Inhibitory effect of HMGN2 protein on human hepatitis B viral HBeAg and HBsAg expression and DNA replication in HBV-transformed HepG2. 2.15 cell line

AIM: We previously demonstrated that HMGN2 is an antibacterial effector molecule in human LAK cells. This study was to examine the antiviral activity of HMGN2 against human hepatitis virus.METHODS: The purification and identify of HMGN2 proteins including preparative acid-urea polyacymide gel electrophoresis elution, reverse-phase high-performance liquid chromatography, mass spectrum, Western blotting and antimicrobial assay were conducted. The cellular toxicity of HMGN2 to the HepG2.2.15 cells was detected by MTT assay. HBeAg and HBsAg expressions were measured by ELISA. HBV DNA copies were determined by real time quantitative PCR.RESULTS: A bulk of HMGN2 was isolated and purified from the acid soluble proteins of human lymph node, and identified. The HBV-transfected HepG2.2.15 cell line was used in the in vitro assay system.In the range of testing 1-100 mg/L of HMGN2, no cytotoxicity to HepG2.2.15 cells was detected by MTT assay.When incubated with HMGN2 at 1-5 mg/L for 72 h or 144 h, a significant reduction in HBeAg and HBsAg expression and in HBV DNA copies was observed in the supernatant of HepG2.2.15 cells. CONCLUSION: HMGN2 protein markedly inhibits HBV expression and replication in vitro.     

Effect of Paecilomyces cicadae polysaccharide on duplication of hepatitis B virus in HepG2.2.15 cell strain

AIM: To investigative the inhibitory effects of Paecilomyces cicadae polysaccharide (PcPS) against HBV in vitro, and the effects on the Toll like receptor 4 (TLR4) mRNA expression in HepG2.2.15 cell strain. METHODS: HepG2.2.15 cell strain was co-cultured in vitro with PcPS in different concentrations, and lamivudine (LMV) was applied as positive control. MTT assay was employed to detect the cytotoxicities of PcPS in vitro, when the HepG2.2.15 cells was used as target cells. The effects of PcPS on the secretion of HBsAg and HBeAg were assayed by ELISA method. Fluorescence quantitative-PCR (FQ-PCR) was used to detect the inhibitory effects of PcPS on the content of HBV-DNA and TLR4 mRNA in HepG2.2.15 cells. RESULTS: The inhibitory effects of PcPS on the HBsAg and HBeAg were observed and the maximum inhibitory ratio up to 44.8% and 31.0%, respectively. The same inhibitory effects of PcPS on the HBV-DNA replication and TLR4 mRNA expression in HepG2.2.15 cells were also found. CONCLUSION: A certain concentration of PcPS significantly inhibits HBV replication in vitro.     

Effects of xeroderma pigmentosum group D and p53 on replication of HBV

AIM:To investigate the effects of xeroderma pigmentosum D (XPD) and p53 on the replication of hepatitis B virus (HBV). METHODS:Recombinant plasmid pEGFP-N2/XPD and vacant vector plasmid pEGFP-N2 were transfected into HepG2.2.15 cells by liposome. On the next day, these cells were incubated with pifithrin-α, a p53 inhibitor, at a concentration of 20 μmol/L for 24 h. The cells were divided into 5 groups: blank control group, pEGFP-N2 group, pEGFP-N2/XPD group, pEGFP-N2/XPD+pifithrin-α group and pifithrin-α group. The mRNA expression of XPD, hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus X protein (HBx) was detected by RT-PCR. The content of HBsAg and HBeAg in the supernatants of culture medium was measured by ELISA. The content of HBV-DNA in the supernatants of culture medium was examined by fluorescence quantitative PCR. Using the method of bDNA, the content of HBV-DNA in the core particles was assessed. RESULTS:The expression of XPD mRNA was elevated by the transfection of recombinant plasmid pEGFP-N2/XPD. The increase in XPD expression significantly down-regulated the mRNA expression of HBsAg, HBeAg and HBx. The content of HBsAg and HBeAg in the supernatants of culture medium was significantly decreased by the increase in XPD expression. The results of fluorescence quantitative PCR showed that the content of HBV-DNA in the supernatants of culture medium was significantly down-regulated by the increase in XPD expression. bDNA results showed that the content of HBV-DNA in the core particles was significantly decreased by the increase in XPD expression.Pifithrin-α abolished the above-mentioned effects of XPD (all P<0.01). CONCLUSION: XPD inhibits the replication of HBV through p53 pathway. Therefore, XPD and p53 may be the targets for antiviral therapy of hepatitis B.     

