乙型肝炎病毒及其抗原成分对干扰素信号传导途径分子和抗病毒蛋白表达的影响

目的 了解HBV及其抗原成分对干扰素(IFN)αJanus激酶-信号传导和转录激活子(JAK-STAT)信号传导途径分子和抗病毒蛋白表达可能存在的影响.方法以人肝胚瘤细胞株HepG2细胞为研究对象,分别经质粒转染(以能够表达完整HBV病毒颗粒或HBsAg、HBcAg的质粒pSM2、pHBS2-S和pHBc-EGFP)、病毒感染(以HepG2.2.15细胞培养上清液感染HepG2细胞,其含有完整HBV病毒颗粒和HBV抗原)以及与HBV抗原直接接触刺激等方式处理不同组HepG2细胞,以Northern blot和RT-PCR等方法分析各处理组HepG2细胞的IFN α应答情况,如检测抗病毒蛋白[如粘病毒抵抗蛋白A(MxA)、2'-5'寡腺苷酸合成酶(2'-5'OAS)、9-27等]和JAKSTAT信号传导途径分子(如STAT1)的表达.对数据进行t检验.结果 转染pSM2、pHBS2-S和pHBc-EGFP质粒后,HepG2细胞能够表达完整的HBV颗粒或HBV抗原,且随着转染时间的延长,HBV颗粒或抗原表达量逐步增多,转染48、96h的细胞培养上清液中HBsAg的S/CO值为0.81±0.11和2.35±0.33(t=10.84,P<0.05),HBeAg的S/CO值为0.69±0.06和1.79±0.13(t=18.82,P<0.05).Northern blot分析提示HepG2细胞能够表达IFN α抗病毒蛋白MxA、2',5'OAS、9-27等,但质粒转染、病毒感染和HBV抗原直接接触刺激的HepG2细胞,IFN α抗病毒蛋白MxA、2',5'OAS、9-27等的表达量明显减低,且随着转染时间的延长而进一步减低;此外,STAT1的表达也随着HBV颗粒或HBV抗原的表达而受到抑制.结论在体外细胞模型中,HBV及其抗原成分影响IFN αJAK-STAT信号传导途径分子和抗病毒蛋白的表达;HBV具有拮抗或反作用于IFN α抗病毒活性的机制.

Abstract：

Objective To investigate the possible influence of HBV and its antigens on the expressions of JAK-STAT signal transduction pathway molecules and the antiviral proteins of IFN α.Methods The HepG2 cells were transfected with pSM2.pHBS2-S and pHBc-EGFP plasmids which express HBV whole particles or S-antigen,Pre-S antigen and core antigens.The infectious supernatant from HepG2.2.15cells and the pured HBV proteins which contained tIle S.Pre-S antigens were used to treat the HepG2 cells.Northern blot and RT-PCR were applied to analyse the expresssions of the antiviral proteins MxA,2'-5'OAS.9-27 and the JAK-STAT signal transduction pathway molecules STAT1 in HepG2 cells responded to the IFN αtreatment.Results The HepG2 cells transfected with pSM2,pHBS2-S and pHBc-EGFP plasmids could express whole HBV particles and HBsAg,Pre-S antigen and HBcAg. The quantitation of expressed HBV particles and antigens increased significantly during the course of transfection. Northern blot hybridization analysis indicated that the HepG2 cells expressed IFN α antiviral proteins MxA,2' -5' OAS and 9-27.When transfected with pHBV-dimer,pHBS2-S,pHBc-EGFP plasmids,the IFN:A antiviral proteins MxA,2' -5' OAS and 9-27 in transfected cells were reduced greatly as compared to the un-transfected HepG2 cells,and the expressed antiviral proteins decreased sharply with the development of transfection time. Furthermore,the expression of IFN α JAK-STAT signal transduction pathway molecule STAT1 was also inhibited with the expression of HBV particles and HBV antigens in transfected HepG2 cells. Conclusions The HBV and its antigens influence the expressions of IFN α JAK-STAT signal transduction pathway molecules and antiviral proteins in the hepatocellular models in vitro. It is idicated that HBV might possess the activity to antagonise or counteract the IFN α antiviral action.     

