Association of CX3CL1 and CX3CR1 Expression with Liver Fibrosis in a Mouse Model of Schistosomiasis.

Immunopathological mechanisms of schistosomiasis, a debilitating parasitic disease, are still unclear. In this study, we investigated the involvement of CX3C chemokine ligand 1 (CX3CL1) and its sole receptor CX3CR1 in the development of liver fibrosis in schistosomiasis. The animal model of schistosomiasis was established by infection of C57BL/6 mice with Schistosoma japonicum cercariae; mice injected with carbon tetrachloride (CCl4) were used as positive control of liver injury. After 4 and 8 weeks, the degree of liver lesions was assessed by hematoxylin and eosin staining, serum levels of hyaluronic acid (HA) were analyzed by a chemiluminescence immunoassay, liver fibrosis was evaluated by immunohistochemistry analysis of α-smooth muscle actin (α-SMA) expression, and CX3CL1 and CX3CR1 expression in the liver was measured by immunohistochemistry and real-time PCR. The results showed that at 8 weeks after Schistosoma infection, serum HA levels were increased and α-SMA-expressing cells appeared in the liver, indicating fibrogenesis. CX3CL1- and CX3CR1-positive cells were observed in the outer layer of granulomas formed around Schistosoma eggs in liver tissues, which was consistent with the significant upregulation of hepatic CX3CL1 and CX3CR1 mRNA expression at 4 and 8 weeks post-infection. Furthermore, correlation analysis revealed positive association between CX3CL1 and CX3CR1 expression and serum HA levels at 8 weeks post-infection, indicating a link between fibrogenesis and the CX3CL1/CX3CR1 axis in schistosomiasis. In conclusion, our data suggest the involvement of CX3CL1 and CX3CR1 in the progression of liver fibrosis caused by Schistosoma infection.

Animal models for the study of hepatitis B virus infection.

Even with an effective vaccine, an estimated 240 million people are chronically infected with hepatitis B virus (HBV) worldwide. Current antiviral therapies, including interferon and nucleot(s)ide analogues, rarely cure chronic hepatitis B. Animal models are very crucial for understanding the pathogenesis of chronic hepatitis B and developing new therapeutic drugs or strategies. HBV can only infect humans and chimpanzees, with the use of chimpanzees in HBV research strongly restricted. Thus, most advances in HBV research have been gained using mouse models with HBV replication or infection or models with HBV-related hepadnaviral infection. This review summarizes the animal models currently available for the study of HBV infection.

Pentoxifylline inhibits liver fibrosis via hedgehog signaling pathway.

Infection of schistosomiasis japonica may eventually lead to liver fibrosis, and no effective antifibrotic therapies are available but liver transplantation. Hedgehog (HH) signaling pathway has been involved in the process and is a promising target for treating liver fibrosis. This study aimed to explore the effects of pentoxifylline (PTX) on liver fibrosis induced by schistosoma japonicum infection by inhibiting the HH signaling pathway. Phorbol12-myristate13-acetate (PMA) was used to induce human acute mononuclear leukemia cells THP-1 to differentiate into macrophages. The THP-1-derived macrophages were stimulated by soluble egg antigen (SEA), and the culture supernatants were collected for detection of activation of macrophages. Cell Counting Kit-8 (CCK-8) was used to detect the cytotoxicity of the culture supernatant and PTX on the LX-2 cells. The LX-2 cells were administered with activated culture supernatant from macrophages and(or) PTX to detect the transforming growth factor-ß gene expression. The mRNA expression of shh and gli-1, key parts in HH signaling pathway, was detected. The mRNA expression of shh and gli-1 was increased in LX-2 cells treated with activated macrophages-derived culture supernatant, suggesting HH signaling pathway may play a key role in the activation process of hepatic stellate cells (HSCs). The expression of these genes decreased in LX-2 cells co-cultured with both activated macrophages-derived culture supernatant and PTX, indicating PTX could suppress the activation process of HSCs. In conclusion, these data provide evidence that PTX prevents liver fibrogenesis in vitro by the suppression of HH signaling pathway.

Molecular cloning, characterization and expression analysis of woodchuck retinoic acid-inducible gene I.

