Synergistic effect of silencing the expression of tick protective antigens 4D8 and Rs86 in Rhipicephalus sanguineus by RNA interference

Tick proteins have been shown to be useful for the development of vaccines which reduce tick infestations. Potential tick protective antigens have been identified and characterized, in part, by use of RNA interference (RNAi). RNAi allows for analysis of gene function by characterizing the impact of loss of gene expression on tick physiology. Herein, we used RNAi in Rhipicephalus sanguineus to evaluate gene functions of two tick protective antigens, 4D8 and Rs86, the homologue of Bm86, on tick infestation, feeding and oviposition. Silencing of 4D8 alone resulted in decreased tick attachment, survival, feeding and oviposition. Although the effect of Rs86 RNAi was less pronounced, silencing of this gene also reduced tick weight and oviposition. Most notably, simultaneous silencing of 4D8 and Rs86 by RNAi resulted in a synergistic effect in which tick survival, attachment, feeding, weight and oviposition were profoundly reduced. Microscopic evaluation of tick tissues revealed that guts from dual injected ticks were distended with epithelial cells sparsely distributed along the basement membrane. These results demonstrated the synergistic effect of the silencing expression of two tick protective genes. Inclusion of multiple tick protective antigens may, therefore, enhance the efficacy of tick vaccines.     

Advances in the identification and characterization of protective antigens for recombinant vaccines against tick infestations

Ticks are economically important ectoparasites of domestic and wild animals and are considered to be second worldwide to mosquitoes as vectors of human pathogens. Current control methods for ticks, based primarily on the use of acaricides, have had limited efficacy in the reduction of tick infestations and the use of acaricides is often accompanied by serious drawbacks, including selection of acaricide-resistant ticks and environmental contamination. Development of improved vaccines against tick infestations offers a cost-effective and environmentally sound control method. Commercial vaccines currently marketed for control of cattle ticks have been effective in field studies when used in concert with integrated control strategies. However, new antigens are needed to increase the efficacy of tick vaccines. Although a limited number of protective antigens against tick infestations have been identified and characterized, discovery of new antigens remains the limiting step for improving the efficacy of tick vaccines. Recent technologies developed for gene discovery, including expression library immunization and evaluation of expressed sequence tags, show promise for rapid, systematic and global antigen screening and should provide a comprehensive approach to selection of candidate vaccine antigens. Design of future tick vaccines should target multiple tick species, as well as interfere with the transmission of pathogens.     

New classes of orthopoxvirus vaccine candidates by functionally screening a synthetic library for protective antigens

The licensed smallpox vaccine, comprised of infectious vaccinia, is no longer popular as it is associated with a variety of adverse events. Safer vaccines have been explored such as further attenuated viruses and component designs. However, these alternatives typically provide compromised breadth and strength of protection. We conducted a genome-level screening of cowpox, the ancestral poxvirus, in the broadly immune-presenting C57BL/6 mouse as an approach to discovering novel components with protective capacities. Cowpox coding sequences were synthetically built and directly assayed by genetic immunization for open-reading frames that protect against lethal pulmonary infection. Membrane and non-membrane antigens were identified that partially protect C57BL/6 mice against cowpox and vaccinia challenges without adjuvant or regimen optimization, whereas the 4-pox vaccine did not. New vaccines might be developed from productive combinations of these new and existing antigens to confer potent, broadly efficacious protection and be contraindicated for none.     

BACE1基因RNA干扰质粒的构建及干扰效果的鉴定

目的构建BACE1基因干扰质粒,并研究其在neuro．2a细胞中的表达,为以其为靶点的基因治疗提供稳定转染的质粒。方法选择人、小鼠和大鼠的BACE1基因共有序列为干扰靶点,设计3组连接有GFP的干扰质粒,将构建好的质粒转染nellro-2a细胞,通过RealtimeRT—PCR及Western—blotting的方法分别在RNA及蛋白质水平上检测BACE1的表达,以分析其干扰的效率。结果经酶切及测序证实,插入的DNA片段序列与设计序列完全一致。与空质粒对照组相比,3个干扰靶点对BACE1基因的表达均有不同程度的抑制作用。其中pYr-1．1-siBACE1在mRNA水平及蛋白质水平干扰效果均最好。结论成功构建了BACE1基因的干扰质粒pYr-1．1-siBACE1,并能有效抑制neuro．2a细胞内源性BACE1基因表达,为靶向BACE1基因的治疗提供了有力的工具。     

