大鼠CXCR4基因RNAi慢病毒载体的构建及其在骨髓间质干细胞中的表达

为深入研究CXCR4在骨髓间质干细胞(MSCs)体内迁移中的作用, 构建CXCR4基因RNA干扰(RNAi)慢病毒载体并实现其在大鼠MSCs (rMSCs)中表达。根据大鼠CXCR4 mRNA序列, 设计并合成包含各靶序列的互补DNA链,插入pSUPER载体的H1 RNA启动子后面, 产生pRiCXCR4, 将其中的CXCR4 shRNA表达结构酶切插入慢病毒载体质粒pNL-EGFP, 产生pNL-RiCXCR4-EGFP。在脂质体介导下与包装质粒pHELPER和包膜质粒pVSVG共转染293T细胞, 包装生产慢病毒,测定慢病毒功能滴度。慢病毒转导rMSCs后, 用Real-time RT-PCR、Western blotting和流式细胞术检测RNAi组(CXCR4a、CXCR4b和CXCR4c)、空载体组(Mock)和对照组(Control)中CXCR4表达情况。结果显示, 酶切和测序证实pRiCXCR4质粒构建正确, 产生能同时表达增强型绿色荧光蛋白(EGFP)和CXCR4 shRNA的慢病毒载体质粒pNL-RiCXCR4-EGFP, 未浓缩和浓缩慢病毒悬液的功能滴度分别为6.4×104TU/mL和6.9×106TU/mL。慢病毒转导rMSCs 48 h后, 与空载体组和空白组相比, 3个RNAi组均不同程度抑制CXCR4表达, CXCR4b-MSC组在mRNA水平抑制了95.6%, 抑制作用最明显。大鼠CXCR4基因RNAi慢病毒载体构建成功, 为深入研究CXCR4在rMSCs向损伤组织定向迁移的作用奠定了基础。     

AKT2 基因短发夹结构RNA 慢病毒载体的构建及鉴定

目的:构建丝/苏氨酸蛋白激酶2(AKT2)基因RNA干扰(RNAi)慢病毒载体。方法:利用公用网站按照RNAi序列设计原则,设计RNAi靶点序列并合成靶序列的Oligo DNA,退火形成双链DNA,与经MluI和ClaI进行酶切后的PLVTHM载体连接产生shRNA慢病毒载体。应用shRNA慢病毒载体转染293T细胞及U87细胞,测定病毒滴度,流式细胞仪测定U87细胞的转染效率,PCR及Western blot鉴定AKT2基因在U87细胞中的下调作用。结果:成功构建了shRNA-AKT2慢病毒载体,经测序与设计合成的靶向链完全一致。荧光显微镜下观察293T细胞感染效率大于90%,病毒滴度为3.59×107TU/ml;流式细胞仪测定对AKT2细胞的转染效率为86.93%。PCR测定shRNA载体感染U87细胞后AKT2的干扰效率为68%。Western Blot结果显示该慢病毒载体对AKT2的表达有较为显著的敲减作用。结论:成功构建了人胶质瘤细胞株AKT2基因RNAi慢病毒载体,为后续的体内外功能学试验创造了条件。     

AKT2基因短发夹结构RNA慢病毒载体的构建及鉴定

目的：构建丝/苏氨酸蛋白激酶2（AKT2）基因RNA干扰（RNAi）慢病毒载体。方法：利用公用网站按照RNAi序列设计原则,设计RNAi靶点序列并合成靶序列的Oligo DNA,退火形成双链DNA,与经MluI和ClaI进行酶切后的PLVTHM载体连接产生shRNA慢病毒载体。应用shRNA慢病毒载体转染293T细胞及U87细胞,测定病毒滴度,流式细胞仪测定U87细胞的转染效率,PCR及Western blot鉴定AKT2基因在U87细胞中的下调作用。结果：成功构建了shRNA-AKT2慢病毒载体,经测序与设计合成的靶向链完全一致。荧光显微镜下观察293T细胞感染效率大于90%,病毒滴度为3.59×107TU/ml;流式细胞仪测定对AKT2细胞的转染效率为86.93%。PCR测定shRNA载体感染U87细胞后AKT2的干扰效率为68%。Western Blot结果显示该慢病毒载体对AKT2的表达有较为显著的敲减作用。结论：成功构建了人胶质瘤细胞株AKT2基因RNAi慢病毒载体,为后续的体内外功能学试验创造了条件。     

