Serum soluble ST2 is a promising prognostic biomarker in HBV-related acute-on-chronic liver failure.

BACKGROUND: The IL-33/ST2 axis is involved in the pathogenesis of many diseases such as autoimmune diseases, cancer, and heart failure. However, studies of the IL-33/ST2 pathway in HBV-related acute-on-chronic liver failure (HBV-ACLF) are lacking. The present study aimed to determine the prognostic role of serum IL-33/soluble ST2 (sST2) in HBV-ACLF. METHODS: Serum levels of IL-33 and sST2 in healthy controls (HC, n=18), chronic hepatitis B (CHB, n=27) and HBV-ACLF (n=51) patients at the 1st and 4th week after enrollment were detected using ELISA, and clinical data were collected. The follow-up of HBV-ACLF patients lasted for 6 months at least. RESULTS: There was no significant difference of serum IL-33 level among HC, CHB and HBV-ACLF patients at week 1. However, serum sST2 level differed significantly among the three groups: highest in the HBV-ACLF group, moderate in the CHB group and lowest in the HC group. There was a reverse correlation between serum sST2 level and the survival of HBV-ACLF patients. The level of serum sST2 in HBV-ACLF survivors was significantly declined from week 1 to week 4 following the treatment, whereas that in HBV-ACLF non-survivors remained at a high level during the same period. Furthermore, serum sST2 level was significantly correlated with laboratory parameters and the most updated prognostic scores (CLIF-C OF score, CLIF-C ACLF score and ACLF grades). The receiver operating characteristics curves demonstrated that serum sST2 level was a good diagnostic marker for predicting the 6-month mortality in HBV-ACLF patients, comparable to the most updated prognostic scores. Serum sST2 cut-off points for predicting prognosis in HBV-ACLF patients were 76 ng/mL at week 1 or 53 ng/mL at week 4, respectively. HBV-ACLF patients with serum sST2 level above the cut-off point often had a worse prognosis than those below the cut-off point. CONCLUSION: Serum sST2 may act as a promising biomarker to assess severity and predict prognosis of patients with HBV-ACLF and help for the early identification and optimal treatment of HBV-ACLF patients at high risk of mortality.

Serum hepatocyte apoptosis biomarker predicts the presence of significant histological lesion in chronic hepatitis B virus infection.

BACKGROUND: Hepatocyte death, either apoptosis or necrosis, is closely associated with hepatic inflammation and fibrosis. AIMS: To investigate the potential values of hepatocytes death biomarker, M30 (apoptosis) and M65 (total death) in predicting histological lesions in chronic hepatitis B virus (HBV) infection. METHODS: Total 201 treatment-naïve patients were prospectively recruited. Liver biopsies were performed prior to antiviral treatments for treatments starting evaluation. Sera were collected on the day of liver biopsy for biomarker measurements. Sera from 200 age-matched healthy volunteers served as healthy controls (HCs). RESULTS: Significant histological lesions (SHL, i.e. significant inflammation and/or significant fibrosis) were confirmed in 150 (74.63%) patients. There were significantly higher serum M30 and M65 in patients with SHL than those without SHL (p<0.001) or than HCs (p<0.001). Serum M30, but not M65, independently predicted SHL [odds ratio:3.4 (95% CI, 1.8-6.2) per increase of 50U/L, p<0.001] after adjusting other potential confounding factors. A novel model based on M30 provided good diagnostic performance in predicting SHL [AUC, 0.87 (0.81-0.92)]. Cut-off value of >0 to confirm or ≤-0.5 to exclude SHL has ∼12% misclassification rate. CONCLUSION: Hepatocyte apoptosis biomarker, M30 is a promising non-invasive alternative to liver biopsy in chronic HBV infection upon treatment evaluation.

[Expression and correlation of angiotensin-converting enzyme 2 in CCl4-induced rat liver fibrosis].