Cytosolic retinoic acid-inducible gene I (RIG-I) is an important innate immune RNA sensor and can induce antiviral cytokines, e.g., interferon-ß (IFN-ß). Innate immune response to hepatitis B virus (HBV) plays a pivotal role in viral clearance and persistence. However, knowledge of the role that RIG-I plays in HBV infection is limited. The woodchuck is a valuable model for studying HBV infection. To characterize the molecular basis of woodchuck RIG-I (wRIG-I), we analyzed the complete coding sequences (CDSs) of wRIG-I, containing 2778 base pairs that encode 925 amino acids. The deduced wRIG-I protein was 106.847 kD with a theoretical isoelectric point (pI) of 6.07, and contained three important functional structures [caspase activation and recruitment domains (CARDs), DExD/H-box helicases, and a repressor domain (RD)]. In woodchuck fibroblastoma cell line (WH12/6), wRIG-I-targeted small interfering RNA (siRNA) down-regulated RIG-I and its downstrean effector-IFN-ß transcripts under RIG-I' ligand, 5'-ppp double stranded RNA (dsRNA) stimulation. We also measured mRNA levels of wRIG-I in different tissues from healthy woodchucks and in the livers from woodchuck hepatitis virus (WHV)-infected woodchucks. The basal expression levels of wRIG-I were abundant in the kidney and liver. Importantly, wRIG-I was significantly up-regulated in acutely infected woodchuck livers, suggesting that RIG-I might be involved in WHV infection. These results may characterize RIG-I in the woodchuck model, providing a strong basis for further study on RIG-I-mediated innate immunity in HBV infection.

Upregulation of toll-like receptor 4 on T cells in PBMCs is associated with disease aggravation of HBV-related acute-on-chronic liver failure.

Immune-mediated inflammatory injury is an important feature of the disease aggravation of hepatitis B virus-related acute-on-chronic liver failure (ACLF). Toll-like receptors (TLRs) have been shown previously to play a pivotal role in the activation of innate immunity. The purpose of this study was to characterize the TLR4 expression in peripheral blood mononuclear cells (PBMCs) of ACLF patients and its possible role in the disease aggravation. Twelve healthy subjects, 15 chronic HBV-infected (CHB) patients and 15 ACLF patients were enrolled in this study. The TLR4 expression in PBMCs and T cells of all subjects was examined by real-time PCR and flow cytometry. The correlation of TLR4 expression on T cells with the markers of disease aggravation was evaluated in ACLF patients. The ability of TLR4 ligands stimulation to induce inflammatory cytokine production in ACLF patients was analyzed by flow cytometry. The results showed that TLR4 mRNA level was upregulated in PBMCs of ACLF patients compared to that in the healthy subjects and the CHB patients. Specifically, the expression of TLR4 on CD4(+) and CD8(+) T cells of PBMCs was significantly increased in ACLF patients. The TLR4 levels on CD4(+) and CD8(+) T cells were positively correlated with serum total bilirubin (TBIL), direct bilirubin (DBIL), international normalized ratio (INR) levels and white blood cells (WBCs), and negatively correlated with serum albumin (ALB) levels in the HBV-infected patients, indicating TLR4 pathway may play a role in the disease aggravation of ACLF. In vitro TLR4 ligand stimulation on PBMCs of ACLF patients induced a strong TNF-α production by CD4(+) T cells, which was also positively correlated with the serum markers for liver injury severity. It was concluded that TLR4 expression is upregulated on T cells in PBMCs, which is associated with the aggravation of ACLF.

Isothiafludine, a novel non-nucleoside compound, inhibits hepatitis B virus replication through blocking pregenomic RNA encapsidation.

