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.     

Combination of small interfering RNA and lamivudine on inhibition of human B virus replication in HepG2.2.15 cells

AIM: To observe the inhibition of hepatitis B virus (HBV) replication and expression by combination of siRNA and lamivudine in HepG2.2.15 cells. METHODS: Recombinant plasmid psil-HBV was constructed and transfected into HepG2.2.15 cells. The transfected cells were cultured in lamivudine-containing medium (0.05 μmol/L) and harvested at 48, 72 and 96 h. The concentration of HBeAg and HBsAg was determined using ELISA. HBV DNA replication was examined by real- time PCR and the level of HBV mRNA was measured by RT-PCR. RESULTS: In HepG2.2.15 cells treated with combination of siRNA and lamivudine, the secretion of HBeAg and HBsAg into the supernatant was found to be inhibited by 91.80% and 82.40% (2.89 ± 0.48 vs 11.73 ± 0.38, P < 0.05; 4.59 ± 0.57 vs 16.25 ± 0.48, P < 0.05) at 96 h, respectively; the number of HBV DNA copies within culture medium was also significantly decreased at 96 h (1.04 ± 0.26 vs 8.35 ± 0.33, P < 0.05). Moreover, mRNA concentration in HepG2.2.15 cells treated with combination of siRNA and lamivudine was obviously lower compared to those treated either with siRNA or lamivudine (19.44 ± 0.17 vs 33.27 ± 0.21 or 79.9 ± 0.13, P < 0.05). CONCLUSION: Combination of siRNA and lamivudine is more effective in inhibiting HBV replication as compared to the single use of siRNA or lamivudine in HepG2.2.15 cells.     

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。     

靶向乙型肝炎病毒X区的siRNAs对HepG2.2.15细胞HBV复制的抑制作用

目的观察siRNA对HBV基因表达和复制的抑制情况。方法针对HBVX区设计并化学合成4条siRNAs,观察在不同浓度下对HepG2.2.15细胞HBV复制的抑制作用。结果 siRNA在30nmoL/L浓度时,4种siRNA对HepG2.2.15细胞HbsAg和HBeAg无明显的抑制作用(P0.05);在60nmoL/L和90nmoL/L浓度下,siR-NA-1和siRNA-4有明显的抑制作用(P0.05),他们对HBsAg和HBeAg的抑制率分别为41%和43%;siRNA能降低HepG2.2.15细胞HBVDNA的拷贝数。结论化学合成的siRNAs可以有效地抑制HBV基因的表达和复制。     

RNA干扰技术用于抗乙型肝炎病毒的实验研究

目的 构建针对乙型肝炎病毒表面抗原(HBsAg)和核心抗原的小干扰RNA(siRNA)表达载体pSuper-C，观察其对HepG2 2．2．15细胞(简称2、2．15细胞)中HBV DNA转录和翻译相应蛋白的影响。方法 根据RNA干扰(RNAi)作用原理设计针对HBV核心区的相应序列，再将其克隆入含聚合酶ⅢH1-RNA启动子的真核表达载体pSuper，将此重组质粒以电转染法转入2．2．15细胞中，用酶联免疫吸附法(Abbott试剂)检测培养上清液中HBsAg和e抗原(HBeAg)的表达。结果 经酶切鉴定、电泳和测序分析证明，成功构建了含作用序列的重组质粒pSuper-C；但以电穿孔法转染 2．2．15细胞后末能发现其对2．2．15细胞培养上清液中的HBsAg和HBeAg的表达有影响。结论 RNAi在2．2．15细胞中的作用还需进一步的实验来证实。     