Role of renal preS1/S2-Ag and other HBV antigen determination in diagnosis of HBV-associated glomerulonephritis

AIM：To detect the expression of preS1/S2 antigen (preS1/S2-Ag) and other antigens of hepatitis B virus (HBV) in renal tissues of patients with HBV-associated glomerulonephritis (HBV-GN), and to analyze their roles in the diagnosis of HBV-GN.
METHODS：Patients hospitalized in our department from January in 2003 to January in 2013 were retrospectively studied. A total of 49 patients with positive HBV surface antigen (HBsAg) serology, clinical manifestations of hematuria and/or proteinuria, and pathological diagnosis of glomerulonephritis, without systemic lupus erythematosus, anaphylactic purpura, diabetes or hepatitis C, were selected. PreS1/S2-Ag, HBV e antigen (HBeAg), HBsAg and HBV core antigen (HBcAg) in the renal tissues were examined. Five cases of glomerular minimal-change disease (MCD) with negative HBsAg and 5 cases of non-glomerulonephritis with positive HBsAg served as controls. RESULTS：The positive rates of preS1/S2-Ag, HBeAg, HBsAg and HBcAg in the renal tissues from the 49 patients of glomerulonephritis with HBV infection were 32.7% (16 cases), 38.8% (19 cases), 14.3% (7 cases) and 46.9% (23 cases), respectively. Total antigen positive rate was 70.2% (36 cases). The expression of preS1/S2-Ag was located in the cytoplasm of renal tubular epithelial cells, glomerular epithelial cells, endothelial cells and mesangial cells, and positively correlated with the expression of HBcAg (r=0.459, P<001). The 4 antigens were not detected in the 5 cases of HBsAg-negative patients with glomerular MCD. In the 5 cases of HBsAg-positive patients with non-glomerulonephritis, there were 2 cases expressing HBeAg and 1 case expressing HBcAg, but no cases expressing preS1/S2-Ag or HBsAg. CONCLUSION：The expression of preS1/S2-Ag in renal tissues suggests that HBV may invade the cells of renal tissue. Combined detection of the 4 antigens could elevate the rate of diagnosis of HBV-GN.     

Effect of proprotein convertases on transforming growth factor β1-induced HBV replication inhibition

AIM: To study the effect of proprotein convertases (PCs) on the transforming growth factor (TGF) β1-induced inhibition of HBV replication.METHODS: HepG2.2.15 cells cultured regularly were exposed to recombinant TGFβ1 at concentration of 2 μg/L or 5 μg/L and/or PC inhibitor at concentration of 20 μmol/L for 18 h. The total RNA and HBV core particle DNA were extracted from these cells, and PC mRNA and core-associated HBV DNA were detected by real-time PCR technique. RESULTS: The mRNA expression levels of 7 PCs in HepG2.2.15 cells were observed with various degrees. Recombinant TGFβ1 significantly up-regulated the mRNA expression of all PCs except for the down-regulation of PC5/6, though PC1/3 and PC2 were up-regulated most obviously. Furin and PACE4 were the predominant PCs before and after TGFβ1 exposure when the basic mRNA expression was taken into account. Further study showed that TGFβ1-induced the inhibition of HBV replication was abrogated by PC inhibitor in HepG2.2.15 cells. CONCLUSION: TGFβ1-induced the inhibition of HBV replication is mediated by the up-regulation of PCs, which might be of many implications in efficient interferences of TGFβ1 on HBV replication.     