AIM: To investigate the action of isothiafludine (NZ-4), a derivative of bis-heterocycle tandem pairs from the natural product leucamide A, on the replication cycle of hepatitis B virus (HBV) in vitro and in vivo. METHODS: HBV replication cycle was monitored in HepG2.2.15 cells using qPCR, qRT-PCR, and Southern and Northern blotting. HBV protein expression and capsid assembly were detected using Western blotting and native agarose gel electrophoresis analysis. The interaction of pregenomic RNA (pgRNA) and the core protein was investigated by RNA immunoprecipitation. To evaluate the anti-HBV effect of NZ-4 in vivo, DHBV-infected ducks were orally administered NZ-4 (25, 50 or 100 mg·kg⁻¹·d⁻¹) for 15 d. RESULTS: NZ-4 suppressed intracellular HBV replication in HepG2.2.15 cells with an IC50 value of 1.33 µmol/L, whereas the compound inhibited the cell viability with an IC50 value of 50.4 µmol/L. Furthermore, NZ-4 was active against the replication of various drug-resistant HBV mutants, including 3TC/ETV-dual-resistant and ADV-resistant HBV mutants. NZ-4 (5, 10, 20 µmol/L) concentration-dependently reduced the encapsidated HBV pgRNA, resulting in the assembly of replication-deficient capsids in HepG2.2.15 cells. Oral administration of NZ-4 dose-dependently inhibited DHBV DNA replication in the DHBV-infected ducks. CONCLUSION: NZ-4 inhibits HBV replication by interfering with the interaction between pgRNA and HBcAg in the capsid assembly process, thus increasing the replication-deficient HBV capsids. Such mechanism of action might provide a new therapeutic strategy to combat HBV infection.

[Assessment of mitochondrial toxicity induced by zidovudine and adefovir dipivoxil in rats].

OBJECTIVE: To explore the mitochondrial toxicities induced by zidovudine (AZT) and adefovir dipivoxil (ADV) antiviral drugs using a rat model system. METHODS: Twelve healthy Sprague-Dawley rats were randomly divided into three equal groups and treated by oral gavage with zidovudine (125 mg/kg/day), adefovir (40 mg/kg/day), or saline (equal volume) for 28 days. The rats' body weights were measured once a week, and blood was collected every two weeks for blood and biochemical tests. All animals were sacrificed at the end of treatment, and liver, kidney, skeletal muscle, and cardiac muscle were collected by necropsy. Mitochondria were isolated from the respective tissue samples, and the activities of respiratory chain complexes were measured. DNA was purified from each sample and the mitochondrial DNA (mtDNA) content was monitored by quantitative real time PCR. Mitochondrial morphology was analyzed under electron microscope. RESULTS: No significant adverse effects, including body weight loss, abnormal blood or biochemistry, were observed in rats treated with AZT or ADV. The activities of mitochondrial cytochrome c oxidase in liver and cardiac muscle were slightly decreased in rats treated with AZT (liver: 9.44+/-3.09 vs. 17.8+/-12.38, P?=?0.21; cardiac muscle: 32.74+/-5.52 vs. 24.74+/-20.59, P?=?0.28; kidney: 4.42+/-1.53 vs. 14.45+/-13.75, P?=?0.18; skeletal muscle: 33.75+/-8.74 vs. 40.04+/-2.49, P?=?0.45). The mtDNA content was significantly decreased in cardiac muscle of AZT-treated rats (cardiac muscle: 0.15+/-0.13 vs. 0.32+/-0.42, P?=?0.85). The morphology of mitochondria in liver, kidney, skeletal muscle, and cardiac muscle was significantly altered in the AZT-treated rats and included disappearance of the outer membrane, severely damaged structure, and swollen or completely absent cristae. No obvious effects were noted in the ADV- or saline-treated rats. CONCLUSION: Significant adverse effects related to mitochondrial toxicity were observed in rats treated with AZT. The slightly decreased mtDNA content in ADV-treated rats may suggest that this antiviral drug can also cause mitochondrial toxic effects.

Immunostaining of PD-1/PD-Ls in liver tissues of patients with hepatitis and hepatocellular carcinoma.

