LNAzyme特异性阻断丙肝病毒5'-NCR/C基因表达

目的 探讨针对HCV 5'-NCR/C双靶基因位点的锁核酸核酶对病毒基因复制与表达的特异性抑制作用.方法 实验分对照组和实验组.对照组分别为空白对照组和脂质体对照组.实验组分别为单靶区NCR组、单靶区C组和双靶区NCR/C组.半乳糖配体介导转染HepG2.9706细胞,用荧光定量PCR检测细胞培养液中HCV mRNA表达;化学发光技术检测细胞培养液中荧光素酶基因表达;荧光显微镜系统检测细胞内荧光蛋白表达;四甲基偶氮唑蓝法检测细胞代谢.应用SPSS 19.0统计学软件分析.各组间比较采用重复测量方差分析的SNK检验和Kruskal Wallis H检验.结果 加入锁核酸核酶后,对HCV RNA的复制均显示有较强的抑制作用(F=77.50,P＜0.05),单靶区NCR组、单靶区C组和双靶区NCR/C组的平均抑制率分别为62.12％、61.39％和75.37％;对荧光素酶的表达有抑制作用(F =48.65,P＜0.05),平均抑制率分别为66.49％、65.06％和73.30％.给药后24、48和96 h,HCV mRNA的平均抑制率分别为52.36％、66.81％和75.05％;荧光素酶的平均抑制率分别为53.02％、62.98％和79.45％;细胞内的荧光蛋白表达阳性细胞数均较对照组明显减少(P＜0.05).结论 针对5'-NCR/C基因位点的LNAzyme能特异性抑制丙型肝炎病毒的复制与表达,且双基因靶位优于单基因靶位.     

脱氧核酶在培养人气道上皮细胞体系内的抗甲型流感病毒NS基因效应

目的 探讨针对甲型病毒(influenza A virus,IFV)NS基因特异性的脱氧核酶(DNAzyme,DZ-NS)在培养的人气道上皮细胞(9HTEo)体系内对甲型流感病毒复制的抑制效应,方法 光镜观察DZ-NS对IFV致9HTEo细胞病变效应变化的影响;病毒空斑形成阻断试验及四甲基偶氮唑盐比色试验(MTT)检测脱氧核酶DZ-NS对IFV复制的抑制和对感染IFV的9HTEo细胞的保护作用;RT-PCR检测DZ-NS对IFV mRNA表达的抑制作用.结果 DZ-NS可明显改善IFV所致的细胞病变并能明显提高细胞感染IFV后的存活率(P＜0.01);可显著抑制IFV-NS基因mRNA的表达;空斑实验病毒抑制率可达80.11%;DZ-NS在细胞内对IFA病毒表达的抑制效率,明显高于作为对照的反义寡核苷酸(antisense oligonucleotides,AS-NS)(P＜0.05).结论 在9HTEo 感染IFV细胞模型系统,DZ-NS能高效阻断IFV的NS基因的表达,是一种特异性的、高效的抗IFV基因治疗剂.     

反义RNA体外抑制丙型肝炎病毒基因表达的研究

目的 研究丙型肝炎病毒(HCV)基因调控方式及反义RNA对HCV基因表达的体外抑制作用。方法 采用业已建立的HCV基因调控细胞模型，以重组质粒共转染策略，将反义RNA重组质粒与HCV5′非翻译区(5′UTR)调控的报道基因——虫荧光素酶(luc)重组质粒共同转染人肝癌细胞系(HepG2)，并以不表达反义RNA的原核重组质粒和不含有HCV5′UTR的luc重组质粒做为对照。转染细胞经短期培养后制备细胞提取液，荧光检测法检测luc基因的表达。结果 针对HCV5′uTR的反义RNA可以在体外有效抑制由HCV5′UTR调控的luc基因的表达，并具有剂量依赖效应。对照重组质粒转染实验证明，上述抑制作用呈序列特异性。结论 HCV5′UTR具有调控下游目的基因表达的重要功能，反义RNA可以在体外有效抑制由HCV5′UTR介导的病毒基因的表达。     

