Multifunctional Envelope-type Nano Device Research Articles

Novel antiangiogenic therapy targeting biglycan using tumor endothelial cell-specific liposomal siRNA delivery system.

Tumor blood vessels play important roles in tumor progression and metastasis. Targeting tumor endothelial cells (TECs) is one of the strategies for cancer therapy. We previously reported that biglycan, a small leucine‐rich proteoglycan, is highly expressed in TECs. TECs utilize biglycan in an autocrine manner for migration and angiogenesis. Furthermore, TEC‐derived biglycan stimulates tumor cell migration in a paracrine manner leading to tumor cell intravasation and metastasis. In this study, we explored the therapeutic effect of biglycan inhibition in the TECs of renal cell carcinoma using an in vivo siRNA delivery system known as a multifunctional envelope‐type nanodevice (MEND), which contains a unique pH‐sensitive cationic lipid. To specifically deliver MEND into TECs, we incorporated cyclo(Arg–Gly–Asp–d–Phe–Lys) (cRGD) into MEND because αVβ3 integrin, a receptor for cRGD, is selective and highly expressed in TECs. We developed RGD‐MEND‐encapsulating siRNA against biglycan. First, we confirmed that MEND was delivered into OS‐RC‐2 tumor‐derived TECs and induced in vitro RNAi‐mediated gene silencing. MEND was then injected intravenously into OS‐RC‐2 tumor‐bearing mice. Flow cytometry analysis demonstrated that MEND was specifically delivered into TECs. Quantitative RT‐PCR indicated that biglycan was knocked down by biglycan siRNA‐containing MEND. Finally, we analyzed the therapeutic effect of biglycan silencing by MEND in TECs. Tumor growth was inhibited by biglycan siRNA‐containing MEND. Tumor microenvironmental factors such as fibrosis were also normalized using biglycan inhibition in TECs. Biglycan in TECs can be a novel target for cancer treatment.

Resveratrol-Encapsulated Mitochondria-Targeting Liposome Enhances Mitochondrial Respiratory Capacity in Myocardial Cells.

The development of drug delivery systems for use in the treatment of cardiovascular diseases is an area of great interest. We report herein on an evaluation of the therapeutic potential of a myocardial mitochondria-targeting liposome, a multifunctional envelope-type nano device for targeting pancreatic β cells (β-MEND) that was previously developed in our laboratory. Resveratrol (RES), a natural polyphenol compound that has a cardioprotective effect, was encapsulated in the β-MEND (β-MEND (RES)), and its efficacy was evaluated using rat myocardioblasts (H9c2 cells). The β-MEND (RES) was readily taken up by H9c2 cells, as verified by fluorescence-activated cell sorter data, and was observed to be colocalized with intracellular mitochondria by confocal laser scanning microscopy. Myocardial mitochondrial function was evaluated by a Seahorse XF Analyzer and the results showed that the β-MEND (RES) significantly activated cellular maximal respiratory capacity. In addition, the β-MEND (RES) showed no cellular toxicity for H9c2 cells as evidenced by Premix WST-1 assays. This is the first report of the use of a myocardial mitochondria-targeting liposome encapsulating RES for activating mitochondrial function, which was clearly confirmed based on analyses using a Seahorse XF Analyzer.

Evolution of drug delivery system from viewpoint of controlled intracellular trafficking and selective tissue targeting toward future nanomedicine

Due to the rapid changes that have occurred in the field of drug discovery and the recent developments in the early 21st century, the role of drug delivery systems (DDS) has become increasingly more important. For the past 20 years, our laboratory has been developing gene delivery systems based on lipid-based delivery systems. One of our efforts has been directed toward developing a multifunctional envelope-type nano device (MEND) by modifying the particle surface with octaarginine, which resulted in a remarkably enhanced cellular uptake and improved intracellular trafficking of plasmid DNA (pDNA). When we moved to in vivo applications, however, we were faced with the PEG-dilemma and we shifted our strategy to the incorporation of ionizable cationic lipids into our system. This resulted in some dramatic improvements over our original design and this can be attributed to the development of a new lipid library. We have also developed a mitochondrial targeting system based on a membrane fusion mechanism using a MITO-Porter, which can deliver nucleic acids/pDNA into the matrix of mitochondria. After the appearance of antibody medicines, Opdivo, an immune checkpoint inhibitor, has established cancer immunology as the 4th strategy in cancer therapy. Our DDS technologies can also be applied to this new field of cancer therapy to cure cancer by controlling our immune mechanisms. The latest studies are summarized in this review article.