AIM: To investigate the expression of programmed death (PD)-1, PD ligand 1 (PD-L1) and PD-L2 in liver tissues in the context of chronic hepatitis and hepatocellular carcinoma (HCC). METHODS: Liver biopsies and HCC specimens from patients were collected and histologically examined. The expression of PD-1, PD-L1, and PD-L2 in biopsy specimens of chronic hepatitis and HCC specimens was evaluated by immunohistochemical staining. The association between the expression level of PD-1, PD-L1, and PD-L2 and clinical and pathological variables was analyzed statistically. RESULTS: Expression of PD-1 was found in liver-infiltrating lymphocytes. In contrast, PD-L1 and PD-L2 were expressed in non-parenchyma liver cells and tumor cells. The expression of PD-L1 was significantly correlated with hepatitis B virus infection (1.42 ± 1.165 vs 0.50 ± 0.756, P = 0.047) and with the stage of HCC (7.50 ± 2.121 vs 1.75 ± 1.500 vs 3.00 ± 0.001, P = 0.018). PD-1 and PD-Ls were significantly up-regulated in HCC specimens (1.40 ± 1.536 vs 5.71 ± 4.051, P = 0.000; 1.05 ± 1.099 vs 4.29 ± 3.885, P = 0.004; 1.80 ± 1.473 vs 3.81 ± 3.400, P = 0.020). CONCLUSION: PD-L1 may contribute to negative regulation of the immune response in chronic hepatitis B. PD-1 and PD-Ls may play a role in immune evasion of tumors.

Establishing a new animal model for hepadnaviral infection: susceptibility of Chinese Marmota-species to woodchuck hepatitis virus infection.

Hepatitis B virus infection (HBV) is a major medical problem in China. The lack of a suitable infection model in China is recognized as an obstacle for research on HBV in China. Chinese Marmota-species is phylogenetically closely related to Marmota monax, thus, it might be suitable to serve as an animal model for HBV infection. Therefore, we attempted to prove the claim about the existence of woodchuck hepatitis virus (WHV)-like viruses in Chinese Marmota-species and to determine the susceptibility of these species to experimental WHV infection. In the present study, 653 sera from three Chinese Marmota-species, Marmota himalayana, Marmota baibacina and Marmota bobak, were screened for WHV-like viruses by serological and molecular assays. The susceptibility to WHV of three species was investigated by experimental infection and monitored by testing of anti-WHc and WHsAg by ELISA, detection of WHV DNA by PCR, and detection of WHV replication intermediates and antigens in liver samples. No evidence for the existence of a genetically closely related virus to WHV in three Chinese Marmota-species was found by serological assays and PCR. M. himalayana was susceptible to WHV infection as inoculated animals became positive for anti-WHc, WHsAg and WHV DNA. Further, WHV replication intermediates and proteins were detected in liver samples. In contrast, M. baibacina remained negative for tested virological parameters. M. bobak species showed a limited susceptibility to WHV. Our data do not support early reports about WHV-like viruses in China. M. himalayana is suitable for the establishment of a model for hepadnaviral infection.

[Expression of IFN-alpha/beta receptor in the PBMCs and liver of patients with hepatitis B and its clinical significance].

OBJECTIVE: To explore the role of interferon (IFN)-alpha/beta receptor beta subunit (IFNAR2) in the patients' response to IFN-alpha therapy as influenced by the grade of chronic hepatic inflammation, and understand the relation of IFNAR2 expression in the peripheral blood mononuclear cells (PBMCs) with HBV infection. METHODS: Liver tissue specimens were obtained from 21 patients with chronic hepatitis B for examination of the hepatic inflammation, and PBMCs were isolated from another 16 patients with chronic hepatitis B and 15 health control subjects. Both the hepatic tissues and PBMCs were examined for IFNAR2 expression using immunohistochemistry. RESULTS: The 21 patients with chronic hepatitis B were divided into 3 groups according to the severity of hepatic inflammation, namely G(1) (n=3), G(2) (n=7) and G(3) (n=11) groups. The patients in G(3) group showed had significantly higher IFNAR2 expressions in liver (25.1307-/+7.0700) than those of the G(1) (5.6913-/+1.8422) and G(2) (7.4706-/+5.3572) groups (P=0.000). The IFNAR2 levels in the PBMCs, however, did not show significant difference between patients with chronic hepatitis B and the healthy control subjects. CONCLUSION: In patients with chronic hepatitis B, IFNAR2 expression level is positively correlated to the severity of hepatic inflammation, and increased IFNAR2 expression in severe hepatic inflammation is therefore likely to result in increased response rate to INF-alpha therapy. The expression of IFNAR2 in the PBMCs is not associated with HBV infection.