地塞米松、环磷酰胺和他克莫司三种免疫抑制剂影响HBV复制的体外研究

目的探讨地塞米松(DEX)、环磷酰胺(CYP)和他克莫司(FK506)在体外对HBV蛋白合成、DNA复制的影响。方法将不同浓度的DEX、CYP和FK506作用于HepG2.2.15细胞系,通过MTT实验确定药物安全浓度范围,通过检测细胞培养上清液中HBsAg和HBeAg水平,以及细胞内HBV DNA水平来评价HBV的表达和复制情况。结果DEX、CYP和FK506的药物安全浓度范围分别为0~500、0~1000和0~10μg/mL。与培养基对照处理相比,FK506处理后HBsAg、HBeAg分泌及HBV DNA复制变化差异无统计学意义;CYP处理增加HBsAg分泌,与对照相比差异有统计学意义(P0.05);但HBeAg分泌及HBV DNA复制变化差异无统计学意义;DEX作用减少HBsAg和HBeAg的分泌,与对照相比差异有统计学意义(P0.05);但是细胞内HBV DNA复制水平差异无统计学意义(P0.05)。结论在药物安全浓度范围内,FK506对HepG2.2.15细胞HBV DNA复制无直接抑制或促进作用。CYP处理后增加HepG2.2.15细胞HBsAg表达,但HBeAg表达及HBV DNA复制变化差异无促进作用;DEX处理抑制HepG2.2.15细胞HBsAg和HBeAg表达,但对HBV DNA复制无抑制作用。     

长片段RNA抑制HepG2.2.15细胞中HBV基因的表达和复制

目的 评估长的反义RNA干扰片段在培养细胞株中对HBV复制的抑制效应.方法将HBV基因组S区的全部核苷酸序列插入至pTARGETTM载体中,并将重组载体转染入HepG2.2.15细胞中.用酶联免疫吸附法检测HBsAg与HBeAg水平,用荧光定量PCR法检测HBVDNA水平.对数据采用多个独立样本Kruskal-Wallis检验与两两比较的Mann-Whitney U检验.结果 经过处理后,HepG2.2.15细胞上清液中HBsAg表达量(A值)在HBS2组(携带长片段反义RNA)为0.621±0.027,在HBS4组(携带正义RNA)为3.399±0.018,对照组为2.232±0.187;HBeAg表达量(A值)在HBS2组、HBS4组和对照组分别为0.749±0.019、1.548±0.025和1.570±0.044; HBV DNA水平(×104拷贝/ml)在HBS2组、HBS4组、对照组分别为1.597±0.082、3.381±0.297和3.610±0.063.与对照组相比,HBS2组HBsAg、HBeAg和HBV DNA表达量均降低,统计量Z值均为-2.309,P值均＜0.05; HBS4组HBsAg表达量增高(Z=-2.309,P＜0.05),而HBeAg和HBV DNA表达量无明显差异,统计量Z值分别为-0.866、-1.155,P值均＞0.05.结论 长片段反义RNA能抑制HBV基因的表达和病毒复制.

Abstract：

Objective To evaluate the inhibitory effects of long antisense RNA on HBV replication in HepG2.2.15 cells. Methods The coding region of HBV S gene was cloned into pTARGET vector in sense and antisense orientations and the recombinant plasmids were transfected into HepG2.2.15 cells which were divided into HBS2 (antisense RNA) group, HBS4 (sense RNA) group and control group. HBsAg and HBeAg in the culture supernant were detected by ELISA. The HBV DNA in the supernant was quantified by real-time PCR. Results After treatment, the levels of HBsAg in HepG2.2.15 cell supernatants of three groups were 0.621 ± 0.027, 3.399 ± 0.018 and 2.232 ± 0.187 respectively; the levels of HBeAg were 0.749 ± 0.019,1.548 ± 0.025 and 1.570 ± 0.044 respectively and the levels of HBV DNA were 1.597 ± 0.082, 3.381 ± 0.297 and 3.610 ± 0.063 respectively. The expressions of HBsAg and HBeAg and the HBV DNA level in HBS2 group were remarkably reduced as compared to the control (Z = -2.309, P ＜ 0.05); whereas the sense plasmid transfection (HBS4) did not affect HBeAg (Z= -0.866) and HBV DNA (Z = -1.155) levels in the culture supernant but slightly increased the HBsAg level (Z = -2.309). Conclusion Antisense RNA might be a useful tool to repress HBV replication.     