HBV preS1反基因锁核酸的设计及体外对病毒复制的抑制

目的:探讨针对乙型肝炎病毒(hepatitis Bvirus,HBV)preS1 dsDNA同聚嘌呤区设计反基因锁核酸分子,并观察其在HepG2 2.2.15细胞内抑制病毒复制的效果.方法:针对HBVpreS1 dsDNA的2941-2962 nt、3 015-3 036 nt和3 089-3 110 nt三个同聚嘌呤区,利用RNA structure软件分别设计合成锁核酸、硫代寡核苷酸、未修饰寡核苷酸及无关对照序列,以阳离子脂质体介导转染HepG22.2.15细胞,采用荧光定量聚合酶链反应技术(FQ-PCR)和时间分辨免疫荧光技术(TRFIA)分别监测1、3、5和7 d细胞培养上清液中HBV DNA和HBsAg的含量;四甲基偶氮唑蓝(MTT)法检测锁核酸对细胞代谢的影响.结果:反基因锁核酸对细胞内的HBV DNA复制与HBsAg表达有明显的抑制作用,且抑制率随时间呈增高趋势,7 d后抑制率分别为64.32%和67.51%.各实验组与对照组比较差异均具有统计学意义(均P<0.05),而封闭2 941-2 962 nt同聚嘌呤靶区的LNA抑制作用最强,且最适序列长度为20-30 bp.LNA对细胞代谢无明显影响.结论:针对preS1 dsDNA同聚嘌呤区的反基因锁核酸分子,体外能有效抑制HBV的复制,以封闭2 941-2 962 nt靶位效果最强,且合适序列长度为20-30 bp.     

Effect of vector-expressed siRNA on HBV replication in hepatoblastoma cells

AIM: To study the effect of siRNA expressed from DNA vector on HBV replication. METHODS: Human U6 promoter was amplified from genomic DNA and cloned into plasmid pUC18 to construct a mammalian siRNA expression vector pUC18U6. Then oligonucleotides coding for a short hairpin RNA against HBV were cloned into pUC18U6 to form pUC18U6HBVsir which was introduced into 2.2.15 cells by using liposome-mediated transfection. 2.2.15 cells transfected by pUC18U6 and pUC18U6GFPsir which expressed siRNA against green fluorescent protein and mock-transfected 2.2.15 cells were used as controls. Concentration of HBsAg in the supernatant of the transfected cells was measured by using solid-phase radioimmunoassay. RESULTS: A mammalian siRNA expression vector pUC18U6 was constructed successfully. Compared with controls, pUC18U6HBVsir which expressed siRNA against HBV decreased concentration of HBsAg significantly by 44%(P<0.05). CONCLUSION: HBV replication in 2.2.15 cells is inhibited by siRNA expressed from the DNA vector.     

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。     

VP22 fusion protein-based dominant negative mutant can inhibit hepatitis B virus replication

AIM: To investigate the inhibitory effect of VP22 fusion protein-based dominant negative (DN) mutant on Hepatitis Bvrus (HBV) replication. METHODS: Full-length or truncated fragment of VP22 was fused to C terminal of HBV core protein (HBc), and subcloned into pcDNA3.1 (-) vector, yielding eukaryotic expression plasmids of DN mutant. After transfection into HepG2.2.15 cells, the expression of DN mutant was identified by immunofluorescence staining. The inhibitory effect of DN mutant on HBV replication was indexed as the supernatant HBsAg concentration determined by RIA and HBV-DNA content by fluorescent quantification-PCR (FQ-PCR). Meanwhile, metabolism of HepG2.2.15 cells was evaluated by MTT colorimetry. RESULTS: VP22-based DN mutants and its truncated fragment were expressed in HepG2.2.15 cells, and had no toxic effect on host cells. DN mutants could inhibit HBV replication and the transduction ability of mutant-bearing protein had a stronger inhibitory effect on HBV replication. DN mutants with full length of VP22 had the strongest inhibitory effect on HBV replication, reducing the HBsAg concentration by 81.94%, and the HBV-DNA content by 72.30%. MTT assay suggested that there were no significant differences in cell metabolic activity between the groups. CONCLUSION: VP22-based DN mutant can inhibit HBV replication effectively.     

