经完整圆窗膜途径EGFP基因在大鼠耳蜗中的表达

目的 研究经完整圆窗膜途径进行耳蜗基因转导的可行性及安全性，为内耳基因治疗提供实验基础和理论依据。方法 24只SD大鼠术前及术后分别行听性脑干反应(ABR)检查。实验组(18只)用阳离子脂质体携带的增强型绿色荧光蛋白(enhanced green fluoresent protein，EGFP)基因，对照组(6只)用生理盐水，注入置于圆窗龛处的明胶海绵内。分别于术后3、7、14天取双侧耳蜗标本做基底膜铺片观察。结果 于圆窗龛处放置明胶海绵的转导方法对听力无明显影响。转染耳蜗呈明显的绿色荧光。3天组表达产物最高，7天组逐渐降低，14天组更弱。对侧及对照组耳蜗均未见荧光表达。结论 于圆窗龛处放置明胶海绵进行基因转导的方法对听力没有影响，且能够成功转染耳蜗组织，是一种行之有效的方法。     

Investigation of the potential therapeutic effect of cationic lipoplex mediated fibroblast growth factor-2 encoding plasmid DNA delivery on wound healing

BackgroundDeveloping an alternative and efficient therapy for wound healing has been an important research topic for pharmaceutical sciences. A straightforward but effective system for delivering fibroblast growth factor-2 (FGF-2) encoding plasmid DNA (pFGF-2) for wound healing therapy was aimed to develop in this study.MethodsIn order to provide the delivery of pFGF-2, a delivery vector, namely, cationic lipid nanoparticle (cLN) was developed by the melt-emulsification process, complexed with pFGF-2 to form a lipoplex system and further characterized. The pFGF-2 binding and protecting ability of lipoplexes were evaluated. The cytotoxicity and transfection efficiency of the lipoplexes, FGF-2 expression levels, and in vitro wound healing ability have been investigated on the L929 fibroblast cell line.ResultsThe obtained lipoplex system has a particle size of 88.53 nm with a low PDI (0.185), and zeta potential values of 27.8 mV with a spherical shape. The ability of cLNs to bind pFGF-2 and protect against nucleases was demonstrated by gel retardation assay. Furthermore, the developed FGF-2 carrying lipoplexes system showed significant transfection and FGF-2 expression ability comparing naked plasmid. Finally, scratch assay revealed that the developed system is able to promote in vitro cell proliferation/migration in 48 h.ConclusionPromising results have been achieved with the use of lipoplexes carrying pFGF-2, and this approach could be considered as a potentially applicable concept for the future gene-based wound healing therapies.Graphical abstract      

脊神经节微血管内皮细胞阴离子微区的分布特点、生物学特性及损伤的影响

目的探讨脊神经节（ＤＲＧ）血－神经屏障微血管内皮细胞阴离子微区（ＡＭＤ）的分布特点、生物学特性以及与损伤后血管通透性增加的关系。方法健康家兔４２只，分为手术对照组、机械性压迫组、炎性损伤组。采用阳离子胶体金（ＣＣＧ）探针和系列酶消化包埋后标记法观测。结果（１）ＤＲＧ血管内皮细胞上存在着阴离子分布的极化区；（２）涎酸葡萄糖轭合物为ＤＲＧ血管内皮细胞阴离子微区分子的主要成分。结论ＤＲＧ血管内皮细胞对血浆中蛋白仍具有阴离子通透性屏障作用，ＤＲＧ微血管内皮细胞阴离子屏障的损伤将导致微血管通透性的显著增加     

Histone deacetylase inhibitor prodrugs in nanoparticle vector enhanced gene expression in human cancer cells

We developed histone deacetylase inhibitor (HDACI) prodrugs to enhance the expression of the external genes transfected into human cells with cationic nanoparticles (NPs). We synthesized five kinds of lipid-linked HDACI prodrugs in which n-dodecanoic acid or cholesterol is linked with a potent HDACI, K-182, by an ester bond or a disulfide carbonate linker. The prodrugs were able to admix as a component of NPs, although the intact K-182 was not incorporated into NPs. Namely, NPs composed of cholesteryl-3β-carboxyamidoethylene-N-hydroxyethylamine and Tween 80 with the 10 mol% K-182 prodrug were prepared as a DNA vector to transfect plasmid DNAs into human prostate cancer cells, PC-3, or human breast cancer cells, Sk-Br-3. The NPs containing K-182 prodrugs with n-dodecanoic acid exhibited two to four times higher the gene expression than the original NPs. The enhancement of the gene expression will be due to the hyperacetylation of core histones caused by intact K-182 degraded from the prodrug in the vector incorporated into the cells.     

