Hepatic progenitor cell-originated ductular reaction facilitates liver fibrosis through activation of hedgehog signaling.

Background: It is poorly understood what cellular types participate in ductular reaction (DR) and whether DR facilitates recovery from injury or accelerates hepatic fibrosis. The aim of this study is to gain insights into the role of hepatic progenitor cell (HPC)-originated DR during fibrotic progression. Methods: DR in liver specimens of PBC, chronic HBV infection (CHB) or NAFLD, and four rodent fibrotic models by different pathogenic processes was evaluated. Gli1 expression was inhibited in rodent models or cell culture and organoid models by AAV-shGli1 or treating with GANT61. Results: Severity of liver fibrosis was positively correlated with DR extent in patients with PBC, CHB or NAFLD. HPCs were activated, expanded, differentiated into reactive cholangiocytes and constituted "HPC-originated DR", accompanying with exacerbated fibrosis in rodent models of HPC activation & proliferation (CCl4/2-AAF-treated), Μdr2-/- spontaneous PSC, BDL-cholestatic fibrosis or WD-fed/CCl4-treated NASH-fibrosis. Gli1 expression was significantly increased in enriched pathways in vivo and in vitro. Enhanced Gli1 expression was identified in KRT19+-reactive cholangiocytes. Suppressing Gli1 expression by administration of AAV-shGli1 or GANT61 ameliorated HPC-originated DR and fibrotic extent. KRT19 expression was reduced after GANT61 treatment in sodium butyrate-stimulated WB-F344 cells or organoids or in cells transduced with Gli1 knockdown lentiviral vectors. In contrast, KRT19 expression was elevated after transducing Gli1 overexpression lentiviral vectors in these cells. Conclusions: During various modes of chronic injury, Gli1 acted as an important mediator of HPC activation, expansion, differentiation into reactive cholangiocytes that formed DR, and subsequently provoked hepatic fibrogenesis.

A mutual regulatory loop between transcription factor Yin Yang 1 and hepatitis B virus replication influences chronic hepatitis B.

Hepatitis B virus (HBV) infections pose a major threat to human health. HBV can upregulate the expression of the transcription factor Yin Yang 1 (YY1) in in vitro cytological experiments, suggesting an association between YY1 and HBV infection. However, data on YY1 expression in chronic hepatitis B (CHB) patients are lacking. In this study, we aimed to assess the correlation between YY1 expression and HBV infection. We detected serum YY1 levels in 420 patients with chronic HBV infection, 30 patients with chronic hepatitis C virus infection, and 32 healthy controls using an enzyme-linked immunosorbent assay. The correlation between YY1 levels and clinical parameters was analyzed. Meanwhile, the changes of YY1 before and after interferon or entecavir treatment were analyzed. YY1 levels in the liver tissues were detected using immunofluorescence staining. The expression of YY1 in HBV-expressing cells was detected through western blotting. Meanwhile, we explored the effects of YY1 on HBV replication and gene expression. We found that YY1 was highly expressed in the serum and liver tissues of CHB patients. Serum YY1 levels positively correlated with HBV DNA and hepatitis B surface antigen (HBsAg). Additionally, HBV DNA levels increased but HBsAg levels decreased after HBV-expressing cells overexpress YY1. In conclusion, our study demonstrates that YY1 plays an important role in HBV replication and gene expression, providing a potential target for the treatment of CHB.

The impact of HBx protein on mitochondrial dynamics and associated signaling pathways strongly depends on the hepatitis B virus genotype.

