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Development of an efficient small interfering RNA (siRNA) delivery method using non-viral carriers is necessary to determine potent therapeutic effects of RNA interference. Inflammatory responses induced by siRNA interaction with Toll-like receptors and retinoic-acid-inducible gene I protein/melanoma differentiation-associated gene 5 (RIG-I/MDA-5) are obstacles to the application of siRNAs in clinically. Here, we evaluated the effects on inflammatory responses by our siRNA delivery method using bubble lipoplexes with ultrasound (US) exposure in cultured macrophages. The effective gene suppression effects were obtained under low-toxic conditions in this siRNA transfer method. The interferon (IFN)-α after siRNA transfer using lipoplexes/bubble lipoplexes with US exposure was not detected. However, low levels of type I IFN mRNA production were induced through interaction of siRNA and cytoplasmic RIG-I/MDA-5, but not Toll-like receptors. Our findings indicate that it is possible to develop a safe and efficient siRNA delivery technique using mannosylated bubble lipoplexes and US exposure. [ABSTRACT FROM AUTHOR]

Drug systems targeting tumor cells using basic fibroblast growth factor (bFGF) have been widely reported. In this study, the peptide KRTGQYKLC (bFGFp), containing cysteine at the carboxyl termination of the bFGF-derived peptide, was applied as a novel ligand targeting tumor cells. bFGFp was conjugated with bovine serum albumin (BSA) and liposomes. The peptide was shown to inhibit the binding of bFGF to FGF receptor-1 (FGFR1). Interestingly, the binding study using surface plasmon resonance (SPR) assay revealed that the bFGFp-BSA was not bound to FGFR1, but was selectively bound to bFGF. Furthermore, the SPR assay showed that bFGFp-BSA is capable of binding to FGFR1 following the pretreatment with bFGF. The confocal microscopy study indicated that the uptake of bFGFp-BSA by NIH3T3 cells, which highly express FGFRs, was significantly enhanced by pretreatment with bFGF. Then, PEGylated liposomes containing bFGFp (bFGFp-liposome) were prepared by conjugating maleimide-PEG-PE with bFGFp. Following the pretreatment of bFGF, the uptake of bFGFp-liposomes by NIH3T3 cells was significantly enhanced. These results suggest that bFGFp-BSA and bFGFp-liposomes are taken by NIH3T3 cells via binding with bFGF. In addition, both bFGFp-BSA and bFGFp-liposomes had no effect on the proliferation of NIH3T3 cells. This strategy can be used as a novel system for targeting tumors highly expressing FGFRs without a proliferation effect. [ABSTRACT FROM AUTHOR]

Cell-specific drug delivery is one of the most promising strategies for improving therapeutic efficiency and minimizing systemic toxicity. Carrier systems devoted to receptor-mediated targeting need to be developed. In the case of liver-non-parenchymal cell-specific targeting systems, glycosylated emulsions have been developed as carriers for lipophilic drugs and/or peptides. This present study demonstrates the in vivo disposition behaviour and pharmacokinetic characteristics of mannosylated (Man-) and fucosylated (Fuc-) emulsions incorporated with cholesten-5-yloxy-N-(4-((1-imino-2-d-thiomannosylethyl)amino)alkyl)formamide (Man-C4-Chol) and its fucosylated derivatives (Fuc-C4-Chol), respectively. Man- (or Fuc-) emulsions are composed of soybean oil, EggPC and Man-C4-Chol (or Fuc-C4-Chol) in a weight ratio of 70:25:5. After intravenous administration to mice, these two types of [ 3 H]cholesteryl hexadecyl ether (CHE)-labelled glycosylated emulsions were rapidly eliminated from the blood circulation and preferentially recovered in the liver. In contrast, bare (Bare-) emulsions composed of soybean oil:EggPC:cholesterol (Chol) in a weight ratio of 70:25:5 were more retained in the blood circulation. The hepatic uptake clearances of Man- and Fuc-emulsions were 3.3- and 4.0-times greater than that of Bare-emulsions. Interestingly, the hepatic uptake clearance of Fuc-emulsions was significantly higher that that of Man-emulsions. The uptake ratios by non-parenchymal cells (NPC) and parenchymal cells (PC) (NPC/PC ratio) for Bare-, Man- and Fuc-emulsions were found to be 0.4, 2.0 and 2.9, respectively. The hepatic uptakes of [ 3 H]CHE-labelled Man- and Fuc-emulsions were reduced by pre-dosing with glycosylated proteins and liposomes. These results clearly support the conclusion that Man- and Fuc-emulsions are promising carrier systems for liver NPC-specific targeting via receptor-mediated mechanism. [ABSTRACT FROM AUTHOR]

