针对HBV X基因的siRNA抑制HepG2细胞HBV的复制和表达

目的构建能转录产生针对乙型肝炎病毒（HBV）X基因转录体的小干扰RNA（siRNA）转录载体pSIH—BV／X,研究其在体外对HBV复制和抗原表达的抑制作用。方法将构建成功的pSIHBV／X与HBV1．3倍体真核表达质粒pHBV1．3共转染HepG2细胞，转染后24、48、72h检测上清液中HBsAg、HBeAg的变化，并检测72h时HBV DNA的变化。结果成功构建了针对HBVX基因转录体的siRNA表达载体pSIHBV／X，并发现它能抑制HBsAg、HBeAg的分泌，抑制高峰在72h．抑制率分别是64％和61％，而无关对照序列的siRNA无此作用。荧光定量PCR证实HBV DNA的复制亦受到抑制，抑制率31％。结论针对HBVX基因转录体的siRNA在体外具有抑制HBV复制和抗原表达的作用。     

靶向HBV C区RNAi对HBV复制和HBeAg表达的抑制作用

目的观察靶向HBVC基因区的RNA干扰（RNAi）对HBV复制的抑制作用。方法选择HBV基因组C区的Nt2021-2049作为靶序列,合成相应的正、反义寡核苷酸,退火后形成双链,克隆人shRNA表达质粒,将得到的质粒与HBV质粒共转染HepG2细胞,观察HepG2细胞中HBV的受抑情况。结果病毒复制及HBeAg的表达明显受到抑制。结论所选靶区通过RNAi可有效抑制HBV复制。     

聚合酶链反应扩增小分子干扰RNA表达框筛选抑制HBV DNA复制的小分子干扰RNA

一些短片段的双链RNA可以通过促使特定基因的mRNA降解来高效、特异地阻断体内特定基因表达，诱使细胞表现出特定基因缺失的表型，称为RNA干扰（RNAi）。小分子干扰RNA（siRNA）就是这种短片段双链RNA分子，能够以序列同源互补的mRNA为靶目标，降解特定的mRNA。本研究针对HBV DNA多聚酶区的siRNA，运用PCR扩增siRNA表达框的方法筛选出对HBV DNA抑制作用最强的siRNA，观察其对HBV DNA复制及HBsAg和HBeAg分泌的抑制作用。     

针对HBV—P基因的RNA干扰抑制乙型肝炎病毒的研究

目的构建针对乙型肝炎病毒P基因编码区、能在体内转录产生发夹状小干扰RNA（siRNA）的表达载体psiHBV／p,观察RNA干扰对HBsAg、HBeAg及乙型肝炎病毒DNA复制的抑制作用。方法针对HBV—P基因区特异序列,构建siRNA的表达载体psiHBV／p。采用脂质体介导方法将其与1．3倍HBV真核表达质粒pHBV1．3共转染HepG2细胞。分别于转染后24小时、48小时、72小时用ELISA法对HepG2细胞培养上清液进行HBsAg、HBeAg的检测;于转染后72小时通过FQ-PCR法分析RNA干扰作用对HBVDNA的抑制效果。结果成功构建了针对HBV—P基因区的siRNA的真核表达重组体psiHBV／p,并发现它能明显抑制HBsAg及HBeAg的分泌,转染后第二天抑制率达高峰,分别为84％、65％。FQ—PCR结果也证实了转染72小时后,随psiHBV／p比例的升高,其对HBV DNA的抑制作用也随之增加。结论成功构建的psiHBV／p,它能在体内持续转录产生针对P基因转录体的发夹状siRNA;在细胞水平上,体内转录产生的、针对乙型肝炎病毒P基因区特异序列的siRNA对共转染的重组载体pHBV1．3有显著和特异的抑制作用。     