针对P基因的siRNA对乙肝病毒S表达稳定性的影响

目的以乙型肝炎病毒（HBV）P基因为靶点，构建表达小干扰RNA（siRNA）的质粒载体psRNA1、psRNA2、psRNA3、psRNA4及对照psiRNA0，体外观察针对P基因的siRNA对HBs表达的影响。方法设计并合成针对HBV-P基因的siRNA寡核苷酸，经退火形成双链后克隆入psiRNA-H1neo质粒中，通过鉴定将构建成功的5个psiRNAs真核表达质粒瞬时转染HepG2．2．15细胞，用半定量RT-PCR对筛选到的位点进行了试验观测抑制效果。结果表明针对P基因的siRNA能下调HBs的表达，其中psiRNA1、psiRNA2的抑制HBs基因表达的效果最强。结论针对P基因的siRNA可以有效的抑制HBs的表达，抑制的效果和siRNA的靶位点有关。     

Alpha‐enolase regulates hepatitis B virus replication through suppression of the interferon signalling pathway

Persistent chronic infection with hepatitis B virus (HBV) is a major risk factor for the development of HBV‐related diseases. The molecular mechanisms that underlie HBV infection and associated carcinogenesis are not fully understood. The aim of this study was to explore the role of ENO1 in HBV replication processes. Here, we examined ENO1 expression levels in HBV‐infected and non‐HBV‐infected liver tissues and cells by Western blot analysis, real‐time PCR and immunohistochemistry. In addition, HBsAg and HBeAg in the media of transfected HepG2.2.15 cells were detected using an electrochemical luminescence analyser within 48 hours after ENO1‐specific siRNA transfection. The expression levels of HBV DNA, type I interferon and 5 downstream IFN‐stimulated genes in HepG2.2.15 cells were examined using real‐time PCR. We found ENO1 expression was upregulated in the HBV‐infected liver tissues and cells. Silencing of ENO1 resulted in a significant reduction in HBV replication, and this siRNA‐mediated reaction also caused the upregulation of expression of type I interferon and downstream IFN‐stimulated genes. Therefore, we come to the conclusion ENO1 is involved in HBV replication. It is therefore likely that HBV replication is enhanced following suppression of the IFN signalling pathway. However, the mechanisms that underpin ENO1‐mediated modulation of the IFN signalling pathway remain to be elucidated.     

靶向S区和C区基因的M1GS RNA核酶共同抑制HBV的表达

目的:研究靶向HBVS区和C区基因的M1GSRNA核酶共同作用对HBV基因表达的影响.方法:选择HBVayw亚型S区基因294nt和C区基因2333nt为切割位点,以含有编码M1RNA的DNA序列的质粒pTK117为模板,通过PCR扩增得到M1GSRNA核酶的DNA模板,并将其克隆至真核表达载体pEGFP-C1得到重组质粒pEGFP-GSS和pEGFP-GSC.将2个重组质粒共转染HepG2.2.15细胞,转染后ELISA法测细胞培养液中的HBsAg和HBeAg,RT-PCR检测HBVmRNA.结果:成功构建了分别靶向HBVS区基因和C区基因的真核表达载体.共转染HepG2.2.15细胞后,HBsAg和HBeAg的表达分别被抑制了33.2%和39.1%,HBVCmRNA和SmRNA分别被抑制了32.5%和29.7%,而HepG2.2.15细胞的增殖无明显变化.结论:靶向HBVS区和C区基因的M1GSRNA核酶共同作用可特异性抑制HBVS区和C区基因的表达.     