OBJECTIVE: To investigate the expression and pathogenic relevance of angiotensin-converting enzyme 2 (ACE2) in liver fibrosis by using the rat model of CCl4-induced liver fibrosis. METHODS: The liver fibrosis model was generated by delivering subcutaneous injections of CCl4 (dissolved in olive oil at a 2:3 ratio; injection dose: 3 ml/kg) every three days for six weeks into male Sprague-Dawley rats. Another group of rats that received simultaneous injections of olive oil alone (3 ml/kg) were used as controls. At week 0, 2, 4, or 6 after the first injection, a subset of rats from each group was sacrificed to obtain liver tissues and serum samples. Pathological analyses were carried out to detect the presence and extent of liver cell degeneration, necrosis, inflammatory cell infiltration, and collagen deposition. ACE2 and ACE gene and protein expressions were measured by real-time PCR and Western blotting, respectively. The significance of differential expression between groups and time points was assessed by t-test and one-way ANOVA or Kruskal-Wallis tests, and correlation with fibrosis was assessed by Spearman's rank correlation coefficient. RESULTS: CCl4 administration led to significantly up-regulated ACE2 mRNA levels at week 2 (3.055+/-1.034), 4 (3.545+/-1.947), and 6 (6.448+/-1.836) (vs. controls; H = 23.224, P less than 0.001). Similarly, hepatic ACE mRNA was significantly increased after the CCl4 injections (week 2: 3.055+/-1.034, week 4: 3.545+/-1.947, week 6: 6.448+/-1.836; vs. controls: F = 12.982, P less than 0.001). There was a significant correlation between the ACE and ACE2 gene expression levels (r = 0.750, P less than 0.001). Protein levels of ACE2 also showed an increasing trend following CCl4 administration (week 0: 0.034, week 2: 0.097, week 4: 0.356, week 6: 0.512). The hepatic ACE2 gene expression strongly correlated with levels of alanine aminotransferase (r = 0.669, P less than 0.0001) and aspartate aminotransferase (r = 0.815, P less than 0.0001), and with the Ishak fibrosis score (r = 0.850, P less than 0.001). Finally, there was a significant correlation between circulating ACE2 and the Ishak fibrosis score (r = 0.730, P less than 0.001). CONCLUSION: A significant relationship exists between ACE2 gene expression and extent of liver fibrosis. ACE2 may play a crucial role in liver fibrogenesis.

The regulatory role of microRNA-1187 in TNF-α-mediated hepatocyte apoptosis in acute liver failure.

In the current study, we aimed at elucidating the regulatory mechanisms through which microR-1187 (miR-1187) participates in hepatocyte apoptosis in acute liver failure (ALF). An ALF model was induced with D-galactosamine (D-GalN) plus lipopolysaccharide (LPS) in BALB/c mice. The hepatic miRNA expression profile was detected by microarray analysis and verified by quantitative real-time PCR (qRT-PCR). The possible underlying mechanism was investigated in vitro using an embryonic murine hepatocyte cell line (BNLCL2) and miR-1187 mimic. Caspase-8 protein was detected by Western blotting and cell apoptosis was assayed by flow cytometry. Hepatic miR-1187 was down-regulated in ALF mice based on microarray data (P<0.001) and verified by qRT-PCR (P<0.01). Target scan revealed that caspase-8 was the putative target of miR-1187. In an in vitro study, miR-1187 showed the highest up-regulation in BNLCL2 cells transfected with the miR-1187 mimic at a 50 nM concentration for 12 h compared with cells transfected with the non-specific mimic (P<0.001). miR-1187 was down-regulated (P<0.01) but caspase-8 mRNA (P<0.01) as well as protein (P<0.05) were up-regulated in the BNLCL2 cells treated with D-GalN/TNF. Furthermore, overexpressed miR-1187 reduced caspase-8 expression at both the mRNA and protein levels significantly (P<0.01 and P<0.05 respectively), and significantly attenuated the apoptotic rate of BNLCL2 cells (P<0.05). We show that miR-1187 regulates hepatocyte apoptosis by targeting caspase-8. miR-1187 may serve as a potential therapeutic target for the treatment of ALF.

