Robust In Vivo Transduction of Nervous System and Neural Stem Cells by Early Gestational Intra Amniotic Gene Transfer Using Lentiviral Vector

Presently, in vivo methods to efficiently and broadly transduce all major cell types throughout both the central (CNS) and peripheral adult nervous system (PNS) are lacking. In this study, we hypothesized that during early fetal development neural cell populations, including neural stem cells (NSCs), may be accessible for gene transfer via the open neural groove. To test this hypothesis, we injected lentiviral vectors encoding a green fluorescent protein (GFP) marker gene into the murine amniotic cavity at embryonic day 8. This method (i) efficiently and stably transduced the entire nervous system for at least 80% of the lifespan of the mice, (ii) transduced all major neural cell types, and (iii) transduced adult NSCs of the subventricular zone (SVZ) and subgranular zones (SGZs). This simple approach has broad applications for the study of gene function in nervous system development and adult NSCs and may have future clinical applications for treatment of genetic disorders of the nervous system.     

Site-specific Gene Insertion Mediated by a Cre-loxP-carrying Lentiviral Vector

Retroviral vectors have been used to treat patients with the X-linked severe combined immunodeficiency disease and chronic granulomatous disease. In both cases, success has been undermined by clonal expansion of transduced cells in some patients due to insertional mutagenesis induced by random vector integration. This outcome underscores the importance of designing vectors for site-specific gene insertion to avoid unanticipated gene disruption or gene activation. In the present study, we incorporated the sequence-specific Cre protein into lentiviral virions. We demonstrated that the virion-associated Cre protein remained enzymatically active and was capable of directing site-specific insertion of a gene in the vector into a defined loxP site in the host genome. As there are loxP-like sequences throughout human genome that can be recognized by either wild-type Cre or Cre variants, our study demonstrates a new strategy of designing lentiviral-based vector for gene targeting.     

Pir-b基因慢病毒载体的构建和表达

本研究构建pir—b基N慢病毒载体并检测其在293T细胞中的表达。从小鼠的mRNA中钓取pir—b基因的开放阅读框,与测序载体连接,经过测序鉴定以后,构建含有pir—b基N的慢病毒穿梭质粒,与包装质粒一起共转染293T细胞,收获上清病毒浓缩纯化后转染293T细胞,用Western blot检测PIR—B蛋白的表达。同时以含有egfp基因的慢病毒作为转染效率的对照,结果表明：含有pir—b开放阅读框的慢病毒穿梭质粒构建成功,序列测定的结果与预期完全一致,含有pir-b的慢病毒载体包装成功。Western blot的结果证实外源PIB—B蛋白在293T细胞中正常表达。结论：本研究成功构建了含有pir—b基因的慢病毒载体,转染293T细胞以后正常表达PIR—B蛋白,这为以后深入研究pir—b在免疫调节中的作用奠定了坚实的基础,     

A Peptide-based Vector for Efficient Gene Transfer In Vitro and In Vivo

Finding suitable nonviral delivery vehicles for nucleic acid–based therapeutics is a landmark goal in gene therapy. Cell-penetrating peptides (CPPs) are one class of delivery vectors that has been exploited for this purpose. However, since CPPs use endocytosis to enter cells, a large fraction of peptides remain trapped in endosomes. We have previously reported that stearylation of amphipathic CPPs, such as transportan 10 (TP10), dramatically increases transfection of oligonucleotides in vitro partially by promoting endosomal escape. Therefore, we aimed to evaluate whether stearyl-TP10 could be used for the delivery of plasmids as well. Our results demonstrate that stearyl-TP10 forms stable nanoparticles with plasmids that efficiently enter different cell-types in a ubiquitous manner, including primary cells, resulting in significantly higher gene expression levels than when using stearyl-Arg9 or unmodified CPPs. In fact, the transfection efficacy of stearyl-TP10 almost reached the levels of Lipofectamine 2000 (LF2000), however, without any of the observed lipofection-associated toxicities. Most importantly, stearyl-TP10/plasmid nanoparticles are nonimmunogenic, mediate efficient gene delivery in vivo, when administrated intramuscularly (i.m.) or intradermally (i.d.) without any associated toxicity in mice.     

重组狗凝血因子Ⅷ的慢病毒介导体外表达的研究

本研究的目的是制备携带狗凝血因子Ⅷ（cFⅧ）基因的慢病毒载体,探讨慢病毒载体能否介导cFⅧ在体外的有效表达。用构建携带cFⅧ基因的慢病毒载体pTK161（含PUB启动子）和pTK162（含2OH1启动子）,同时构建含绿色荧光蛋白（GFP）的慢病毒载体pTK161′（含PUB启动子）和pTK162′（含2OH1启动子）的方法,分别与包装质粒ΔNRF、包膜蛋白质粒VSV-G共转染293T包装细胞,将包装好的病毒颗粒再感染293T细胞,检测病毒滴度和培养细胞上清中cFⅧ活性。结果显示：经限制性酶切鉴定,成功构建了pTK161、pTK162、pTK161′和pTK162′正向连接载体;pTK161′和pTK162′的病毒滴度分别为1.54×10^6U/ml和2.83×106U/ml;pTK161、pTK162感染靶细胞后24小时细胞上清中即可检测到cFⅧ的表达,72小时表达量达高峰。pTK162载体cFⅧ表达活性接近正常狗血浆FⅧ活性,而且明显高于pTK161（p〈0.05）,6周后cFⅧ表达活性仍达最高值的1/4。结论：构建的自身失活慢病毒载体可携带较大片段的cFⅧ基因,并在体外可获得有效表达;本研究为慢病毒载体介导的血友病A的基因治疗研究提供实验依据。     