Chronic hepatitis B virus (HBV) infections are strongly associated with liver cirrhosis, inflammation, and hepatocellular carcinoma. In this context, the viral HBx protein is considered as a major factor influencing HBV-associated pathogenesis through deregulation of multiple cellular signaling pathways and is therefore a potential target for prognostic and therapeutic applications. However, HBV-associated pathogenesis differs significantly between genotypes, with the relevant factors and in particular the contribution of the genetic diversity of HBx being largely unknown. To address this question, we studied the specific genotype-dependent impact of HBx on cellular signaling pathways, focusing in particular on morphological and functional parameters of mitochondria. To exclusively investigate the impact of HBx of different genotypes on integrity and function of mitochondria in the absence of additional viral factors, we overexpressed HBx in Huh7 or HepG2 cells. Key signaling pathways were profiled by kinome analysis and correlated with expression levels of mitochondrial and pathogenic markers. Conclusively, HBx of genotypes A and G caused strong disruption of mitochondrial morphology alongside an induction of PTEN-induced putative kinase 1/Parkin-mediated mitophagy. These effects were only moderately dysregulated by genotypes B and E, whereas genotypes C and D exhibit an intermediate effect in this regard. Accordingly, changes in mitochondrial membrane potential and elevated reactive oxygen species production were associated with the HBx-mediated dysfunction among different genotypes. Also, genotype-related differences in mitophagy induction were identified and indicated that HBx-mediated changes in the mitochondria morphology and function strongly depend on the genotype. This indicates a relevant role of HBx in the process of genotype-dependent liver pathogenesis of HBV infections and reveals underlying mechanisms.IMPORTANCEThe hepatitis B virus is the main cause of chronic liver disease worldwide and differs in terms of pathogenesis and clinical outcome among the different genotypes. Furthermore, the viral HBx protein is a known factor in the progression of liver injury by inducing aberrant mitochondrial structures and functions. Consequently, the selective removal of dysfunctional mitochondria is essential to maintain overall cellular homeostasis and cell survival. Consistent with the intergenotypic difference of HBV, our data reveal significant differences regarding the impact of HBx of different genotypes on mitochondrial dynamic and function and thereby on radical oxygen stress levels within the cell. We subsequently observed that the induction of mitophagy differs significantly across the heterogenetic HBx proteins. Therefore, this study provides evidence that HBx-mediated changes in the mitochondria dynamics and functionality strongly depend on the genotype of HBx. This highlights an important contribution of HBx in the process of genotype-dependent liver pathogenesis.

HIV coinfection exacerbates HBV-induced liver fibrogenesis through a HIF-1α- and TGF-ß1-dependent pathway.

BACKGROUND & AIMS: Persons with chronic HBV infection coinfected with HIV experience accelerated progression of liver fibrosis compared to those with HBV monoinfection. We aimed to determine whether HIV and its proteins promote HBV-induced liver fibrosis in HIV/HBV-coinfected cell culture models through HIF-1α and TGF-ß1 signaling. METHODS: The HBV-positive supernatant, purified HBV viral particles, HIV-positive supernatant, or HIV viral particles were directly incubated with cell lines or primary hepatocytes, hepatic stellate cells, and macrophages in mono or 3D spheroid coculture models. Cells were incubated with recombinant cytokines and HIV proteins including gp120. HBV sub-genomic constructs were transfected into NTCP-HepG2 cells. We also evaluated the effects of inhibitor of HIF-1α and HIV gp120 in a HBV carrier mouse model that was generated via hydrodynamic injection of the pAAV/HBV1.2 plasmid into the tail vein of wild-type C57BL/6 mice. RESULTS: We found that HIV and HIV gp120, through engagement with CCR5 and CXCR4 coreceptors, activate AKT and ERK signaling and subsequently upregulate hypoxia-inducible factor-1α (HIF-1α) to increase HBV-induced transforming growth factor-ß1 (TGF-ß1) and profibrogenic gene expression in hepatocytes and hepatic stellate cells. HIV gp120 exacerbates HBV X protein-mediated HIF-1α expression and liver fibrogenesis, which can be alleviated by inhibiting HIF-1α. Conversely, TGF-ß1 upregulates HIF-1α expression and HBV-induced liver fibrogenesis through the SMAD signaling pathway. HIF-1α small-interfering RNA transfection or the HIF-1α inhibitor (acriflavine) blocked HIV-, HBV-, and TGF-ß1-induced fibrogenesis. CONCLUSIONS: Our findings suggest that HIV coinfection exacerbates HBV-induced liver fibrogenesis through enhancement of the positive feedback between HIF-1α and TGF-ß1 via CCR5/CXCR4. HIF-1α represents a novel target for antifibrotic therapeutic development in HBV/HIV coinfection. IMPACT AND IMPLICATIONS: HIV coinfection accelerates the progression of liver fibrosis compared to HBV monoinfection, even among patients with successful suppression of viral load, and there is no sufficient treatment for this disease process. In this study, we found that HIV viral particles and specifically HIV gp120 promote HBV-induced hepatic fibrogenesis via enhancement of the positive feedback between HIF-1α and TGF-ß1, which can be ameliorated by inhibition of HIF-1α. These findings suggest that targeting the HIF-1α pathway can reduce liver fibrogenesis in patients with HIV and HBV coinfection.