阳离子脂质体介导反义寡核苷酸肿瘤治疗的初步探索

目的：探讨阳离子脂质体（CL）介导反义寡核苷酸（ASODN）肿瘤治疗的效果。方法：以CL／ASODN复合物处理7721肝癌细胞，观察肝癌细胞的生长增殖和凋亡情况以及在体荷瘤小鼠治疗情况的考察。结果：CL／ASODN对7721肝癌细胞的抑制作用具有剂量和时间依赖性；荷瘤小鼠的实体瘤体积明显减小。结论：阳离子脂质体（CL）有望成为肿瘤治疗的理想载体。     

Hepatocytes targeting of cationic liposomes modified with soybean sterylglucoside and polyethylene glycol

AIM: In this study, a hepatocyte-spedfic targeting technology was developed by modifying cationic liposomes with soybean sterylglucoside (SG) and polyethylene glycol (PEG) (C/SG/ PEG-liposomes). METHODS: The liposomal transfection efficiencies in HepG2 2.2.15 cells were estimated with the use of fluorescein sodium (FS) as a model drug, by flow cytometry. The antisense activity of C/SG/PEG-liposomes entrapped antisense oligonucleotides (ODN) was determined as HBsAg and HBeAg in HepG2 2.2.15 cells by ELISA. The liposome uptake by liver and liver cells in mice was carried out after intravenous injection of 3H-labeled liposomes. RESULTS: C/SG-liposomes entrapped FS were effectively transfected into HepG22.2.15 cells In vitro. C/SG/PEG-liposomes entrapped ODN, reduced the secretion of both HBsAg and HBeAg in HepG2 2.2.15 cells when compared to free ODN. After in vivo injection of 3H-labeled C/SG/PEG-liposomes, higher radiation accumulation was observed in the hepatocytes than non-parenchymal cells of the liver. CONCLUSION: C/SG/PEG-liposomes mediated gene transfer to the liver is an effective gene-delivery method for hepatocytes-specific targeting, which appears to have a potential for gene therapy of HBV infections.     

Determinant for the inhibition of ecotropic murine leukemia virus infection by N-linked glycosylation of the rat receptor

Ecotropic murine leukemia viruses (MLVs) recognize the third extracellular loop of the receptor, cationic amino acid transporter type 1 (CAT1). The CAT1 protein contains two conserved N-linked glycosylation sites in the third extracellular loops of the mouse, rat, and hamster receptors (mCAT1, rCAT1, and hCAT1, respectively). Glycosylation of the rCAT1 and hCAT1 receptors inhibits ecotropic MLV infection of CAT1-expressing cells, but that of the mCAT1 does not afford the cells this protection. As compared to the mCAT1 protein, the rCAT1 and hCAT1 proteins possess three and six amino acid insertions, respectively, in the third extracellular loop. To determine whether these inserted amino acids are associated with ecotropic MLV infection inhibition by glycosylation, several mutants of mCAT1 and rCAT1 receptors were constructed. Of all the mutants generated in the present study, only rCAT1 mutant 1 exhibited detectable protein expression levels. The rCAT1 mutant 1-expressing human NP2 cells were more susceptible to transduction by ecotropic MLV vectors than the wild-type rCAT1-expressing cells. Tunicamycin, an N-glycosylation inhibitor, increased transduction titer in the wild-type rCAT1-expressing cells, but did not do so in the cells expressing either the mCAT1 or rCAT1 mutation 1. An amino acid substitution in the glycosylation site of the wild-type rCAT1 conferred higher infection susceptibility, but that of the rCAT1 mutant 1 did not. As with the wild-type mCAT1 and rCAT1 proteins, the rCAT1 mutants were detected on the cell surface by immunofluorescence microscopy. Tunicamycin treatment did not affect cellular distribution of the rCAT1 mutant 1, wild-type mCAT1 or rCAT1 proteins. These results indicate that the extra amino acids in the rCAT1 (as compared to the mCAT1) are associated with inhibition of ecotropic MLV infection by the rCAT1 glycosylation.     

