HBx facilitates ferroptosis in acute liver failure via EZH2 mediated SLC7A11 suppression.

BACKGROUND: Acute liver failure (ALF) is a syndrome of severe hepatocyte injury with high rate of mortality. Hepatitis B virus (HBV) infection is the major cause of ALF worldwide, however, the underlying mechanism by which HBV infection leads to ALF has not been fully disclosed. METHODS: D-GalN-induced hepatocyte injury model and LPS/D-GalN-induced ALF mice model were used to investigate the effects of HBV X protein (HBx) in vitro and in vivo, respectively. Cell viability and the levels of Glutathione (GSH), malondialdehyde (MDA) and iron were measured using commercial kits. The expression of ferroptosis-related molecules were detected by qRT-PCR and western blotting. Epigenetic modification and protein interaction were detected by chromatin immunoprecipitation (ChIP) assay and co-immunoprecipitation (co-IP), respectively. Mouse liver function was assessed by measuring aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The histological changes in liver tissues were monitored by hematoxylin and eosin (H&E) staining, and SLC7A11 immunoreactivity was assessed by immunohistochemistry (IHC) analysis. RESULTS: D-GalN triggered ferroptosis in primary hepatocytes. HBx potentiated D-GalN-induced hepatotoxicity and ferroptosis in vitro, and it suppressed SLC7A11 expression through H3K27me3 modification by EZH2. In addition, EZH2 inhibition or SLC7A11 overexpression attenuated the effects of HBx on D-GalN-induced ferroptosis in primary hepatocytes. The ferroptosis inhibitor ferrostatin-1 (Fer-1) protected against ALF and ferroptosis in vivo. By contrast, HBx exacerbates LPS/D-GalN-induced ALF and ferroptosis in HBx transgenic (HBx-Tg) mice. CONCLUSION: HBx facilitates ferroptosis in ALF via EZH2/H3K27me3-mediated SLC7A11 suppression.

The strategy and efficacy of prophylaxis against hepatitis B virus recurrence after liver transplantation for HBV-related diseases in the era of potent nucleos(t)ide analogues: A meta-analysis.

OBJECTIVES: This meta-analysis aimed to evaluate the clinical outcome of liver transplant (LT) recipients under potent nucleoside or nucleotide analogue (NA)-based regimens and investigate different prophylactic schemes. METHODS: We followed PRISMA statement to conduct this study. Two reviewers independently searched relevant literature via PubMed, Embase, Ovid MEDLINE, Web of Science and Insightmeme. Studies were included if they evaluated hepatitis B virus (HBV) recurrence under potent NA-based regimens in patients who received HBV-related LT. Primary and secondary outcomes were HBV recurrence, hepatocellular carcinoma (HCC) recurrence, all-cause and HBV recurrence-related mortality. Incidences with 95% confidence intervals were calculated and assessed by fixed and random effects models. Subgroup analyses were used to examine the impact of different treatment strategies. RESULTS: Altogether 25 studies (N = 2327) were included, with a pooled HBV recurrence rate of 1.01% (95% CI 0.53%-1.59%). HBV viremia or hepatitis D virus superinfection did not influence HBV recurrence significantly (P = 0.23 and 0.71, respectively). The recurrence rate under an indefinite combination of potent NA and hepatitis B immunoglobulin (HBIG) was lower than that under potent NA monotherapy (P = 0.000) and similar to that under NA plus a finite course of HBIG (P = 0.48). The pooled HCC recurrence rate was 5.34% (95% CI 0.78%-12.48%). HBV recurrence-related mortality and all-cause mortality were 0% and 6.95% (95% CI 4.30%-10.08%), respectively. CONCLUSIONS: Potent NA-based regimens provide satisfactory HBV antiviral prophylaxis and improve long-term outcomes for LT recipients. A finite combination of potent NA and HBIG is an alternative to life-long dual therapy.

Long non-coding RNA MALAT1 promotes angiogenesis and immunosuppressive properties of HCC cells by sponging miR-140.

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer in adults. Previous studies in our laboratory found that long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was upregulated in HCC cells, which could affect the metastasis and invasion of HCC. However, the underlying mechanism remains unknown. Herein, we studied the interaction between MALAT1 and miR-140 on the regulation of angiogenesis and immunosuppressive properties. We revealed that the expression of MALAT1 and VEGF-A was significantly increased in HCC cells. Knockdown of MALAT1 in HCC cells suppressed the production of VEGF-A, impaired the angiogenesis of HUVECs, and facilitated the polarization of macrophage toward the M1 subset. Mechanistically, the interaction between MALAT1 and miR-140 or between miR-140 and VEGF-A was confirmed by multiple assays. Besides, a negative correlation between MALAT1 and miR-140 was found in HCC tissues. Furthermore, miR-140 inhibition significantly increased VEGF-A expression, promoted angiogenesis of HUVECs, and redirected the polarization of macrophages toward the M2 subset. In addition, in vivo studies also verified the regulatory network of the MALAT1/miR-140 axis on VEGF-A in HCC progression. In summary, this study revealed the mechanism that MALAT1 worked as a putative HCC promotor via inhibiting miR-140. Therefore, targeting MALAT1 or miR-140 might alleviate the progression of HCC in the future.