G-quadruplexes control hepatitis B virus replication by promoting cccDNA transcription and phase separation in hepatocytes.

Phase separation regulates fundamental processes in gene expression and is mediated by the local concentration of proteins and nucleic acids, as well as nucleic acid secondary structures such as G-quadruplexes (G4s). These structures play fundamental roles in both host gene expression and in viral replication due to their peculiar localisation in regulatory sequences. Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is an episomal minichromosome whose persistence is at the basis of chronic infection. Identifying the mechanisms controlling its transcriptional activity is indispensable to develop new therapeutic strategies against chronic hepatitis B. The aim of this study was to determine whether G4s are formed in cccDNA and regulate viral replication. Combining biochemistry and functional studies, we demonstrate that cccDNA indeed contains ten G4s structures. Furthermore, mutations disrupting two G4s located in the enhancer I HBV regulatory region altered cccDNA transcription and viral replication. Finally, we showed for the first time that cccDNA undergoes phase separation in a G4-dependent manner to promote its transcription in infected hepatocytes. Altogether, our data give new insight in the transcriptional regulation of the HBV minichromosome that might pave the way for the identification of novel targets to destabilize or silence cccDNA.

Comparisons of Insulin Resistance- and Steatosis-Based Scores in Monitoring Metabolic Associated Fatty Liver Disease Treatment Response.

BACKGROUND: Quantitative measurements of liver fat contents (LFCs) by magnetic resonance imaging derived-proton density fat fraction (MRI-PDFF) are accurate but limited by availability, convenience, and expense in the surveillance of metabolic associated fatty liver (MAFLD). Insulin resistance (IR) and steatosis-associated serum indices are useful in screening for MAFLD, but their value in monitoring MAFLD with or without chronic hepatitis B virus (CHB) infection remains unclear and we aimed to evaluate these scores in predicting changes in LFC. METHODS: We conducted a prospective study between January 2015 and December 2021 with 620 consecutive participants with MAFLD (212 participants with CHB) who received a 24-week lifestyle intervention. The homeostasis model assessment of IR (HOMA-IR), HOMA2 index, glucose-insulin ratio, quantitative insulin sensitivity check index, fasting insulin resistance index, fatty liver index (FLI), hepatic steatosis index (HSI), liver fat score (LFS), visceral adiposity index, and triglycerides * glucose were calculated. RESULTS: When using endpoints such as LFS improvements of ≥5% or 10% or escalations of ≥5%, LFS had the highest area under the curve (AUC) values at all endpoints for MAFLD alone (0.756, 95% CI: 0.707-0.805; 0.761, 95% CI: 0.705-0.818; 0.807, 95% CI: 0.713-0.901, all p < 0.05, respectively). With CHB, the FLI (AUC = 0.750) and HIS (AUC = 0.770) exhibited the highest AUCs between the former two outcomes, respectively, but no score could predict LFC escalation of ≥5%. CONCLUSION: Among IR and steatosis scores, changes in LFC through lifestyle interventions can be captured with LFS possessing moderate precision but not in those with CHB.

Enolase represents a metabolic checkpoint controlling the differential exhaustion programmes of hepatitis virus-specific CD8+ T cells.