钙粘附蛋白N-cadherin基因RNAi质粒载体的构建与鉴定

目的:构建有效的小鼠神经型钙粘附蛋白(N-cadherin)基因RNA干扰质粒载体。方法:在小鼠基因库中选择3个靶序列并设计合成相应3对寡核苷酸序列,同时合成1对阴性对照寡核苷酸序列,然后将以上4对寡核苷酸序列退火后连入pSilencerTM 3.1-H1 hygro质粒并分别命名为pSicad1、pSicad2、pSicad3、pSi-control。酶切和测序鉴定后,将以上重组质粒转染MN9D细胞,用Western Blot和半定量RT-PCR方法检测N-cadherin基因mR-NA和蛋白的表达水平。结果:酶切和测序证实目的寡核苷酸片段已被准确克隆到pSilencerTM 3.1-H1 hygro质粒,与对照组相比,pSicad2和pSicad3转染MN9D细胞后,N-cadherin mRNA和蛋白水平的表达均受到明显抑制,其中N-cadherin蛋白水平在pSicad3组下降50%(P0.01)。结论:结果表明已成功构建了小鼠N-cadherin基因RNAi质粒载体,为N-cadherin功能研究奠定了基础。     

抑制骨髓基质干细胞雌激素受体β基因表达的有效序列

背景：雌激素受体β是否参与介导骨髓间充质干细胞的增殖与分化需进一步实验论证。 目的：以RNAi技术寻找和验证对大鼠骨髓基质干细胞雌激素受体β基因表达抑制的有效序列。 方法：根据GeneBank 数据库提供的SD大鼠雌激素受体β基因核苷酸序列,选择设计能转录小发卡结构RNA (Small hairpin RNAs,shRNA)的DNA 序列。再在两条互补碱基序列的5’端分别加上BamH Ⅰ(GATCC)和Hind Ⅲ (AGCTT)酶的酶切位点,最后形成两条互补的克隆入pSilencer 3.1-H1载体的发夹状siRNA模板序列,进行重组载体的碱基序列测定。 结果与结论：重组质粒碱基序列鉴定后,证实真核表达载构建正确。雌激素受体β特异性siRNA真核表达载体构建成功。     

人树突状细胞SOCS1基因RNA干扰慢病毒载体的构建及鉴定

目的构建人树突状细胞（hDCs）信号传导通路抑制因子1（SOCS1）基因RNA干扰（RNAi）慢病毒载体。方法根据人树突状细胞SOCS1基因（NM-0037）,筛选出一个靶序列,设计并合成包含正反义靶序列的互补单链寡核苷酸,与经BamH和Xho酶切后的慢病毒载体质粒pRNA-Lenti-增强型绿色荧光蛋白（EGFP）（含U6启动子和EGFP）连接产生pRNA-Lenti-SOCS1-EGFP慢病毒重组质粒,与慢病毒包装混合物共转染293T细胞,包装产生慢病毒,收集病毒上清,采取系列稀释法测定慢病毒滴度。然后转染hDCs,通过荧光显微镜观察细胞转染情况,利用荧光实时定量PCR和Westernblot检测干扰组、阴性对照组、空白对照组SOCS1的表达情况。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。荧光实时定量PCR及Westernblot检测显示慢病毒重组质粒感染hDCs后,与空白对照组及阴性对照组比较,siRNA组mRNA和SOCS1蛋白的表达量显著降低,差异均有统计学意义（P〈0.05）。结论构建的pRNA-Lenti-SOCS1-EGFP慢病毒载体可有效地抑制hDCs的SOCS1的表达,为进一步研究DCs增强抗肿瘤免疫应答效应奠定基础。     

细胞因子信号转导抑制因子1 RNA干扰慢病毒载体的构建与鉴定*☆

背景：以往关于细胞因子信号转导抑制因子1的研究多用脂质体或其他载体转染的技术,但存在效率低和安全性差等问题。 目的：构建细胞因子信号转导抑制因子1 RNA干扰慢病毒载体并进行鉴定。 方法：实验设计3组针对细胞因子信号转导抑制因子1的短发夹RNA序列,应用基因重组技术插入pPll3.7载体,测序正确的重组病毒质粒与包装质粒通过共转染293T细胞,培养48 h后,收集细胞培养上清液,感染A549细胞,western blot检测目的蛋白细胞因子信号转导抑制因子1在靶细胞中的表达。 结果与结论：实验通过对重组载体进行测序分析证实短发夹RNA插入慢病毒载体,慢病毒载体上清成功转染A549细胞后western blot检测结果显示该载体抑制了细胞因子信号转导抑制因子1蛋白在A549细胞有表达。说明实验成功构建了细胞因子信号转导抑制因子1 RNA干扰慢病毒载体。 关键词：细胞因子信号转导抑制因子1;慢病毒载体;RNA干扰;A549细胞;组织构建 doi:10.3969/j.issn.1673-8225.2012.07.030     