Abstract: Cytokine production by Kupffer cells, which is regulated by NFκB, causes severe liver injury in endotoxin syndrome. NFκB decoy has been reported to inhibit NFκB-mediated transcription. The purpose of this study is to inhibit LPS-induced cytokine production by Kupffer cell-targeted delivery of NFκB decoy using fucosylated cationic liposomes (Fuc-liposomes). Cholesten-5-yloxy-N-{4-[(1-imino-2-l-thiofucosyl-ethyl)-amino] butyl-}formamide (Fuc-C4-Chol) was synthesized to prepare Fuc-liposomes. Tissue accumulation, intrahepatic distribution and serum cytokine concentrations were investigated after intravenous injection of Fuc-liposomes/NFκB decoy complexes. Intravenously injected Fuc-liposome complexes rapidly and highly accumulated in the liver while little naked NFκB decoy accumulated in the liver. An intrahepatic distribution study showed that Fuc-liposome complexes are mainly taken up by non-parenchymal cells. The liver accumulation of Fuc-liposome complexes was inhibited by GdCl3 pretreatment, which selectively inhibited Kupffer cell uptake. This result suggested that Kupffer cells contribute to liver accumulation. TNFα, IFNγ, ALT and AST serum levels in LPS-infected mice were significantly attenuated by treatment with Fuc-liposome complexes compared with naked NFκB decoy. Fuc-liposome complexes also reduced the amount of activated NFκB in the liver nuclei. Fuc-liposomes would be a useful carrier for Kupffer cell-selective delivery of NFκB decoy by intravenous injection. [Copyright &y& Elsevier]

Abstract: Carbohydrate grafted emulsions are one of the most promising cell-specific targeting systems for lipophilic drugs. We have previously reported that mannosylated (Man-) emulsions composed of soybean oil, EggPC and cholesten-5-yloxy-N-(4-((1-imino-2-d-thiomannosylethyl)amino)alkyl)formamide (Man-C4-Chol) with a ratio of 70:25:5 were significantly delivered to liver non-parenchymal cells (NPC) via mannose receptor-mediated mechanism after intravenous administration in mice. Since the efficient targeting through a receptor-mediated mechanism is largely controlled by ligand–receptor interaction, the effect of mannose density on Man-emulsions was studied with regard to both the disposition in vivo in mice and the uptake in vitro, using elicited macrophages which express a number of mannose receptors. After intravenous injection, Man-emulsions with 5.0% (Man-5.0-emulsions) and 7.5% (Man-7.5-emulsions) of Man-C4-Chol were rapidly eliminated from the blood circulation and preferentially accumulated in the liver-NPC compared with Man-emulsions with 2.5% of Man-C4-Chol (Man-2.5-emulsions) and bare emulsions (Bare-emulsions). The in vitro study showed increased internalization of Man-5.0- and Man-7.5-emulsions and significant inhibition of uptake in the presence of mannan. The enhanced uptake of Man-emulsions was related to the increasing of Man-C4-Chol content that corresponded to confocal microscopy study. These results suggest that the mannose density of Man-emulsions plays an important role in both cellular recognition and internalization via a mannose receptor-mediated mechanism. [Copyright &y& Elsevier]

Galactosylated (Gal) liposomes containing various molar ratios of cholesten-5-yloxy-N-(4-((1-imino-2-D-thiogalactosylethyl)formamide (Gal-C4-Chol) as a ligand for asialoglycoprotein receptors were prepared to study the effect of the galactose content of Gal-liposomes labeled with [3H]cholesteryl hexadecyl ether on their targeted delivery to hepatocytes. The uptake characteristics of Gal-liposomes having Gal-C4-Chol of 1.0%, 2.5%, 3.5%, 5.0%, and 7.5% were evaluated. The uptake and internalization by HepG2 cells was enhanced by the addition of Gal-C4-Chol to the Gal-liposomes. In the presence of excess galactose, the uptake of Gal-liposomes having Gal-C4-Chol of 3.5%, 5.0%, and 7.5% was inhibited suggesting asialoglycoprotein receptor mediated uptake. After intravenous injection, Gal-liposomes having Gal-C4-Chol of 3.5%, 5.0%, and 7.5%, rapidly disappeared from the blood and exhibited rapid liver accumulation with up to about 80% of the dose within 10 min whereas Gal-liposomes having low Gal-C4-Chol (1.0% and 2.5%) showed a slight improvement in liver accumulation compared with bare-liposomes. Gal-liposomes with high Gal-C4-Chol are preferentially taken up by hepatocytes and the highest uptake ratio by parenchymal cells (PC) and nonparenchymal cells (NPC) (PC/NPC ratio) was observed with Gal-liposomes having of 5.0% Gal-C4-Chol. We report here that the galactose density of Gal-liposomes prepared by Gal-C4-Chol is important for both effective recognition by asialoglycoprotein receptors and cell internalization. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:2266–2275, 2005 [ABSTRACT FROM AUTHOR]