乙型肝炎病毒X蛋白及其截短体与损伤DNA结合蛋白1在HBV复制中的作用

目的 探讨乙型肝炎病毒X蛋白(HBx)及其两个截短体(HBx1 ～ 101、HBx43～ 154)与损伤DNA结合蛋白(DDB)1在HBV复制中的作用.方法 用质粒瞬时转染HepG2细胞,72 h后分别提取细胞总蛋白质和总RNA,通过Western blot分析验证DDB1蛋白表达,逆转录实时定量PCR在基因的mRNA水平观察HBx蛋白及其截短体对DDB1蛋白表达的影响.提取转染72 h后细胞胞质DNA,收集细胞的培养上清液,通过实时定量PCR及酶联免疫吸附试验检测各组细胞胞质HBV DNA复制及培养上清液中病毒标志物HBsAg、HBeAg表达水平,从而观察HBx蛋白及其两个截短体与DDB1对HBV复制的影响.对数据进行单因素方差分析及t检验.结果 在有HBV复制的HepG2细胞中,缺失HBx转染组细胞中DDB1蛋白在mRNA水平明显下降(相对表达水平为野生型转染组的52.74％±8.95％,t=9.143,P＜0.05),胞质DNA的复制及培养上清液中病毒标志物HBsAg、HBeAg表达水平也明显下降(相对表达水平分别为野生型转染组的55.49％±1.19％、48.05％±2.90％、46.22％±2.20％,P值均＜0.05).共转染HBx N-端截短体HBx43～54后细胞中DDB1蛋白mRNA水平恢复到野生型水平,且能使缺失HBx蛋白的HepG2细胞中胞质HBV DNA的复制及培养上清液中病毒标志物HBsAg、HBeAg的表达恢复到野生型水平.但共转染HBx C-端截短体HBx1 ～ 101的细胞中DDB1蛋白在mRNA水平较野生组明显下降(相对表达水平为野生型转染组的59.95％±9.09％,t=7.629,P＜0.05),且不能使转染缺失HBx蛋白的HepG2细胞中胞质HBVDNA的复制及培养上清液中病毒标志物HBsAg、HBeAg的表达恢复到野生型水平(相对表达水平分别为野生型转染组的62.53％±0.67％、63.13％±2.14％、55.40％±0.99％,P值均＜0.05).并且各转染组DDB1蛋白mRNA水平变化与胞质HBV DNA复制和培养上清液中病毒标志物HBsAg、HBeAg表达水平是一致的.结论 C-端53个氨基酸及DDB1蛋白对于HBV野生型水平的复制是需要的,而N-端42个氨基酸对于HBV复制水平无明显影响.C-端53个氨基酸对HBV复制的影响作用可能是通过影响DDB1蛋白水平实现的.     

细胞内La蛋白对乙型肝炎病毒蛋白质表达的影响

目的 探讨细胞内La蛋白对HBV蛋白质表达的影响.方法 针对人La蛋白序列设计特异性的小分子干扰RNA(siRNA),通过体外转录的方法合成双链siRNA,并转染进入稳定表达HBV的HepG2.2.15细胞,实时荧光定量基因扩增技术测定HepG2.2.15细胞中的La蛋白mRNA变化水平;电化学发光分析技术检测HepG2.2.15细胞分泌的HBsAg和HBeAg变化情况.所得数据进行配对假设检验的统计学分析.结果 特异性siRNA干扰La蛋白mRNA的表达,使La蛋白在HepG2.2.15细胞中的表达降低;HepG2.2.15细胞分泌在培养上清液中的HBsAg和HBeAg表达显著下降,相关性分析显示,HBsAg、HBeAg变化水平与La蛋白mRNA变化水平呈正相关,相关系数分别为0.938和0.899.结论 特异性siRNA能够抑制细胞内La蛋白mRNA的表达,La蛋白可通过某种方式影响HBV蛋白质的表达.     