核酶在HIV-1基因治疗中的研究进展

HIV- 1是一种特殊的逆转录病毒 ,其基因可转导入宿主细胞的基因内进行复制。核酶是一类具有催化活性的小分子 RNA,能特异性与靶 RNA分子结合后进行切割而抑制 HIV- 1,甚至一些 RNA中间产物亦被核酶破坏。多项研究已证实核酶可抑制细胞内 HIV- 1复制。与 HIV- 1的传统疗法相比 ,核酶基因治疗法干扰了病毒的装载和免疫系统的重建 ,能高效抑制病毒增殖 ,有助于患者免疫系统重建     

慢性HCV感染者中分离的不同长度3''UTR-PolyU/UC段对IRES介导的翻译及NS5B合成RNA影响

目的研究丙型肝炎病毒3’非编码区(3’UTR)及不同长度PolyU／UC段对内在核糖体进入位点(IRFS)介导翻译的影响以及对NS5B聚合酶合成RNA的影响。方法通过构建含有HCV IRES、荧光素酶(firefly luciferase)报道基因和内含不同长度PolyU／UC区的3’UTR序列的系列重组质粒，采用体外翻译和细胞转染等方法检测报道基因表达的水平。结果体外翻译实验和细胞转染实验显示3’UTR对IRES介导的翻译具有增强作用，在体外翻译体系中这种增强作用与PolyU／UC区的长度相关，而在细胞中则与：PolyU／UC区的长度无明显相关性；3’UTR对共转染的重组NS5B质粒的复制活性具有抑制作用，这种抑制作用也与PolyU／UC区长度不成正比。结论HCV 3’UTR与蛋白翻译及RNA合成有关．在细胞中并不与PolvU/UC区的长度相关。     

preS2反义RNA肝癌特异性表达载体的构建及相关特性研究

目的 构建针对preS2基因的肝癌特异性反义RNA表达载体，并对其特异性和有效性进行研究。方法 PCR扩增preS2(3203—340)基因，克隆至含甲胎蛋白启动子的EB病毒表达载体pEBAF，构建反义RNA表达载体pEBAF-as—preS2。脂质体转染肝癌细胞和ECV304细胞，3d后Northern blot检测preS2 mRNA的表达，ELISA检测HBV抗原，荧光定量PCR检测HBV DNA。结果序列分析表明，pEBAF-as-preS2构建成功，Northern blot证实反义RNA仅在AFP阳性的肝癌细胞中表达，pEBAF-as-preS2转染3d后，可显著抑制HepG2．2．15细胞HBV复制和抗原表达，对HBsAg、HBeAg表达的抑制率分别为33．4％和41．5％；对HBV复制抑制率为86％。结论 反义RNA表达载体pEBAF-as-preS2仅在肝癌细胞中特异表达、并可有效抑制HBV，有良好的开发应用前景。     

RNAi抑制XJ-160病毒复制的研究

目的通过建立RNA干扰(RNA interference，RNAi)抑制XJ-160病毒复制的模型，在序列特异性、位置效应和量效关系等方面，探讨RNAi对XJ-160病毒复制的影响，为进一步研究RNAi的抗病毒作用和机制奠定基础。方法按照siRNA(short interferencing RNA)的设计要求合成XJ-160病毒特异siRNA，脂质体法转染BHK-21细胞后感染XJ-160病毒，通过测定病毒滴度、蛋白表达量及XJ-160病毒：RNA合成研究siRNA对XJ-160病毒复制的抑制。结果成功建立了RNAi抑制XJ-160病毒复制的模型，探讨了RNAi抑制该病毒复制作用的特点。结论外源导入的siRNA能够抑制XJ-160病毒的复制，并且这种抑制作用具有明显的序列特异性、位置效应和存在量效关系等特点；siRNA是通过降解病毒RNA实现抑制病毒复制作用的。     