Lipid nanoparticles fuse with cell membranes of immune cells at low temperatures leading to the loss of transfection activity.

Delivering nucleic acid using a non-viral vector is a potent strategy for gene modification and controlling gene expression in immune cell therapy. Since the low-temperature storage (0-4°C) or cryopreservation of cells are indispensable for performing immune cell therapy, we investigated the interactions between an siRNA-loaded lipid nanoparticle (LNP), a multifunctional envelope-type nanodevice (MEND) containing YSK12-C4 (YSK12-MEND), and human immune cell lines (NK-92 and Jurkat) at low-temperature and its effect on transfection activity. The YSK12-MEND readily bound to the cell membrane of NK-92 cells at low-temperature, but no internalization of the YSK12-MEND by cells was observed, even after returning the temperature to 37°C. Gene silencing activity was completely impaired. The cause of this inhibition appears to be membrane fusion between the YSK12-MEND and cell membrane at the low-temperature. Collectively, our results suggest that the exposure of siRNA-loaded LNPs to cells at low-temperature should be avoided in defining transfection protocols in immune cell therapy.

Improved Stability of siRNA-Loaded Lipid Nanoparticles Prepared with a PEG-Monoacyl Fatty Acid Facilitates Ligand-Mediated siRNA Delivery.

Peptide modification is a popular strategy for developing an active targeting lipid nanoparticle (LNP). In modifying the surface of an LNP with a peptide, the sequence and structure of the peptide strongly affects the formation of the LNP. Specifically, a peptide with a high hydrophobicity can induce coarsening and aggregation of the LNP. In an attempt to prevent this from occurring, we incorporated monoacyl and diacyl group-conjugated poly(ethylene glycol) (PEG) into a LNP. We previously developed an original LNP, a multifunctional envelope type nanodevice (MEND) modified with an Epi-1 peptide, a ligand with a high affinity for the epithelial cell adhesion molecule (EpCAM). Using this peptide-modified MEND, the efficiency of delivery of a small interfering RNA (siRNA) encapsulated in the MEND was significantly improved. Although increasing the ratio of modification enhanced cellular uptake, the increase also induced aggregation of the LNP, particularly in the case of a large scale preparation. Our results indicate that a monoacyl PEG-lipid can prevent aggregation, even when the LNP is modified with higher molar ratios of peptide, but that this also results in a decrease in delivery efficiency. Moreover, the Epi-1-modified MEND exhibited a strong silencing effect in an ovarian cancer peritoneal dissemination model. Our results suggest that the simple incorporation of a monoacyl derivative into the PEG-lipid resulted in the formation of a peptide-modified LNP with improved characteristics.

A nanocarrier for the mitochondrial delivery of nucleic acids to cardiomyocytes

Cardiomyopathy caused by mitochondrial dysfunction associated with the mutation/deletion of mitochondrial DNA has been reported, and nucleic acid therapy targeting cardiac mitochondria represents a possible therapy for treating these diseases. Such a treatment, however, has not yet been achieved because delivering nucleic acids to mitochondria of cardiac muscle is difficult. In this study, H9c2 cells a type of rat cardiac myoblasts, were used as model cardiac muscle cells. The use of a lipid composition used to prepare the β-MEND (where MEND denotes multifunctional envelope-type nano device) permitted the particles to be efficiently internalized by H9c2 cells, as evidenced by flow cytometry analyses. Intracellular observations by confocal laser scanning microscopy showed that the β-MEND efficiently accumulated in mitochondria of H9c2 cells. We also constructed an RP/β-MEND that contained a mitochondrial RNA aptamer to achieve mitochondrial delivery in H9c2 cells. The successful direct mitochondrial transfection of exogenous RNA was confirmed using these carrier systems, based on PCR experiments after reverse transcription. Thus, the β-MEND holds promise as a direct mitochondrial transfection system for delivering nucleic acids targeted to H9c2 cells.

