Establishment and Application of Hepatitis B Virus Persistent Replication Model in IFNAR^(-/-) Mouse

Summary： The type I interferon and IFNAR play an important role in hepatitis B virus （HBV） infection and anti-HBV therapy. However, its mechanism of action is still poorly understood. To gain more in- sights into the role of type I interferon and type I interferon receptor （IFNAR） in HBV infection, we established an HBV persistent replication IFNAR knockout （IFNAR-/-） mouse model and preliminarily applied this model. At first, the progeny of IFNAR-/- mouse was reproduced. Then hydrodynamic injec- tion with pAAV/HBV1.2 plasmid was conducted to establish the persistent HBV replication IFNAR-/- mouse model. At last, we applied this model to evaluate the effect of nucleoside analogues entecavir （ETV） on HBV replication. It was found that there was no difference in the serum HBsAg and HBeAg levels and HBcAg expression in the liver tissue between the ETV treated groups and normal saline （NS） treated group, but the serum HBV DNA levels were significantly suppressed 10, 25, 40 and 55 days af- ter the ETV treatment [P=0.035, P=0.00, P=0.149 and P=-0.084, IFNAR knockout （KO） control group vs. C57BL/6 ETV groups, respectively; P=0.081, P=0.001, P=0.243 and P=-0.147, IFNAR KO control group vs. IFNAR KO ETV groups, respectively]. Interestingly, there was no difference in serum HBV DNA levels between the ETV treated IFNAR/- and C57BL/6 mice. This result suggests that HBV sup- pression during ETV treatments doesn＇t depend on type Ⅰinterferon and IFNAR. Collectively, persis- tent HBV replication IFNAR/ mouse model that we established is a useful and convenient tool to detect the function of the type Ⅰ interferon and IFNAR in HBV infection and anti-HBV treatments.

Hepatocellular carcinoma mouse models:Hepatitis B virusassociatedhepatocarcinogenesis and haploinsufficienttumor suppressor genes

The multifactorial and multistage pathogenesis of hepatocellular carcinoma(HCC)has fascinated a wide spectrum of scientists for decades.While a number of major risk factors have been identified,their mechanistic roles in hepatocarcinogenesis still need to be elucidated.Many tumor suppressor genes(TSGs)have been identified as being involved in HCC.These TSGs can be classified into two groups depending on the situation with respect to allelic mutation/loss in the tumors:the recessive TSGs with two required mutated alleles and the haploinsufficient TSGs with one required mutated allele.Hepatitis B virus(HBV)is one of the most important risk factors associated with HCC.Although mice cannot be infected with HBV due to the narrow host range of HBV and the lack of a proper receptor,one advantage of mouse models for HBV/HCC research is the numerous and powerfulgenetic tools that help investigate the phenotypic effects of viral proteins and allow the dissection of the dose-dependent action of TSGs.Here,we mainly focus on the application of mouse models in relation to HBV-associated HCC and on TSGs that act either in a recessive or in a haploinsufficient manner.Discoveries obtained using mouse models will have a great impact on HCC translational medicine.

SOCS3 Expression Correlates with Severity of Inflammation in Mouse Hepatitis Virus Strain 3-induced Acute Liver Failure and HBV-ACLF

Summary： Recently, suppressor of cytokine signaling-3 （SOCS3） has been shown to be an inducible endogenous negative regulator of Janus kinase/signal transducers and activators of transcription （JAK/STAT） pathway which is relevant in inflammatory response, while its functions in acute liver failure and HBV-induced acute-on-chronic liver failure （HBV-ACLF） have not been fully elucidated. In this study, we explored the role of SOCS3 in the development of mouse hepatitis virus strain 3 （MHV-3）-induced acute liver failure and its expression in liver and peripheral blood mononuclear cells （PBMCs） of patients with HBV-ACLF. Inflammation-related gene expression was detected by real-time PCR, immtmohistochemistry and Western blotting. The correlation between SOCS3 level and liver injury was studied. Our results showed that the SOCS3 expression was significantly elevated in both the liver tissue and PBMCs from patients with HBV-ACLF compared to mild chronic hepatitis B （CHB）. Moreover, a time course study showed that SOCS3 level was increased remarkably in the liver of BALB/cJ mice at 72 h post-infection. Pro-inflammatory cytokines, interleukin （IL）-1 β, IL-6, and tumor necrosis factor （TNF）-α, were also increased significantly at 72 h post-infection. There was a close correlation between hepatic SOCS3 level and IL-6, and the severity of liver injury defined by alanine aminotransferase （ALT） and aspartate aminotransferase （AST） levels, respectively. These data suggested that SOCS3 may play a pivotal role in the pathogenesis of MHV-3-induced acute liver failure and HBV-ACLF.