逆转录病毒介导双靶区反义RNA在转基因小鼠肝细胞中的表达及对HBV DNA复制的影响

目的:探讨逆转录病毒介导的乙型肝炎病毒(HBV)X,P单、双靶区的反义RNA在乙型肝炎转基因小鼠肝细胞中HBV复制的影响．方法:构建表达HBV X,P双靶区正、反义RNA的重组载体质粒,与脂质体混合,注入小鼠体内,第8周时取小鼠肝脏,提取肝组织总RNA,进行逆转录,将逆转录后的cDNA用PCR扩增,琼脂凝胶电泳和DNA测序定性,荧光聚合酶链反应定量:提取肝组织基因组DNA,利用荧光聚合酶链反应定量测定HBV DNA含量.结果:经过PCR扩增,琼脂凝胶电泳和DNA测序定性,荧光聚合酶链反应定量等方法检测到小鼠肝脏内反义RNA得到高效表达;8 wk后,对HBV DNA(×105 copies／g)的作用:与对照组相比(7．24±1．62),空质粒组(9．49±3．34)及正义RNA组(6．52±1．53)之间无明显差异,单(2．60±1．13,2．83±1．67)、双靶区反义RNA组(3．24±0．45)与对照组之间有明显差异(P<0．05),但单、双靶区反义RNA组间无明显差异(P>0．05)．结论:将脂质体包裹逆转录病毒载体(质粒)介导的单、双靶区乙肝病毒反义RNA经iv导入转基因小鼠细胞的方法可行;反义RNA对乙型肝炎病毒转基因小鼠有显著抗HBV复制作用;对转基因小鼠肝脏中HBV DNA的复制有明显的抑制作用,但单、双靶区反义RNA组间无明显差异．     

载体法筛选乙型肝炎病毒S基因小干扰RNA靶位体系的建立

目的 构建4个针对乙型肝炎病毒(HBV)S基因序列的小发央RNA(shRNA)表达载体，作用于增强型绿色荧光蛋白(EGFP)和HBV S基因融合表达载体，观察shRNA对融合蛋白的抑制作用，筛选出有效靶位。方法 利用pAVU6 27质粒，设计并掏建4个shRNA表达载体，与融合表达载体共转染AD293细胞，荧光显做镜下观察融合蛋白的荧光表达情况并通过流式细胞仪分析shRNA对融合蛋白的抑制作用。同时，逆转录聚合酶链反应法验证其筛选的有效性。结果 成功掏建shRNA表达载体和HBs-EGFP融合表达载体；4组shRNA表达载体均可不同程度抑制融合基因的表达，其中以579位点最有效，荧光表达抑制率为69．8％，RNA水平抑制率为74．6％。结论 筛选出有效抑制HBV S基因的siRNA靶位。     

乙型肝炎病毒S/C基因位点反义锁核酸在小鼠体内抗病毒疗效研究

目的 探讨针对HBV S/C双基因位点反义锁核酸对乙型肝炎转基因小鼠HBV复制和表达的影响.方法 将30只HBV转基因小鼠随机分为5组,每组6只.分别为5%葡萄糖液对照组、空脂质体对照组、单靶区S组,单靶区C组、双靶区SC组.反义锁核酸片段经尾静脉注入小鼠体内,采用时间分辨免疫荧光技术定量检测血清HBsAg;实时荧光聚合酶链反应定量检测血清HBV DNA含量;逆转录聚合酶链反应检测肝组织HBV C-mRNA的表达;免疫组织化学法检测肝细胞HBsAg、HBcAg的表达,自动牛物化学分析仪检测血清白蛋白、ALT、尿素氮、肌酐;小鼠肝,肾脏做常规病理切片,观察反义锁核酸对小鼠脏器的影响.应用SPSS12.0统计学软件分析.各组问比较采用重复测量方差分析的SNK检验和Kruskal Wallis H检验. 结果注射锁核酸后,对HBsAg的表达均显示有较强的抑制作用,单靶区S组,单靶区C组和双靶区SC组的平均抑制率分别为36.6%、31.5%和54.9%;对HBV DNA的复制也有抑制作用,平均抑制率分别为24.0%,21.1%和35.8%.注射后1、3、5 d,HBsAg的平均抑制率分别为14.4%、25.6%和31.3%;HBVDNA的平均抑制率分别为11.0%、19.2%和24.1%;血清中白蛋白、ALT、尿素氮、肌酐等指标,各组结果与对照组比较,差异均无统计学意义;小鼠肝细胞的HBsAg、HBcAg阳性细胞数均较对照组明显减少.小鼠肝,肾脏组织学表现未见异常. 结论 HBV S/C基因位点反义锁核酸对乙型肝炎病毒转基冈鼠HBV复制和表达有显著抑制作用,且双基因靶位优于单基因靶位.     