小鼠XBP1基因RNA干扰慢病毒载体的构建及筛选

目的:构建小鼠XBP1基因RNA干扰(RNA interference,RNAi)慢病毒载体,筛选具有较好干扰效率的小鼠XBP1 siRNA靶序列.方法:针对小鼠XBP1基因特异性序列,设计4个RNAi靶序列及1个阴性对照序列,合成含有正义和反义Oligo DNA的互补DNA序列,退火形成双链DNA,并克隆到经Age Ⅰ和EcoR Ⅰ酶切后的pGCL-GFP载体连接产生短发卡RNA(shRNA)慢病毒载体,PCR筛选阳性克隆,DNA测序鉴定.由病毒包装系统进行包装,经滴度测定后感染NIH3T3细胞,应用Real-time PCR鉴定干扰效率.结果:PCR鉴定与DNA测序证实合成的寡核苷酸链插入正确,293T细胞测定病毒滴度为1×108TU/ml.Real-timePCR证实XBP1-siRNA-3靶点的干扰效率最高,其干扰效率达到95%以上.结论:成功构建并筛选了小鼠XBP1基因RNAi慢病毒载体,为研究XBP1在巨噬细胞免疫功能调控中的作用奠定了基础.     

EGFL7 基因RNAi慢病毒表达载体的构建及鉴定

目的：构建人类表皮生长因子域7（EGFL7）基因RNA干扰（RNAi）重组慢病毒表达载体。方法：参照小分子干扰RNA 的设 计原则,应用OligoDesigner 3.0 软件设计三条靶向人EGFL7 基因的RNA干扰序列（hEGFL7-RNAi）,并将其分别插入含有绿色 荧光蛋白（GFP）的慢病毒载体pLV3 中,获得重组质粒,与包装质粒pRsv-REV、pMDlg-pRRE 和pMD2G共同转染293T细胞,包 装产生重组慢病毒,培养72 h后,应用qRT-PCR 检测慢病毒感染人脐静脉内皮细胞（HUVEC）后靶基因mRNA 的水平,以评价 其基因沉默效果。结果：筛选出3 条人EGFL7 基因的RNAi 序列,分别包装出重组慢病毒,其滴度分别为1× 108、2× 108和5× 108TU/mL,将其转染入HUVEC 后,EGFL7mRNA表达均受到明显抑制(P<0.05)。结论：成功筛选出三条针对人EGFL7基因的 RNAi有效靶序列,并成功构建重组慢病毒表达载体,证明该序列可沉默HUVECs 中EGFL7 基因的表达。     

慢病毒介导的大鼠肝BRL-3A 细胞Tmub1 基因沉默及稳定感染细胞 系的建立

目的:构建Tmub1基因慢病毒干扰载体,建立稳定转染细胞系,检测大鼠肝BRL-3A细胞中Tmub1基因表达的干扰效果。方法:设计并构建4对针对大鼠Tmub1基因的特异性shRNA干扰质粒,酶切鉴定、DNA测序所得质粒。将由pRSV-Rev、pMDLg-pRRE、pMD2G和pll3.7干扰质粒组成的包装系统共转染293T细胞,产生慢病毒。所得慢病毒感染大鼠正常肝细胞BRL-3A,Western Blot检测不同靶点RNAi后Tmub1蛋白表达情况,确定有效靶点。针对有效靶点大量包装慢病毒。测定病毒滴度并以最适感染复数(multiplicity of infection,MOI)感染BRL-3A细胞后,G418抗生素筛选稳定感染细胞系BRL-3A/256。RT-PCR和Western Blot检测各组细胞Tmub1 mRNA和蛋白质的表达差异。结果:结果显示Tmub1 RNAi慢病毒载体构建成功,C0020Sh2-Hops-256干扰靶点RNAi效果最强。成功包装Tmub1基因RNAi慢病毒,测定病毒滴度为2.3×108TU/ml,对293T细胞的最适感染复数为60。成功建立Tmub1 RNAi慢病毒载体稳定感染细胞系BRL-3A/256,且在该细胞系中Tmub1 mRNA和蛋白质表达明显降低。结论:成功构建Tmub1 RNAi慢病毒载体,有效干扰BRL-3A细胞中Tmub1 mRNA和蛋白表达;成功筛选出Tmub1RNAi慢病毒稳定感染细胞系BRL-3A/256。     