Replication of clinical hepatitis B virus isolate and its application for selecting antiviral agents for chronic hepatitis B patients.

AIM: To establish a cell model harboring replicative clinical hepatitis B virus (HBV) isolates and evaluate its application in individualized selection of anti-HBV agents for chronic hepatitis B (CHB) patients. METHODS: The full-length HBV genomic DNA from 8 CHB patients was amplified by polymerase chain reaction (PCR). All the patients were treated with lamivudine for at least seven months and finally became resistant to lamivudine. The amplified HBV DNA fragments were inserted into pHY106 vectors by Sap I digestion. The recombinant plasmids containing 1.1 copies of HBV genome were transiently transfected into Huh7 cell line, and the levels of HBsAg, HBeAg and intercellular HBV replicative intermediates were determined by ELISA and Southern blot analysis, respectively, with or without lamivudine and adefovir treatment. The antiviral treatment with adefovir was administered to the patients and analyzed in parallel. RESULTS: A total of 25 independent HBV isolates were obtained from the sera of 8 patients, each patient had at least two isolates. One isolate from each individual was selected and subcloned into pHY106 vector, including 5 isolates with YVDD mutation and 3 isolates with YIDD mutation. All recombinant plasmids harboring HBV isolates were transfected into Huh7 cells. The results indicated that HBV genome carried in HBV replicons of clinical HBV isolates could effectively replicate and express in Huh7 cells. Adefovir, but not lamivudine, inhibited HBV replication both in vitro and in vivo, and in vitro inhibition was dose-dependent. CONCLUSION: The novel method described herein enables individualized selection of anti-HBV agents in clinic and is useful in future studies of antiviral therapy for CHB.

[Prokaryotic expression and polyclonal antibody preparation of truncated duck hepatitis B virus core protein].

AIM: To construct a prokaryotic plasmid expressing truncated duck hepatitis B virus core protein (DHBc(1-214)), purify the recombinant protein, and to develop polyclonal antibodies against DHBc. METHODS: DHBc(1-214) was cloned into vector pRSET-B, then expressed in E.coli Rosetta(DE3) pLacI induced by IPTG. The recombinant protein was purified using Ni-NTA spin column. Polyclonal antibody was developed by immunizing BALB/c mice with the purified recombinant protein, and their sensitivity and specificity were tested using enzyme-linked immunosorbent assay, immunohistochemical staining and Western blot analysis. RESULTS: Recombinant plasmid expressing truncated DHBc(1-214) was successfully constructed. A protein of 28,000 was expressed and purified. Polyclonal serum antibody with a high specificity was obtained by immunizing BALB/c mice with the purified recombinant protein. CONCLUSION: The truncated recombinant DHBc(1-214) developed in this study is purified and shown strong antigenecity. The polyclonal antibody against DHBc protein is generated by regular immunization method, demonstrating both high sensitivity and specificity. The protein and the antibody can be used for further clinical examination and research of DHBV.

[The growth inhibition effects of TSLC1 gene on human hepatocyte carcinoma cell line HepG2].

OBJECTIVES: To study the effects of tumor suppressor in lung cancer-1 (TSLC1) on human hepatocyte carcinoma cell line HepG2. METHODS: A full length of TSLC1 cDNA was amplified from RNA of normal human liver cells by RT-PCR, and it was cloned into a pCI-neo expression vector and transfected into human hepatocellular carcinoma cell line HepG2. The HepG2 cells transfected with this plasmid (experimental group) and those treated with pCI-neo vector (control group) and without any treatment (blank group) were compared. Cell morphology was studied microscopically and cell growth was analyzed with MTT assay. FACSort flow cytometry analysis was performed to assess the cell cycle distribution and apoptosis. RESULTS: A stable cell line expressing TSLC1 protein was successfully established. Morphologically, cells of the experimental group were tightly aggregated when compared with those of the control and blank groups. The growth of TSLC1-transfected cells was significantly suppressed in vitro compared with those of the control and blank groups. The amount of G0-G1 cells was 63.66%+/-3.83% (P less than 0.01) in the experimental group, while those of the control and blank groups were 47.45%+/-0.91% and 54.47%+/-0.96% respectively. The amount of S phase cells in the experimental group, 22.90%+/-6.04%, was significantly lower (P less than 0.05) than that of the control group (36.58%+/-0.61%) and the blank group (33.61%+/-2.99%), which suggested a G0-G1 cell cycle arresting. The number of cells in early and late phase apoptosis (17.09%+/-0.20% and 16.11%+/-0.40% respectively) were significantly higher than those of the control and blank groups (P less than 0.01). CONCLUSIONS: TSLC1 strongly inhibits the growth of HepG2 cells in vitro and induces apoptosis of the cells, suggesting that TSLC1 may have a tumor suppressor function in HCC.