Application of hepatitis B virus replication mouse model

AIM:To evaluate the value of the hepatitis B virus(HBV) replication mouse model with regard to several aspects of the study of HBV biology.METHODS:To evaluate the HBV replication mouse model in detecting the efficacy of anti-HBV agents,the interferon inducer polyinosinic-polytidylin acid(polyIC) and nucleotide analogues adefovir and entecavir were administered to mice injected with wild type pHBV4.1,and the inhibiting effect of these agents on HBV DNA replication was evaluated.To identify the model's value in a replication ability study of HBV drug-resistant mutants and a HBx-minus mutant,telbivudine resistance mutants(rtM204I,ayw subtype),adefovir resistance mutants(rtA181V + rtN236T,ayw subtype) and HBxminus mutants were injected respectively,and their corresponding HBV DNA replication intermediates in mouse liver were assessed.RESULTS:Compared with the wild type HBV replication mouse model without antiviral agent treatment,the HBV DNA replication intermediates of the polyICtreated group were decreased 1-fold;while in the entecavir-and adefovir-treated groups,the levels of HBV DNA replication intermediates were inhibited 13.6-fold and 1.4-fold,respectively.For the mouse models injected with telbivudine resistance mutant,adefovir resistance mutant and HBx-minus mutant,HBV DNA replication intermediates could still be detected,but the levels of HBV DNA replication intermediates of these mutants decreased 4.5-fold,5.6-fold and 2.9-fold respectively,compared with the mouse model with wild type HBV plasmid.CONCLUSION:The HBV replication mouse model we established was a useful and convenient tool to detect the efficacy of antiviral agents and to study the replication ability of HBV mutants in vivo.

Expression of hepatitis B virus 1.3-fold genome plasmid in an SV40 T-antigen-immortalized mouse hepatic cell line

AIM:To investigate the expression of the hepatitis B virus(HBV)1.3-fold genome plasmid(pHBV1.3)in an immortalized mouse hepatic cell line induced by SV40T-antigen(SV40T)expression.METHODS:Mouse hepatic cells were isolated from mouse liver tissue fragments from 3-5 d old Kunming mice by the direct collagenase digestion method and cultured in vitro.The pRSV-T plasmid was transfected into mouse hepatic cells to establish an SV40LT-immortalized mouse hepatic cell line.The SV40LT-immortalized mouse hepatic cells were identified and transfected with the pHBV1.3 plasmid.The levels of hepatitis B surface antigen(HBsAg)and hepatitis B e antigen(HBeAg)in the supernatant were determined by an electrochemiluminescence immunoassay at 24,48,72 and 96 h after transfection.The expressions of HBsAg and hepatitis B c antigen(HBcAg)in the cells were investigated by indirect immunofluorescence analysis.The presence of HBV DNA replication intermediates in the transfected cells and viral particles in the supernatant of the transfected cell cultures was monitored using the Southern hybridization assay and transmission electronic microscopy,respectively.RESULTS:The pRSV-T plasmid was used to immortalize mouse hepatocytes and an SV40LT-immortalized mouse hepatic cell line was successfully established.SV40LT-immortalized mouse hepatic cells have the same morphology and growth characteristics as primary mouse hepatic cells can be subcultured and produce albumin and cytokeratin-18 in vitro.Immortalized mouse hepatic cells did not show the characteristics of tumor cells,as alpha-fetoprotein levels were comparable(0.58±0.37 vs 0.61±0.31,P=0.37).SV40LTimmortalized mouse hepatic cells were then transfected with the pHBV1.3 plasmid,and it was found that the HBV genome replicated in SV40LT-immortalized mouse hepatic cells.The levels of HBsAg and HBeAg continuously increased in the supernatant after the transfection of pHBV1.3,and began to decrease 72 h after transfection.The expressions of HBsAg and HBcAg were observed in the pHBV1.3-transfected cells.HBV DNA replication intermediates were also observed at72 h after transfection,including relaxed circular DNA,double-stranded DNA and single-stranded DNA.Furthermore,a few 42 nm Dane particles,as well as many22 nm subviral particles with a spherical or filamentous shape,were detected in the supernatant.CONCLUSION:SV40T expression can immortalize mouse hepatic cells,and the pHBV1.3-transfected SV40T-immortalized mouse hepatic cell line can be a new in vitro cell model.