Two-unit ribozyme inhibit hepatitis B virus expressed in 2.2.15 cell

AIM: To observe the inhibition of HBc/HBeAg expression in the 2.2.15 cell transfected by two-unit ribozyme. METHODS: By use of subclone technique, two-unit ribozyme gene which was cutted from pGEM-Rz123 was ligated into the eukaryotic expression vector pBBS212. The recombinant plasmid was cotransfected into 2.2.15 cell using lipofectamine. Ribozyme was detected by dot-blot hybridization. The s and e/c antigen of HBV were detected by using ELISA, immunohistochemical technique, image analysis system and Western blot. RESULTS: After the transfected cell was selected two weeks by hygromycin B and G418. We found by dot-blot hybridization that ribozyme can express on 2.2.15 cell. HBeAg level can be reduced by 48.6% in the transfected 2.2.15 cell with two-ribozyme. Using immunohistochemical technique and image analysis system, Western blot, we observed that the level of HBcAg expressed in endocellular went down. CONCLUSION:Al these results strongly indicate that two-unit ribozyme can inhibit hepatitis B virus expression in the cell.     

Mechanism of hepatitis B virus infection in renal tissues with IgA nephropathy

AIM: To identify the pathogenesis of renal lesions induced by hepatitis B virus (HBV) infection in IgA nephropathy (IgAN). METHODS: Forty-eight renal biopsy tissues of IgAN were selected, and were divided into five grades from Ⅰ to Ⅴ according to the classified standard of Meadow. HBsAg and HBcAg in renal tissues were detected by immunohistochemistry methods of Envision. Eighteen renal tissues with IgAN among 48 renal biopsy tissues were selected randomly, and then HBV DNA in these tissues was detected by direct in site polymerase chain reaction (IS-PCR) method. RESULTS: Thirty-six (36/48, 75.00%) and twenty-one (21/39, 53.85%) cases were positive with HBcAg and HBsAg in 48 cases renal tissues with IgAN, respectively. The positive rate of HBV DNA in 18 cases with IgAN was 61.11% (11/18). The positive rate of HBcAg， HBsAg and HBV DNA in renal tissues were all no significance betwen every grade (P＞0.05), but the positive rate of HBcAg, HBsAg and HBV DNA in renal tubule were all higher than that in glomeruli (P＜0.05). CONCLUSIONS: HBV really takes part in the occurrence of IgAN. HBV maybe induces the renal injury by cell-mediated immunity or a series of cytokines but not by virus direct damage. The renal tubule epithelium may be the targeting cells of HBV infection.     

Correlation between HBsAg level and HBV DNA titer during chronic hepatitis B treatment

AIM: Viral load is widely used as an indicator for the diagnosis and monitoring the treatment efficacy of chronic hepatitis B (CHB). Previous studies suggested that the quantity of hepatitis B surface antigen (HBsAg) in serum could be a surrogate marker of serum hepatitis B virus (HBV) DNA level. In this study, we aimed to investigate whether HBsAg level correlates with HBV DNA titer during CHB treatment. METHODS: Sera were collected from 47 CHB patients ［35 male, 12 female, mean age: (35±8) years］ treated for 48 weeks with a monotherapy (pegylated interferon alpha-2a, 18 patients; lamivudine, 15 patients) or a combination therapy (pegylated interferon alpha-2a and lamivudine, 14 patients). Serum samples were obtained at week 0 (just before the treatment), 4, 8, 24, 48 and week 72 (24 weeks after the treatment). HBV DNA was measured with real-time polymerase chain reaction (PCR). HBsAg was quantified with an automated chemiluminescent microparticle immunoassay. RESULTS: The titer of HBsAg correlated with the HBV DNA level in the 18 patients with monotherapy of pegylated interferon alpha-2a and the 14 patients with combination therapy (pegylated interferon alpha-2a and lamivudine). The significant correlation (canonical correlation=0.83) was found. However, no correlation in 15 patients with the monotherapy of lamivudine was observed. CONCLUSION: HBsAg titer correlates with HBV DNA level in CHB patients during the treatment with interferon or interferon and lamivudine, which can be a surrogate marker for monitoring the treatment efficacy.     