The silencing of indoleamine 2,3-dioxygenase 1 (IDO1) in dendritic cells by siRNA-loaded lipid nanoparticles enhances cell-based cancer immunotherapy

Cell-based therapy using dendritic cells (DC) represents a potent cancer immunotherapy. However, activated DC express indoleamine 2,3-dioxygenase 1 (IDO1), a counter-regulatory and tolerogenic molecule, leading to the inhibition of T cell activation and the promotion of T cell differentiation into regulatory T cells. Silencing the IDO1 gene in DC by small interfering RNA (siRNA) represents a potent therapeutic strategy. We report on the successful and efficient introduction of a siRNA targeting IDO1 into mouse DCs by a means of a multifunctional envelope-type nanodevice (MEND) containing a YSK12-C4 (YSK12-MEND). The YSK12-C4 has both fusogenic and cationic properties. The YSK12-MEND induced an effective level of gene silencing of IDO1 at siRNA doses in the range of 1–20 nM, a concentration that commercially available transfection reagents are not able to silence. The YSK12-MEND mediated IDO1 silencing had no effect on the characteristic determinants of DC phenotype such as CD11c, CD80 and MHC class II. The silencing of IDO1 in DC by the YSK12-MEND significantly enhanced the antitumor effect against E.G7-OVA tumor. Moreover, a decrease in the numbers of regulatory T cells in the tumor was observed in mice that were treated with the IDO1-silenced DC. The YSK12-MEND appears to be a potent delivery system for IDO1-silenced DC based cancer immunotherapy.

Lung‐Endothelium‐Targeted Nanoparticles Based on a pH‐Sensitive Lipid and the GALA Peptide Enable Robust Gene Silencing and the Regression of Metastatic Lung Cancer

AbstractThe development of efficient gene delivery systems targeting the lung endothelium remains a serious challenge. This study reports on the design and optimization of a multifunctional envelope‐type nanodevice (MEND) for an efficient siRNA delivery to the lung endothelium based on GALA‐peptide targeting ability. The incorporation of a pH‐sensitive lipid (YSK05) results in a dramatic improvement in silencing efficiency by enhancing endosomal escape, but this also causes a reduction in the lung selectivity. Contrary to the assumption that active targeting is largely dependent on the presence of a targeting ligand, the findings of the present study indicate that nanocarrier composition is critical for achieving the organ selectivity. Interestingly, helper lipids substantially mask the liver delivery resulting in optimum lung targeting. The optimized YSK05‐MEND is 40‐fold more efficient than a previously developed MEND, with a robust lung endothelium gene knockdown at small doses. The YSK05‐MEND strongly inhibits a metastatic lung cancer model and exerts superior control over lung metastasis compared to chemotherapy or the previously developed MEND. The YSK05‐MEND is well‐tolerated in mice after acute or chronic administration. As far as it is known, YSK05‐MEND achieves the most efficient lung endothelium gene silencing reported thus far with a median effective dose of 0.01 mg siRNA kg−1 while minimally affecting the endothelium of other organs.

Development of a Novel Liposomal DDS by Manipulating Pharmacokinetics and Intracellular Trafficking for Drug Therapy and Nucleic Acid Medicine