Contributions of transgenic mouse studies on the research of hepatitis B virus and hepatitis C virus-induced hepatocarcinogenesis

Transgenic mouse technology has enabled the investigation of the pathogenic effects, including those on development, immunological reactions and carcinogenesis, of viral genes directly in living organism in a real-time manner. Although viral hepatocarcinogenesis comprises multiple sequences of pathological events, that is, chronic necroinflammation and the subsequent regeneration of hepatocytes that induces the accumulation of genetic alterations and hepatocellular carcinoma(HCC), the direct action of viral proteins also play significant roles. The pathogenesis of hepatitis B virus X and hepatitis C virus(HCV) core genes has been extensively studied by virtue of their functions as a transactivator and a steatosis inducer, respectively. In particular, the mechanism of steatosis in HCV infection and its possible association with HCC has been well studied using HCV core gene transgenic mouse models. Although transgenic mouse models have remarkable advantages, they are intrinsically accompanied by some drawbacks when used to study human diseases. Therefore, the results obtained from transgenic mouse studies should be carefully interpreted in the context of whether or not they are well associated with human pathogenesis.

Effect of Ligands to Toll-Like Receptors (TLR) 3, 7 and 9 on Mice Infected with Mouse Hepatitis Virus A59

Mice infected with mouse hepatitis virus A59 (MHV-A59), an enveloped, positive-strand RNA Co-ronavirus, induce hepatitis, thymus involution, IgG2a-restricted hypergammaglobulinaemia, transaminase release and autoantibodies (autoAb) to liver and kidney fumarylacetoacetate hy-drolase (FAH). Since Toll-like receptors (TLR) play a central role in innate immunity, we explored the effects of TLR3, 7 and 9 stimulation on MHV mouse infection. Thus, the animals were treated with Poly (I:C), Loxoribine and CpG, the respective TLR ligands. MHV-infected mice inoculated with Poly (I:C) had significant lower levels of plasma transaminases and Ig, anti-MHV Ab, and uric acid than MHV-infected animals, whereas autoAb to kidney tissue were observed. Loxoribine only produced a slight decrease of uric acid levels and serum Ig. CpG showed deleterious effects on MHV-infected mice, since survival of animals dramatically dropped to about 10%. AutoAb to murine tissues and uric acid release were not affected, whereas transaminases and anti-MHV Ab were slightly elevated. Besides, CpG administration produced a decrease of the high levels of serum Ig induced by the virus. Therefore, results indicated that TLR3 stimulation appeared to protect the animals against the viral infection, whereas CpG aggravated its signs. Loxoribine, the TLR7 ligand, did not show major effects.

Hepatocellular carcinoma xenograft supports HCV replication:A mouse model for evaluating antivirals

AIM: To develop a hepatocellular carcinoma (HCC) xenograft model for studying hepatitis C virus (HCV) replication in a mice, and antiviral treatment.METHODS: We developed a stable S3-green fluorescence protein (GFP) cell line that replicated the GFP-tagged HCV sub-genomic RNA derived from a highly efficient JFH1 virus. S3-GFP replicon cell line was injected subcutaneously into γ-irradiated SCID mice. We showed that the S3-GFP replicon cell line formed human HCC xenografts in SCID mice. Cells were isolated from subcutaneous tumors and then serially passaged multiple times in SCID mice by culturing in growth medium supplemented with G-418. The mouse-adapted S3-GFP replicon cells were implanted subcutaneously and also into the liver of SCID mice via intrasplenic infusion to study the replication of HCV in the HCC xenografts. The tumor model was validated for antiviral testing after intraperitoneal injection of interferon-α (IFN-α). RESULTS: A highly tumorigenic S3-GFP replicon cell line was developed that formed subcutaneous tumors within 2 wk and diffuse liver metastasis within 4 wk in SCID mice. Replication of HCV in the subcutaneous and liver tumors was confirmed by cell colony assay, detection of the viral RNA by ribonuclease protection assay and real-time quantitative reverse transcription polymerase chain reaction. High-level replication of HCV sub-genomic RNA in the tumor could be visualized by GFP expression using fluorescence microscopy. IFN-α cleared HCV RNA replication in the subcutaneous tumors within 2 wk and 4 wk in the liver tumor model. CONCLUSION: A non-infectious mouse model allows us to study replication of HCV in subcutaneous and metastatic liver tumors. Clearance of HCV by IFN-α supports use of this model to test other anti-HCV drugs.