反义锁核酸与拉米夫定在HepG2.2.15细胞中抗HBV作用的比较

目的:应用反义锁核酸与拉米夫定作用HepG2.2.15细胞,对他们抗乙型肝炎病毒(hepatitis B virus,HBV)效果进行比较.方法:设计针对HBV翻译起始区S基因mRNA的反义寡核苷酸,并进行锁核酸修饰,以阳离子脂质体介导反义锁核酸转染HepG2.2.15细胞;拉米夫定组直接作用HepG2.2.15细胞;分别于用药后第2、4、6、8、10天收集细胞培养上清液.用ELISA法和FQ-PCR法检测收集上清液HBsAg、HBeAg和HBVDNA的含量.MTT法分别检测反义锁核酸与拉米夫定对细胞存活率的影响.结果:拉米夫定对HBVDNA具有明显抑制作用,最高可达46.52%,但对HBsAg、HBeAg影响较小;反义锁核酸对HBsAg、HBeAg及HBVDNA均有较强抑制作用,对HBsAg、HBeAg和HBVDNA的最高抑制率分别达67.69%、59.71%和62.96%(P<0.05),且抑制随时间呈增高趋势.反义锁核酸与拉米夫定对细胞代谢均无明显影响.结论:反义锁核酸抗HBV作用机制与拉米夫定不同,反义锁核酸抗HBV作用明显优于拉米夫定.     

Evaluation of hepatitis B viral replication and proteomic analysis of HepG2.2.15 cell line after knockdown of HBx

BACKGROUND:Hepatitis B virus (HBV) is one of the major pathogens of human liver disease.Studies have shown that HBV X protein (HBx) plays an important role in promoting viral gene expression and replication.In this study we performed a global proteomic profiling to identify the downstream functional proteins of HBx,thereby detecting the mechanisms of action of HBx on virion replication.METHODS:HBx in the HepG2.2.15 cell line was knocked down by the transfection of small interfering RNA (siRNA).The replicati...     

Inhibition effect produced by dominant negative mutant fusion protein PreS2-TLM-ScFv-HBcDN on HBV replication in vitro

A mammalian expression vector comprised of the PreS2-TLM (translocation motif), a single-chain variable fragment (ScFv) that binds to hepatitis B surface antigen (HBsAg) and the EGFP gene was constructed. A stably transformed cell line that could express and secrete the fusion protein (PreS2-TLM-ScFv-EGFP) was established. HBsAg-positive HepG2.2.15 cells and HepG2 and HeLa cells were incubated with the supernatant of the transformed cell line cultures for evaluating the cellular permeability of PreS2-TLM-ScFv-EGFP. The location of the fusion protein PreS2-TLM-ScFv-EGFP in HepG2.2.15 cells was observed with immunofluorescence staining. EGFP was next replaced by a dominant negative mutant of the hepatitis B virus core gene (HBcDN) for producing fusion protein PreS2-TLM-ScFv-HBcDN, which was detected by western blot. The supernatant containing fusion protein PreS2-TLM-ScFv-HBcDN was added to the cultures of HepG2.2.15 cells, and the packaged hepatitis B virus (HBV) pregenomic RNA expression levels in the cells were measured using qRT-PCR. The results of the in vitro study indicated that the packaged HBV pregenomic RNA expression levels in HepG2.2.15 cells significantly decreased when these cells were exposed to the supernatant at the dose of 25% for 24, 48 and 72 h, or at the dose of 12.5% for 72 h.     

Inhibition of hepatitis B virus replication in 2.2.15 cells by expressed shRNA

Summary.  Hepatitis B virus (HBV) infection is a worldwide health problem. To determine whether RNA interference (RNAi) could inhibit ongoing HBV replication in 2.2.15 cells, we constructed shRNA-producing vector pU6P based on the mouse U6 RNA promoter and cloned 12 targeted sequences against HBV into the vector, resulting in a series of pU6-siHBV vectors. The recombinant vectors were transfected into 2.2.15 cells, HBsAg and HBeAg in cultured media were assayed using enzyme-linked immunosorbent assay at various days after transfection. The amount of HBV DNA in the culture medium was quantitated by real-time polymerase chain reaction. HBsAg and HBeAg expression were inhibited by 72.8 ± 5.4% ( P  = 0.00003) and 55.8 ± 6.2% ( P  = 0.000026), respectively, 4 days after transfection with pU6-siHBV5. The greatest inhibition of HBV DNA was decreased by approximately 1.9-fold ( P  = 0.013) on day 6 post transfection with pU6-siHBV11 compared with that of empty vector. No change was found for HBV protein expression and DNA replication on pU6-siGFP (negative control) transfected cells. Our data demonstrate that the transfection of HBV-targeted shRNA-producing vector in 2.2.15 cells could inhibit the HBV protein expression and HBV DNA replication specifically. RNAi may be considered as a potential antiviral approach for human HBV infection.     