[Effect of microRNA on proliferation caused by mutant HBx in human hepatocytes].

To study the effect of micro (mi)RNA on cellular proliferation induced by hepatitis B x protein, HBx, in human liver cells and to investigate the underlying molecular mechanism of this cancer-related effect. The human L02 hepatocyte cell line was stably transfected with HBx (L02/HBx) or an HBx mutant (L02/HBx-d382) that induces higher levels of cellular proliferation. The differential miRNA expression profiles were determined by microarray analysis and confirmed by real-time PCR. Two miRNAs, miR-338-3p and miR-551b, that were found to be significantly down-regulated in the L02/HBx-d382 cells were selected for further study and transfected individually into cells using the lipofectamine procedure. The cell survival rate was analyzed by MTT assay, and cell cycles were assessed by flow cytometry. Expressions of cyclinD1, cyclinG1, and E2F1 were assessed by real-time PCR and Western blotting. Compared with the microarray miRNA profile of L02/pcDNA3.0 cells, six miRNAs were up-regulated and five miRNAs were down-regulated in the L02/HBx-d382 cells, while four miRNAs were up-regulated and 12 were down-regulated in the L02/HBx cells. The microarray results were consistent with real-time PCR results. Transfection of miR-338-3p and miR-551b significantly inhibited the cell survival rates (P less than 0.001) and induced G0/G1 phase cycle arrest. According to MTT results: for L02/HBx-d382 cells, compared with lipofectamine or non-transfected (NC) controls, the t value of miR-338-3p was 10.402, 9.133 and the t value of miR-551b was 8.763, 7.403; for L02/HBx cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 9.105, 8.074 and the t value of miR-551b was 7.673, 7.52. According to flow cytometry results: for L02/HBx-d382 cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 12.173, 11.107 and the t value of miR-551b was 15.364, 13.377; for L02/HBx cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 15.416, 13.378, and the t value of miR-551b was 13.276, 13.109. The protein levels of cyclinD1, cyclinG1, and E2F1 were significantly reduced by both miR-338-3p and miR-551b ( P less than 0.001). For L02/HBx-d382 cells, compared with lipofectamine or NC controls: E2F1 had t = 11.132, 10.031 and 12.017, 10.973, respectively; cyclinD1 had t = 15.654, 15.013 and 15.447, 14.733, respectively; cyclinG1 had t = 8.017, 7.661 and 7.402, 7.417, respectively. For L02/HBx cells, compared with lipofectamine or NC controls: E2F1 had t = 14.244, 13.331 and 15.022, 14.468, respectively; cyclinD1 had t = 8.695, 8.137 and 7.877, 7.503, respectively; cyclinG1 had t = 7.73, 7.471 and 7.596, 7.41, respectively. In contrast, the mRNA levels for E2F1, cyclinD1, and cylcinG1 showed no significant differences between the miRNA transfected cells and controls. Wild-type HBx and the high proliferation-inducing mutant HBx can influence the miRNA expression profile of L02 cells. HBx down-regulates miR-338-3p and miR-551b in L02 cells, and the high proliferation-inducing mutant has a more robust effect. The mechanism of miR-338-3p- or miR-551b-mediated cell growth inhibition appears to be related to the direct modulation of cyclinD1, cyclinG1, and E2F1.

Mycophenolate mofetil prevents lethal acute liver failure in mice induced by bacille Calmette-Guérin and lipopolysaccharide.