Effect of ribavirin and interferon beta on miRNA profile in the hepatitis C virus subgenomic replicon-bearing Huh7 cells.

Hepatitis C virus (HCV) infection is still a major global health issue despite decades of research. The liver-specific microRNA-122 (miR-122) can stimulate HCV replication/translation in vitro, indicating that miR-122 contributes to pathogenesis of HCV. However, it remains controversial whether interferon (IFN) inhibits HCV via modulating miR-122 expression. The underlying mechanism of ribavirin (RBV) in enhancing IFN treatment for HCV patients has yet to be explored. We investigated the relationship between miR-122 expression and anti-HCV activity of IFN beta in combination with RBV in vitro, due to difficulty accessing an HCV animal model. Upregulation of ISG54 mRNA or cytostatic effect was detected in Huh7 and HCV replicon cell lines in response to IFN beta or RBV stimulation, respectively. It was found that IFN beta and/or RBV suppressed miR-122 expression marginally, with a synergetic anti-HCV effect between IFN beta and RBV. Marginal modification of other miRNAs was also observed in these cell lines, using miRNA array following IFN beta and RBV treatment. Taken together, our data suggest that miRNAs are not crucial in anti-HCV action, following IFN beta and/or RBV stimulation in vitro.

[Real-time quantification of microRNAs in Huh7 cells by stem-loop reverse transcriptase polymerase chain reaction].

OBJECTIVE: To establish a convenient realtime PCR which can detect microRNAs in the human hepatoma cell line, Huh7 cells. METHODS: Total RNAs in Huh7 cells were extracted. MicroRNA 122, 24 and 146a were assayed by microRNA array, and then verified by Northern blot. Stem-loop RT-PCR and poly(A)-tailed RT-PCR were used to detect the above microRNAs. Data were analyzed with Quantity One software and 7500 system software. RESULTS: Microarray signal intensity of microRNA 122, 24 and 146a in Huh7 cells was 2201.49, 410.20 and 4.70, whose relative expression was confirmed as 0.0383, 0.0249, 0.0001 through Northern blot. While the poly(A)-tailed RT-PCR might only measure microRNA 122, Stem-loop RT-PCR could detect microRNA 122, 24 and 146a, whose average dCt was 2.5, 5.8 and 12.1 in accordance with microRNA array and Northern blot. CONCLUSION: Stem-loop RT-PCR can specifically and sensitively quantity microRNA levels, regardless of their abundance.

Expression of angiotensin-converting enzyme 2 in CCL4-induced rat liver fibrosis.

The renin angiotensin system (RAS) plays a major role in liver fibrosis. A novel homologue of angiotensin converting enzyme, ACE2, was identified as a negative regulator of RAS as it degrades Ang II to Ang1-7. We investigated in vivo the expression of ACE2 in liver fibrosis. We evaluated the relationship between biochemical variables and liver tissue expression of ACE2, the correlation between a histological assessment of liver fibrosis and liver tissue expression of ACE2. Male SD rats were randomly divided into a CCL4 group which received injections of CCL4 and the control group which received injections of olive oil. Liver pathology was examined by H&E and Sirius red staining, and real-time PCR was performed to determine the gene expression levels of ACE2 and ACE. Real-time PCR analysis revealed that ACE2 mRNA was higher at the two-, four-, and six-week time points, respectively (p<0.01). Similarly, hepatic ACE mRNA was significantly increased after CCL4 injection. There was a significant correlation between ACE and ACE2 gene expression (r=0.750, P<0.001). ACE2 gene expression strongly correlated with ALT (r=0.669, P<0.0001) and AST levels (r=0.815, P<0.0001). There was a significant correlation between circulating ACE2 and histological scores of liver fibrosis. ACE2 and ACE gene expression correlated with the ISHAK score (r=0.850, P<0.001; r=0.806, P<0.001). There was a significant relationship between ACE2 gene expression and the degree of liver fibrosis. ACE2 plays a crucial role in liver fibrogenesis.