Role of hepatitis B virus in intrahepatic TGF-β1/Smads signaling pathway

AIM:To explore the effects of hepatitis B virus (HBV) on intrahepatic expression of transforming growth factor β1（TGF-β1） and Smads. METHODS:The expression of intrahepatic TGF-β1, HBsAg and HBcAg in control group and chronic hepatitis B (CHB) group was detected by immunohistochemical method.The serum HBV DNA content was determined by real-time PCR. The role of HBV in the expression of TGF-β1, Smad3 and Smad7 in human hepatic stellate cell line LX-2 in vitro was observed by cell culture and Western blotting. RESULTS:The average score of intrahepatic TGF-β1 expression in CHB group was higher than that in control group. With the increase in serum HBV DNA content, intrahepatic TGF-β1 expression was also enhanced. In the HBcAg positive hepatic tissue, there was higher TGF-β1 expression than that in the liver tissue of HBcAg negative. Compared with control group and HBV+anti-TGF-β1 group, HBV caused increased expression of TGF-β1 and Smad3 in HBV group in vitro. No difference of Smad7 protein among control group, HBV group and HBV+anti-TGF-β1 group was observed. CONCLUSION: The expression of intrahepatic TGF-β1 is related to serum HBV DNA and hepatocellular HBcAg in the patients with CHB. HBV-induced liver fibrosis mainly relies on positive regulatory mechanisms of Smad3,and the negative regulation by Smad7 almost does not function.     

Effect of hepatitis virus B protein on the functions of PBMCs isolated from patients with chronic HBV infection

AIM: To study the effect of hepatitis virus B proteins on peripheral blood mononuclear cells (PBMCs) from patients among various types of chronic hepatitis B virus (HBV) infection.METHODS: 80 patients of various types of chronic HBV infection were observed, including 40 HBeAg positive with abnormal alanine aminotransferase (ALT) (A group), 20 HBeAg positive with persistent normal ALT(B group), 20 HBeAg and HBV-DNA negative with persistent normal ALT level(C group). IL-10, IFN-γ in CD8+CD28+T cells, after stimulation with PHA, HBeAg and HBcAg for 48 h, were inspected respectively in PBMCs.RESULTS: IFN-γ was significantly lower in HBeAg positive patients. IL-10 was significantly higher in HBeAg positive with normal ALT. CD8+CD28+T were significantly lower than others. CONCLUSION: In HBeAg positive group, secretion of cytotoxic T lymphocyte (CTL) and Th1 type cellular immunologic reaction is decreased, Th2 type cellular immunologic reaction is enhanced.     

Role of heat shock protein 90 and tubulin in oxidative stress preconditioning

AIM:To find the role of heat shock protein 90 （HSP90） and tubulin in oxidative stress preconditioning in HepG2 cells. METHODS:The different doses of H2O2 were used to induce cell injury in HepG2 cells. MTT assay, Western blotting and confocal laser microscopy were also used. RESULTS:MTT colorimetry showed that preconditioning (50 mmo1/L H2O2) provided a temporary resistance against subsequent oxidative stress (500 mmol/L H2O2). Western blotting demonstrated that preconditioning increased the levels of HSP90 and tubulin in HepG2 cells, and lessen the declining of HSP90 and tubulin after stress. Tubulin and HSP90's colocalizations in cells with different doses of H2O2 were also observed under laser scanning confocal microscope. CONCLUSION:Tubulin might play important role in oxidative stress preconditioning in HepG2 cells by combining with HSP90.     