OBJECTIVE: Exhausted T cells with limited effector function are enriched in chronic hepatitis B and C virus (HBV and HCV) infection. Metabolic regulation contributes to exhaustion, but it remains unclear how metabolism relates to different exhaustion states, is impacted by antiviral therapy, and if metabolic checkpoints regulate dysfunction. DESIGN: Metabolic state, exhaustion and transcriptome of virus-specific CD8+ T cells from chronic HBV-infected (n=31) and HCV-infected patients (n=52) were determined ex vivo and during direct-acting antiviral (DAA) therapy. Metabolic flux and metabolic checkpoints were tested in vitro. Intrahepatic virus-specific CD8+ T cells were analysed by scRNA-Seq in a HBV-replicating murine in vivo model of acute and chronic infection. RESULTS: HBV-specific (core18-27, polymerase455-463) and HCV-specific (NS31073-1081, NS31406-1415, NS5B2594-2602) CD8+ T cell responses exhibit heterogeneous metabolic profiles connected to their exhaustion states. The metabolic state was connected to the exhaustion profile rather than the aetiology of infection. Mitochondrial impairment despite intact glucose uptake was prominent in severely exhausted T cells linked to elevated liver inflammation in chronic HCV infection and in HBV polymerase455-463 -specific CD8+ T cell responses. In contrast, relative metabolic fitness was observed in HBeAg-negative HBV infection in HBV core18-27-specific responses. DAA therapy partially improved mitochondrial programmes in severely exhausted HCV-specific T cells and enriched metabolically fit precursors. We identified enolase as a metabolic checkpoint in exhausted T cells. Metabolic bypassing improved glycolysis and T cell effector function. Similarly, enolase deficiency was observed in intrahepatic HBV-specific CD8+ T cells in a murine model of chronic infection. CONCLUSION: Metabolism of HBV-specific and HCV-specific T cells is strongly connected to their exhaustion severity. Our results highlight enolase as metabolic regulator of severely exhausted T cells. They connect differential bioenergetic fitness with distinct exhaustion subtypes and varying liver disease, with implications for therapeutic strategies.

Assessment of compensated advanced chronic liver disease based on serum bile acids in chronic hepatitis B patients.

Patients with chronic liver disease progressed to compensated advanced chronic liver disease (cACLD), the risk of liver-related decompensation increased significantly. This study aimed to develop prediction model based on individual bile acid (BA) profiles to identify cACLD. This study prospectively recruited 159 patients with hepatitis B virus (HBV) infection and 60 healthy volunteers undergoing liver stiffness measurement (LSM). With the value of LSM, patients were categorized as three groups: F1 [LSM ≤ 7.0 kilopascals (kPa)], F2 (7.1 < LSM ≤ 8.0 kPa), and cACLD group (LSM ≥ 8.1 kPa). Random forest (RF) and support vector machine (SVM) were applied to develop two classification models to distinguish patients with different degrees of fibrosis. The content of individual BA in the serum increased significantly with the degree of fibrosis, especially glycine-conjugated BA and taurine-conjugated BA. The Marco-Precise, Marco-Recall, and Marco-F1 score of the optimized RF model were all 0.82. For the optimized SVM model, corresponding score were 0.86, 0.84, and 0.85, respectively. RF and SVM models were applied to identify individual BA features that successfully distinguish patients with cACLD caused by HBV. This study provides a new tool for identifying cACLD that can enable clinicians to better manage patients with chronic liver disease.

The Role of CTLA-4 in T Cell Exhaustion in Chronic Hepatitis B Virus Infection.

Patients with chronic hepatitis B (CHB) gradually develop T cell exhaustion, and the inhibitory receptor molecule, cytotoxic T-lymphocyte antigen-4 (CTLA-4), may play a role in this phenomenon. This systematic review investigates the role of CTLA-4 in the development of T cell exhaustion in CHB. A systematic literature search was conducted on PubMed and Embase on 31 March 2023 to identify relevant studies. Fifteen studies were included in this review. A majority of the studies investigating CD8+ T cells demonstrated increased expression of CTLA-4 in CHB patients, though one study found this only in HBeAg-positive patients. Three out of four studies investigating the expression of CTLA-4 on CD4+ T cells found upregulation of CTLA-4. Several studies showed constitutive expression of CLTA-4 on CD4+ regulatory T cells. CTLA-4 blockade resulted in heterogeneous responses for all T cell types, as it resulted in increased T cell proliferation and/or cytokine production in some studies, while other studies found this only when combining blockade of CTLA-4 with other inhibitory receptors. Although mounting evidence supports a role of CTLA-4 in T cell exhaustion, there is still insufficient documentation to describe the expression and exact role of CTLA-4 in T cell exhaustion in CHB.