Nucleic acid therapy is expected to be a next generation medicine. We recently developed a multifunctional envelope-type nano device (MEND) for use as a novel delivery system. The modification of polyethylene glycol (PEG), i.e., PEGylation, is useful for achieving the delivery of MENDs to tumors via an enhanced permeability and retention (EPR) effect. However, PEGylation strongly inhibits the cellular uptake and endosomal escape of MEND, which results in significant loss of action, and therefore lost effectiveness, of the cargo therapeutic. For successful nucleic acid delivery in cancer treatment, the crucial problem associated with the use of PEG, known as the "PEG dilemma", must be solved. In this review, we describe the development and application of MEND in overcoming the PEG dilemma based on manipulating both the pharmacokinetics and intracellular trafficking of cellular uptake and endosomal release using a cleavable PEG lipid, a pH-sensitive fusogenic peptide, and a pH-sensitive cationic lipid. We also developed dual-ligand liposomes with a controlled diameter of around 300 nm, then modified these with a specific ligand and a cell penetrating peptide designed to target the neovasculature of tumors. Dual-ligand liposomes could induce an anti-tumor effect in drug resistant tumors by delivering drugs to tumor blood vessels, rather than to the cancer cells themselves. Here, we review our recent efforts to develop a novel liposomal drug delivery system (DDS) by manipulating pharmacokinetics and intracellular trafficking for drug therapy and nucleic acid medicine.

Reducing the Cytotoxicity of Lipid Nanoparticles Associated with a Fusogenic Cationic Lipid in a Natural Killer Cell Line by Introducing a Polycation-Based siRNA Core.

Introducing siRNA into human immune cells by an artificial delivery system continues to be a challenging issue. We previously developed a multifunctional envelope-type nanodevice (MEND) containing the YSK12-C4, a fusogenic cationic lipid, (YSK12-MEND) and succeeded in the efficient delivery of siRNA into human immune cell lines. Significant cytotoxicity, however, was observed at siRNA doses needed for gene silencing in NK-92 cells. NK-92 cells, a unique natural killer (NK) cell line, would be applicable for use in clinical NK therapy. Thus, reducing the cytotoxicity of the YSK12-MEND in NK-92 cells would strengthen the efficacy of NK-92 cell-based therapy. The amount of the YSK12-C4 in the MEND needed to be reduced to reduce the cytotoxicity, because the cytotoxicity was directly associated with the YSK12-C4. In the present study, we decreased the total amount of lipid, including the YSK12-C4, by introducing a core formed by electrostatic interactions of siRNA with a polycation (protamine) (siRNA core), which led to a decrease in cytotoxicity in NK-92 cells. We prepared a YSK12-MEND containing an siRNA core (YSK12-MEND/core) at charge ratios (CR: YSK12-C4/siRNA) of 10, 5, 3, and 2.5 and compared the YSK12-MEND/core with that for a YSK12-MEND (CR16.9). Cell viability was increased by more than 2 times at a CR5 or less. On the other hand, the YSK12-MEND/core (CR5) maintained the same gene silencing efficiency (60%) as the YSK12-MEND. Interestingly, the cellular uptake efficiency and hemolytic activity of the YSK12-MEND/core (CR5) was reduced compared to that for the YSK12-MEND. In calculating the silencing activity per cellular uptake efficiency and hemolytic activity, the value for the YSK12-MEND/core (CR5) was more than 2 times as high as that of the YSK12-MEND. The fact indicates that after endosomal escape, the process can be enhanced by using a YSK12-MEND/core (CR5). Thus, introducing an siRNA core into lipid nanoparticles can be a potent strategy for decreasing cytotoxicity without an appreciable loss of gene silencing activity in NK-92 cells.

Preparation of envelope-type lipid nanoparticles containing gold nanorods for photothermal cancer therapy

The use of gold nanorods (AuNRs) that produce heat in response to near infrared (NIR) irradiation is an attractive approach to cancer photothermal therapy. AuNRs are usually prepared by using a highly toxic detergent: cetyltrimethylammonium bromide (CTAB). Thus, the removal of CTAB from the reaction mixture, and further stabilization of the surface of the AuNRs is required. In the present study, AuNRs were encapsulated in a multifunctional envelope-type nano device (AuNR-MEND) formed with an SS-cleavable and pH-activated lipid-like material. In the process of encapsulation, AuNRs were first stabilized with bovine serum albumin (AuNR-BSA), and then further encapsulated in the lipid envelope by the ethanol dilution method. The in vitro photothermal cytotoxicity of AuNR-MEND was further demonstrated on 4T1 breast cancer cells. After NIR radiation, the temperature of the medium was increased to approximately 60°C, and cell viability was drastically decreased to approximately 11%. However, this cytotoxic effect cannot simply be explained by medium heating. It therefore appears that intracellular delivery of the AuNRs is a key factor for achieving a high degree of cytotoxicity. Dose dependent cytotoxicity data revealed that a higher dose of AuNR-MEND resulted in the complete destruction of the cells when they were subjected to NIR irradiation, while the cell survival rate reached a plateau at 30% in the case of AuNR-BSA. Apoptosis was induced after treatment with the nanoparticles. AuNR-MEND showed superior cellular uptake activity over AuNR-BSA. Thus, delivering AuNR by means of functionalized lipid nanoparticles represents a promising approach to induce NIR-triggered apoptosis.