乙型肝炎病毒复制调控元件对HBV DNA疫苗诱导的免疫应答

目的研究乙型肝炎病毒（HBV）复制调控元件增强子Ⅰ（ENHⅠ）及前S2（Pre-S2）抗原基因对HBV DNA疫苗诱导的免疫应答的影响。方法采用常规聚合酶链反应（PCR）从HBV adr亚型全基因DNA序列中分别扩增HBsAg、PreS2-HBsAg、HBsAg-ENHI和PreS2-HBsAg-ENHⅠ基因片段，重组到VR1012载体中，构建4种HBV DNA疫苗，转染HepG2细胞并免疫Balb／C小鼠。通过细胞免疫化学、酶联免疫分析（ELISA）、酶联免疫斑点试验（ELISPOT）等方法检测其在HepG2细胞内的表达及小鼠的体液及细胞免疫应答。结果转染的HepG2细胞表达相应的目的蛋白．ENHⅠ及Pre-S2抗原基因均可增强HBV DNA疫苗转染HepG2细胞表达HBsAg；免疫接种小鼠后第2周产生抗-HBs及HBsAg特异性细胞毒T淋巴细胞（CTL），Pre—S2抗原基因可增强HBV DNA疫苗免疫Balb／C小鼠诱导的抗-HBs及HBsAg特异性CTL的产生，ENHⅠ基因对免疫应答无影响。结论ENHI及Pre—s2抗原基因均可增强HBVDNA疫苗转染HepG2细胞表达HBsAg．Pre-S2抗原基因可增强HBVDNA疫苗免疫Balb／C小鼠引起的免疫应答。     

逆转录病毒载体介导双靶区乙型肝炎病毒反义RNA模型的构建

构建在真核细胞内转录表达乙型肝炎病毒(HBV)双靶区反义核酸重组载体用以抗HBV基因治疗的研究。方法为合成互补于HBV(ayw亚型)X区核苷酸X片段以及互补于HBV P区的P片段,利用基因重组技术将X、P片段分别正向、反向插入逆转录病毒载体pLXSN的相应酶切位点构建成单靶区重组载体质粒。在构建单靶区载体质粒的基础上,类似方法再构建双靶区重组载体质粒。经酶切电泳、PCR扩增和DNA测序鉴定成功构建了HBV双靶区反义核酸重组载体。为探索在真核细胞内转录表达HBV反义RNA的方法及研究多基因区抗病毒治疗和抗变异病毒打下基础。     

血红素加氧酶-1表达对HBV复制的反向调控作用

目的评价血红素加氧酶-1（HO-1）对HBV复制的调控作用。方法采用分子克隆的方法分别构建人H（）_1真核表达载体——pH0和HO-1RNA干扰质粒——pHi，同HBV可复制性克隆pHBV1．3体外共转染人肝癌细胞系Huh-7，检测HBV抗原分泌情况和HBV相关mRNA含量。利用HBV急性感染小鼠模型，腹腔注射钴原卟啉（CoPP）IX和锌原卟啉（ZnPP）IX分别诱导和抑制HO-1表达，检测血清HO～1水平、HBV效价，免疫组织化学染色观察HBcAg在肝细胞内表达情况。分别在细胞水平和动物体内水平，评价HO-1表达对HBV复制的调控作用。结果同空载体共转染细胞相比，pHO共转染后HO-1的分泌水平明显上调（P〈0．01），HBsAg／HBeAg的分泌受到抑制（均P〈0．01）；pHi共转染后HO-1的分泌水平下降（P〈0．01），而HBsAg／HBeAg分泌增加（P均〈0．01）；但各组HBV相关RNA水平无明显差异。CoPPIX注射后诱导小鼠血清H0—1高表达（P％0．01），ZnPPIX则有效抑制了HO-1表达（P％0．01）。同对照组相比，CoPPIX组小鼠血清HBVDNA含量降低，肝脏内HBcAg阳性染色信号也随之明显减弱（P均〈0．01）；而ZnPPIX组小鼠血清HBVDNA含量增加，肝脏内HBcAg表达明显增强（均P〈0．01）。结论上调HO-1表达可有效抑制HBV复制，而下调其表达有利于HBV复制，且其可能是在转录后环节上发挥抗HBV作用。     

Inhibition of hepatitis B virus by retroviral vectors expressing antisense RNA

Two retroviral vectors carrying an antisense gene from the hepatitis B virus (HBV) preS/S or preC/C were constructed and used to infect the human hepatoblastoma cell line 2.2.15, which expresses HBV surface antigen (HBsAg), HBV e antigen (HBeAg) and releases HBV particles. The results showed that the inhibitory effects of antisense gene transfer, mediated by retroviral vectors on the expression of HBV antigens, appeared as early as day 3 after transduction, reached a maximum on day 5 and persisted for at least 11 days. Our data indicate that, on day 5 after introduction, antisense preS/S inhibited HBsAg and HBeAg expression by 71% and 23%, and the antisense preC/C inhibited HBsAg and HBeAg expression by 23% and 59%. HBV DNA production, in the supernatant of the 2.2.15 cells transduced with either antisense preS/S or preC/C, was also reduced on day 5, but the viability of the 2.2.15 cells was not affected. Our results demonstrate that the replication and expression of HBV can be inhibited through antisense gene transfer mediated by retroviral vectors and that the antisense-preC/C or antisense-preS/S may be potentially useful for clinical gene therapy against HBV.     