In vivo comparison of transduction efficiency with recombinant adenovirus-mediated p53 in a human colon cancer mouse model by different delivery routes

Objective： To evaluate transduction efficiency with recombinant adenovirus-mediated p53 （rAd/p53） therapy in a human colon cancer mouse model by intra-tumoral injection and intra-arterial delivery. Methods： The tumor pieces of human colon cancer SW480 were implanted in the livers of 45 nude mice. These mice were administrated with rAd/p53 by intratumoral injection and intra-artedal delivery. After 24 h, 48 h and 72 h tAd/p53 administration, 5 mice each group were killed with over anesthesia and their livers were removed. P53 expression and apoptosis of tumor and liver were assessed. Results： P53 expression and apoptosis of intratumoral administration group was higher than tail vein group and control group. Apoptosis and p53 expression of livers in three groups had no significant difference. Conclusion： p53 gene transducUon efficiency and anticancer effect of rAd/p53 is much better by intra-tumoral injection than intra-arterial delivery,

Antibiotic-induced gut bacteria depletion has no effect on HBV replication in HBV immune tolerance mouse model

Commensal microbiota is closely related to Hepatitis B virus(HBV)infection.Gut bacteria maturation accelerates HBV immune clearance in hydrodynamic injection(HDI)HBV mouse model.However,the effect of gut bacteria on HBV replication in recombinant adeno-associated virus(AAV)-HBV mouse model with immune tolerance remains obscure.We aim to investigate its role on HBV replication in AAV-HBV mouse model.C57BL/6 mice were administrated with broad-spectrum antibiotic mixtures(ABX)to deplete gut bacteria and intravenously injected with AAV-HBV to establish persistent HBV replication.Gut microbiota community was analyzed by fecal qPCR assay and 16S ribosomal RNA(rRNA)gene sequencing.HBV replication markers in blood and liver were determined by ELISA,qPCR assay and Western blot at indicated time points.Immune response in AAV-HBV mouse model was activated through HDI of HBV plasmid or poly(I:C)and then detected by quantifying the percentage of IFN-γ^(+)/CD8^(+)T cells in the spleen via flow cytometry as well as the splenic IFN-γmRNA level via qPCR assay.We found that antibiotic exposure remarkably decreased gut bacteria abundance and diversity.Antibiotic treatment failed to alter the levels of serological HBV antigens,intrahepatic HBV RNA transcripts and HBc protein in AAV-HBV mouse model,but contributed to HBsAg increase after breaking of immune tolerance.Overall,our data uncovered that antibiotic-induced gut bacteria depletion has no effect on HBV replication in immune tolerant AAV-HBV mouse model,providing new thoughts for elucidating the correlation between gut bacteria dysbiosis by antibiotic abuse and clinical chronic HBV infection.

Calcitriol attenuates liver fibrosis through hepatitis C virus nonstructural protein 3-transactivated protein 1-mediated TGF β1/Smad3 and NF-κB signaling pathways