PEGylation of the GALA Peptide Enhances the Lung-Targeting Activity of Nanocarriers That Contain Encapsulated siRNA

A α-helical GALA peptide (WEAALAEALAEALAEHLAEALAEALEALAA) has been found to possess dual functions: a pH-dependent inducer of endosomal escape, and a ligand that targets lung endothelium. In the present study, the flexibility of GALA was improved by modifying the edge with polyethylene glycol linker, to increase lung-targeting activity. We first investigated the uptake of the GALA-modified liposomes in which GALA was directly conjugated to the lipid (Cholesterol: GALA/Chol) or the phospholipid-PEG (GALA/PEG2000). The liposomes that were modified with GALA/PEG2000 (GALA/PEG2000-LPs) were taken up at a higher level by human lung endothelial cells (HMVEC-L), in comparison with particles that were modified with GALA/Chol (GALA/Chol-LPs). Small-interfering RNA–encapsulating liposomal-based nanocarriers (multifunctional envelope-type nano device: MEND) that were formulated with a vitamin E-scaffold SS-cleavable pH-activated lipid-like material, namely GALA/PEG2000-MENDssPalmE were also modified with GALA/PEG2000. Gene silencing activity in the lung endothelium was then evaluated against an endothelial marker; CD31. In comparison with the unmodified MENDssPalmE, GALA/PEG2000-MENDssPalmE exhibited a higher silencing activity in the lung. Optimization of GALA/PEG2000-MENDssPalmE resulted in silencing activity in the lung with an ED50 value of 0.21 mg/kg, while non-specific gene silencing in liver was marginal. Collectively, PEGylated GALA is a promising device for use in targeting the lung endothelium.

Lipid nanoparticle-based co-delivery of epirubicin and BCL-2 siRNA for enhanced intracellular drug release and reversing multidrug resistance

At present, combined therapy has become an effective strategy for the treatment of cancer. Co-delivery of the chemotherapeutic drugs and siRNA can more effectively inhibit tumor growth by nano drug delivery systems (NDDSs). Here, we prepared and evaluated a multifunctional envelope-type nano device (MEND). This MEND was a kind of composite lipid-nanoparticles possessing both the properties of liposomes and nanoparticles. In this study, an acid-cleavable ketal containing poly (β-amino ester) (KPAE) was used to bind siBCL-2 and the KPAE/siBCL-2 complexes were further coated by epirubicin (EPI) containing lipid to form EPI/siBCL-2 dual loaded lipid-nanoparticles. The results showed that the average size of EPI/siBCL-2-MEND was about 120 nm, and the average zeta potential was about 41 mV. The encapsulation efficiency (EE) of EPI and siBCL-2 was 86.13% and 97.07%, respectively. EPI/siBCL-2 dual loaded lipid-nanoparticles showed enhanced inhibition efficiency than individual EPI-loaded liposomes on HepG2 cells by MTT assay. Moreover, western blot experiment indicated co-delivery of EPI/siBCL-2 can significantly down-regulate the expression of P-glycoprotein (P-gp), while free EPI and EPI-loaded liposomes up-regulated it. Therefore, the strategy of co-delivering EPI and siBCL-2 simultaneously by lipid-nanoparticles showed promising potential in reversing multidrug resistance of tumor cells.