大鼠硫酸软骨素蛋白多糖基因shRNA慢病毒载体的构建及干扰效率鉴定

背景：最近研究发现硫酸软骨素蛋白多糖(NG2)在中枢神经系统中参与多种生理病理功能,慢病毒载体可感染分裂期细胞或非分裂期的细胞,并能在细胞内高效稳定的表达。 目的：构建大鼠源性NG2基因shRNA慢病毒载体并检测其干扰效率。 方法：选择大鼠NG2基因RNA干扰的靶序列,合成Oligo DNA,退火形成双链DNA,与Hpa Ⅰ和Xho Ⅰ双酶切后的pFU-GW-RNAi载体连接产生pLV-NG2-RNAi,PCR筛选阳性克隆,测序鉴定。将重组载体与pHelper 1.0载体、pHelper 2.0载体通过lipofectamineTM 2000共转染293T细胞包装产生慢病毒LV-NG2-RNAi,收集病毒上清并浓缩。采用孔稀释滴度测定法计算病毒滴度。将LV-NG2-RNAi慢病毒感染C6细胞,于感染后96 h提取细胞总蛋白,采用Western blot检测NG2的表达。 结果与结论：经PCR和测序证实构建片段大小及DNA序列与目的序列一致,实验成功构建大鼠NG2基因shRNA慢病毒载体LV-NG2-RNAi。包装浓缩慢病毒的滴度为8×1011 TU/L。Western blot检测显示在感染复数为50时,感染LV-NG2-RNAi慢病毒的C6细胞较感染对照慢病毒及未感染细胞NG2的表达明显降低,干扰效率可达100%(P < 0.05)。结果证实了实验成功构建大鼠NG2基因shRNA慢病毒载体,且该载体能够在细胞水平有效沉默靶基因。     

Slug基因RNAi慢病毒载体的构建与鉴定

目的构建Slug基因RNA干扰(RNA interference,RNAi)慢病毒表达载体。方法针对人Slug基因的序列,设计出RNA干扰的靶序列,合成靶序列Oligo DNA,退火形成双链DNA,通过Age I和EcoR I酶切后的pGCSIL-GFP载体连接产生shRNA慢病毒载体,质粒转化感受态细菌,筛选阳性克隆并用插入鉴定引物进行PCR鉴定阳性克隆并测序,同时应用Real-time PCR和Western blot方法检测HCT116结肠癌细胞中Slug基因mRNA和蛋白的表达情况。结果 PCR鉴定与DNA测序证实合成的含Slug shRNA慢病毒载体寡核苷酸链插入正确。Western blot证实Slug RNAi慢病毒载体能够抑制Slug的表达。结论成功构建Slug基因RNAi慢病毒表达载体,为后续感染结肠癌细胞,为探索在结直肠癌发生和发展中的作用奠定基础。     

针对HO-2基因的四种RNA干扰序列构建和效应观察

目的:构建和筛选出血红素氧合酶-2(HO-2)基因的RNA干扰载体,并观察其在小鼠脑血管内皮细胞中的表达情况。方法:根据小鼠HO-2基因的c DNA序列设计了4个HO-2基因干扰序列,克隆到干扰载体p GPU6-GFP-Neo上,利用电穿孔法将干扰载体对小鼠脑血管内皮细胞进行转染。Real-time PCR和Western Blot检测小鼠脑血管内皮细胞中HO-2的表达。结果:干扰载体显著抑制小鼠脑血管内皮细胞中HO-2的表达,其中干扰载体p GPU6-GFP-Neo-HO-2-mus-768对HO-2 mRNA的表达抑制达显著水平(P0.01),蛋白的表达抑制达显著水平(P0.05)。结论:成功构建并筛选了HO-2表达干扰载体,为下一步的HO-2基因的功能鉴定奠定了基础。     

