-RC-2 tumor growth. This result suggests that the combination of si-PLK1 delivery and doxorubicin by YSK-MEND holds potential for RCC therapy via cell CCNB1 regulation.

A nanocarrier system for the delivery of nucleic acids targeted to a pancreatic beta cell line

Pancreatic β cells secrete insulin in response to glucose levels and thus are involved in controlling blood glucose levels. A line of pancreatic β cells “MIN6” has been used in studies related to the function of β cells and diabetes therapy. Regulating gene expression in MIN6 cells could accelerate these studies, but an efficient method for the transfection of nucleic acids targeted to MIN6 cells is required. We report here on a liposome-based carrier targeted to pancreatic β cells (Multifunctional envelope-type nano device for pancreatic β cells, β-MEND). We identified a lipid composition for use in preparing the β-MEND, which permits the particles to be efficiently internalized into MIN6, as evidenced by flow cytometry analyses. Intracellular observation by confocal laser scanning microscopy showed that the β-MEND efficiently delivered the oligo nucleic acids to the cytosol of MIN6 cells. Moreover, using a β-MEND encapsulating a 2′-O-Methyl RNA complementary to a microRNA that suppresses insulin secretion, the knockdown of the targeted microRNA and an up-regulation of insulin secretion were observed in MIN6. Thus, the β-MEND holds promise as an efficient system for delivering nucleic acids targeted to MIN6 and can contribute to research and therapy aimed at diabetes.

"Programmed packaging" for gene delivery.

We report on the development of a multifunctional envelope-type nano device (MEND) based on our packaging concept "Programmed packaging" to control not only intracellular trafficking but also the biodistribution of encapsulated compounds such as nucleic acids/proteins/peptides. Our strategy for achieving this is based on molecular mechanisms of cell biology such as endocytosis, vesicular trafficking, etc. In this review, we summarize the concept of programmed packaging and discuss some of our recent successful examples of using MENDs. Systematic evolution of ligands by exponential enrichment (SELEX) was applied as a new methodology for identifying a new ligand toward cell or mitochondria. The delivery of siRNA to tumors and the tumor vasculature was achieved using pH sensitive lipid (YSK05), which was newly designed and optimized under in vivo conditions. The efficient delivery of pDNA to immune cells such as dendritic cells has also been developed using the KALA ligand, which can be a breakthrough technology for DNA vaccine. Finally, ss-cleavable and pH-activated lipid-like surfactant (ssPalm) which is a lipid like material with pH-activatable and SS-cleavable properties is also introduced as a proof of our concept.

In vivo therapeutic potential of Dicer-hunting siRNAs targeting infectious hepatitis C virus.

The development of RNA interference (RNAi)-based therapy faces two major obstacles: selecting small interfering RNA (siRNA) sequences with strong activity, and identifying a carrier that allows efficient delivery to target organs. Additionally, conservative region at nucleotide level must be targeted for RNAi in applying to virus because hepatitis C virus (HCV) could escape from therapeutic pressure with genome mutations. In vitro preparation of Dicer-generated siRNAs targeting a conserved, highly ordered HCV 5′ untranslated region are capable of inducing strong RNAi activity. By dissecting the 5′-end of an RNAi-mediated cleavage site in the HCV genome, we identified potent siRNA sequences, which we designate as Dicer-hunting siRNAs (dh-siRNAs). Furthermore, formulation of the dh-siRNAs in an optimized multifunctional envelope-type nano device inhibited ongoing infectious HCV replication in human hepatocytes in vivo. Our efforts using both identification of optimal siRNA sequences and delivery to human hepatocytes suggest therapeutic potential of siRNA for a virus.

Multifunctional enveloped nanodevices (MENDs).

It is anticipated that nucleic acid medicines will be in widespread use in the future, since they have the potential to cure diseases based on molecular mechanisms at the level of gene expression. However, intelligent delivery systems are required to achieve nucleic acid therapy, since they can perform their function only when they reach the intracellular site of action. We have been developing a multifunctional envelope-type nanodevice abbreviated as MEND, which consists of functional nucleic acids as a core and lipid envelope, and can control not only biodistribution but also the intracellular trafficking of nucleic acids. In this chapter, we review the development and evolution of the MEND by providing several successful examples, including the R8-MEND, the KALA-MEND, the MITO-Porter, the YSK-MEND, and the PALM.