利用慢病毒载体观察microRNA-194 对人骨肉瘤细胞系U2-OS 生物学特性的影响

目的：通过构建携带针对microRNA-194 的shRNA载体及过表达载体,包装慢病毒,感染人骨肉瘤细胞系U2-OS,改变细胞 内microRNA-194 基因的表达水平,研究microRNA-194 对细胞增殖、凋亡及细胞周期的影响,为探索microRNA-194作为骨肉瘤 生物治疗的新靶点提供理论和实验依据。方法：PCR扩增pri-miR-194 及miR-194-5 成熟体,克隆于慢病毒载体plent-i GFP 中,转 染大肠杆菌感受态细胞,收获并浓缩慢病毒颗粒,感染人骨肉瘤细胞系U2-OS。进行MTT,流式,平板克隆等试验。结果：1.重组慢 病毒表达质粒构建正确,过表达及抑制过表达重组慢病毒的滴度分别为1.5× 108 TU/ml及4× 108 TU/ml;2. microRNA-194过表 达的人骨肉瘤细胞系U2-OS 细胞增殖速度,凋亡率及细胞周期相较于其它实验组都有明显变化(P<0.01)。结论：成功构建了 microRNA-194 过表达及抑制过表达慢病毒表达载体;miR-194 的表达水平对U2-OS 细胞的增殖和凋亡造成显著影响。 microRNA-194 可能成为骨肉瘤治疗的潜在新靶点,但该基因对骨肉瘤发生发展的作用及其机制尚待进一步研究。     

靶向ADAM17基因RNA干扰慢病毒载体的构建及慢病毒包装

目的构建靶向ADAM17基因RNA干扰（RNAi）慢病毒载体及包装慢病毒。方法根据人ADAM17mRNA序列设计4个靶序列,合成4对寡核苷酸序列,同时合成1对阴性对照寡核苷酸序列;将以上5对寡核苷酸序列退火后连入pLVTHM质粒,经酶切和测序鉴定。将重组慢病毒质粒转染至A549细胞,以Real-time PCR检测A549细胞中ADAM17 mRNA表达。将干扰效果最佳的质粒载体和包装质粒共转染至293T细胞,包装产生病毒颗粒。以流式细胞术检测重组慢病毒的滴度。结果酶切和测序证实干扰靶序列已被准确克隆到pLVTHM质粒载体。pLVTHM-ADAM17-siRNA1-4均可显著抑制A549细胞ADAM17 mRNA的表达,其中pLVTHM-ADAM17-siRNA4的抑制效果最佳。LV-ADAM17-siRNA4重组慢病毒的滴度为2.16×108TU/ml。结论成功构建了靶向人ADAM17基因RNAi慢病毒载体及包装了重组慢病毒。     

SGK3基因RNAi慢病毒载体的构建及其对乳腺癌MB-474细胞增殖和凋亡的影响

旨在构建SGK3基因RNAi慢病毒表达载体,观察其对人乳腺癌细胞MB-474增殖和凋亡的影响。构建靶向SGK3的shRNA序列慢病毒载体,将其转染至人乳腺癌MB-474细胞以沉默SGK3基因,Real-time PCR、Western bloting方法检测MB-474细胞SGK3 mRNA及蛋白表达,MTT法和流式细胞术检测SGK3基因沉默对MB-474细胞增殖、细胞周期和凋亡的影响。测序结果显示,成功构建4组SGK3基因RNAi慢病毒表达载体,经293T细胞包装,病毒滴度为(3-8)×108 TU/m L;将慢病毒转染MB-474细胞后,Real-time PCR、Western bloting结果显示,干扰组SGK3的表达水平较对照组均降低,且PGC-LV3-SGK3-1序列对其干扰效果最佳,SGK3基因沉默可抑制MB-474细胞增殖、促进凋亡,但其对细胞周期进程无明显影响。成功构建靶向SGK3基因的RNAi慢病毒载体,SGK3基因沉默可影响乳腺癌细胞增殖和凋亡等生物学行为。     