肽核酸抑制HBV复制与表达的体外研究

合成肽核酸(PNA)片段,由OligofectamineTm转染至HepG2.2.15细胞与HBV各编码区保守区域相结合。用ELISA方法测定HepG2.2.15细胞中HBsAg、HBeAg滴度,PCR测定HBV DNA含量。通过计算抑制百分率,筛选有效PNA片段。结果在500 mol/L浓度下,PG3 HBsAg、HBeAg、HBV DNA表达抑制率分别为51.03%、55.38%、20.10%;PG6 HBsAg、HBeAg、HBV DNA表达抑制率分别为47.00%、43.10%、51.03%。表明PNA可由OligofectamineTm转染至HepG2.2.15细胞,从而抑制HBV的复制和抗原系统的表达。     

复方六月雪体外抗HBV的实验研究

目的观察复方六月雪(CLYX)体外抗乙型肝炎病毒(HBV)的作用。方法在最大无毒浓度(TC0)基础上观察不同浓度药物作用于HepG2.2.15细胞,分别在第4天和8天收集细胞培养上清液,采用实时荧光定量PCR法检测上清液HBV DNA的含量,采用ELISA法测定上清液HBsAg和HBeAg的滴度。结果无毒浓度的复方六月雪在HepG2.2.15细胞培养中可有效地抑制细胞HBV DNA的复制及HBsAg和HBeAg的分泌。结论CLYX在体外有显著的抗HBV的作用。     

基因重组HBV联合表达反义RNA和显性阴性突变体抗HBV作用及HBV包装细胞系的构建

目的探讨HBV作为基因治疗载体的可能性并检验其联合表达反义RNA和显性阴性突变体抗HBV的作用.方法在表达完整HBV颗粒的质粒上,经基因修饰后联合表达S区反义RNA和核心-p蛋白的融合蛋白,整合于具有HBV复制的2.2.15细胞,形成细胞克隆,ELISA法检测细胞培养上清液中HBsAg和HBeAg,斑点杂交法检测细胞内HBV核壳中HBV DNA,PCR检测上清液中重组HBV颗粒.HBV全基因经删除包装信号ε区后,插入到G418抗性pCI-neo载体,转染HepG2细胞系,用G418筛选形成细胞克隆,检测表达HBsAg及HBcAg较多者作为HBV包装细胞系,进一步转染表达复制缺损型HBV的质粒,经两种抗生素同时筛选,PCR方法观察上清液中的病毒.结果2.2.15-pMEP4组、2.2.15-CP组、2.2.15-SAS组和2.2.15-CPAS组,对HBsAg平均抑制率分别为2.74%±3.83%、40.08%±2.05%(t=35.5,P＜0.01)、66.54%±4.45%(t=42.3,P＜0.01)和73.68%±5.07%(t=51.9,P＜0.01);对HBeAg平均抑制率分别为4.46%±4.25%、52.86%±1.32%(t=36.2,P＜0.01)、26.36%±1.69%(t=22.3,P＜0.01)和59.28%±2.10%(t=39.0,P＜0.01);对HBV复制的抑制率分别为0、82.0%、59.9%和96.6%.在各治疗组培养上清液中均能检测出重组HBV颗粒.证明包装细胞系具有HBsAg和HBcAg表达,pMEP-CPAS质粒转染G418抗性包装细胞系,在细胞培养上清液中检出重组HBV,未检出野生型HBV.结论在同一载体上联合表达S区反义RNA及核心蛋白与部分P蛋白的融合蛋白,具有较单一机制更强的抗HBV作用;经修饰后的HBV基因组在野生型HBV辅助下,仍能包装并分泌完整的HBV样颗粒.包装细胞系能为复制缺损型HBV提供包装,但效率较低.     

APOBEC3F剪接亚型与全长APOBEC3F、APOBEC3G对乙肝病毒作用的比较

目的比较APOBEC3F剪接亚型3F79与完整APOBEC3F以及APOBEC3G对HepG2.2.15细胞中HBV DNA复制及HBsAg、HBeAg抗原分泌的影响。方法用PCR合成法扩增人APOBEC3F剪接亚型3F79,构建真核表达载体pEGFPC1-3F79和原核表达质粒pET28a-3F79,将pEGFPC1-3F79与含有全长APOBEC3F和APOBEC3G的质粒Pflag-APOBEC3F、PC-APOBEC3G-HA转染入HepG2.2.15中,检测转染后细胞上清中HBV DNA以及HBsAg和HBeAg的水平。结果构建的重组载体经酶切和PCR鉴定,表明3F79基因正确地插入。将pEGFPC1-3F79与Pflag-APOBEC3F、PC-APOBEC3G-HA转染HepG2.2.15细胞后,pEGFPC1-3F79对细胞中HBV的复制及HBsAg和HBeAg的分泌无明显的抑制作用(P0.05),而转染含有完整APOBEC3F和APOBEC3G质粒的HepG2.2.15细胞与对照组相比,HBsAg、HBeAg、HBV DNA含量明显下降,差异有统计学意义(P0.05)。结论 3F79不能像完整APOBEC3F和APOBEC3G一样抑制HepG2.2.15细胞中HBV DNA复制以及抗原的分泌。     