BACKGROUND Hepatic fibrosis is a serious condition,and the development of hepatic fibrosis can lead to a series of complications.However,the pathogenesis of hepatic fibrosis remains unclear,and effective therapy options are still lacking.Our group identified hepatitis C virus nonstructural protein 3-transactivated protein 1(NS3TP1) by suppressive subtractive hybridization and bioinformatics analysis,but its role in diseases including hepatic fibrosis remains undefined.Therefore,additional studies on the function of NS3TP1 in hepatic fibrosis are urgently needed to provide new targets for treatment.AIM To elucidate the mechanism of NS3TP1 in hepatic fibrosis and the regulatory effects of calcitriol on NS3TP1.METHODS Twenty-four male C57BL/6 mice were randomized and separated into three groups,comprising the normal,fibrosis,and calcitriol treatment groups,and liver fibrosis was modeled by carbon tetrachloride(CCl4).To evaluate the level of hepatic fibrosis in every group,serological and pathological examinations of the liver were conducted.TGF-β1 was administered to boost the in vitro cultivation of LX-2 cells.NS3TP1,α-smooth muscle actin(α-SMA),collagen I,and collagen Ⅲ in every group were examined using a Western blot and real-time quantitative polymerase chain reaction.The activity of the transforming growth factor beta 1(TGFβ1)/Smad3 and NF-κB signaling pathways in each group of cells transfected with pcDNA-NS3TP1 or siRNA-NS3TP1 was detected.The statistical analysis of the data was performed using the Student’s t test.RESULTS NS3TP1 promoted the activation,proliferation,and differentiation of hepatic stellate cells(HSCs)and enhanced hepatic fibrosis via the TGFβ1/Smad3 and NF-κB signaling pathways,as evidenced by the presence of α-SMA,collagen I,collagen Ⅲ,p-smad3,and p-p65 in LX-2 cells,which were upregulated after NS3TP1 overexpression and downregulated after NS3TP1 interference.The proliferation of HSCs was lowered after NS3TP1 interference and elevated after NS3TP1 overexpression,as shown by the luciferase assay.NS3TP1 inhibited the apoptosis of HSCs.Moreover,both Smad3 and p65 could bind to NS3TP1,and p65 increased the promoter activity of NS3TP1,while NS3TP1 increased the promoter activity of TGFβ1 receptor I,as indicated by coimmunoprecipitation and luciferase assay results.Both in vivo and in vitro,treatment with calcitriol dramatically reduced the expression of NS3TP1.Calcitriol therapy-controlled HSCs activation,proliferation,and differentiation and substantially suppressed CCl4-induced hepatic fibrosis in mice.Furthermore,calcitriol modulated the activities of the above signaling pathways via downregulation of NS3TP1.CONCLUSION Our results suggest that calcitriol may be employed as an adjuvant therapy for hepatic fibrosis and that NS3TP1 is a unique,prospective therapeutic target in hepatic fibrosis.

2-甲氧基雌二醇对布-加综合征模型小鼠肝纤维化的影响

目的:探讨2-甲氧基雌二醇(2-MeOE2)对布-加综合征(BCS)所致肝纤维化的影响和可能机制。方法:40只C57BL/6J雄性小鼠随机分为4组,每组10只,BCS组、BCS+2-MeOE2组采用下腔静脉部分结扎法制备BCS模型,假手术组和2-MeOE2组行造模操作但不结扎;2-MeOE2组和BCS+2-MeOE2组每隔1日腹腔注射2-MeOE2(15 mg/kg)1次。6周后处死小鼠,取血清检测ALT与AST水平;取肝组织,HE染色观察病理改变,天狼星红染色观察胶原沉积情况,免疫组化染色观察α-平滑肌肌动蛋白(α-SMA)的表达,实时荧光定量PCR法检测肝组织中纤维连接蛋白(FN)、Ⅰ型胶原(ColⅠ)和缺氧诱导因子-1α(HIF-1α)mRNA的表达,Western blot法检测上述蛋白的表达。结果:与假手术组相比,BCS组小鼠肝脏淤血,胶原沉积,ALT、AST水平升高,α-SMA表达水平升高,FN、ColⅠ、HIF-1αmRNA和蛋白表达水平升高(P<0.05);2-MeOE2可拮抗BCS导致的上述指标的变化(P<0.05)。结论:2-MeOE2可以改善BCS所致的小鼠肝纤维化,作用机制可能与改善肝细胞缺氧有关。