靶向白介素-1α基因沉默的Hela229稳定细胞系的构建

目的：构建针对IL-1α基因的shRNA表达载体,筛选能够抑制Hela229细胞内源性IL-1α表达的shRNA,建立无内源性IL-1d表达的Hela229稳定细胞系.方法：根据shRNA的设计原则,以IL-1 αcDNA oligo为模板设计一段21 bp核苷酸目标序列,构建成siRNA的DNA模板并克隆到shRNA表达载体pRNAT-U6.1/Neo中,获得靶向抑制IL-1α基因的重组shRNA质粒,转染Hela229细胞,经G418筛选后获得单克隆稳定细胞株,用ELISA方法在蛋白水平上检测IL-1α基因的沉默效果.结果：经酶切鉴定和测序分析确定IL-1 α-shRNA重组质粒构建正确,ELISA筛选出能够显著抑制内源性IL-1α表达的shRNA,获得沉默内源性IL-1 α表达的单克隆稳定的Hela229细胞株.结论：靶向IL-1α基因的重组shRNA表达质粒可显著抑制Hela229细胞内源性IL-1α的表达,成功构建靶向IL-1α基因沉默的Hela229稳定细胞系.     

MISSION LentiPlex Pooled shRNA Library Screening in Mammalian Cells

RNA interference (RNAi) is an intrinsic cellular mechanism for the regulation of gene expression. Harnessing the innate power of this system enables us to knockdown gene expression levels in loss of gene function studies.There are two main methods for performing RNAi. The first is the use of small interfering RNAs (siRNAs) that are chemically synthesized, and the second utilizes short-hairpin RNAs (shRNAs) encoded within plasmids ¹. The latter can be transfected into cells directly or packaged into replication incompetent lentiviral particles. The main advantages of using lentiviral shRNAs is the ease of introduction into a wide variety of cell types, their ability to stably integrate into the genome for long term gene knockdown and selection, and their efficacy in conducting high-throughput loss of function screens. To facilitate this we have created the LentiPlex pooled shRNA library.The MISSION LentiPlex Human shRNA Pooled Library is a genome-wide lentiviral pool produced using a proprietary process. The library consists of over 75,000 shRNA constructs from the TRC collection targeting 15,000+ human genes ². Each library is tested for shRNA representation before product release to ensure robust library coverage. The library is provided in a ready-to-use lentiviral format at titers of at least 5 x 10⁸ TU/ml via p24 assay and is pre-divided into ten subpools of approximately 8,000 shRNA constructs each. Amplification and sequencing primers are also provided for downstream target identification.Previous studies established a synergistic antitumor activity of TRAIL when combined with Paclitaxel in A549 cells, a human lung carcinoma cell line ^{3, 4}. In this study we demonstrate the application of a pooled LentiPlex shRNA library to rapidly conduct a positive selection screen for genes involved in the cytotoxicity of A549 cells when exposed to TRAIL and Paclitaxel. One barrier often encountered with high-throughput screens is the cost and difficulty in deconvolution; we also detail a cost-effective polyclonal approach utilizing traditional sequencing.     