ELOVL fatty acid elongase 7 (ELOVL7), upregulated by Mdr2-knockout, predicts advanced liver fibrosis in patients with chronic hepatitis B.

OBJECTIVE: This study aims to investigate the correlations between gene alterations induced in Mdr2-knockout (Mdr2-/-) models and liver fibrosis. SUBJECTS AND METHODS: The overlapping genes in Mdr2-/- models were determined and included in logistic regression analysis to identify potential candidates for predicting liver fibrosis. Correlations between the expression levels of the identified candidates and hepatic stellate cells (HSCs) were addressed. Functional enrichment of the identified candidates was also evaluated via bioinformatic analysis. RESULTS: Twenty-two overlapping genes in the GSE4612, GSE8642 and GSE14539 datasets were identified. Univariate and multivariate analysis indicated that ELOVL fatty acid elongase 7 (ELOVL7) was significantly associated with liver fibrosis S ≥ 2 (OR = 11.8, 95% CI = 2.0 - 69.2, p = 0.006). ELOVL7 was significantly upregulated in patients with various types of liver injury including hepatitis B virus (HBV) infection and fatty liver diseases, and in multiple liver injury models, including bile duct ligation (BDL), carbon tetrachloride (CCl4) and paracetamol injection-induced liver damage models (all p < 0.05). The ELOVL7 levels were significantly higher in HSCs than in other liver cells (all p < 0.05) and were significantly upregulated in activated HSCs compared to quiescent HSCs (all p < 0.05). In addition, ELOVL7 expression was positively associated with transforming growth factor ß (TGFß) and bone morphogenic protein 9 (BMP9) expression and negatively associated with BMP7 expression. Bioinformatic analysis of functional enrichment indicated that ELOVL7 is mainly involved in fatty acid synthesis and metabolism. CONCLUSIONS: ELOVL7 could accurately predict advanced liver fibrosis. It might be involved in the activation of HSCs and the TGFß signaling pathway.

A functional variant of CD40 modulates clearance of hepatitis B virus in hepatocytes via regulation of the ANXA2/CD40/BST2 axis.

More than 250 million people in the world are chronically infected with hepatitis B virus (HBV), which causes serious complications. Host genetic susceptibility is essential for chronic hepatitis B (CHB), and our previous genome-wide association study identified a single-nucleotide polymorphism (SNP), rs1883832, in the 5' untranslated region of CD40 predisposing to chronic HBV infection, but the underlying mechanism remains undefined. This study aimed to investigate whether rs1883832 was the real functional SNP (fSNP) of CD40 and how it modulated HBV clearance in hepatocytes. We determined the fSNP of CD40 and its regulatory protein(s) using luciferase reporter assays, electrophoretic mobility shift assay, flanking restriction enhanced pulldown and chromatin immunoprecipitation. The potential anti-HBV activity of CD40 and its downstream molecule BST2 was assessed in HBV-transfected and HBV-infected hepatoma cells and HBV-infected primary human hepatocytes. Moreover, the mechanism of CD40 was investigated by mRNA sequencing, quantitative real-time polymerase chain reaction, immunofluorescence and western blot. We revealed rs1883832 as the true fSNP of CD40 and identified ANXA2 as a negative regulatory protein that preferentially bound to the risk allele T of rs1883832 and hence reduced CD40 expression. Furthermore, CD40 suppressed HBV replication and transcription in hepatocytes via activating the JAK-STAT pathway. BST2 was identified to be the key IFN-stimulated gene regulated by CD40 after activating JAK-STAT pathway. Inhibition of JAK/STAT/BST2 axis attenuated CD40-induced antiviral effect. In conclusion, a functional variant of CD40 modulates HBV clearance via regulation of the ANXA2/CD40/BST2 axis, which may shed new light on HBV personalized therapy.

CpG DNA-triggered upregulation of TLR9 expression affects apoptosis and immune responses in human plasmacytoid dendritic cells isolated from chronic hepatitis B patients.