滋肾丸对KKay小鼠肝脏胰岛素抵抗以及PI3K-Akt-FOXO1通路的影响

目的 探究不同剂量滋肾丸水提物对于糖尿病小鼠降糖效果及该药对肝脏胰岛素抵抗的作用机制。方法 21只KKay小鼠随机分为模型组、滋肾丸高剂量组和滋肾丸低剂量组,每组7只;7只C57BL/6J小鼠作为正常组。连续灌胃给药6周,滋肾丸高剂量组予2.8 g/(kg·d),滋肾丸低剂量组予1.4 g/(kg·d),模型组、正常组予等体积蒸馏水。观察每周空腹血糖(fasting blood glucose, FBG),最后一周进行口服葡萄糖耐量试验(oral glucose tolerance test, OGTT),酶联免疫吸附法(enzyme-linked immunosorbent assay, ELISA)检测各组小鼠血清中的空腹胰岛素(fasting insulin, FINS)并计算胰岛素抵抗指数(homeostasis model assessment-insulin resistance, HOMA-IR),qPCR法检测胰岛素受体底物(insulin receptor substrate, IRS)、磷脂酰肌醇3-激酶(phosphoinositide 3-kinase, PI3K)、蛋白激酶B(protein kinase B,PKB/Akt)、叉头框蛋白1(forkhead box O1,FOXO1)、磷酸烯醇丙酮酸羧激酶(phosphoenolpyruvate carboxykinase, PEPCK)、葡萄糖-6-磷酸酶(glucose-6-phosphatase, G6pase)、葡萄糖激酶(glucokinase, GCK)基因表达水平;苏木素-伊红(hematoxylin-eosin staining, HE)染色和糖原过碘酸雪夫染色(periodic Acid-Schiff staining, PAS)观察肝脏病理情况和糖原分布。结果 与模型组相比,滋肾丸高剂量组和滋肾丸低剂量组小鼠FBG、HOMA-IR、OGTT曲线下面积明显下降,肝脏形态学改变部分减少,脂滴减少,糖原分布增加,FOXO1、PEPCK、G6pase基因表达均明显下降,滋肾丸高剂量组GCK基因表达水平显著上升,差异有统计学意义。结论 滋肾丸对于KKay小鼠降糖效果显著,能明显改善肝脏胰岛素抵抗,其机制可能是降低FOXO1、PEPCK、G6pase的转录水平,提高GCK的转录水平,从而抑制糖异生,促进糖原合成有关。

Chevrier＇s Field Mouse(Apodemus chevrieri) and Père David＇s Vole(Eothenomys melanogaster) in China Carry Orthohepeviruses that form Two Putative Novel Genotypes Within the Species Orthohepevirus C

Hepatitis E virus(HEV)is the prototype of the family Hepeviridae and the causative agent of common acute viral hepatitis.Genetically diverse HEV-related viruses have been detected in a variety of mammals and some of them may have zoonotic potential.In this study,we tested 278 specimens collected from seven wild small mammal species in Yunnan province,China,for the presence and prevalence of orthohepevirus by broad-spectrum reverse transcription(RT)-PCR.HEV-related sequences were detected in two rodent species,including Chevrier’s field mouse(Apodemus chevrieri,family Muridae)and Père David’s vole(Eothenomys melanogaster,family Cricetidae),with the infection rates of 29.20%(59/202)and 7.27%(4/55),respectively.Further four representative full-length genomes were generated:two each from Chevrier’s field mouse(named Rd HEVAc14 and Rd HEVAc86)and Père David’s vole(Rd HEVEm40 and Rd HEVEm67).Phylogenetic analyses and pairwise distance comparisons of whole genome sequences and amino acid sequences of the gene coding regions showed that orthohepeviruses identified in Chinese Chevrier’s field mouse and Père David’s vole belonged to the species Orthohepevirus C but were highly divergent from the two assigned genotypes:HEV-C1 derived from rat and shrew,and HEV-C2 derived from ferret and possibly mink.Quantitative real-time RT-PCR demonstrated that these newly discovered orthohepeviruses had hepatic tropism.In summary,our work discovered two putative novel genotypes orthohepeviruses preliminarily named HEVC3 and HEV-C4 within the species Orthohepevirus C,which expands our understanding of orthohepevirus infection in the order Rodentia and gives new insights into the origin,evolution,and host range of orthohepevirus.