脱氧核酶抑制人脐动脉平滑肌细胞增殖

目的：观察增殖细胞核抗原（PCNA）基因特异性的10-23脱氧核酶（DNAzyme）对人脐动脉平滑肌细胞（HUASMC）增殖的影响。 方法： 设计合成针对PCNA基因起始密码AUG的DNAzyme，应用脂质体转染法将其转入体外培养的HUASMC。检测DNAzyme干预HUASMC 2 d后［3H］-TdR的掺入量；通过四甲基偶氮唑蓝（MTT）比色法分析HUASMC的增殖；采用流式细胞仪检测细胞周期。 结果： 1.0 μmol/L DNAzyme干预HUASMC 2 d后，［3H］-TdR的掺入量低于对照组（P<0.05）。1.0 μmol/L的DNAzyme和反义寡聚核苷酸（ASODN）组处理2、3和5 d后，MTT比色吸光度值低于对照组（均P<0.01）。DNAzyme对细胞增殖的抑制呈剂量依赖性。细胞干预2 d后，DNAzyme、ASODN和对照组的G0/G1期细胞的比率分别为73.8%、54.7%和41.1%。 结论： 针对PCNA的DNAzyme能有效抑制HUASMC的体外增殖。     

短双链RNA对CVB3病毒细胞内清除作用的可行性研究及其机制探讨

目的 通过观察短双链RNA(Short interfering RNA,siRNA)体外转染HeLa细胞评价siRNA抗CVB3病毒感染的可行性和抑制作用机制.方法 通过细胞病变作用保护实验,选择合适的siRNA剂量.Western Blot、RT-PCR等方法在体外检测siRNA抗CVB3病毒复制作用及作用途径.结果siRNA-3753通过脂质体转染试剂能高效转入HeLa细胞,转染效率可达98.77%,在细胞内可稳定长达48 h.siRNA-3753的浓度为0.6 μmol/L对病毒抑制率高同时对细胞不会产生毒性作用,该浓度作为本次研究的实验剂量.siRNA-3753抗CVB3病毒感染作用是通过siRNA直接降解病毒基因得到的,而不是通过激活PKR或干扰素等其他未知因素起效的.结论 siRNA可以高效、较长时间的转染入HeLa细胞内,在低剂量时即产生较好的抗病毒感染作用,通过直接降解病毒基因组的途径特异性抑制CVB3病毒的复制及感染.     

Hepatitis C virus (HCV) status in newborns born to HCV positive women performing intracytoplasmic sperm injection

Background

A low risk of HCV vertical transmission has been reported especially in those born to women with viraemia. Intracytoplasmic sperm injection (ICSI) being an assisted reproduction technique includes procedures that may increase risk of transmission.

Objective

To determine the rate of vertical transmission of HCV to newborns born to HCV positive mothers in ICSI cycles.

Methods

In a cross-sectional observational study, serum samples have werecollected within the first week after birth from newborns of two groups of ICSI cycles females. Group one: 30 women HCV antibody (Ab) positive/HCV RNA negative. Group two: 30 women HCV Ab positive/HCV RNA positive. Newborn sera were subjected to HCV antibody testing, and detection of HCV viral RNA by PCR.

Results

None of the newborns born to PCR negative females undergoing ICSI cycles showed positive results neither for HCV antibody, or for HCV RNA. Only one out of the 30 newborns born to PCR positive females was positive for HCV antibody and HCV RNA.

Conclusion

HCV vertical transmission in ICSI cycles seemed to be of low incidence in PCR positive women, while in the case of HCV PCR negative/sero-positive women, it appeared to be completely absent. This observation could have an impact on the clinicians'' counseling for HCV positive females seeking ICSI.     

Spontaneous elimination of serum hepatitis C virus (HCV) RNA in chronic HCV carriers: a population-based cohort study

The natural course of hepatitis C virus (HCV) infection has not been fully elucidated. To investigate whether HCV is spontaneously eliminated in chronic carriers, a long-term population-based cohort study was conducted on 435 chronic HCV carriers. Individual characteristics, serum HCV RNA, and liver function tests were analyzed, and ultra sonography (US) was performed in all subjects. Subjects were followed up for 7.2 +/- 2.4 years (mean +/- SD). Serum HCV RNA was spontaneously eliminated in 16/435 (3.7%) individuals during this period; thus, the incidence of spontaneous elimination of serum HCV RNA was 0.5%/year/person. Multivariate analysis revealed that both a low value of ZTT and no US finding of chronic liver disease were associated with spontaneous viral elimination in HCV carriers. Three of these 16 individuals had chronic hepatitis, and 13 of them had normal ALT levels. When the neutralization of binding (NOB) assay that evaluates inhibition of the HCV envelope-2 protein binding to human cells was examined using sera from these 16 individuals, the NOB antibody was detected in only 3 cases with chronic hepatitis. These results suggest that serum HCV RNA is spontaneously eliminated in chronic HCV carriers in a population, and that the development of NOB antibody is associated with a natural resolution of chronic hepatitis in the minority of them.     