转铁蛋白受体介导的Bcl-2shRNA转移对HL-60细胞生长的抑制作用

目的 探讨Bcl一2短发夹状RNA（shRNA）表达载体对白血病细胞HL-60生长的抑制作用。方法 采用转铁蛋白-多聚乙烯亚胺介导的转染方法将携带绿色荧光蛋白基因的重组Bcl-2 shRNA1、shRNA2表达载体转入HL-60细胞。通过荧光显微镜和流式细胞仪观察绿色荧光蛋白的表达;采用台盼蓝拒染法计数活细胞;用免疫细胞化学方法检测Bcl-2蛋白表达水平。结果 Bcl-2 shRNA1、shRNA2载体分别转入HL-60细胞后,细胞中Bcl-2蛋白表达水平均显著降低（P〈0．05）,转染后48、72、96h细胞生长明显受到抑制。结论 转铁蛋白受体介导的Bcl-2 shRNA可显著抑制HL-60细胞生长。     

Inhibition of multiple gene expression and virus replication of HBV by stable RNA interference in 2.2.15 cells

BACKGROUND/AIMS: Hepatitis B virus (HBV) infection is a world-wide health problem. Recent studies have demonstrated the efficacy of RNA interference (RNAi) against HBV replication at cell culture and animal levels using transient transfection. The present study was to determine whether the stable transfection of short hairpin RNA (shRNA)-producing vector could achieve potent and sustained inhibition of the HBV replication in 2.2.15 cells. METHODS: shRNA-producing vector against HBV and the empty vector were stably transfected into the 2.2.15 cells respectively. A series of experiments were performed in the producing stable lines to determine the changes of viral protein expression and replication. RESULTS: The HBV protein expression and viral replication were suppressed dramatically and stably by the integrated shRNA-producing vectors. Most importantly, this suppression effect persists after 30 passages. CONCLUSIONS: Our data provided the possibility of continuous and stable inhibition of HBV protein expression and replication in patients using RNAi, suggesting a potential clinical application of this novel approach. Furthermore, the established stable transfected cell lines provided a good platform for understanding the mechanism of anti-HBV by RNAi.     

ShRNA-mediated gene silencing of β-catenin inhibits growt of human colon cancer cells

AIM: To observe the gene silencing mediated by the specific shRNA targeted against β-catenin and its effect on cell proliferation and cycle distribution in the human colon cancer cell line Colo205. METHODS: Two shRNA plasmid vectors against β-catenin were constructed and transfected into Colo205 cells with LipofectamineTM2000. The down-regulations of β-catenin, c-myc and cyclinD1 expressions were detected by RT-PCR and western blot analysis. The cell proliferation inhibitions were determined by MTT assay and soft agar colony formation assay. The effect of these two β-catenin shRNAs on cell cycle distribution and apoptosis was examined by flow cytometry. RESULTS: These two shRNA vectors targeted against β-catenin efficiently suppressed the expression of β-catenin and its down stream genes, c-myc and cyclinD1. The expression inhibition rates were around 40%-50% either at the mRNA or at the protein level. The shRNA-mediated gene silencing of β-catenin resulted in significant inhibition of cell growth both on the culture plates and in the soft agar. Moreover, the cancer cells showed significant G0/G1 arrest and increased apoptosis at 72 h post transfection due to gene silencing. CONCLUSION: These specific shRNAs targeted against β-catenin could have a gene silencing effect and block the WNT signaling pathway. They could inhibit cell growth, increase apoptosis, and induce cell cycle arrest in Colo205 cells. ShRNA interference against β-catenin is of potential value in gene therapy of colon cancer.     