基于线粒体氧化应激损伤探究异钩藤碱对小鼠肝纤维化的保护作用

目的 探讨异钩藤碱(IHY)对四氯化碳(CCl_(4))诱导的小鼠肝纤维化(HF)的影响及其潜在机制。方法 C57BL/6小鼠随机分对照(CON)组、CCl_(4)组、IHY 20 mg/kg组和IHY 40 mg/kg组,每组各10只。20%CCl_(4)橄榄油溶液(0.05 ml/10 g)灌胃8周制备肝纤维化模型,造模后第5周开始每天连续灌胃给予IHY治疗4周。白蛋白(ALB)、丙氨酸氨基转移酶(ALT)和天门冬氨酸氨基转移酶(AST)水平分别采用溴甲酚绿法、丙氨酸底物法及天门冬氨酸底物法检测。ELISA检测白细胞介素6(IL-6)、肿瘤坏死因子-α(TNF-α)及转化生长因子-β1(TGF-β1)的水平。HE和Masson染色观察肝组织病理变化及胶原沉积情况。透射电镜观察肺组织线粒体结构。免疫组化检测肝组织Ⅰ型胶原(COL1A1)和基质金属蛋白酶2(MMP2)的表达。比色法检测肝组织丙二醛(MDA)及4-羟基壬烯醛(4-HNE)含量。制备肝组织单细胞悬液,使用DCFH-DA探针检测细胞内活性氧(ROS)水平。Western blot法检测IL-6、TNF-α、TGF-β1、8-氧鸟嘌呤DNA糖基化酶1(OGG1)及沉默信号调节因子3(SIRT3)的蛋白水平。结果 与CON组相比,CCl_(4)组肝组织结构紊乱,肝细胞样结节再生,中央静脉周围可见炎症细胞浸润和大量蓝色胶原纤维沉积;COL1A1和MMP2蛋白表达明显升高;肝功能明显下降;炎症因子IL-6、TNF-α和TGF-β1水平明显升高;ROS、MDA及4-HNE水平明显增加,OGG1和SIRT3的表达明显降低,线粒体损伤明显加剧。与CCl_(4)组相比,IHY连续给药4周后,小鼠肝组织病理损伤明显减轻,胶原沉积明显减少,COL1A1和MMP2蛋白表达显著降低;肝功能明显改善;炎症因子IL-6、TNF-α和TGF-β1水平明显降低;ROS、MDA及4-HNE的水平也明显下降,OGG1和SIRT3的表达明显增加,线粒体损伤明显减轻。结论 IHY具有抗肝纤维化作用,其机制可能与其抗氧化,减轻线粒体氧化应激损伤,抑制炎症反应有关。

靶向抑制黑质网状部GABA能神经元的DRP1改善肝性脑病小鼠运动功能

目的:探讨黑质网状部(SNr)的GABA能神经元中线粒体分裂对急性肝性脑病(AHE)小鼠运动障碍的影响。方法:利用硫代乙酰胺(TAA)腹腔注射制备AHE小鼠模型,通过苏木精-伊红(HE)染色观察AHE小鼠肝小叶的变化,利用生化检测试剂盒检测AHE小鼠血清天冬氨酸转氨酶(AST)、丙氨酸转氨酶(ALT)和血氨的变化。接下来通过转棒疲劳实验、高架十字迷宫实验、旷场实验观察AHE小鼠运动功能。进一步利用透射电镜观察分析AHE小鼠SNr的线粒体面积、周长、圆率等形态学指标的变化,Western Blot观察AHE小鼠SNr的线粒体分裂融合相关分子的表达变化。接下来,利用重组腺相关病毒(AAV)靶向调控AHE小鼠SNr的线粒体动力相关蛋白1(DRP1)的表达,在荧光酶标仪上检测SNr的线粒体膜电位(MMP)、细胞的ATP和活性氧(ROS),并观察小鼠运动功能的变化。结果:较对照组,AHE小鼠运动功能明显降低,SNr的线粒体分裂明显增强,线粒体分裂相关蛋白表达显著升高;AHE小鼠SNr的MMP显著下降,细胞的ATP下降,ROS升高。靶向抑制AHE小鼠SNr的DRP1表达后,运动改善;进一步观察发现,AHE小鼠SNr的线粒体分裂被抑制后,MMP显著升高,细胞的ATP升高,ROS下降,证明线粒体功能明显改善。结论:靶向抑制AHE小鼠黑质网状部GABA能神经元的线粒体分裂,可以改善线粒体形态和功能,从而缓解其运动障碍。

Uric acid enhances T cell immune responses to hepatitis B surface antigen-pulsed-dendritic cells in mice