Evaluation of the clinical usefulness of COBAS AMPLICOR HCV MONITOR assay (ver2.0): Comparison with AMPLICOR HCV MONITOR assay (ver1.0) and HCV core protein level

The quantitation of serum levels of hepatitis C virus (HCV) RNA in chronic hepatitis C has been regarded as one of the most important indicators for the outcome of interferon (IFN) therapy. The AMPLICOR HCV MONITOR version 1.0 (AMPLICOR v1.0) assay is widely used for the evaluation of the HCV level. A new generation assay called the COBAS AMPLICOR HCV MONITOR version 2.0 (COBAS v2.0) assay, which is semiautomated and modified to amplify all genotypes equally, has been developed. The aim of this study was to evaluate the clinical relevance of the COBAS v2.0 assay in comparison with the AMPLICOR v1.0 assay and HCV core protein assay in patients with chronic hepatitis C before IFN therapy. HCV RNA was detectable in 230 cases (97.5%) and undetectable in 6 cases (2.5%) by the COBAS v2.0 assay. The RNA levels measured by the AMPLICOR v1.0 assay correlated significantly with those measured by the COBAS v2.0 assay, and the sensitivity of the new version 2.0 assay was better than that of version 1.0, especially in serotype 2. In relation to the outcome of IFN therapy, HCV RNA levels from virologically sustained responders by the AMPLICOR v1.0 assay were 82.3 +/- 22.9 kcopies/ml in serotype 1 and 36.9 +/- 13.4 kcopies/ml in serotype 2, and those from virologically nonsustained responders were 525.2 +/- 48.6 kcopies/ml in serotype 1 and 76.7 +/- 19.5 kcopies/ml in serotype 2.The rates of sustained response to <100 kcopies/ml were 34/63 (54.0%) in serotype 1 and 24/48 (50.0%) in serotype 2. A statistically significant virological response was seen in serotype 1 (P < 0.0001), but not in serotype 2. In contrast, the levels in virologically sustained responders by the COBAS v2.0 assay were 88.2 +/- 20.5 KIU/ml in serotype 1 and 136.8 +/- 40.1 KIU/ml in serotype 2, and those in virologically nonsustained responders were 608.8 +/- 48.4 KIU/ml in serotype 1 and 328.3 +/- 62.8 KIU/ml in serotype 2. The rates of sustained response to <100 KIU/ml were 33/60 (55.0%) in serotype 1 and 21/35 (60.0%) in serotype 2. Statistical significance in virological response was seen in both serotype 1 (P < 0.0001) and serotype 2 (P < 0.05). Although the sensitivity of the HCV core protein assay was lower than that with the COBAS v2.0 assay, the HCV core protein levels also correlated well with the results of the COBAS v2.0 assay. The HCV core protein levels of virologically sustained responders were 37.6 +/- 12.0 pg/ml in serotype 1, 81.3 +/- 37.0 pg/ml in serotype 2, and those of virologically nonsustained responders were 289.9 +/- 23.5 pg/ml in serotype 1, 191.4 +/- 32.1 pg/ml in serotype 2. This assay could predict the outcome of IFN therapy in both serotype 1 (P < 0.0001) and serotype 2 (P < 0.05). Thus, both the COBAS v2.0 assay and the HCV core protein assay showed that the viral load was an indicator of virologically sustained response in serotype 2 and in serotype 1.     