[Expressions of phosphorylated-Smad2 and PTEN in hepatocellular carcinomas and adjacent liver tissues].

OBJECTIVE: To investigate the expressions of phosphorylated Smad2 (P-Smad2) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) in hepatocellular carcinoma (HCC) tissues. METHODS: The expressions of P-Smad2 and PTEN were detected using Envision immunohistochemical technique in 31 cases of HCC tissues, 25 cases of HCC adjacent liver tissues and 13 cases of non-hepatocellular carcinoma tissues. RESULTS: The positive expression and staining intensity of PTEN in the cytoplasm of HCC cells (64.5%, 4.19+/-3.31) was significantly lower than those of the cells of the cancer adjacent tissues and non-cancerous tissues (96.0%, 7.88+/-0.93; 100%, 7.77+/-0.93). The staining intensity of PTEN in the cytoplasm of Edmondson pathologic grade III HCC cells was lower than those of the Edmondson grade I. The expression of PTEN was negatively correlated with intrahepatic vascular cancer thrombi (r=-0.43) and the expression of PTEN in the nuclei or cytoplasm of liver cells was negatively correlated with the liver disease progressions (r=-0.34). The positive rate and expression intensity of phosphorylated Smad2 in nuclei of HCC cells were the same as those in cancer adjacent and non-tumor liver tissues. The expression was mostly in the nucleus and cytoplasm of Edmondson grade I HCC cells, cancer adjacent liver tissue cells and non-tumor liver tissues, but its expression was only in the nuclei of Edmondson grade II and III HCC cells. The phosphorylated Smad2 expression appeared in the nuclei and in the cytoplasm of liver cells and it was positively correlated with the severity of the tumor pathology (r=0.22). Spearman correlation analysis revealed a significant inverse correlation between PTEN and phosphorylated Smad2 in HCC tissues (r=-0.73). CONCLUSIONS: The aberrant expressions of PTEN and phosphorylated Smad2 and their interaction may play an important role in the pathogenesis of hepatocellular carcinoma.

Expression of PTEN, PPM1A and P-Smad2 in hepatocellular carcinomas and adjacent liver tissues.

AIM: To investigate the expressions of PTEN, PPM1A and P-Smad2 in hepatocellular carcinoma (HCC) and their significance. METHODS: The expressions of PTEN, PPM1A and P-Smad2 in 31 HCC tissues, 25 adjacent liver tissues and 13 non-tumor liver tissues were detected by using Envision immunohistochemical technique. RESULTS: The positive expression (64.52%) and staining intensity (4.19 +/- 3.31) of PTEN in the cytoplasm of HCC were significantly lower and weaker than those in the adjacent or non-tumor liver tissues (97.37%, 7.88 +/- 0.93; 100%, 7.77 +/- 0.93, respectively) (P < 0.05), and its staining intensity in the cytoplasm of HCC, which belongs to Edmondson pathologic grades II-III and above, was also lower than that of grade I and I-II. Furthermore, its location in the nucleus or cytoplasm of liver cells was negatively correlated with the progression of liver disease (r = -0.339, P = 0.002); most of PPM1A might be only expressed in the nucleus of adjacent liver tissues, non-HCC tissues or Edmondson grade I and I-II HCC, but it was mainly expressed in the cytoplasm of HCC with Edmondson grade > or = II, weakly or negatively expressed in the nucleus (P < 0.05), and its location was negatively correlated with the progression of liver disease (r = -0.45, P = 0.0000). P-Smad2, which was mostly located in the nucleus and cytoplasm of grade I and I-II HCC, surrounding or non-tumor liver tissues, was only in the nucleus of HCC with Edmondson grade II and above (P < 0.001), and its location was positively correlated with the disease progression (r = 0.224, P = 0.016). Spearman correlation analysis revealed that P-Smad2 was significantly negatively correlated with PTEN and PPM1A (r = -0.748, P = 0.000; r = -0.366, P = 0.001, respectively); and PTEN and PPM1A were positively correlated with HCC carcinogenesis (r = 0.428, P = 0.000). CONCLUSION: The aberrant location of expression and staining intensity of PTEN, PPM1A and P-Smad2 in HCC and their relationship might have an impact on the pathogenesis of HCC.