Abstract: Galactosylated (Gal) emulsions containing various molar ratios of cholesten-5-yloxy-N-(4-((1-imino-2-d-thiogalactosylethyl)amino)butyl)formamide (Gal-C4-Chol) as a ligand for asialoglycoprotein receptors were prepared to study the effect of the galactose content of Gal-emulsions labeled with [3H]cholesteryl hexadecyl ether on their targeted delivery to hepatocytes. The uptake characteristics of Gal-emulsions having Gal-C4-Chol of 1, 3, 4, 6, and 9mol% were evaluated in HepG2 cells which posses asialoglycoprotein receptors and NIH3T3 cells which are lack of asialoglycoprotein receptors. The uptake and internalization by HepG2 cells was enhanced by the addition of Gal-C4-Chol to the Gal-emulsions whereas the uptake of Gal-emulsions by NIH3T3 cells was not much and was comparable with that of bare-emulsions. In the presence of excess Gal-BSA, the uptake of Gal-emulsions having Gal-C4-Chol of 4, 6, and 9% was inhibited suggesting asialoglycoprotein receptor mediated uptake. Moreover, Gal-emulsions having Gal-C4-Chol of 4, 6, and 9% showed a slight increase in surface binding and exhibited extensive uptake and internalization into HepG2 cells. The present study strongly suggested that the Gal-emulsions are taken up by the asialoglycoprotein receptor-mediated endocytosis and galactose density of Gal-emulsions is important for effective recognition and cell internalization. [Copyright &y& Elsevier]

Abstract: The nuclear factor kappa B (NFκB) signaling pathway is a key mechanism in the pathophysiology of lung inflammation. NFκB is critically responsible for the expression of pro-inflammatory mediators following activation. The specific inhibition of NFκB by a NFκB decoy via inhalation appears to improve therapeutic effects. However, administration of naked NFκB decoy limits the efficacy of the decoy strategy due to low targeting ability to immune cells such as alveolar macrophages. In this study, we have assessed the effect of alveolar macrophage-targeted NFκB decoy by mannosylated (Man) cationic liposomes in a LPS-induced lung inflammation model after intratracheal administration. The complex of Man-cationic liposome/NFκB decoy was physically stable during spraying. Man-cationic liposome/NFκB decoy complex was selectively delivered to alveolar macrophages for subsequent localization of NFκB decoy in the cytoplasm and to a lesser extent in the nucleus. In the LPS-induced lung inflammation model, pre-treatment with Man-cationic liposome/50μg NFκB decoy complex significantly inhibited the release of TNF-α, IL-1β and CINC-1, neutrophil infiltration and NFκB activation compared with naked NFκB decoy, cationic liposome/NFκB decoy complex and Man-cationic liposome/scrambled decoy complex treatments. This study demonstrates the sufficient targeting of NFκB decoy using Man-cationic liposomes in a novel effective anti-inflammatory therapy for lung inflammation. [ABSTRACT FROM AUTHOR]

Abstract: The success of targeting systems to alveolar macrophages critically depends on internalization into these cells for pharmacological intervention. Direct respiratory delivery via inhalation of mannose modified liposomal carriers to alveolar macrophages is of great interest. To evaluate the targeting efficiency to alveolar macrophages by intratracheal administration of mannosylated liposomes (Man-liposomes), Man-liposomes with various ratio of mannosylated cholesterol derivatives, cholesten-5-yloxy-N-(4-((1-imino-2-d-thiomannosylethyl)amino)alkyl)formamide (Man-C4-Chol) as mannose receptor ligand were investigated with regard to their in vitro uptake in primary cultured alveolar macrophages and in vivo intratracheal administration in rats. The in vitro uptake of Man-liposomes took place in a concentration-dependent manner. The internalization of Man-liposomes with 7.5% (Man-7.5-liposomes) and 5.0% (Man-5.0-liposomes) Man-C4-Chol was considerably higher than that of Man-liposomes with 2.5% of Man-C4-Chol (Man-2.5-liposomes) and Bare-liposomes and significantly inhibited by an excess of mannan, suggesting mannose receptor-mediated endocytosis. After intratracheal administration of Man-7.5 and Man-5.0-liposomes in rats, a significantly high internalization and selective targeting to alveolar macrophages was observed. The enhanced cellular uptake in alveolar macrophages related to the mannose density of Man-liposomes was also confirmed both in vitro and in vivo confocal microscopy studies. These results demonstrate the efficient targeting to alveolar macrophages by the intratracheally administered Man-liposomes via mannose receptor-mediated endocytosis. [Copyright &y& Elsevier]