EZH2基因RNAi慢病毒载体的包装及鉴定

目的 外周T细胞淋巴瘤（PTCL）源于成熟的胸腺后淋巴细胞,是一类少见的生物学行为及临床表现均高度异质性的疾病,且预后差.包装zeste基因增强子同源物2（EZH2）RNA干扰（RNAi）慢病毒载体,可为今后相关实验研究奠定基础.方法 靶向EZH2基因的短发夹RNA（EZH2-shRNA）质粒转化感受态细菌,筛选阳性克隆,经测序鉴定正确后通过脂质体将慢病毒三质粒系统共转染293T细胞,进行慢病毒包装.病毒载体感染Hut78细胞后,观察感染效率,并用反转录定量PCR（RT-qPCR）和Western Blot检测EZH2mRNA和蛋白表达水平.结果 成功包装了慢病毒表达载体,对Hut78细胞的感染效率在95％以上.RT-qPCR和Western Blot检测结果显示,EZH2基因在靶细胞中的表达水平降低.结论 成功包装并鉴定了EZH2基因RNAi慢病毒表达载体.     

兔膜联蛋白A1基因短发夹RNA慢病毒载体构建与RNA干扰效率的鉴定*

背景：膜联蛋白A1参与细胞凋亡的调控。 目的：针对兔膜联蛋白A1基因构建短发夹RNA慢病毒载体,并检测其对成骨细胞的沉默效率。 方法：针对兔膜联蛋白A1基因设计RNA干扰靶序列,合成Oligo DNA,退火形成双链DNA,与BamHI和EcoRI 双酶切后的pGLV/H1/GFP载体连接成pGLV-shANXA1,PCR筛选阳性克隆,测序鉴定。pGLV-shANXA1和pGLV/helper-1、pGLV/helper-2、pGLV/helper-3共转染293FT细胞包装产生慢病毒颗粒LV-shANXA1,并测定其滴度,随后将LV-shANXA1感染兔成骨细胞。 结果与结论：经PCR和测序证实构建片段大小及DNA序列与目标序列一致,shANXA1片段完全正确插入慢病毒载体pGLV/H1/GFP中。包装浓缩慢病毒颗粒LV-shANXA1的滴度为3.8×108 TU/L。经嘌呤霉素筛选后,感染复数为50时,LV-shANXA1对成骨细胞感染效率为80%;感染复数为100时,感染效率为95%。Real-time PCR 和Western blot检测显示,LV-shANXA1-901对膜联蛋白A1基因的沉默效率最高,在感染复数为50时,沉默效率可达71.2%。表明实验成功构建的兔膜联蛋白A1基因短发夹RNA慢病毒载体能够在细胞水平有效沉默靶基因。     

脯氨酰羟化酶RNA干扰慢病毒载体的构建与鉴定

背景：慢病毒载体可稳定介导基因沉默且具有较高的转染效率。 目的：构建并鉴定脯氨酰羟化酶 RNA干扰慢病毒载体。 方法：针对脯氨酰羟化酶2基因序列设计RNA干扰靶序列,合成靶序列的寡聚DNA,退火形成双链DNA,与经Age Ⅰ和EcoR Ⅰ酶切的pGCSIL-GFP连接、转化大肠杆菌感受态细胞,产生重组RNA干扰慢病毒表达载体,PCR筛选阳性克隆,测序鉴定。 结果与结论：PCR和DNA测序证实合成的含脯氨酰羟化酶短发卡RNA慢病毒载体寡核苷酸链正确插入pGCSIL-GFP载体。说明实验成功构建脯氨酰羟化酶基因RNA干扰慢病毒载体。     

RNA干扰技术新进展

20世纪90年代初,科学家在矮牵牛花中导入与花青素合成有关的查尔酮合成酶基因,原以为转基因的牵牛花会变得更鲜艳,结果却发现一些花反而变成白色,这种现象引起人们的高度关注,之后的研究将这种过度表达内源基因而引发的基因沉默称为共阻遏。     

Induction of RNA interference in dendritic cells

Dendritic cells (DC) reside at the center of the immunological universe, possessing the ability both to stimulate and inhibit various types of responses. Tolerogenic/regulatory DC with therapeutic properties can be generated through various means of manipulations in vitro and in vivo. Here we describe several attractive strategies for manipulation of DC using the novel technique of RNA interference (RNAi). Additionally, we overview some of our data regarding yet undescribed characteristics of RNAi in DC such as specific transfection strategies, persistence of gene silencing, and multi-gene silencing. The advantages of using RNAi for DC genetic manipulation gives rise to the promise of generating tailor-made DC that can be used effectively to treat a variety of immunologically mediated diseases.