The systemic administration of an anti-miRNA oligonucleotide encapsulated pH-sensitive liposome results in reduced level of hepatic microRNA-122 in mice

Efficient delivery continues to be a challenge in microRNA (miRNA) therapeutics. We utilized a pH-sensitive multifunctional envelope-type nano device (MEND) containing a pH-sensitive lipid YSK05 (YSK05-MEND) to regulate liver specific miRNA-122 (miR-122). Anti-microRNA oligonucleotides including 2′-OMe and phosphorothioate modifications against miR-122 (AMO122) were encapsulated in the YSK05-MEND. Despite the lower uptake, the YSK05-MEND showed a higher activity in liver cancer cells than Lipofectamine2000 (LFN2k) due to efficient endosomal escape. Cytotoxicity was minimal at 100nM of AMO122 in YSK05-MEND treated cells, but LFN2k showed toxicity at 50nM. When mice were administrated with free AMO122, it was eliminated via the kidney due to its molecular weight, and lesser amounts were detected in the liver. Conversely, the YSK05-MEND delivered higher amounts of the AMO122 to the liver. Systemic administration of YSK05-MEND induced the knockdown of miR-122 and an increase in target genes in the liver, and a subsequent reduction in plasma cholesterol at a dose of 1mg AMO/kg while free AMO122 showed no activity at the same dose. The effect of AMO122 delivered by YSK05-MEND persisted for over 2weeks. These results suggest that YSK05-MEND is a promising system for delivering AMOs to the liver.

Lipid Envelope-Type Nanoparticle Incorporating a Multifunctional Peptide for Systemic siRNA Delivery to the Pulmonary Endothelium

A system that permits the delivery of cargoes to the lung endothelium would be extraordinarily useful in terms of curing a wide variety of lung-related diseases. This study describes the development of a multifunctional envelope-type nanodevice (MEND) that targets the lung endothelium, delivers its encapsulated siRNA to the cytoplasm, and eradicates lung metastasis. The key to the success can be attributed to the presence of a surface-modified GALA peptide that has dual functions: targeting the sialic acid-terminated sugar chains on the pulmonary endothelium and subsequently delivering the encapsulated cargoes to the cytosol via endosomal membrane fusion, analogous to the influenza virus. The active targeting of MENDs without the formation of large aggregates was verified by intravital real-time confocal laser scanning microscopy in living lung tissue. The GALA-modified MEND is a promising carrier that opens a new generation of therapeutic approaches for satisfying unmet medical needs in curing lung diseases.

A DNA microarray-based analysis of immune-stimulatory and transcriptional responses of dendritic cells to KALA-modified nanoparticles

Technologies for the transfection of antigen-encoding genes into the dendritic cells, and subsequent immune-activation are both prerequisites for a successful DNA vaccine. We herein report on the density-dependent enhancement of transgene expression by the simple modification by stearyl-conjugated KALA, an α-helical peptide (STR-KALA), onto a lipid envelope-type nanoparticle (the R8-MEND, an octaarginine-modified multifunctional envelope-type nano device). The enhanced transgene expression in the KALA-modified R8-MEND (R8/KALA-MEND) cannot be explained by cellular uptake and nuclear delivery efficacy. Thus, the post-nuclear delivery process (i.e. transcription), but not intracellular trafficking processes attributed the enhanced transfection efficacy. Microarray analyses revealed that transfection with the R8/KALA-MEND resulted in a greater perturbation in host genes expression in comparison with the R8-MEND and that this effect was time-dependent. Further pathway analyses in the category of transcription-related genes and a gene ontology analysis indicated that the R8/KALA-MEND stimulated the expression of transcription factors that are closely related to immune-activation (i.e. NF-kB and STAT). Inhibition of the transfection efficacy by blockage of the STAT pathways revealed that the enhanced transcription activity is the result of immune-stimulation. Collectively, the R8/KALA-MEND mounts a “switch-on” function that triggers signal transduction forward to the immune-stimulation analogous to an adjuvant, and consequently elicits active transcription.

Gene Silencing via RNAi and siRNA Quantification in Tumor Tissue Using MEND, a Liposomal siRNA Delivery System

Small interfering RNA (siRNA) would be predicted to function as a cancer drug, but an efficient siRNA delivery system is required for clinical development. To address this issue, we developed a liposomal siRNA carrier, a multifunctional envelope-type nanodevice (MEND). We previously reported that a MEND composed of a pH-sensitive cationic lipid, YSK05, showed significant knockdown in both in vitro and in tumor tissue by intratumoral injection. Here, we report on the development of an in vivo siRNA delivery system that is delivered by systemic injection and an analysis of the pharmacokinetics of an intravenously administered siRNA molecule in tumor tissue. Tumor delivery of siRNA was quantified by means of stem-loop primer quantitative reverse transcriptase PCR (qRT-PCR) method. PEGylation of the YSK-MEND results in the increase in the accumulation of siRNA in tumor tissue from 0.0079% ID/g tumor to 1.9% ID/g tumor. The Administration of the MEND (3 mg siRNA/kg body weight) showed about a 50% reduction in the target gene mRNA and protein. Moreover, we verified the induction of RNA interference by 5' RACE-PCR method. The collective results reported here indicate that an siRNA carrier was developed that can deliver siRNA to a target cell in tumor tissue through an improved siRNA bioavailability.

