Livin shRNA慢病毒载体的成功构建及鉴定

目的构建携带livin基因短片段发卡RNA（livin shRNA）的慢病毒载体。方法针对已经筛选确定的干扰人livin基因的有效靶序列,设计、合成靶序列的寡聚脱氧核苷酸DNA序列（OligoDNA）,退火形成双链DNA,与经HpaⅠ和XhoⅠ酶切后的携带U6启动子和绿色荧光蛋白的pGCL—GFP载体连接产生短片段发卡RNA慢病毒载体,PCR筛选阳性克隆,测序鉴定。结果PCR鉴定与DNA测序证实合成的含livin shRNA慢病毒载体寡核苷酸链插入正确。结论成功构建人livin shRNA慢病毒载体。     

RPS20RNA干扰慢病毒的构建及其对CT26细胞生长的影响

目的 研究脾虚证差异表达基因——核糖体蛋白S20 (RPS20)RNA干扰慢病毒转染对小鼠结肠癌细胞(CT26)细胞指数的影响,验证前期筛选的RNA干扰序列的有效性,为后续在小鼠体内以RNA干扰进行RPS20的功能鉴定提供参考.方法 根据前期筛选的RPS20 RNA干扰有效序列,进行质粒载体的重组,包装RPS20干扰慢病毒并转染CT26细胞,采用xCELLigence细胞动态分析仪实时监测转染后细胞的细胞指数以反映细胞的生长情况.结果 测序图谱和Blast比对结果表明重组慢病毒包装载体构建成功,慢病毒滴度为1.2×105 TU/mL,RNA干扰慢病毒转染后CT26细胞指数的增长受到明显抑制,转染后30 h细胞指数抑制率达到82.24％.结论 前期筛选的RPS20 RNA干扰序列可成功构建包装干扰慢病毒,转染后能有效抑制CT26细胞的生长,可为后续研究提供参考.     

人EGFL7基因短发夹结构RNA慢病毒载体的构建及鉴定

目的构建人类表皮生长因子域7（EGFL7）基因RNA干扰（RNAi）慢病毒载体。方法将靶向EGFL7基因的短发夹结构RNA（shRNA）表达序列连接到包含U6启动子及绿色荧光蛋白（GFP）报告基因的慢病毒载体pGCL-GFP中,获得重组质粒,命名为pGCL-GFP-vshEGFL7,经多聚酶链反应（PCR）和测序鉴定后,与慢病毒包装质粒pHelper 1.0及pHelper 2.0通过lipofectamine 2000共转染至包装细胞293T,包装产生病毒液,测定其滴度。结果PCR扩增和测序结果证实EGFL7shRNA核苷酸链序列插入正确,包装慢病毒产生病毒悬液的滴度为4.8×107TU/ml。结论成功构建人EGFL7基因shRNA慢病毒载体。     

A new surgical approach to improve gene transfer in liver using lentiviral vectors

Purpose

Metabolic inherited liver diseases are attractive targets for gene therapy. Recombinant lentiviruses are very powerful viral vectors able to infect nonmitotic cells. We wanted to develop a new surgical approach to improve gene transfer in adult liver using low viral doses.

Materials and methods

Adult rats were injected with 2.108 infectious particles of lentiviral vectors encoding the green fluorescent protein marker gene under control of a liver-specific promoter transthyretin. In the control group (n = 5), gene delivery was performed by inflow intraportal injection. In the surgical group (n = 5), liver was completely excluded from systemic circulation before viral injection in infrahepatic vena cava with high pressure.

Results

At day 9, transduction efficiency was 14.35% in the surgical group 3 and 0.39% in the control group (P = .016). At month 2, the number of transduced hepatocytes decreased in the most part of rats, except in half of rats in the surgical group. Antibodies against green fluorescent protein were detected in all rats at month 2, except one in the surgical group.

Conclusions

We developed a new surgical approach allowing an efficient transduction of hepatocytes in adult rats using lentivirus at low viral doses. We have now to control the immune response to permit long-term expression of transgene.     

Stable Expression of a Novel Fusion Peptide of Thioredoxin-1 and ABAD-Inhibiting Peptide Protects PC12 Cells from Intracellular Amyloid-Beta

Amyloid-β peptide-binding alcohol dehydrogenase (ABAD) inhibiting peptide, as a specific inhibitor between ABAD and amyloid-β (Aβ), has been demonstrated to effectively inhibit Aβ peptide cytotoxicity. However, a major drawback is its short half-life, which results in the need for multiple applications and high synthesis costs. To overcome this, we established a lentiviral expression system that allowed the stable expression of the small ABAD-inhibiting peptide by fusion with cytosolic thioredoxin-1 (TRX). The fusion peptide, TA aptamer, was observed within PC12 cytoplasm and maintained both Aβ-binding ability and antioxygenic property similar to TRX. Our data showed that overexpression of both TRX and TA aptamer could protect PC12 cells from intracellular Aβ cytotoxicity. The present study suggests that TRX, as a cytosolic protein and a fusion motif, could not only assist ABAD-inhibiting peptide expression, cytoplasmic localization, but rebalance the disturbed “redox equilibrium” caused by intracellular Aβ in PC12 cells.     