Effect of vector-expressed shRNAs on hTERT expression

AIM: To study the effect of short hairpin RNAs (shRNAs) expressed from DNA vector on hTERT expression. METHODS: Oligonucleotides coding for four shRNAs against hTERT were cloned into a mammalian shRNA expression vector pUC18U6 to form pUC18U6ht1-4, which were then introduced into HepG2 cells by using liposome-mediated transfection. HepG2 cells transfected by pUC18U6 and pUC18U6GFPsir, which expressed shRNA against green fluorescent protein (GFP), were used as controls. hTERT mRNA in the transfected cells were quantified by using real-time fluorescent RT-PCR. RESULTS: Among the four shRNAs against hTERT, two decreased the hTERT mRNA level. Compared with the controls, pUC18U6ht which expressed the two shRNAs reduced hTERT mRNA by 39% and 49% (P<0.05). CONCLUSION: hTERT expression is inhibited by the shRNAs expressed from the DNA vector.     

ShRNA-mediated gene silencing of β-catenin inhibits growth of human colon cancer cells

AIM: To observe the gene silencing mediated by the specific shRNA targeted against β-catenin and its effect on cell proliferation and cycle distribution in the human colon cancer cell line Colo205.METHODS: Two shRNA plasmid vectors against β-catenin were constructed and transfected into Colo205 cells with LipofectamineTM2000. The down-regulations of β-catenin, c-myc and cyclinD1 expressions were detected by RT-PCR and western blot analysis. The cell proliferation inhibitions were determined by MTT assay and soft agar colony formation assay. The effect of these two β-catenin shRNAs on cell cycle distribution and apoptosis was examined by flow cytometry.RESULTS: These two shRNA vectors targeted against β-catenin efficiently suppressed the expression of β-catenin and its down stream genes, c-myc and cyclinD1. The expression inhibition rates were around 40%-50% either at the mRNA or at the protein level.The shRNA-mediated gene silencing of β-catenin resulted in significant inhibition of cell growth both on the culture plates and in the soft agar. Moreover, the cancer cells showed significant G0/G1 arrest and increased apoptosis at 72 h post transfection due to gene silencing.CONCLUSION: These specific shRNAs targeted against β-catenin could have a gene silencing effect and block the WNT signaling pathway. They could inhibit cell growth, increase apoptosis, and induce cell cycle arrest in Colo205 cells. ShRNA interference against β-catenin is of potential value in gene therapy of colon cancer.     

Inhibition of hepatitis B virus gene expression and replication by artificial microRNA

AIM： To investigate the inhibitory effects of hepatitis B virus （HBV） replication and expression by transfecting artificial microRNA （amiRNA） into HepG2.2.15 cells. METHODS： Three amiRNA-HBV plasmids were constructed and transfected into HepG2.2.15 cells. HBV antigen secretion was detected in the cells with transient and stable transfection by time-resolved fluoroimmunoassays （TRFIA）. HBV DNA replication was examined by ？ uorescence quantitative PCR, and the level of HBV S mRNA was measured by semi- quantitative RT-PCR. RESULTS： The efficiency of transient transfection of the vectors into 2.2.15 cells was 55%-60%. All the vectors had significant inhibition effects on HBsAg and HBeAg at 72 h and 96 h after transfection （P 〈 0.01 for all）. The secretion of HBsAg and HBeAg into the supernatant was inhibited by 49.8% ± 4.7% and 39.9% ± 6.7%, respectively, at 72 h in amiRNA- HBV-S608 plasmid transfection group. The copy of HBV DNA within culture supernatant was also significantly decreased at 72 h and 96 h after transfection （P 〈0.01 for all）. In the cells with stable transfection, the secretion of HBsAg and HBeAg into the supernatant was significantly inhibited in all three transfection groups （P 〈 0.01 for all, vs negative control）. The copies of HBV DNA were inhibited by 33.4% ± 3.0%, 60.8% ± 2.3% and 70.1% ± 3.3%, respectively. CONCLUSION： In HepG2.2.15 cells, HBV replication and expression could be inhibited by artif icial microRNA targeting the HBV S coding region. Vector-based artificial microRNA could be a promising therapeutic approach for chronic HBV infection.     

乙型肝炎病毒C区反义RNA靶向肝细胞抗病毒的研究

目的探讨靶向肝细胞的反义RNA抗HBV作用。方法以糖化多聚赖氨酸为载体,将能转录HBVC区反义RNA的真核质粒pREP4-aC定向导入2.2.15细胞,潮霉素筛选阳性克隆。研究过程中用ELISA和斑点杂交方法检测多个时期培养上清液中HBsAg、HBeAg和HBVDNA,同时观察对细胞的毒性作用。结果导向后24h出现对HBsAg、HBeAg和HBVDNA的抑制,6d左右抑制率达最高水平。未发现对2.2.15细胞的毒性作用。结论糖化多聚赖氨酸导向肝细胞的C区反义RNA,能有效抑制HBV抗原表达和DNA复制。