Patients with chronic hepatitis B infection display deficiency of plasmacytoid dendritic cells with reduced expression of TLR9.

Chronic hepatitis B virus (HBV) infection is a complex interaction between replicating noncytopathic virus and dysregulatory host antiviral immunity. Plasmacytoid dendritic cells (pDCs) contribute to innate antiviral immunity via secreting type I interferons. Toll-like receptor (TLR) 9 is involved in major pattern recognition receptors expressed in pDCs. The frequency of pDCs and TLR9 expression in peripheral blood mononuclear cells (PBMC) was determined, using flow cytometry. IFN-alpha production by PBMC was evaluated in vitro in the presence of cytidine phosphate guanosine (CpG) with/without pDCs. The correlation between TLR9, pDCs frequency and viral load was also evaluated. TLR9 expression in pDCs in chronic HBV patients was significantly ( approximately 50%) reduced, supported by approximately 70% reduction of TLR9 mRNA, in comparison to healthy controls, correlating with the impairment of IFN-alpha production in vitro. Furthermore, pDCs frequency in these patients was substantially reduced ( approximately 30%), inversely correlating with serum ALT levels and HBV viral load. HBsAg and HBcAg were detected by immunohistochemistry in pDCs in chronic HBV patients. We conclude that HBV infection results in reduced frequency of circulating pDCs and their functional impairment via inhibiting the expression of TLR9. These data may provide useful information in both basic research and clinical treatment of chronic HBV infection.

[The effect of N-acetyl-L-cysteine on endoplasmic reticulum stress mediated apoptosis of HepG2 cells].

OBJECTIVE: To analyze the mechanisms of NAC on endoplasmic reticulum (ER) stress mediated cells apoptosis of HepG2 cells and to evaluate the potential role of NAC in the treatment of liver injury. METHODS: HepG2 cells were treated with H2O2 to make a model of oxidative ER stress mediated apoptosis. To evaluate the apoptosis, various methods such as MTT, DNA ladder, Western blot and flow cytometry were used. Then the optimal dosage and incubation time of NAC intervention in apoptosis were ascertained, and the differences between induction and intervention of apoptosis, including the percentage of apoptosis, the expression of apoptotic protein (GRP78, Caspase-12, PARP) and the production of reactive oxygen species (ROS) were compared. RESULTS: The activity of the cells decreased by H2O2 (0, 1, 3, 5 mmol/L) treatments in a dose-dependent manner. The ratio of apoptotic cells increased (0.7%+/-0.5%, 26.4%+/-1.8%, 29.7%+/-1.2% and 51.2%+/-9.4%, respectively) as did the production of ROS (14.0%+/-0.5%, 95.2%+/-0.1%, 97.5%+/-0.2% and 98.3%+/-0.2%, respectively). The HepG2 cells showed typical morphologic change of ER stress 6 hr after they were treated with 3 mmol/L H2O2. ER stress mediated-apoptosis was confirmed by Western blot. NAC (10 mmol/L and 20 mmol/L) protected cells from apoptosis. Typical features of ER stress apoptosis were seen accompanied by diminishing the ratio of apoptotic cells from 29.7%+/-1.2% to 23.3%+/-4.7% and 14.3%+/-1.2%. The production of ROS also decreased from 97.5%+/-0.2% to 52.2%+/-0.8% and 51.2%+/-2.9%. The effect was related to the concentration: 20 mmol/L NAC was more effective than 10 mmol/L. CONCLUSIONS: As an oxidizing agent, H2O2 may induce ROS in cells and induce oxidative stress, causing ER stress and apoptosis. NAC can inhibit the procession of ROS directly and prevent injuries to the hepatocytes.