不同结合臂长10-23 DNAzymes对乙型肝炎病毒S基因和C基因表达的抑制作用

目的探讨不同结合臂长10-23DNAzymes在2．2．15细胞内对乙型肝炎病毒S基因和C基因表达的抑制作用。方法设计并合成不同结合臂长的10-23 DNAzymes,能分别针对乙型肝炎病毒S基因和C基因开放阅读框A^157UG和A^1816UG。不同的10-23 DNAzymes分别转染2．2．15细胞,放射免疫分析法测定2．2．15细胞培养上清中HBsAg和HBeAg水平,实时荧光定量PCR法测定2．2．15细胞培养上清中HBVDNA水平。MTT法检测细胞毒性。结果不同结合臂长的10-23 DNAzymes在0．1—2．5μmol／L浓度范围内均能有效抑制HBsAg和HBeAg的表达,抑制效应可长达72h。在同一剂量相同转染时间的条件下,不同结合臂长的10．23 DNAzymes对HBsAg和HBeAg表达的抑制率呈以下关系：DrzBS-9〉DrzBS．8〉DrzBS-7;DrzBC-9〉DrzBC．8〉DrzBC-7。DrzBS-9和DrzBC-9在2．5~mol／L剂量条件下,转染48h后对HBsAg和HBeAg表达的抑制率可分别高达95％和92％。不同结合臂长的10-23DNAzymes对2．2．15细胞培养上清中HBVDNA水平并无明显影响。MTT细胞毒性检测表明,在0．1～2．5μmol／L浓度范围内未见10-23 DNAzymes对2．2．15细胞的毒性作用。结论不同结合臂长10-23 DNAzymes在2．2．15细胞内对乙型肝炎病毒s基因和c基因表达均有一定的抑制作用,DrzBS-9和DrzBC-9的抑制作用较强。     

Inhibition of hepatitis B virus replication by pokeweed antiviral protein in vitro

AIM： To explore the inhibitory effects of pokeweed antiviral protein seed （PAP-S） and PAP encoded by a eukaryotic expression plasmid on hepatitis B virus （HBV） replication in vitro. METHODS： HepG2 2.2.15 cells in cultured medium were treated with different concentrations of PAP-S. HBsAg, HBeAg and HBV DNA in supernatants were determined by ELISA and fluorescent quantitative PCR respectively. MTT method was used to assay for cytotoxicity. HepG2 were cotransfected with various amounts of PAP encoded by a eukaryotic expression plasmid and replication competent wild-type HBV 1.3 fold overlength plasmid. On d 3 after transfection, HBsAg and HBeAg were determined by using ELISA. Levels of HBV core-associated DNA and RNA were detected by using Southern and Northern blot, respectively. RESULTS： The inhibitory effects of PAP-S on HBsAg, HBeAg and HBV DNA were gradually enhanced with the increase of PAP concentration. When the concentration of PAP-S was 10 μg/mL, the inhibition rates of HBsAg, HBeAg and HBV DNA were 20.9%, 30.2% and 50%, respectively. After transfection of 1.0 μg and 2.0 μg plasmid pXF3H-PAP, the levels of HBV nucleocapside- associated DNA were reduced by 38.0% and 74.0% respectively, the levels of HBsAg in the media by 76.8% and 99.7% respectively, and the levels of HBeAg by 72.7% and 99.3% respectively as compared with controls. Transfection with 2 μg plasmid pXF3H-PAP reduced the levels of HBV nucleocapside-associated RNA by 69.0%.CONCLUSION： Both PAP-S and PAP encoded by a eukaryotic expression plasmid could effectively inhibit HBV replication and antigen expression in vitro, and the inhibitory effects were dose-dependent.