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.

Development of an Efficient Short Interference RNA (siRNA) Delivery System with a New pH-Sensitive Cationic Lipid

The development of a carrier for the delivery of siRNA is a factor in the realization of RNA interference (RNAi) therapeutics. Modification of siRNA carriers with polyethylene glycol, i.e., PEGylation, is a general strategy for stabilizing a particle in the blood stream and delivering it to tissue or cells. However, it is well-known that, when a carrier is modified by PEGylation, it results in a significant inhibition of both cellular uptake and the endosomal escape process. In a previous study, we reported on the development of a multifunctional envelope-type nano device (MEND) for delivering siRNA and peptide-based functional devices for overcoming the effects conferred by PEGylation and succeeded in the delivery of siRNA to tumor tissue. In this study, we noticed that the pH-sensitive property, changing from neutral to cationic in response to a decrease in pH, could avoid the inhibition caused by PEGylation and succeeded in synthesizing a pH-sensitive cationic lipid, YSK05. The YSK05-MEND had a higher fusogenicity and potency for endosomal escape than other MENDs containing conventional cationic lipids. The PEGylated YSK05-MEND induced efficient gene silencing and avoided the inhibition of endosomal escape caused by PEGylation followed by optimization of the lipid composition. Furthermore, the intratumoral injection of the PEGylated YSK05-MEND resulted in a more efficient gene silencing compared with MENDs containing conventional cationic lipids. Thus, the YSK05-MEND is a promising siRNA carrier for avoiding the inhibition in intracellular trafficking caused by PEGylation both in vitro and in vivo.

A pH-sensitive cationic lipid facilitates the delivery of liposomal siRNA and gene silencing activity in vitro and in vivo

Modification of liposomal siRNA carriers with polyethylene glycol, i.e., PEGylation, is a generally accepted strategy for achieving in vivo stability and delivery to tumor tissue. However, PEGylation significantly inhibits both cellular uptake and the endosomal escape process of the carriers. In a previous study, we reported on the development of a multifunctional envelope-type nano device (MEND) for siRNA delivery and peptide-based functional devices for overcoming the limitations and succeeded in the efficient delivery of siRNA to tumors. In this study, we synthesized a pH-sensitive cationic lipid, YSK05, to overcome the limitations. The YSK05-MEND had a higher ability for endosomal escape than other MENDs containing conventional cationic lipids. The PEGylated YSK05-MEND induced efficient gene silencing and overcame the limitations followed by optimization of the lipid composition. Furthermore, the intratumoral administration of the YSK05-MEND resulted in a more efficient gene silencing compared with MENDs containing conventional cationic lipids. Collectively, these data confirm that YSK05 facilitates the endosomal escape of the MEND and thereby enhances the efficacy of siRNA delivery into cytosol and gene silencing.

Pretreatment of Hepatocyte Growth Factor Gene Transfer Mediated by Octaarginine Peptide-Modified Nanoparticles Ameliorates LPS/D-Galactosamine-Induced Hepatitis

We previously reported that an octaarginine- and pH-sensitive fusogenic peptide-modified multifunctional envelope-type nano device (R8-GALA-MEND) produces a high level of gene expression in the liver. In this study, we report on an examination of whether this gene delivery system exerts potent hepatoprotective effects against lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced acute liver injury. In vivo-jetPEI(™)-Gal, a commercially available in vivo transfection reagent, was used as a reference. The systemic administration of the R8-GALA-MEND or in vivo-jetPEI(™)-Gal showed that the latter was more toxic than the R8-GALA-MEND, indicating that R8-GALA-MEND is a safer system than in vivo-jetPEI(™)-Gal. Pretreatment with R8-GALA-MEND or in vivo-jetPEI(™)-Gal loaded with hepatocyte growth factor (HGF) pDNA inhibited serum GPT and GOT levels from becoming elevated. However, the survival rate of the mice was significantly enhanced in the case of R8-GALA-MEND, but not for the in vivo-jetPEI(™)-Gal treatment. These results demonstrate that R8-GALA-MEND has the potential for use in the pretreatment of an acute liver injury.