Lack of monomeric IgM anti-hepatitis C virus (HCV) core antibodies in patients with chronic HCV infection

Antibodies of the IgM class against the hepatitis C virus core antigen are found in up to 70% of patients with either acute or chronic hepatitis C. The sedimentation rate of such IgM was analyzed by rate-zonal centrifugation of nine sera taken from seven patients, two acutely and five persistently infected with hepatitis C virus. All patients had circulating high-molecular weight (i.e. pentameric) IgM, indicating that the production of low molecular weight IgM, commonly observed in other persistent viral infections, does not apply to hepatitis C virus and cannot be used to distinguish acute from chronic hepatitis C virus infection.     

A peptide derived from hepatitis C virus (HCV) core protein inducing cellular responses in patients with HCV with various HLA class IA alleles

C35‐44 peptide is a well known HLA‐A2‐restricted CTL epitope originating from hepatitis C virus (HCV) core protein. It was reported that the majority of HCV positive patients had significant levels of serum IgG specific to this peptide. This study addressed whether C35‐44 peptide could induce CTL activity restricted to various HLA class IA alleles or could not. This peptide demonstrated binding activity to HLA‐A*2402, ‐A*2601, ‐A*3101, and ‐A*3303 molecules, but not to HLA‐A*1101 by means of stabilization assay. This peptide also induced CTL activity restricted to each of them, except HLA‐A11⁺ peripheral blood mononuclear cells from HCV 1b⁺ patients by means of ⁵¹Cr‐release assay. With regard to HLA‐A2 subtypes, this peptide demonstrated binding activity to HLA‐A*0201 and ‐A*0206, but not to ‐A*0207 molecules. Furthermore, this peptide induced CTL activity from both the patients and healthy donors with all the HLA class IA molecules mentioned above by means of interferon‐γ production assay. These results may provide new insights for the development of a novel peptide vaccine against HCV compatible with various HLA class IA types. J. Med. Virol. 81:1232–1240, 2009. © 2009 Wiley‐Liss, Inc.     

PREVALENCE OF HEPATITIS C VIRUS (HCV) COINFECTION IN HIV INFECTED INDIVIDUALS IN SOUTH INDIA AND CHARACTERIZATION OF HCV GENOTYPES

Purpose: To determine anti-HCV antibodies and genomic subtype of HCV in 1487 confirmed human immunodeficiency virus (HIV) positive samples. Methods: A total of 1487 confirmed HIV-positive samples were tested for anti-HCV antibodies by using a third generation ELISA kit (Ortho 3.0) and by RT PCR for HCV. HIV and HCV coinfected samples were selected for HCV genotyping by RFLP and subtyping with NS5-type specific primers. Results: A total of 1487 HIV-infected serum samples were screened for HCV infection, of which, a 1443 (97.04%) were negative and 45 (3.02%) were coinfected. HIV–HCV coinfection was predominant in the age group 41–50 years (51.1%). HCV genotyping and subtyping was done for the 45 HCV RNA-positive specimens of which genotype 1 was observed in 31 (68.8%) and genotype 3 was observed in 14 (31.1%) subjects. Further subtyping analysis showed the genotype 1b in 23 (51.1%), 1a in eight (17.7%), 3a in 10 (22.2%) and 3b in four (8.8%) subjects. Conclusion: HIV and HCV seroprevalence is higher in South India, and the most prevalent genotype in coinfection was genotype 1b.     

Autoantibody prevalence in children with liver disease due to chronic hepatitis C virus (HCV) infection

HCV infection and interferon-alpha (IFN-α) therapy have been associated with autoimmunity. To assess whether chronic liver disease (CLD) due to HCV infection or its treatment with IFN-α cause autoimmune manifestations, the prevalence of tissue autoantibodies in 51 children with chronic HCV infection and 84 with other CLD was analysed by standard techniques. Sixty-five percent of patients with chronic HCV infection, 66% with chronic hepatitis B infection and 60% with Wilson's disease were positive for at least one autoantibody. In the 51 subjects with chronic HCV infection (29 treated with IFN-α, 22 untreated), tested on 165 occasions over a median of 9 months (range 5–42 months), autoantibodies to nuclei (ANA), smooth muscle (SMA), gastric parietal cell (GPC) and/or liver kidney microsomal type 1 (LKM-1) were similarly prevalent in treated and untreated patients (90% versus 68%, P = 0.12). Positivity for SMA was present in 67%, GPC in 32%, ANA in 10%, LKM-1 in 8% of cases. Treatment with IFN-α had to be suspended due to transaminase elevation in one SMA-positive, one ANA-positive but in three of four LKM-1-positive patients. Our results show that: (i) autoantibodies are common in viral-induced hepatitis and Wilson's disease; (ii) positivity for SMA, GPC, ANA is part of the natural course of chronic HCV infection, their prevalence being unaffected by IFN-α; and (iii) IFN-α should be used cautiously in the treatment of LKM-1/HCV-positive patients.     