Relationship between precore/basal core promoter mutations of hepatitis B virus and therapeutic effect of peginterferon α-2b,and changes of mutations before and after treatment

AIM:To investigate the relationship between therapeutic effect of peginterferon α-2b (Peg-IFNα-2b) and precore (PC) region G1896A and basal core promoter (BCP) region A1762T/G1764A mutations of hepatitis B virus (HBV), and the changes of the mutations before and after treatment. METHODS:The patients with HBeAg-positive chronic hepatitis B (CHB) (n=69) were treated with Peg-IFNα-2b for 48 weeks and followed up for 24 weeks. The PC and BCP sequences at baseline and the 72th week were determined using polymerase chain reaction (PCR) and direct sequencing. Serum HBsAg, HBeAg, alanine aminotransferase (ALT) and HBV DNA was quantified in the samples taken at baseline (week 0), during the treatment period (weeks 4, 8, 12, 24, 36 and 48), and during follow-up (weeks 60 and 72). RESULTS:Within the total cohort, wild-type (WT) virus was detectable in only 14 patients (20.29%), and mutants were detected in 55 patients (79.71%). The serum HBeAg level in the patients with mutant virus was significantly lower than that in the patients with WT virus (P=0.024). The proportion of WT, PC mutant, BCP mutant and PC+BCP mutant was significantly changed at baseline and week 72 (P=0.004). No significant difference of HBeAg seroconversion and combined response between patients with WT virus or mutants (PC, BCP and PC+BCP) was observed. CONCLUSION:PC and BCP mutations have no effect on the response of HBeAg-positive CHB patients to Peg-IFNα-2b. The proportion of each mutation was significantly changed before and after treatment.     

Effect of Raptor on invasion ability of glioma cells

AIM：To study the influence of Raptor on the invasion ability of glioma cells. METHODS：The technique of RNA interference was used. U87 cells were transfected with Raptor restricted siRNA plasmid, and the expression level of Raptor in the transfected cells was detected by Western blotting. The invasive ability of the cancer cells in vitro was determined. The phosphorylation level of ARK5 and the expression of MMP-2 and MMP-9 were detected by Western blotting. The expression levels of Raptor in the tumor samples of low-grade gliomas (WTO grade I and grade II) and high-grade gliomas (WTO grade III and grade IV) were also analyzed by immunohistochemical staining. RESULTS：Raptor siRNA was transfected into U87 cells and the cells were named siRaptor/U87 cells. The cells transfected with the control plasmid was named Scr/U87 cells. The expression level of Raptor in siRaptor/U87 cells was lower than that in Scr/U87 cells. The results of in vitro invasion assay showed that the number of siRaptor/U87 cells penetrating the Matrivgel matrix membrane was less than that of Scr/U87 cells (P＜0.01). The protein expression of MMP-2 and MMP-9, and phosphorylation of ARK5 protein in the cells in the experimental group were lower than those in control group. The correlation between the expression of Raptor in gliomas and the degree of deterioration was also observed (P＜0.01). CONCLUSION：The expression of Raptor may contribute to the invasion ability of glioma cells by phosphorylation of ARK5 and increase in the levels of MMP-2 and MMP-9.     

Effect of GPNMB on proliferation,apoptosis and invasion of human hepatoma cells

AIM：To investigate the effect of glycoprotein nonmetastatic melanoma protein B (GPNMB) on the proliferation, apoptosis and invasion of human hepatoma HepG2 cells and its molecular mechanisms. METHODS：The GPNMB siRNA and GPNMB-overexpressing vector were constructed, and then transfected into HepG2 cells. MTT assay, flow cytometry and Transwell chamber were used to determine the effects of GPNMB down-regulation and up-regulation on the proliferation, apoptosis and invasive ability of HepG2 cells. RESULTS：The proliferation of HepG2 cells was obviously promoted by the up-regulation of GPNMB. No effect of GPNMB on the apoptosis of HepG2 cells was observed. The invasion of HepG2 cells was also significantly promoted by the up-regulation of GPNMB. When integrin β1 was silenced by siRNA, the promoting effect of GPNMB on the proliferation and invasive ability of HepG2 cells was significantly suppressed. CONCLUSION: GPNMB may promote the proliferation and invasion of HepG2 cells by the interaction with integrin β1, and may be used as a potential therapeutic target in liver cancer.     