BACKGROUND/AIMS: To investigate the effect of mycophenolate mofetil (MMF) on acute liver injury induced by bacille Calmette-Guérin (BCG) and lipopolysaccharide (LPS). METHODS: Acute liver failure was induced in male Kunming strain mice by injecting the animals with BCG 2.5 mg per mouse, and LPS 10 microg per mouse 10 days later. The mice in the treatment groups were given MMF 2 h before, simultaneous with, or 2 h after administration of LPS, and the mice in the control group were given the same dose of saline. The 24-h survival rate, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were compared. Serum levels of tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin 6 (IL-6) were measured and the expressions of TNF-alpha, IFN-gamma, and IL-6 mRNA in the liver tissue were determined by reverse transcription-polymerase chain reaction (RT-PCR). Concanavalin A (Con A)-induced splenocyte proliferation were determined by methods of methyl thiazolyl tetrazolium. RESULTS: Injecting a small dose of LPS into BCG-primed mice caused a lethal hepatic injury mimicking acute hepatitis, from which 16 of the 20 mice died within 24 h (20% survival rate). Massive necrosis of parenchymal hepatocytes with marked inflammatory cell infiltration was observed by histological examination. In parallel, serum ALT and TNF-alpha, IFN-gamma, and IL-6 levels were increased. Expression of TNF-alpha, IFN-gamma, and IL-6 mRNA in the liver were significantly increased also. Treatment with MMF markedly reduced the death rate in a dose-dependent manner. It reached its maximal effect at the dosage of 150 mg per kg of body weight when pretreated 2 h before LPS injection, with improvement of histological feather and survival rate (84.2%, 16/19). MMF significantly inhibited serum levels of TNF-alpha, IFN-gamma, and IL-6, and significantly reduced TNF-alpha, IFN-gamma, and IL-6 expression in the liver, which increased after BCG and LPS injection. Moreover, splenocyte proliferation response induced by Con A was also inhibited by MMF treatment. CONCLUSIONS: Treatment with MMF has a protective effect on endotoxin-induced fatal liver failure by regulating the production of inflammatory cytokines and T-cell proliferation.

[Study on quasispecies of hepatitis B virus and the clinical manifestation of their infection by melt curve analysis].

OBJECTIVES: To study the relationship between quasispecies of hepatitis B virus and the clinical manifestations of their infection, and to find the answer of why different quasispecies of HBV with the same genotype can induce different clinical situations. METHODS: Sixty serum samples, in all of which HBVs of genotype B exist, taken from 32 chronic asymptomatic carriers and 28 severe chronic hepatitis patients, were collected to detect quasispecies of HBV DNA by melt curve approach. Then the relationship between quasispecies of HBV of the same genotype and the clinical situation of their infection was studied by comparing the wave crests of the two sample groups. RESULTS: The data of the 60 serum samples of HBV of genotype B detected by melt curve showed that HBV DNA in severe chronic hepatitis patients had more wave crests than that in chronic asymptomatic carriers (P < 0.05), suggesting that HBV in severe chronic hepatitis patients had more quasispecies than in the chronic asymptomatic carriers. CONCLUSION: The numbers of quasispecies of HBV correlate with the clinical situations of their infection. In the patients infected by HBV of the same genotype, those who have more HBV quasispecies would have more severe clinical manifestations.

[Establishment and the significance of a cell model of secreted alkaline phosphatase co-controlled by HCV 5'NCR and NS3 serine protease].

OBJECTIVE: To establish a cell model of secreted alkaline phosphatase (SEAP) co-controlled by HCV 5'NCR and NS3 serine protease in an effort to develop new antiviral agents. METHODS: The fragments of HCV 5'NCR and NS3/4A-SEAP were amplified by PCR. They were fused into pBluescript SK+ to generate 5'NCR-NS3/4A-SEAP chimeric plasmid. The resulting chimeric gene was subcloned into HindIII/Bsu36 I site of pSEAP2-Control (a SEAP eukaryotic expression plasmid), to generate pNCR-NS3/4A-SEAP, in which the SEAP was fused in-frame to the downstream of NS4A/4B cleavage site. The SEAP activity in the culture media of transiently transfected cells was monitored quantitatively. The regulatory effect of HCV 5'NCR and NS3 serine protease on SEAP expression was measured by treatment of transfected cells with antisense oligodeoxynucleotide (ASODN) against HCV 5'NCR and TPCK, a irreversible serine protease inhibitor. RESULTS: The SEAP activity in the culture media reached 80801+/-4794 RLU, and was significantly inhibited by 5 micromol/L, 10 micromol/L of ASODN (t=4.315, p<0.01; t=6.985, p<0.001) and 100 micromol/L of TPCK (t=6.949, P<0.001). CONCLUSION: A cell model of SEAP co-controlled by HCV 5'NCR and NS3 serine protease has been successfully established. This might promote the screening of anti-viral drugs

[Relation between genotype of HBV and its clinical manifestation by PCR with genotype-specific primers].