TLR3 polymorphisms are associated with virologic response to hepatitis C virus (HCV) treatment in HIV/HCV coinfected patients

BackgroundToll-like receptor-3 (TLR3) is a cellular receptor that may recognize double-stranded RNA (dsRNA) from viruses, resulting in production of proinflammatory cytokines and interferons, which are important for the adaptive immune response.ObjectivesTo analyze the association between Toll-like receptor-3 (TLR3) polymorphisms (rs3775291 and rs13126816) and virologic response to pegylated interferon-alpha plus ribavirin (pegIFNα/RBV) therapy in HIV/HCV coinfected patients.Study designWe performed a retrospective study in 321 naïve patients treated with pegIFNα/RBV. Genotyping was performed by using the GoldenGate^® assay with VeraCode^®. The outcome variables were early virologic response (EVR) and sustained virologic response (SVR).ResultsIn a multivariate analysis, rs3775291 A allele decreased the likelihood of achieving EVR (aOR = 0.20; p = 0.018) and SVR (aOR = 0.38; p = 0.024). Regarding rs13126816, the percentage of EVR decreased with each minor A allele (p = 0.034) in HCV-GT2/3 patients, although no significant association was obtained in the multivariate analysis (p = 0.076). Regarding TLR3 haplotypes (comprised of rs3775291 and rs13126816), GT2/3 patients with AA haplotype had decreased odds of achieving EVR (p = 0.030), whereas GG haplotype increased the likelihood (p = 0.018). Regarding SVR, GG haplotype carriers had increased odds of achieving SVR (p = 0.019, p = 0.043 and p = 0.070 for all, GT2/3 and GT1/4 patients, respectively). Besides, GT1/4 patients with GA haplotype had lower odds of achieving SVR (p = 0.039).ConclusionsOur study shows the first evidence that two TLR3 polymorphisms (rs3775291 and rs13126816) seem to be related to the HCV therapy response in HCV/HIV coinfected patients.     

Autoimmune forms of chronic hepatitis associated with hepatitis C virus (HCV) infection with and without HCV-RNA: histological differences from pure autoimmune hepatitis and chronic hepatitis C

Liver biopsy specimens of pure autoimmune hepatitis (pAIH), autoimmune forms of chronic hepatitis with positivity for anti-hepatitis C virus (anti-HCV) and negativity for HCV-RNA (cAIH-RNA(-)), autoimmune forms of chronic hepatitis with positivity for anti-HCV and HCV-RNA (cAIH-RNA(+)), and chronic hepatitis C (CHC) were compared histologically and statistically to clarify the histological character of the autoimmune form of chronic hepatitis with HCV infection. The following representative histological features were used to investigate: inflammation, fibrosis, plasma cell infiltration, lymphoid aggregates/follicles, non-suppurative destructive cholangitis, and the shape of the enlarged portal tracts. While a considerable overlap in histological features between the pAIH and cAIH-RNA(-) groups and between the CHC and cAIH-RNA(+) groups was recognized, the overlap between the pAIH and CHC groups was small. Significant differences were found between cAIH-RNA(-) and cAIH-RAN(+) groups, especially in necroinflammatory findings. In conclusion, most cases of cAIH-RNA(-) with histological features similar to those of pAIH were shown to be AIH. The remaining cases might be CHC with subsidence of viral duplication. Conversely, many cases of cAIH-RNA(+) with histological findings similar to those of CHC were shown to be CHC clinically mimicking pAIH. The remaining cases might represent coexistence of pAIH and HCV infection.