ミトコンドリアを標的とする多機能性エンベロープ型ナノ構造体の創製とナノ医療への展開

A single cell contains a variety of organelles, including a nucleus, mitochondria, the golgi apparatus and others. If it were possible to prepare a nano craft that could specifically target a specific organelle, it would open a new field of research directed toward therapeutic treatments for a variety of diseases. We recently developed a new concept that we refer to as “Programmed Packaging”, by which we succeeded in creating a multifunctional envelope-type nano device (MEND) as a non-viral vector. Our attempts to target mitochondria are discussed here, mainly focusing on a MITO-Porter, a MEND for delivering cargoes to mitochondria. A variety of human diseases, including various neurodegenerative disorders, ischemic heart disease, diabetes and cancer have been reported to be associated with mitochondrial dysfunction. Because of this, mitochondrial therapy would be expected to be useful and productive in the treatment of such diseases. Our findings regarding mitochondrial drug delivery systems that are directed toward mitochondrial nano medicine development are summrized herein.

Small-sized, stable lipid nanoparticle for the efficient delivery of siRNA to human immune cell lines.

Gene silencing by small interfering RNA (siRNA) is useful for analyzing the functions of human immune cells. However, the transfection of siRNA to human immune cells is difficult. Here, we used a multifunctional envelope-type nanodevice (MEND) containing YSK12-C4 (YSK12-MEND) to efficiently introduce siRNA to human immune cell lines, Jurkat, THP-1, KG-1 and NK92. The YSK12-MEND was transfected to human immune cell lines at a siRNA dose range of 1–30 nM, resulting that maximum gene silencing efficiencies at the mRNA level in Jurkat, THP-1, KG-1 and NK92 were 96%, 96%, 91% and 75%, respectively. The corresponding values for Lipofectamine RNAiMAX (RNAiMAX) were 37%, 56%, 43% and 19%, respectively. The process associated with cellular uptake played a role in effective gene silencing effect of the YSK12-MEND. The small size and high non-aggregability of the YSK12-MEND were advantageous for the cellular internalization of siRNA to immune cell lines. In the case of RNAiMAX, a drastic increase in particles size was observed in the medium used, which inhibited cellular uptake. The YSK12-MEND reported in herein appears to be appropriate for delivering siRNA to human immune cells, and the small particle size and non-aggregability are essential properties.

Development of a multifunctional envelope-type nano device and its application to nanomedicine

Successful nanomedicines should be based on sound drug delivery systems (DDS) the permit intracellular trafficking as well as the biodistribution of cargos to be controlled. We have been developing new types of DDS that are multifunctional envelope-type nano devices referred to as MENDs. First, we will focus the in vivo delivery of siRNA to hepatocytes using a YSK-MEND which is composed of pH-responsive cationic lipids. The YSK-MEND is capable of inducing efficient silencing activity in hepatocytes and can be used to cure mice that are infected with hepatitis C or B. The YSK-MEND can also be applied to cancer immunotherapy through the activation of immune cells by delivering different compounds such as cyclic-di-GMP, siRNA or alpha-galactosylceramide as a lipid antigen. The findings indicate that, as predicted, these compounds, when encapsulated in the YSK-MEND, can be delivered to the site of action and induced immune activation through different mechanisms. Finally, a MITO-Porter, a membrane fusion-based delivery system to mitochondria, is introduced as an organelle targeting DDS and a new strategy for cancer therapy is proposed by delivering gentamicin to mitochondria of cancer cells. These new technologies are expected to extend the therapeutic area of Nanomedicine by increasing the power of DDS, especially from the view point of controlled intracellular trafficking.

A Multifunctional Envelope-Type Nano Device Containing a pH-Sensitive Cationic Lipid for Efficient Delivery of Short Interfering RNA to Hepatocytes In Vivo.

Various types of nanoparticles have been developed with the intent of efficiently delivering short interfering RNA (siRNA) to hepatocytes to date. To achieve efficient SiRNA delivery, various aspects of the delivery processes and physical properties need to be considered. We recently developed an original lipid nanoparticle, a multifunctional envelope-type nano device (MEND) containing YSK05, a pH-sensitive cationic lipid (YSK05-MEND). The YSK05-MEND with SiRNA in its formulation showed hepatocyte-specific uptake and robust gene silencing in hepatocytes after intravenous administration. Here, we describe the procedure used in the preparation and characterization method of the YSK05-MEND.