APOBEC3G体外抗乙型肝炎病毒的研究

目的探讨载脂蛋白B mRNA编辑酶催化多肽样蛋白3G（apolipoprotein B mRNA editing enzyme catalytic polypeptide like3G,APOBEC3G）（也称为CEM15）体外抗乙型肝炎病毒（HBV）的作用及其机制。方法脂质体转染pcDNA3.1 Human APOBEC3G-Myc-6Xhis、pcDAN3.1/His-C进入HepG2.2.15细胞,转染后,RT-PCR证实转染基因的表达,Western Blot证实蛋白的表达。通过ELISA方法检测细胞上清液中乙型肝炎表面抗原（HBsAg）及乙型肝炎e抗原（HBeAg）,RT-PCR分析APOBEC3G对HBV mRNA转录的影响。结果APOBEC3G基因与蛋白在HepG2.2.15细胞都有表达,与空质粒转染组相比,pcDNA3.1 Human APOBEC3G-Myc-6Xhis转染组HBsAg含量下降70.38%,HBeAg含量下降62.88%,未转质粒细胞为空白对照组。结论APOBEC3G在体外可以抑制HBV复制,可以作为一种新型的抗病毒制剂治疗乙肝病毒感染。     

Interferon-α response in chronic hepatitis B-transfected HepG2.2.15 cells is partially restored by lamivudine treatment

AIM: To characterize the IFN-response and its modulation by the antiviral compound lamivudine in HBVtransfected HepG2.2.15 cells.METHODS: HepG2.2.15 and HepG2 cells were stimulated with various concentrations of IFN-α2a in the presence or absence of lamivudine. Then, total RNA was extracted and analysed by customised cDNA arrays and northern blot for interferon-inducible genes (ISGs). In addition, cellular proteins were extracted for EMSA and western blot. HBV replication was assessed by southern blot or ELISAs for HBsAg and HBeAg.RESULTS: Two genes (MxA, Cig5) with completely abolished and 4 genes (IFITM1, -2, -3, and 6-16)with partially reduced IFN-responses were identified in HepG2.2.15 cells. In 2 genes (IFITM1, 6-16), the response to IFN-α could be restored by treatment with lamivudine. This effect could not be explained by a direct modulation of the Jak/Stat signalling pathway since EMSA and western blot experiments revealed no suppression of Stat1 activation and ISGF3 formation after stimulation with IFN-α in HepG2.2.15 compared to HepG2 cells.CONCLUSION: These results are consistent with the assumption that chronic hepatitis B may specifically modulate the cellular response to IFN by a selective blockage of some ISGs. Antiviral treatment with lamivudine may partially restore ISG expression by reducing HBV gene expression and replication.     

Interferon-α response in chronic hepatitis B-transfected HepG2.2.15 cells is partially restored by lamivudine treatment

INTRODUCTION Hepatitis B (HBV) is a hepatotropic DNA virus capable of causing both acute and chronic hepatitis in humans. It is estimated that over 350 million people are chronically infected with HBV worldwide. Currently approved thera- peutic strategies for treatment of HBV include interferon- alpha (IFN-a), the nucleoside analogue lamivudine and the nucleotide analogue adefovir[1,2]. However, only a minority of patients treated with IFN-a has a long-term sustained response with …     

Interferon-α response in chronic hepatitis B-transfected HepG2.2.15 cells is partially restored by lamivudine treatment