N-terminal and C-terminal cytosine deaminase domain of APOBEC3G inhibit hepatitis B virus replication.

AIM: To investigate the effect of human apolipoprotein B mRNA-editing enzyme catalytic-polypeptide 3G (APOBEC3G) and its N-terminal or C-terminal cytosine deaminase domain-mediated antiviral activity against hepatitis B virus (HBV) in vitro and in vivo. METHODS: The mammalian hepatoma cells HepG2 and HuH7 were cotransfected with APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain expression vector and 1.3-fold-overlength HBV DNA as well as the linear monomeric HBV of genotype B and C. For in vivo study, an HBV vector-based mouse model was used in which APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain expression vectors were co-delivered with 1.3-fold-overlength HBV DNA via high-volume tail vein injection. Levels of hepatitis B virus surface antigen (HBsAg) and hepatitis B virus e antigen (HBeAg) in the media of the transfected cells and in the sera of mice were determined by ELISA. The expression of hepatitis B virus core antigen (HBcAg) in the transfected cells was determined by Western blot analysis. Core-associated HBV DNA was examined by Southern blot analysis. Levels of HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by quantitative PCR and quantitative RT-PCR analysis, respectively. RESULTS: Human APOBEC3G exerted an anti-HBV activity in a dose-dependent manner in HepG2 cells, and comparable suppressive effects were observed on genotype B and C as that of genotype A. Interestingly, the N-terminal or C-terminal cytosine deaminase domain alone could also inhibit HBV replication in HepG2 cells as well as Huh7 cells. Consistent with in vitro results, the levels of HBsAg in the sera of mice were dramatically decreased, with more than 50 times decrease in the levels of serum HBV DNA and core-associated RNA in the liver of mice treated with APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain as compared to the controls. CONCLUSION: Our findings provide probably the first evidence showing that APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain could suppress HBV replication in vitro and in vivo.

[Inhibition of hepatitis B and duck hepatitis B virus replication by APOBEC3G].

OBJECTIVE: To investigate the effect of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) mediated antiviral activity against hepatitis B virus (HBV) and duck hepatitis B virus (DHBV). METHODS: Total RNA was extracted from peripheral blood mononuclear cells (PBMCs), RT-PCR product was cloned into the EcoR I/Hind III restriction sites of the CMV-driven expression vector fused with a hemagglutinin fusion epitope tag at its carboxyl terminal. Replication competent 1.3 fold over-length HBV was constructed with full-length HBV of ayw subtype. The mammalian hepatoma cell HepG2 was cotransfected with the replication competent 1.3 fold over-length HBV and various amounts of CMV-driven expression vector encoding APOBEC3G-HA. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA, HBV DNA. RNA from intracellular core particles was examined using Northern and Southern blot analyses. Chicken hepatoma cell LMH was cotransfected with head-to-tail dimer of an EcoR I monomer of DHBV and various amounts of CMV-driven expression vector encoding APOBEC3G-HA. DHBV DNA from intracellular core particles was examined using Southern blot analysis. RESULTS: CMV-driven expression vector encoding APOBEC3G-HA and replication competent 1.3 fold over-length HBV were constructed. There was a dose dependent decrease in the levels of intracellular core-associated viral (HBV and DHBV) DNA and extracellular production of HBsAg and HBeAg. Levels of intracellular core-associated viral RNA were also decreased, but the expression of HBcAg remained almost unchanged. CONCLUSION: APOBEC3G suppresses HBV and DHBV replication and also suppresses HBsAg and HBeAg expression.