B区缺失的人凝血因子Ⅷ基因在293T细胞表达

本研究目的是构建含有人凝血因子Ⅷ(FⅧ)基因的慢病毒载体,观察其在293T细胞中的表达情况。用限制性内切酶法获得B区缺失的人凝血因子Ⅷ基因(BDDhFⅧcDNA)片段,将其克隆至慢病毒载体pXZ208,构建了慢病毒表达载体pXZ208-BDDhFⅧ;用限制性内切酶法鉴定载体的连接方向,用磷酸钙共沉淀法将重组质粒pXZ208-BDDhFⅧ分别与包装质粒ΔNRF、包膜蛋白质粒VSV-G共转染293T包装细胞,包装后感染293T细胞,并以pXZ171作为对照。在感染后用逆转录-聚合酶链反应(RT-PCR)检测BDDhFⅧ基因的转录,一期法检测细胞培养上清FⅧ的活性,流式细胞仪(FCM)检测载体的感染效率,PCR检测BDDhFⅧ基因的整合。结果表明:成功构建了慢病毒表达载体pXZ208-BDDhFⅧ,其基因转导染效率达到了59.57%。RT-PCR法能够检测到BDDhFⅧ转录的mRNA。感染后24、48、72小时检测到细胞上清中FⅧ活性(FⅧ∶C)分别为12%、43%、87%。PCR法扩增出了534bp的特异性片段。结论:成功构建的慢病毒表达载体pXZ208-BDDhFⅧ,在体外可以有效感染293T细胞并表达有活性的FⅧ,提示基因治疗可应用于血友病A。     

大鼠Ngb基因慢病毒表达载体构建及鉴定

目的:克隆大鼠脑红蛋白(Ngb)基因,构建其慢病毒表达载体Lentivirus-Ngb,并转染原代培养的大鼠骨髓间充质干细胞(BMSCs)。方法:人工合成大鼠Ngb cDNA,连接至pLenti6.3-IRES-EGFP慢病毒载体,选择阳性克隆进行酶切鉴定和测序,并将其包装至慢病毒,共转染293T细胞,收获病毒颗粒,检测病毒滴度,PCR检测Ngb的表达。用包装成功的病毒液感染BMSCs,显微镜下观察BMSCs细胞,Western-blot检测Ngb蛋白在BMSCs中的表达。结果:PCR产物双酶切和基因测序确定Ngb连接正确;感染72 h后,荧光显微镜下可以看到GFP阳性的BMSCs细胞,Westen-blot检测表明Ngb在感染慢病毒的BMSCs中表达。结论:成功构建大鼠Ngb基因慢病毒表达载体pLen-ti-Ngb-IRES-EGFP,并成功转染BMSCs。     

重组Mash1慢病毒表达载体的构建

目的:克隆小鼠Mash1基因的全长cDNA,构建其慢病毒表达载体Lentivirus-Mash1,为进一步研究Mash1在神经发育及干细胞神经分化中的作用奠定基础。方法:应用RT-PCR从小鼠13d胚胎中扩增出Mash1cDNA片段,经回收纯化与pGEM-T载体连接并转化感受态细菌J M109,通过蓝白筛选、PCR扩增和双酶切鉴定出阳性菌落,并对其进行基因测序。BamHⅠ和XholⅠ双酶切pGEM-T-Mash1和Lentivirus获得的目的基因双粘片段与Lentivirus双粘线性质粒相连接,转化J M109,酶切方法鉴定重组阳性菌落。结果:PCR扩增、酶切分析及序列测定证实成功获取Mash1cDNA克隆;酶切鉴定证实Lentivirus-Mash1含有大小正确的正向Mash1cDNA片段。结论:成功建立了小鼠Mash1cDNA克隆并构建了慢病毒表达载体Lentivirus-Mash1。     

慢病毒载体介导绿色荧光蛋白基因在小鼠T淋巴细胞中的表达

本研究构建含绿色荧光蛋白基因的慢病毒载体三质粒系统,并观察其在小鼠T淋巴细胞中的表达情况。应用亚克隆技术将多聚嘌呤通道(PPT)元件、泛醌启动子(PUB)和绿色荧光蛋白基因(GFP)连接至pLO134载体,构建成pTK153载体。之后应用磷酸钙沉淀法将慢病毒载体三质粒系统(包括包装质粒△NRF、转移质粒pTK153和包膜蛋白质粒VSV-G)共转染293T细胞,12小时后在荧光显微镜下观察绿色荧光蛋白表达情况,72小时收集病毒上清并感染小鼠T淋巴细胞,在荧光显微镜下和应用流式细胞仪(FACS)观察感染情况。结果表明:慢病毒载体的三质粒系统转染293T细胞12小时后在荧光显微镜下观察到绿色荧光蛋白表达,FACS分析转染效率为(63.04±7.24)%,病毒滴度测定为(3.09±0.61)×106U/ml。感染小鼠T淋巴细胞后,荧光显微镜下观察到GFP的表达,FACS分析转导效率为(37.98±6.26)%。结论:成功构建了含绿色荧光蛋白基因的慢病毒载体,对小鼠T淋巴细胞有较高的感染效率。