Stable EGFP gene expression in C6 glioma cell line after transduction with HIV-1-based lentiviral vector

Objective： To establish a stable C6/EGFP glioma cell transfected with the human immunodeficiency virus line for studies on glioma. Methods： The C6 glioma cell line was type I （HIV-1） based lentivirus vector containing two enhancer-promoters CMV and EF1α. Enhanced green fluorescent protein （EGFP）-positive C6 cells were sorted out by fluorescence-activated cell sort. Expression of EGFP was observed by fluorescent microscopy. EGFP gene in C6 genome was assessed by Polymerase chain reaction （PCR） and DNA sequencing. Original and transfected cells were compared biologically and cytomorphologically. Results： Lentivirus vector transfection produced up to 40% EGFP-positive cells. After fluorescence-activated cell sort selection, a pure cell line C6/EGFP was established. PCR and DNA sequencing revealed integration of EGFP gene in C6 cell genome. Analysis of cell characteristics revealed no difference between transfected and original cells. Conclusion： A C6/EGFP cell line expressing EGFP as a marker is established, in which the EGFP gene is integrated into the genome. This cell line can be served as a promising tool for further basic research and gene therapy studies.     

The potential of gene transfer into primary B-CLL cells using recombinant virus vectors

Despite recent advances, chronic lymphocytic leukemia (CLL) as the most common leukemia remains a largely incurable disease. Modern treatment options include novel drugs like purine analogues, monoclonal antibodies and transplantation strategies. Moreover, gene transfer of immunostimulatory molecules is another, but still experimental approach that can be used to potentiate immune responses against leukemic cells. CD40 ligand (CD40L) was shown to be a promising molecule for immunotherapy of B-CLL playing a critical role in immune activation. However, CLL B cells are resistant to transduction with most currently available vector systems. Improving the efficiency and specificity of gene vectors is critical for the success of gene therapy in this area. Using replication defective adenovirus encoding CD40L (Ad-CD40L), immunologic and clinical responses were seen in CLL patients after infusion of autologous Ad-CD40L-CLL cells in a recent phase I trial. Due to the immunogenic nature of adenovirus vectors, alternative vector systems are currently explored. Recombinant adeno-associated virus (rAAV) was shown to enable efficient transduction of primary B-CLL cells. By use of a library of AAV clones with randomly modified capsids, receptor-targeting mutants with a tropism for CLL cells can be selected. Furthermore, helper-virus free Epstein-Barr virus (EBV)-based gene transfer vectors hold promise for development of CLL-targeted vaccines after remaining safety issues will be resolved. Herpes simplex virus (HSV)-based vectors, especially HSV amplicons, have favorable features for B-CLL gene transfer including high transduction efficiency, ability to infect postmitotic cells and a large packaging capacity. The challenge for the future will be to transfer these alternative vector systems into clinic and allow the detection of a CLL-specific immune response by use of defined tumor antigens. This will make it possible to establish the potential clinical role of gene therapy for CLL patients.     

慢病毒携带的双自杀基因对淋巴瘤细胞杀伤作用的实验研究

背景与目的:慢病毒载体具有可感染非分裂细胞、目的基因整合至靶细胞基因组长期表达、免疫原性低等优点,适于体内基因治疗。本研究探讨慢病毒介导的双自杀基因对淋巴瘤细胞Raji的杀伤作用。方法:将表达慢病毒的3种质粒,即包装结构基因质粒pCMVΔ8.2、包膜基因质粒pCMV.VSVG、目的基因质粒pHR'CS.GFP或pHR'CS.CDglytk分两组(pHR'CS.Cdglytk为实验组、pHR'CS.GFP为对照组),经脂质体导入病毒包装细胞293T,包装成病毒后,收集病毒上清,浓缩后转染Raji细胞,用荧光显微镜及RT-PCR检测基因的表达。给予前体药物5-氟胞嘧啶(5-FC)和/或无环鸟苷(GCV),用MTT法测定Raji细胞的生长抑制率,检测CD和HSV-tk双自杀基因对Raji细胞的作用。结果:表达慢病毒的3种质粒可高效转染入293T细胞。荧光显微镜下观察可见大量的绿色荧光,透射电镜下观察可见富集的病毒颗粒。慢病毒介导的双自杀基因在Raji细胞中高效、稳定表达。单独使用GCV或5-FC对细胞的生长抑制率分别为51%、50%,与未转染组Raji细胞比较,差异有显著性(P<0.01);联合使用5-FC和GCV对细胞的生长抑制率为73%,明显高于单独使用5-FC或GCV(P<0.01)。结论:慢病毒介导的双自杀基因可高效稳定转染淋巴瘤细胞;双自杀基因系统较单一自杀基因系统(CD/5-FC或HSVtk/GCV)对淋巴瘤细     

线粒体细胞色素C氧化酶RNAi慢病毒载体的构建

目的：通过构建携带细胞色素C氧化酶基因的RNAi慢病毒载体，获得可供转染的滴度，为下一步研究该基因缺陷在真核细胞中的影响提供物质基础。 方法： 根据线粒体细胞色素C氧化酶设计的两条互补的单链寡核苷酸退火后形成双链，插入到pENTR/U6质粒缺口末端，连接在质粒上生成含RNAi盒的pENTR/U6载体；通过重组作用将pENTR/U6载体的RNAi盒重组到pLenti6/BLOCK-iT-Dest 载体上,构建含U6启动子、靶序列和Pol Ⅲ终止子表达框的MTCOX-I shRNA表达重组体；经脂质体导入293FT细胞，包装成慢病毒，收集病毒上清并检测其滴度。Western blotting检测干扰后细胞内线粒体细胞色素C氧化酶I亚基的表达。 结果： 将目的序列成功连接到载体上，并经测序分析证实载体构建成功；成功包装成高滴度的慢病毒。Western blotting检测结果证实构建的MTCOX-I shRNA表达重组体可显著抑制线粒体细胞色素C氧化酶I亚基的表达。 结论： 成功构建了携带细胞色素C氧化酶基因的RNAi慢病毒载体。