Inhibition of hepatitis B virus replication by APOBEC3G in vitro and in vivo.

AIM: To investigate the effect of APOBEC3G mediated antiviral activity against hepatitis B virus (HBV) in cell cultures and replication competent HBV vector-based mouse model. METHODS: The mammalian hepatoma cells Huh7 and HepG2 were cotransfected with various amounts of CMV-driven expression vector encoding APOBEC3G and replication competent 1.3 fold over-length HBV. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA. The expression of HBcAg in transfected cells was detected by western blot. HBV DNA and RNA from intracellular core particles were examined by Northern and Southern blot analyses. To assess activity of the APOBEC3G in vivo, an HBV vector-based model was used in which APOBEC3G and the HBV vector were co-delivered via high-volume tail vein injection. Levels of HBsAg and HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by ELISA and quantitative PCR analysis respectively. RESULTS: There was a dose dependent decrease in the levels of intracellular core-associated HBV DNA and extracellular production of HBsAg and HBeAg. The levels of intracellular core-associated viral RNA also decreased, but the expression of HBcAg in transfected cells showed almost no change. Consistent with in vitro results, levels of HBsAg in the sera of mice were dramatically decreased. More than 1.5 log10 decrease in levels of serum HBV DNA and liver HBV RNA were observed in the APOBEC3G-treated groups compared with the control groups. CONCLUSION: These findings indicate that APOBEC3G could suppress HBV replication and antigen expression both in vivo and in vitro, promising an advance in treatment of HBV infection.

[Expression of interferon alpha family gene of Chinese marmot in eukaryotic and prokaryotic cells].

OBJECTIVE: To investigate the function of interferon alpha (IFNalpha) in a Chinese marmot model of hepatitis B, we expressed the Chinese marmot (Marmota himalayana) IFNalpha family gene (IFNA) in eukaryotic cells and prokaryotic cells. METHODS: Eukaryotic and prokaryotic expression plasmids harboring Chinese marmot interferon alpha gene with different genotypes were generated using molecular cloning technology. We detected the biological activity of all expression products by viral protection assay, and analyzed their differences and species restriction of the biological activity. RESULTS: The Chinese marmot functional genotype IFNalpha was expressed in the baby hamster kidney (BHK) cell line, and these products protected WH12/6 cells challenged by encephalomyocarditis virus (EMCV). The Chinese marmot IFN-alpha5 also expressed in E. Coli induced by IPTG, and purified fusion protein had antiviral biological activity. The biologic activity displayed differences among different subtype IFNalpha, and it had strict species restriction. CONCLUSION: The IFNalpha family gene of the Chinese marmot can be expressed in both eukaryotic and prokaryotic cells, and the expression products show antiviral activity in a protection assay. This study provides, for the first time, evidence that IFNalpha from the Chinese marmot has an antiviral function in vitro and can be used to improve the efficacy of current therapies for HBV infection in our Chinese marmot model.

[Distribution of hepatitis B virus genotypes in Hubei province and its clinical significance].

OBJECTIVE: To investigate the distribution of hepatitis B virus genotype in Hubei province (China) and its clinical significance. METHODS: Serum samples from 190 HBV DNA positive patients with chronic HBV infection,including 52 asymptomatic HBV carriers (ASC), 56 chronic hepatitis (CH), 32 fulminant hepatic failure (FHF), 22 liver cirrhosis (LC), and 28 hepatocellular carcinoma (HCC) patients were collected and tested for HBV genotypes by type-specific primers. RESULTS: A simple and precise genotyping system based on PCR using type-specific primers was developed for the determination of genotypes of hepatitis B virus (HBV). Of the 190 patients, 140 (73.7%) were genotype B and 42 (22.1%) were genotype C. Genotype B was more prevalent in the FHF and HCC patients than in the ASC patients; the ALT value was significantly higher in genotype B than in genotype C patients. The rate of anti-HBe was significantly higher in genotype B than in genotype C except in the patients of the ASC group. CONCLUSION: The system we used seems to be a useful tool for the molecular diagnosis of HBV infection and for large-scale surveys. Genotype B, genotype C and BC combination exist in Hubei province, and genotype B is the major genotype in this area especially in FHF and HCC patients.