Changes of Kupffer cells during tree shrew chronically infected with hepatitis B virus

AIM：To explore the changes and significance of Kupffer cells in the process of tree shrew chronically infected with hepatitis B virus (HBV). METHODS：The animals were divided into 3 groups. Group A consists of 6 tree shrews that were identified as persistently infected with HBV; group B consists of 3 tree shrews that were suspected as persistently infected with HBV; group C consists of 4 tree shrews that were not inoculated with HBV and were applied as normal controls. Liver biopsies were collected regularly from all animals, and the Kupffer cells were isolated, purified and primarily cultured. The techniques of flow cytometry, immunohistochemistry, lysosomal fluorescent probe staining and real-time RT-PCR were applied to determine the number and function of these Kupffer cells. RESULTS：The result showed that the count and proportion of CD163+ cells in group A were significantly higher than those in group B and group C (P<0.05). Meanwhile, the fluorescence intensity levels of lysosomal, the number of lysozyme-positive cells and the mRNA expression level of TNF-α in the Kupffer cells in group A were significantly lower than those in group B and group C (P<0.05). CONCLUSION：Kupffer cells may play a regulatory role during host’s chronic HBV infection.     

Effects of luteolin on invasion,migration and adhesion of human hepatocellular carcinoma HepG2 cells

AIM: To investigate the effects of luteolin on invasion, migration and adhesion of human hepatocelluar carcinoma HepG2 cells.METHODS: HepG2 cells were cultured and treated with luteolin at 10, 20 and 40 μmol/L respectively. The invasion capability was examined by cell invasion assay. The migration ability was examined by wound healing assay. The adhesion capability was measured by adhesion assay. The protein levels of E-cadherin, N-cadherin, vimentin and Snai1 were determined by Western blot analysis.RESULTS: Luteolin inhibited the invasion, migration and adhesion ability of HepG2 cells in vitro in a dose-dependent manner. After treatment with luteolin, the expression of E-cadherin was increased significantly and the expression of N-cadherin, vimentin and Snai1 were decreased significantly.CONCLUSION: Luteolin inhibits the invasion, migration and adhesion ability of human hepatocelluar carcinoma HepG2 cells. The mechanism may be related to the regulatory effects of luteolin on epithelial-mesenchymal transition.     

Inhibition of TNF-α-mediated NF-κB activation by 4-hydroxynonenal contributes to liver injury in alcoholic liver disease

AIM: To study the role of 4-hydroxynonenal (4-HNE) in hepatocyte death induced by tumor necrosis factor α (TNF-α).METHODS: Human liver cell line HepG2 and primary mouse hepatocytes were used to establish the cell model. The effect of 4-HNE on TNF-α-induced cell death was determined by lactate dehydrogenase (LDH) release and MTT assays. The intracellular levels of 4-HNE-protein adducts were determined by Western blotting. The intranuclear NF-κB (p65) and its DNA binding activity were detected by Western blotting and ELISA, respectively. Long-term intake of alcohol in C57BL/6 mice was performed to establish the animal model. The histological changes of mouse hepatic tissues and the apoptosis of hepatocytes were observed by HE staining and TUNEL assay, respectively. The hepatic levels of triglyceride (TG), TNF-α and 4-HNE-protein adducts, and the plasma activity of alanine aminotransferase (ALT) were also detected.RESULTS: (1) 4-HNE significantly increased the sensitivity of HepG2 cells and primary mouse hepatocytes to the killing effect of TNF-α. (2) 4-HNE significantly increased the intracellular levels of 4-HNE-protein adducts. (3) 4-HNE inhibited TNF-α-mediated NF-κB (p65) activation in HepG2 cells. (4) Long-term intake of alcohol in mice resulted in high hepatic levels of 4-HNE and TNF-α, accompanied with the increases in hepatic TG content, plasma ALT activity and hepatocyte death.CONCLUSION: Long-term intake of alcohol induces oxidative stress and produces 4-HNE as a hepatocyte-sensitizing factor, which inhibits TNF-α-mediated NF-κB anti-apoptotic signaling pathway in hepatocytes, thus inducing alcoholic liver damage.