AIM: To characterize the IFN-response and its modulation by the antiviral compound lamivudine in HBV-transfected HepG2.2.15 cells. METHODS: HepG2.2.15 and HepG2 cells were stimulated with various concentrations of IFN-alpha2a in the presence or absence of lamivudine. Then, total RNA was extracted and analysed by customised cDNA arrays and northern blot for interferon-inducible genes (ISGs). In addition, cellular proteins were extracted for EMSA and western blot. HBV replication was assessed by southern blot or ELISAs for HBsAg and HBeAg. RESULTS: Two genes (MxA, Cig5) with completely abolished and 4 genes (IFITM1, -2, -3, and 6-16) with partially reduced IFN-responses were identified in HepG2.2.15 cells. In 2 genes (IFITM1, 6-16), the response to IFN-alpha could be restored by treatment with lamivudine. This effect could not be explained by a direct modulation of the Jak/Stat signalling pathway since EMSA and western blot experiments revealed no suppression of Stat1 activation and ISGF3 formation after stimulation with IFN-alpha in HepG2.2.15 compared to HepG2 cells. CONCLUSION: These results are consistent with the assumption that chronic hepatitis B may specifically modulate the cellular response to IFN by a selective blockage of some ISGs. Antiviral treatment with lamivudine may partially restore ISG expression by reducing HBV gene expression and replication.     

维甲酸诱导基因-I诱导干扰素的产生在乙型肝炎病毒感染清除中的作用

目的探讨维甲酸诱导基因-I(RIG-I)在诱导HBV感染IFN产生中的影响,以期对阐明乙型肝炎慢性化机制,寻找新的治疗靶点提供新的思路。方法以RIG-I表达载体flagRIG-l-ful1转染培养6孔板中的HepG2、HepG2.2.15,24h后用水疱性口炎病毒(VSV)感染细胞,然后在0、8、16和24h收集细胞及培养上清液,采用quantitive RT-PCR、Western印迹检测RIG-I、MDA5、IPS-1、ISG54等基因的表达,ELISA检测培养上清液中分泌的IFN-β水平。结果 HepG2.2.15细胞在VSV感染后IFN-β分泌水平(11.18±1.34)pg/mL明显低于HepG2细胞(275.50±22.97)pg/mL(P<0.01);通过质粒flagRIG-I-ful1转染高表达RIG-I后,HepG2.2.15分泌IFN-β的能力恢复至(548.78±57.99)pg/mL与HepG2细胞(532.10±39.34)pg/mL接近的水平(P=0.7013)。结论 HepG2.2.15细胞感染VSV后IFN产生障碍,高表达RIG-I后IFN表达水平得到恢复,提示RIG-I功能缺陷导致抗病毒免疫应答降低,RIG-I可能在HBV感染清除中起重要作用。     

乙型肝炎病毒X基因转染人肝癌细胞株双向凝胶电泳图谱分析

目的 研究转染HBV X基因的人肝癌细胞株中蛋白质表达谱的改变,为筛查在HBV相关性肝细胞癌发生中发挥重要作用的关键蛋白质分子奠定基础.方法 利用分子生物学方法建立稳定表达HBV X蛋白(HBx)的肝癌细胞株HepG2+HBx,同时设空载体peDNA3转染细胞HepG2-pcDNA3及HBV全基因转染的人肝癌细胞株HepG2.2.15为对照.PCR法扩增Neo基因检测质粒DNA片段的插入,免疫印迹法检测HBx蛋白的表达.利用固相pH梯度双向凝胶电泳分离3种肝癌细胞株HepG2-pcDNA3、HepG2-HBx和HepG2.2.15的总蛋白,用图像分析软件比较、分析、识别细胞间的差异表达蛋白质.统计学分析采用t检验.结果 获得分辨率高、重复性好的3种细胞的双向电泳(2-DE)图谱.软件分析表明,HepG2-pcDNA3、HepG2-HBx和HepG2.2.15细胞的2-DE凝胶可识别蛋白点分别为(2 095±137)、(2 188±105)和(2 109±20)个.比较HepG2-pcDNA3与HepG2-HBx细胞的2-DE图谱发现37个差异显著的蛋白点,其中21个在HepG2-HBx表达上调,16个下调.6个表达量差异在5倍以上(t=0.027,P＜0.05);HepG2.2.15与HepG2-HBx细胞相比,有38个差异显著的蛋白点,其中35个在HepG2-HBx细胞中上调,3个下调,14个表达量差异在5倍以上(t=0.031,P＜0.05).结论 HBx基因转染引起人肝癌细胞株蛋白质表达谱的变化,可能与感染的肝细胞发生恶性转化的分子生物学机制有关.     