Novel pH-sensitive multifunctional envelope-type nanodevice for siRNA-based treatments for chronic HBV infection

Antiviral agents including entecavir (ETV) suppress the replication of the hepatitis B virus (HBV) genome in human hepatocytes, but they do not reduce the abundance of viral proteins. The present study focused on effectively reducing viral protein levels. We designed siRNAs (HBV-siRNA) that target consensus sequences in HBV genomes. To prevent the emergence of escaped mutant virus, we mixed three HBV-siRNAs (HBV-siRNAmix); the mixture was encapsulated in a novel pH-sensitive multifunctional envelope-type nanodevice (MEND), a hepatocyte-specific drug delivery system. Coagulation factor 7 siRNA was used to assess delivery and knockdown efficiencies of MEND/siRNA treatments in mice. The potency of MEND/HBV-siRNAmix was evaluated in primary human hepatocytes and in chimeric mice with humanized liver persistently infected with HBV. Effective knockdown of targets, efficient delivery of siRNA, and liver-specific delivery were each observed with MEND. MEND/HBV-siRNA caused efficient reduction of HBsAg and HBeAg in vitro and in vivo. However, ETV treatment did not efficiently reduce HBsAg or HBeAg when compared with a single MEND/HBV-siRNAmix treatment. Furthermore, the suppressive effects of a single dose of MEND/HBV-siRNAmix persisted for 14days in vitro and in vivo. We demonstrated that MEND/HBV-siRNA controlled HBV more efficiently than did ETV. Furthermore, the effect of a single dose of MEND/HBV-siRNA persisted for a long time. These results indicated that MEND/HBV-siRNA may be a promising novel HBV treatment that is more effective than reverse transcriptase inhibitors.

Multifunctional Envelope-Type Nano Device: Evolution from Nonselective to Active Targeting System.

A paradigm shift has occurred in the field of drug delivery systems (DDS), one being intracellular targeting, and the other, active targeting. An important aspect of intracellular targeting involves delivering nucleic acids such as siRNA/pDNA rather than small molecular compounds, since the mechanism responsible for their entering a target cell is usually via endocytosis, and the efficiency of endosomal escape is a critical factor in determining the functional activities of siRNA/pDNA. A multifunctional envelope-type nano device (MEND) was developed to control the intracellular trafficking of nano carriers containing siRNA/pDNA. An octaarginine (R8) modified MEND was developed to achieve this. Considerable progress has been made in active targeting to selective tissue vasculature such as tumor, adipose tissue, and the lung where endothelial barrier is tight against nanoparticles with diameters larger than 50 nm. A dual-ligand system is proposed to enhance active targeting ability by virtue of a synergistic interaction between a selective ligand and a cell penetrating ligand. Prohibitin targeted nanoparticles (PTNP) were developed to target endothelial cells in adipose tissue, which deliver apoptotic peptides/proteins to the adipose vasculature. Lung endothelial cells can be targeted by means of the GALA peptide, which is usually used to enhance endosomal escape. These active targeting systems can induce pharmacological effects in in vivo conditions. Finally, a novel strategy for producing an original ligand has been developed, especially for the tumor vasculature. This progress in DDS promises to extend the area of nanomedicine as a breakthrough technology.

Preparation and evaluation of a non-viral gene vector for SiRNA: Multifunctional envelope-type nano device

We prepared and evaluated a multifunctional envelope-type nano device (MEND) as a liver-targeting and long-circulation carrier for SiRNA. The polymer GA-PEG-Pp-DOPE was synthesized by modifying polyethylene glycol (PEG) with glycyrrhetinic acid (GA), peptide (Pp), and dioleoyl phosphoethanolamine (DOPE). The Pp is a substrate of matrix metalloproteinase 2. MEND was prepared with GA-PEG-Pp-DOPE and cationic phospholipids by the filming-rehydration method, and the orthogonal test was applied to optimize the prescription. The results of the biological evaluation results suggest that MEND is a promising delivery system for SiRNA.