AIM： To study the induction of T cellular immune responses in BALB/c mice immunized with uric acid and dendritic cells （DCs） pulsed with hepatitis B virus surface antigen （HBsAg）. METHODS： DCs were generated from bone-marrow cells of BABL/c mice, and then pulsed or unpulsed with HBsAg protein （HBsAg-pulsed-DCs or unpulsed-DCs） in vitro. BABL/c mice were immunized with HBsAg-pulsed- DCs （1 × 10^6） and uric acid, injected through the tail vein of each mouse. The mice in control groups were immunized with HBsAg-pulsed-DCs alone, unpulsed- DCs alone or 200 μg uric acid alone or PBS alone. The immunization was repeated 7 d later. Cytotoxic T lymphocytes （CTLs） in vivo were determined by the CFSE labeled spleen lysis assay. Spleen cells or spleen T cells were isolated, and re-stimulated in vitro with HBsAg for 120 h or 72 h. Production of IFN-γ, and IL-4 secreted by spleen cells were determined by ELISA method; proliferation of spleen T cells were detected by flow cytometry. RESULTS： The cytotoxicities of HBsAg-specific-CTLs, generated after immunization of HBsAg-pulsed-DCs and uric acid, were 68.63% ±11.32% and significantly stronger than that in the control groups （P 〈 0.01）. Compared with control groups, in mice treated with uric acid and HBsAg-pulsed-DCs, the spleen T cell proliferation to HBsAg re-stimulation was stronger （1.34 ± 0.093 vs 1.081±0.028, P 〈 0.01）, the level of IFN-t, secreted by splenocytes was higher （266.575 ± 51.323 vs 135.223 ±32.563, P 〈 0.01） , and IL-4 level wasower （22.385 ± 2.252 vs 40.598 ± 4.218, P 〈 0.01）. CONCLUSION： Uric acid can strongly enhance T cell immune responses induced by HBsAg-pulsed-DCs vaccine. Uric acid may serve as an effective adjuvant of DC vaccine against HBV infection.

Animal models for studying hepatitis C and alcohol effects on liver

Chronic consumption of ethanol has a dramatic effect on the clinical outcome of patients with hepatitis C virus (HCV) infection, but the mechanism linking these two pathologies is unknown. Presently, in vitro systems are limited in their ability to study the interaction between a productive wild-type HCV infection and chronic ethanol exposure. Mouse models are potentially very useful in dissecting elements of the HCV-ethanol relationship. Experiments in mice that transgenically express HCV proteins are outlined, as are experiments for the generation of mice with chimeric human livers. The latter models appear to have the most promise for accurately modeling the effects of chronic ethanol intake in HCV-infected human livers.

Hepatitis B virus X protein regulates the mEZH2 promoter via the E2F1-binding site in AML12 cells

Histone lysine methyltransferase EZH2 has been reported to be frequently overexpressed in hepatocellular carcinoma(HCC) tissues and associated with hepatocarcinogenesis.However,the exact mechanism of EZH2 up-regulation in HCC has not been determined.In this study,we used murine hepatocyte AML12 cells to investigate the role of hepatitis B virus X protein(HBx) in regulating the expression of mEZH2.Western blot analysis demonstrated that the expression level of mEZH2 protein in AML12 cells was up-regulated by HBx in a dose-dependent manner.To further investigate the mechanism of mEZH2 overexpression,the 2500 bp regulatory sequence upstream from the first exon of the mEZH2 gene was amplified from AML12 genomic DNA and constructed into a luciferase reporter plasmid.The luciferase activity of the mEZH2 promoter significantly increased in AML12 cells co-transfected with HBx plasmid,and deleting the-486/-214 promoter region decreased HBx-induced mEZH2 promoter activation by nearly 50%.The-486/-214 region was then analyzed in the TRANSFAC 6.0 database and a typical E2F1-binding site was found.Mutation of this E2F1-binding site or knockdown of E2F1 expression by RNAi led to a dramatic decrease in HBx-induced activation of the mEZH2 promoter and mEZH2 overexpression in AML12 cells.These results provide evidence that HBx up-regulates mEZH2 expression by transactivating the mEZH2 promoter through E2F1 transcription factor,thereby providing new epigenetic evidence for the carcinogenic effect of HBx.