人干扰素-α基因转移、表达及其抗乙型肝炎病毒的实验研究

目的研究人干扰素-α(hIFN-α)基因的转移、表达及其抗乙型肝炎病毒的作用.方法利用聚合酶链反应(PCR)技术和基因重组技术,体外扩增hIFN-α基因并构建重组表达hIFN-α基因的逆转录病毒表达载体(pDOR-IFN-α),用NIH 3T3细胞扩增法测定其假病毒颗粒滴度,用染料吸收法检测hIFN-α活性;将假病毒颗粒感染2.2.15细胞,用固相放免法检测其上清HBsAg和HBeAg,用斑点杂交法结合计算机扫描检测其细胞HBV DNA密度.结果PCR克隆出648 bphIFN-α全基因;假病毒颗粒滴度为1×106CFU/ml;hIFN-α生物活性为239 IU/ml/1×106/48 h;对HBsAg的抑制率随培养时间(2、4、6和8 d)的延长而逐渐增高,抑制率分别为33%、55%、55%和62%,而对HBeAg的抑制则在转染后的第2天抑制率最高,以后随培养时间延长而逐渐下降,其抑制率分别为67.7%、40%、19.5%和25.3%.而对照组对HBsAg第2、4、6、8天的抑制率分别为0%、10.8%、0%和13%,对HBeAg的抑制率分别为0%、0%、0%和1.2%.而且对HBV DNA亦有明显的抑制作用,抑制率达66%;而对照组(空白载体)抑制作用不明显.结论hIFN-α基因可以成功地转移和表达,并有抑制HBV复制和表达的作用.     

IPS-1SNP在调控HBV感染后干扰素应答机制的研究

目的：探讨干扰素β启动子刺激因子1（IPS-1）不同单核苷酸多态性（SNP）基因型对HBV感染后干扰素应答作用机制。方法利用IPS-1野生型和rs17857295、rs7262903、rs7269320三种SNP基因型慢病毒表达载体,转染目的细胞HepG2、HepG2．2．15细胞,qPCR检测HBV感染和IPS-1不同SNP基因型对目的基因表达情况的影响,检测细胞转染后IFN-βmRNA表达水平,探讨IPS-1不同SNP基因型对HBV感染后细胞干扰素应答的机制。结果IPS-1rs17857295和rs7262903两种SNP基因型转染HepG2．2．15细胞后,IPS-1基因表达水平显著低于野生型转染组（451．77比712．53,498．71比712．53,P＜0．01）;但IFN-βmRNA表达水平显著高于野生型转染组（分别为5．33比0．98和3．59比0．98,P＜0．01）;rs7269320SNP基因型过表达后,IPS-1基因表达水平显著低于野生型转染组（290．63比712．53,P＜0．01）,但IFN-βmRNA表达水平无明显变化（0．74比0．98）。另外,rs17859295基因型分别转染HepG2和HepG2．2．15细胞后,后者IFN-βmRNA表达水平显著高于前者（5．33比2．25,P＜0．01）。结论IPS-1rs17857295和rs7262903两种SNP基因型HBV感染者,尤其rs17857295SNP基因型,清除病毒的能力可能强于野生型的感染者;而IPS-1野生型和rs7269320SNP基因型HBV感染者可能更易形成病毒感染的慢性化。     

MxA inhibits hepatitis B virus replication by interaction with hepatitis B core antigen

Human MxA, an interferon-inducible cytoplasmic dynamin-like GTPase, possesses antiviral activity against multiple RNA viruses. Recently, MxA has also been demonstrated to have activity against the hepatitis B virus (HBV), a well-known DNA virus responsible for acute and chronic liver disease in humans. We investigated the molecular mechanism for the anti-HBV activity of MxA. Our results demonstrated that in HepG2.2.15 cells, MxA GTPase independently suppressed the production of hepatitis B surface antigen and HBV DNA without changing the level of hepatitis B core antigen (HBcAg) and the distribution of HBV mRNA. MxA significantly reduced the level of the encapsidated pregenomic RNA. Through its central interactive domain, MxA interacted with HBcAg, causing accumulation of the proteins in perinuclear compartments. MxA-HBcAg interaction significantly affected the dynamics of HBcAg by immobilizing HBcAg in the perinuclear structures. CONCLUSION: MxA displays antiviral activity against HBV involving a mechanism of MxA-HBcAg interaction that may interfere with core particle formation.