[Expression of Toll-like receptor 3 on peripheral blood dendritic cells in HBeAg positive patients with chronic hepatitis B].

OBJECTIVE: To elucidate the roles of Toll-like receptor 3 (TLR3) on dendritic cells (DCs) in HBV infection. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from 48 healthy volunteers (HV) and 50 chronically HBV-infected patients (CH). DCs were induced and proliferated in a culture medium with rhGM-CSF and rhIL-4. We stimulated DCs with poly I:C and then TLR3, HLA-DR, and CD86, and CD1a expressions were examined by flow cytometry at 0 h, 12 h, 24 h and 48 h. The mRNA expressions of TLR3 were quantified by real-time PCR. RESULTS: TLR3 expression on DCs before the poly I:C stimulation and afterwards on the 12 h, 24 h, and 48 h were 69.2%+/-20.4%, 76.0%+/-18.6%, 78.2%+/-19.5% and 85.5%+/-6.9% respectively in the CH group, and 70.8%+/-11.2%, 67.5%+/-20.9%, 86.3%+/-14.7%, 68.6%+/-16.9% in the HV group. The expressions of TLR3 were up-regulated significantly at 24 h and 48 h after stimulation with poly I:C in the HV group, and in the CH group they were not significantly increased at 24 h but obviously increased at 48 h. The mRNA expressions of TLR3 increased significantly at 12 h in the HV groups, and at 48 h in CH group. The rate of CD86 expressions increased after poly I:C stimulation, and the increased rates were 12.6%+/-9.8%, 23.8%+/-20.0%, 20.7%+/-14.3% in the CH group, and 31.0%+/-25.0%, 43.4%+/-24.7%, 44.6%+/-25.5% in the HV group at 12 h, 24 h and 48 h after poly I:C stimulation. There was a marked increase of the expression level of CD86 in the HV group. In contrast, the level was only slightly increased in the CH group (31.0% vs 12.6%). The differences between the two groups were significant at 24 h and 48 h. No significant differences were detected in HLA-DR and CD1a between the two groups. CONCLUSIONS: The increase of expression level of TLR3 is slower in the CH group than that in the HV group. A marked increase of the expression level of CD86 is observed in the HV group. Our results suggest that abnormal expression of TLR3 and CD86 may relate to the persistence of HBV infection.

[Hepatitis C virus nonstructural 5A protein inhibits tumor necrosis factor alpha mediated apoptosis of HepG2 cells].

OBJECTIVE: To study the suppressive effect of HCV nonstructural 5A (NS5A) protein on tumor necrosis factor alpha (TNF alpha) mediated apoptosis of HepG2 cells. METHODS: NS5A gene fragment was amplified by reverse transcription and nested polymerase chain reaction from serum samples positive for anti-HCV. The PCR product was directly cloned using TA cloning kit, and 2 independent clones were isolated, digested and sequenced. Then we constructed HCV NS5A expression plasmid (pcDNA3.1-NS5A), stably transfected into HepG2 cells with lipofectamine. Successful transfection of NS5A gene and expression of NS5A protein were confirmed by Western blot. Transfected cells were incubated with TNFalpha for 48 h, then labeled with Annexin V and visualized by fluorescence microscopy. To examine the effects of NS5A protein on the apoptotic signaling pathway, caspase-3 cleavages and release of cytochrome C were investigated in the transfectant treated with TNF alpha for 48 h and the cell cytosol was subjected to SDS-PAGE and Western blot analysis. RESULTS: The stable transfectant of HepG2 cells lines for HCV NS5A protein expression was achieved. The NS5A protein blocked the activation of caspase-3 and the release of cytochrome C in the TNF alpha treated cells. CONCLUSION: HCV NS5A protein inhibits TNF alpha mediated apoptosis of HepG2 cells in vitro.