Abstract: We have previously shown that the peptide, KRTGQYKLC (bFGF), is recognized by fibroblast growth factor (FGF) receptor (FGFR) via binding to basic FGF (bFGF), and is capable of being used for drug delivery to tumors highly expressing FGFR and bFGF. However, although the binding and uptake of the liposomes (bFGFp-liposomes) modified by the peptide increased in the presence of bFGF, the modification induced non-specific uptake. To overcome this problem, here, we prepared bFGFp-liposomes including mPEG-DSPE. The 5 and 10% mPEG5000/ and 10% mPEG3000/bFGFp-liposomes reduced most of the interaction with erythrocytes and the uptake by macrophages, suggesting the sustained blood circulation of bFGFp grafted PEGylated liposomes. Furthermore, 10% mPEG3000/bFGFp-liposomes produced a significant increase in uptake in NIH3T3, A549, and B16BL6 cells with the expression of FGFR following pre-incubation with bFGF, but no increase in CHO-K1 cells lacking FGFR expression. Taken together, these results lead us to believe that bFGFp grafted PEGylated liposomes possess the functions of both PEGylated stealth liposomes and the tumor-targeting liposomes. This strategy could be applied to the development of novel tumor-selective drug delivery systems. [Copyright &y& Elsevier]

Abstract: The purpose of this study was to investigate whether all-trans retinoic acid (ATRA), an active metabolite of retinal, incorporated in cationic liposomes composed of 1,2 dioleoyl-3-trimethylammonium propane (DOTAP)/cholesterol could inhibit established metastatic lung tumors by delivery to the pulmonary tumor site after intravenous injection. After intravenous injection in mice, the highest lung accumulation of [3H]ATRA was observed by the DOTAP/cholesterol liposomes formulation, while other formulations including [3H]ATRA dissolved in serum or [3H]ATRA incorporated in distearoyl-l-phosphatidylcholine (DSPC)/cholesterol liposomes produced little accumulation in the lung. In mice used as a model of lung cancer metastasis, ATRA incorporated in DOTAP/cholesterol liposomes, injected intravenously, reduced the number of tumor nodules compared with free ATRA or ATRA incorporated in DSPC/cholesterol liposomes. These results suggest that ATRA incorporated in cationic liposomes would be an effective strategy for differentiation therapy of lung cancer metastasis. [Copyright &y& Elsevier]

Abstract: In order to obtain an HCC-selective drug delivery system, a novel functional lipid, which is cleaved by the protease activity of matrix metalloproteinase-2 (MMP-2), was developed. The amino group of dioleoylphosphatidylethanolamine (DOPE) was conjugated with PEGylated MMP-2 substrate peptide (Gly–Pro–Leu–Gly–Ile–Ala–Gly–Gln), and MMP-2-cleavable PEG-Peptide-DOPE (PEG-PD) was synthesized. When PEG-PD was incorporated in galactosylated liposomes (Gal-PEG-PD-liposomes), we expected that Gal-PEG-PD-liposomes would not be taken up by normal hepatocytes due to the steric hindrance effect, but would be activated around HCC cells by secreted MMPs. In the pretreatment by hMMP2 (1, 5, and 10μg/ml), an hMMP2 concentration-dependent higher uptake of Gal-PEG-PD-liposomes was observed in HepG2 cells, suggesting PEG-PD cleavage. In the presence of an excess of galactose, the uptake of Gal-PEG-PD-liposomes with hMMP2 was significantly inhibited, suggesting asialoglycoprotein receptor-mediated uptake of Gal-PEG-PD-liposomes following the PEG-PD cleavage. Pretreatment of Gal-PEG-PD-liposomes with the conditioned medium of B16BL6, which contained secreted MMPs, enhanced the binding to HepG2 cells, as in the case of hMMP-2 treatment. Moreover, the cytotoxicity of N 4-octadecyl-1-β-d-arabinofuranosylcytosine (NOAC) incorporated Gal-PEG-PD-liposomes was enhanced by hMMPs (5μg/ml) and its cytotoxicity was significantly reduced by the presence of an excess of galactose in HepG2 cells. In conclusion, Gal-PEG-PD-liposomes were successfully developed for novel HCC-selective targeting. [Copyright &y& Elsevier]