New technology for an old favorite: lentiviral transgenesis and RNAi in rats

The ability to produce targeted deletions in the mouse genome via homologous recombination has been a hallmark of mouse genetics, and has lead to the production of thousands of gene knockouts. New technologies are making it possible to disrupt gene function in many other species. This article reviews some of these methods, highlighting the powerful combination of lentiviral vectors with RNA interference (RNAi), which allows one to produce transgenic animals expressing short hairpin RNA (shRNA) to “knock down” specific gene expression. Lentiviral transduction of embryos has been shown to be a highly efficient means of transgenesis, and is particularly promising for animals that are considered difficult to genetically modify by DNA pronuclear injection. This technique has been popular for introducing transgenes for shRNA expression into rodents and its utility for creating new genetic models has already been demonstrated. One of the purported advantages of in vivo RNAi is that shRNA expressing transgenes would be expected to act in a dominant nature, resulting in a phenotype in founder animals. However, one possible concern with lentiviral-mediated transgenesis is the potential for mosaicism in founders, and the data for this phenomenon and the potential causes and solutions are discussed. Emphasis is placed on the application of in vivo RNAi, and other reverse genetic methods, for creating new genetic models in the rat.     

Lentiviral delivery of a shRNA sequence analogous to miR-4319/miR-125-5p induces apoptosis in NSCLC cells by arresting G2/M phase

In this study, we explored the therapeutic potential of microRNA (miR) analogs against non–small-cell lung cancer (NSCLC) using lentiviral delivery of short hairpin RNA (shRNA). By using A549 as a model cell line, we used analogs and mimics of miR-4319/miR-125-5p to target the tumorigenic RAF1 gene. Lentiviral vectors carrying shRNA of a highly efficient miRNA analog of miR-4319/miR-125-5p, Analog2, were constructed to infect A549 cells. Our results showed that, compared with the noncancerous bronchial epithelial cell line 16HBE, lentivirus delivering Analog2 shRNA induced significant G2/M arrest and subsequent apoptosis in A549 cells, but not in 16HBE cells. Western blot analysis revealed that key factors regulating cell cycle were downregulated following RAF1 inhibition. In vivo xenograft experiments showed that lentivirus carrying Analog2 shRNA markedly decreased tumor size. Therefore, lentiviral delivery of Analog2 shRNA is a valid RNA interference-based treatment against NSCLC with high potency and specificity.     

RNA干扰沉默缺氧诱导因子1α逆转肺癌细胞耐药性

目的：观察RNA干扰沉默缺氧诱导因子1α（HIF-1α）对肺癌细胞耐药性的影响。方法：构建靶向HIF-1α小干扰RNA基因,并转染到人肺腺癌耐顺铂细胞株A549／DDP细胞中。逆转录聚合酶链反应RT—PCR）检测细胞的HIF-1α、多药耐药基因-（MDR-1）以多药耐药相关蛋白基因（MRP）mRNA变化,免疫细胞化学法观察干扰后HIF-1α、P-糖蛋白以及MRP蛋白的变化。MTT法检测不同浓度的顺铂作用下细胞死亡率。结果：HIF-1αsiRNA组中H1F-1α、MDR—1、MRPmRNA水平显著降低（P〈0．05）。且蛋白水平也显著下降（P〈0．05）。HIF-1αsiRNA组细胞死亡率较未转染组均明显增高（P〈0．05）,转染siRNA阴性组不影响肿瘤细胞的耐药性。结论：HIF-1αsiRNA可显著降低A549／DDP细胞中H1F-1α、MDR-1、MRP表达,从而起到逆转肺腺癌A549／DDP细胞的耐药作用。     

Anti-HIF-1α-pEGFP重组质粒的构建及表达

目的构建EGFP-HIF-1α反义重组质粒,转染人宫颈癌Hela细胞,用以探讨HIF-1α蛋白在宫颈癌的生长、转移中的作用。方法应用基因重组技术构建EGFP-HIF-1α反义重组质粒,通过脂质体介导将其转染入Hela细胞,倒置荧光显微镜观察转染效果,Western blot检测HIF-1α蛋白的表达。结果酶切鉴定结果显示含EGFP-HIF-1α反义重组质粒构建成功,并能在Hela细胞中封闭HIF-1α蛋白的表达。结果 EGFP-HIF-1α反义重组质粒构建及转染成功,封闭Hela细胞中HIF-1α蛋白的表达,为进一步研究HIF-1α蛋白在宫颈癌的生长、转移中的作用提供试验基础。