Interactions of Surface-active Alkyltrimethylammonium Salts with the Plasma Membrane of Acanthamoeba castellanii

Abstract The interactions of three surface-active alkyltrimethylammonium salts (C₁₂-C₁₆) with the plasma membrane of Acanthamoeba custellanii were studied. The surfactants caused a release of K⁺ from the cells at premicellar concentrations. The lytic effectiveness of the surfactants increased with an increase in the length of the alkyl chain with about an order of magnitude for every two carbon atoms added to the alkyl chain. Binding studies with the C₁₆ homologue revealed that at a concentration corresponding to 50% release of K⁺ there were about 1.9 × 10¹⁰ molecules bound per cell. At prelytic concentrations the surfactants stimulated phagocytosis and pinocytosis. The mode of action of the surfactants on the plasma membrane of Acanthamoeba castellanii is discussed and it is hypothesized that the stimulation of endocytosis is due to a “fluidizing” effect of the surfactants on the lipid bilayer of the plasma membrane.     

Efficient in vivo transfection and safety profile of a CpG-free and codon optimized luciferase plasmid using a cationic lipophosphoramidate in a multiple intravenous administration procedure

As any drug, the success of gene therapy is largely dependent on the vehicle that has to selectively and efficiently deliver therapeutic nucleic acids into targeted cells with minimal side-effects. In the case of chronic diseases that require a life-long treatment, non-viral gene delivery vehicles are less likely to induce an immune response, thereby allowing for repeated administration. Beyond the gene delivery efficiency of a given vector, the nature of nucleic acid constructs also has a central importance in gene therapy protocols.Herein, we investigated the impact of two firefly luciferase encoding plasmids on the transgene expression profile following systemic delivery of lipoplexes in mice, as well as their potential to be safely and efficiently readministered. Whereas pTG11033 plasmid is driven by a strong ubiquitous cytomegalovirus promoter, pGM144 plasmid, which has been designed to avoid inflammation and provide sustained transgene expression in lungs, is CpG-free and is under control of the human elongation factor-1 alpha promoter.Combined to the efficient cationic lipophosphoramidate BSV4, bioluminescence data showed that both plasmids were mostly expressed in the lungs of mice following a primary injection of lipoplexes. However, mice transfected with pGM144 exhibited a higher and more sustained transgene expression than those treated with pTG11033. Repeated administration studies revealed that several injections of lipoplexes could lead to similar transgene expression profiles if an interval of several weeks between subsequent injections was respected. A transient hepatotoxicity and a partial inflammatory response were caused by lipoplex injection, irrespective of the plasmid used.Altogether, these results indicate that repeated systemic administration of lipophosphoramidate-based lipoplexes in mice conducts to an effective lung transfection without serious side effects, and highlight the need to use long-lasting expressing and well tolerated plasmids in order to efficiently renew transgene expression by the successive doses.     

Mono-guanidine heterolipid based SMEDDS: A promising tool for cytosolic delivery of antineoplastics

In the present work, we designed and synthesized a novel mono-guanidine heterolipid (MGH) and confirmed its structure by NMR and ESI-MS. The MGH was used as cationic lipid in developing etoposide loaded cationic self-microemulsifying drug delivery system (ECS) intended to be delivered by intratumoral route. The ECS exhibited size <50 nm and zeta potential +32.6 mV on dilution with various isotonic vehicles with no phase separation or drug precipitation. The ECS could be easily sterilized by membrane filtration method and showed excellent stability for 6 months. The ECS demonstrated excellent in vitro antiproliferative activity against B16F10 cells which is attributed to its high transfection efficiency and capability to cause prolonged drug release in cytosolic space. In vivo antitumor activity of ECS was conducted in B16F10 induced melanoma tumor model. ECS at 12 mg/kg dose showed superior tumor suppression ability and exhibited 100% survival compared to other formulations. Mice treated with ECS by intratumoral route, showed neither systemic side effect nor any evidences of hepatotoxicity and nephrotoxicity. In contrast, etoposide administered by intravenous route showed remarkable systemic toxicity, hepatotoxicity and nephrotoxicity.