In this study, we demonstrated that the presence of an essential amount of sodium chloride (NaCl) during the formation of cationic liposome/plasmid DNA complexes (lipoplexes) stabilizes the lipoplexes according to the surface charge regulation (SCR) theory. Fluorescence resonance energy transfer analysis revealed that cationic liposomes in an SCR lipoplex (5 and 10 mM NaCl solution in lipoplex) increased fusion. Also, aggregation of SCR lipoplexes was significantly delayed after exposure to saline (150 mM NaCl) as a model of physiological conditions. After intraportal administration, the hepatic transfection activity of galactosylated SCR lipoplexes (5 and 10 mM NaCl solution in lipoplex) was approximately 10- to 20-fold higher than that of galactosylated conventional lipoplexes in mice. The transfection activity in hepatocytes of galactosylated SCR lipoplexes was significantly higher than that of conventional lipoplexes, and preexposure to competitive asialoglycoprotein-receptor blocker significantly reduced the hepatic gene expression, suggesting that hepatocytes are responsible for high hepatic transgene expression of the galactosylated SCR lipoplexes. Pharmacokinetic studies both in situ and in vivo demonstrated a higher tissue binding affinity and a greater expanse of intrahepatic distribution by galactosylated SCR lipoplexes. Moreover, enhanced transfection activity of galactosylated SCR lipoplexes was observed in HepG2 cells, and investigation of confocal microscopic images showed that the release of plasmid DNA in the cell was markedly accelerated. These characteristics partly explain the mechanism of enhanced in vivo transfection efficacy by galactosylated SCR lipoplexes. Hence, information in this study will be valuable for the future use, design, and development of ligand-modified lipoplexes for in vivo applications. [Copyright &y& Elsevier]

The present study investigated the potency of the mannosylated cationic liposomes (Man liposomes) that we have developed in novel DNA vaccine carrier. Ovalbumin (OVA) was selected as a model antigen for vaccination; accordingly, OVA-encoding pDNA (pCMV-OVA) was constructed to evaluate DNA vaccination. The potency of the Man liposome/pCMV-OVA complex was compared with naked pCMV-OVA and that complexed with DC-Chol liposomes. In cultured mouse peritoneal macrophages, MHC class I-restricted antigen presentation of the Man liposome/pCMV-OVA complex was significantly higher than that of naked pCMV-OVA and that complexed with DC-Chol liposomes. After intravenous administration, OVA mRNA expression and MHC class I-restricted antigen presentation on CD11c+ cells and inflammatory cytokines, such as TNF-α, IL-12, and IFN-γ, that can enhance the Th1 response of the Man liposome/pCMV-OVA complex were higher than that of naked pCMV-OVA and that complexed with DC-Chol liposomes. Also, the spleen cells from mice immunized by intravenous administration of the Man liposome/pCMV-OVA complex showed the highest proliferation response and IFN-γ secretion. These findings suggest that the targeted delivery of DNA vaccine by Man liposomes is a potent vaccination method for DNA vaccine therapy. [Copyright &y& Elsevier]

To achieve a sustained and targeted delivery of liposomes to liver parenchymal cells (PC), we modified distearoyl-l-phosphatidylcholine (DSPC)/cholesterol (Chol) (60:40) (DSPC/Chol) liposomes with a galactosylated cholesterol derivative (Gal-C4-Chol), and polysorbate (Tween) 20 or 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-polyethylene glycol (PEGx-DSPE). After intravenous injection, DSPC/Chol/Gal-C4-Chol (60:35:5) (Gal) liposomes were rapidly eliminated from the blood circulation and mostly recovered in the liver. The blood elimination of DSPC/Chol/Gal-C4-Chol/Tween 20 (55:35:5:5) (Tween 20-Gal) liposomes was slightly reduced as compared to Gal-liposomes. In contrast, a significant reduction in the blood elimination was observed with DSPC/Chol/Gal-C4-Chol/PEG2000-DSPE (59:35:5:1) (PEG2000-Gal) liposomes. Hepatic uptake of DSPC/Chol/Gal-C4-Chol/PEG350-DSPE (59:35:5:1) (PEG350-Gal) liposomes was intermediate between PEG2000-Gal-liposomes and Tween 20-Gal-liposomes. The uptake of PEG350-Gal-liposomes by liver PC was 7.7-fold higher than that by non-parenchymal cells (NPC). These results suggest that PEG350-DSPE can control the delivery rate of Gal-liposomes to liver PC without losing its targeting capability. [Copyright &y& Elsevier]