OBJECTIVE: To determine the relation between genotype of HBV and its clinical manifestation. METHODS: Sera of 220 patients from Hunan Province of China, infected chronically with asymptomatic, mild, moderate, severe and fulminant hepatitis hepatitis B, were genotyped by PCR with genotype-specific primers. The results were statistically analyzed. RESULTS: Only genotype B (86.4%) and C (13.6%) were found. With the aggravations of patients' condition, genotype C was found more often (P < 0.05). The levels of alanine aminotransferase (ALT), total bilirubin (TBIL) and HBV-DNA of genotype C was higher than those of genotype B, but there was no statistical difference. However, the ALT elevation rates of genotype C (96.7%) were significantly higher than those of genotype B (75.2%) (P < 0.05). There was no statistical difference in HBeAg rate between genotype B and C in general, but in patients with chronic fulminant hepatitis or aged 21 approximately 30, the HBeAg rates of genotype C (35.0% and 50.0%) were significantly higher than those of genotype B (14.4% and 24.5%) (P < 0.05). CONCLUSION: The dominant genotype of HBV in Hunan Province of China is genotype B and C. Genotype of HBV correlates with its clinical manifestation and genotype C of HBV can lead to more severe hepatitis than genotype B of HBV.

[Expression of secreted alkaline phosphatase in hepatocytes controlled by HCV IRES].

OBJECTIVE: To establish a cell model of secreted alkaline phosphatase (SEAP) controlled by HCV internal ribosome entry site (IRES). METHODS: The fragment of HCV 5' noncoding region (5' NCR) was amplified by polymerase chain reaction (PCR), and was immediately cloned the upstream of the SEAP gene of pSEAP2-Control, an SEAP eukaryotic expression plasmid. With the liposome transfection technique, the resulting recombinant plasmid pdNCRSEAP was transfected into hepatocytes QSG7710, and the SEAP activity of cell culture media was monitored quantitatively by the chemiluminescent method. The regulatory effect of the HCV 5' NCR on the SEAP expression was measured by the treatment of transfected cells with antisense oligodeoxynucleotide (ASODN) at 5 mumol and 10 mumol, respectively. RESULTS: The light emission intensity of pdNCRSEAP expression was 76% that of pSEAP2-Control. The inhibition rates of pNCRSEAP luminescence intensity affected by ASODN of 5 mumol and 10 mumol were 29.2% and 44.6%, respectively, while ASODN had no significant effect on the pSEAP2-Control expression. CONCLUSION: The SEAP expression of pdNCRSEAP is controlled by HCV 5'NCR. The cell model of drug evaluation targeted at HCV 5'NCR is successfully established and can be analyzed conveniently.

[Construction of an expression vector with a bicistron of green fluorescent protein and HCV 5'NCR controlled luciferase gene and its expression in hepatocytes].

OBJECTIVE: To construct an expression vector with a bicistron of green fluorescent protein (GFP) and HCV 5'NCR controlled luciferase gene and to explore its expression in hepatocytes. METHODS: With molecular cloning techniques, the DNA fragment of HCV 5'NCR and its controlled luciferase gene was obtained from plasmid pCMVNCRLuc and subcloned into pEGFP-C1, an expression plasmid of GFP. A recombinant plasmid pGFPNCRLuc with a bicistron of GFP and HCV 5'NCR controlled luciferase gene was constructed, and liposome-mediated transient expression was detected in hepatocyte QSG7701 cells. RESULTS: The recombinant plasmid expressed both GFP and luciferase at a high level. The expression activity of GFP showed no significant difference compared to that of pEGFP-C1 (P > 0.05), nor did that of luciferase to pCMVNCRLuc (P > 0.05). CONCLUSION: An expression vector with a bicistron of GFP and HCV 5'NCR controlled luciferase gene was successfully constructed. GFP and luciferase could express independently. This study can promote the establishment of an anti-HCV drug screen system.

[Clinical significance of gene quasispecies of transfusion transmitted virus].

OBJECTIVE: To investigate the clinical significance of gene variant of transfusion transmitted virus (TTV). METHODS: A nested polymerase chain reaction (nested-PCR) assay with specific primers from open reading frame one (ORF1) of TTV genome was established to detect TTV DNA in the serum samples from patients with hepatitis B and blood donors. Asymmetric PCR was established to get single strand DNA in the TTV DNA positive cases, and then single strand conformation polymorphism (SSCP) was applied. RESULTS: 1.25 +/- 0.50, 1.60 +/- 0.55, 3.36 +/- 1.36 and 4.59 +/- 1.83 SSCP bands were detected in the blood donors, chronic HBV carriers, chronic hepatitis B patients and chronic severe hepatitis B patients respectively. SSCP bands were much more complicated in chronic hepatitis patients and chronic severe hepatitis than those of chronic HBV carriers and blood donors (P < 0.05). CONCLUSION: There is gene variant in TTV infection. The complication of gene variant strain or quasispecies infection of TTV may be one of the causes responsible for clinical exacerbation of TTV superinfection in chronic hepatitis patients.