Plasmacytoid dendritic cells (pDCs) were treated with cytosine-phosphate-guanine (CpG) DNA, and cell apoptosis, signals and immune responses were measured to investigate the effects and mechanism of CpG DNA in pDCs from chronic hepatitis B patients. CpG DNA-stimulated pDCs secreted more IFN-α than the control pDCs. CpG DNA activated Toll-like receptor 9 (TLR9), thereby resulting in the upregulated expression of myeloid differentiation primary response gene 88 (MyD88), interferon regulatory factor 7 (IRF7) and nuclear factor kappa B (NF-κB). Furthermore, CpG DNA down-regulated apoptosis and promoted the expression of IFN-α, interleukin-12 (IL-12), IL-21, IL-26 and tumour necrosis factor-α (TNF-α) in pDCs. Following treatment with NF-κB inhibitor, pyrollidine dithiocarbamate (PDTC), the influence of CpG DNA on pDCs was inhibited. Our results suggest that CpG DNA may directly interfere with the function of pDCs through TLR9-mediated upregulation of MyD88, IRF7 and NF-κB expression, which can partially explain the activation of pDCs in chronic hepatitis B patients.

Small Hepatitis B Virus Surface Antigen Promotes Hepatic Gluconeogenesis via Enhancing Glucagon/cAMP/Protein Kinase A/CREB Signaling.

Hepatitis B virus (HBV) is a major risk factor for serious liver diseases. The liver plays a unique role in controlling carbohydrate metabolism to maintain the glucose level within the normal range. Chronic HBV infection has been reported to associate with a high prevalence of diabetes. However, the detailed molecular mechanism underlying the potential association remains largely unknown. Here, we report that liver-targeted delivery of small HBV surface antigen (SHBs), the most abundant viral protein of HBV, could elevate blood glucose levels and impair glucose and insulin tolerance in mice by promoting hepatic gluconeogenesis. Hepatocytes with SHB expression also exhibited increased glucose production and expression of gluconeogenic genes glucose-6-phosphatase (G6pc) and phosphoenolpyruvate carboxykinase (PEPCK) in response to glucagon stimulation. Mechanistically, SHBs increased cellular levels of cyclic AMP (cAMP) and consequently activated protein kinase A (PKA) and its downstream effector cAMP-responsive element binding protein (CREB). SHBs-induced activation of CREB enhanced transcripts of gluconeogenic genes, thus promoting hepatic gluconeogenesis. The elevated cAMP level resulted from increased transcription activity and expression of adenylyl cyclase 1 (AC1) by SHBs through a binary E-box factor binding site (BEF). Taken together, we unveiled a novel pathogenic role and mechanism of SHBs in hepatic gluconeogenesis, and these results might highlight a potential target for preventive and therapeutic intervention in the development and progression of HBV-associated diabetes. IMPORTANCE Chronic HBV infection causes progressive liver damage and is found to be a risk factor for diabetes. However, the mechanism in the regulation of glucose metabolism by HBV remains to be established. In the current study, we demonstrate for the first time that the small hepatitis B virus surface antigen (SHBs) of HBV elevates AC1 transcription and expression to activate cAMP/PKA/CREB signaling and subsequently induces the expression of gluconeogenic genes and promotes hepatic gluconeogenesis both in vivo and in vitro. This study provides a direct link between HBV infection and diabetes and implicates that SHBs may represent a potential target for the treatment of HBV-induced metabolic disorders.

Interleukin-33 mediates both immune-related and non-immune-related inhibitory effects against hepatitis B virus.

Chronic infection by hepatitis B virus (HBV) is associated with high risks of liver fibrosis, cirrhosis and hepatocellular carcinoma. HBV covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocyte serves as transcription template. Neither natural resolution of acute infection nor current treatment options for chronic infection are believed to cause cccDNA clearance. We previously showed that injection of IL-33-expressing plasmid facilitated clearance of intrahepatic HBV DNA in a mouse model of HBV persistence. In this work, HBV-targeting therapeutic effects of IL-33 were further explored. Murine IL-33 delivered by recombinant adeno-associated virus (AAV-mIL-33) induced clearance of both serum HBV markers and intrahepatic HBV DNA in two mouse models of HBV persistence based on replicon plasmid and recombinant cccDNA (rcccDNA) respectively. Clearance was associated with serum ALT elevations and liver infiltrations by CD4+ and CD8+ T cells, indicating IL-33-induced cellular immune responses against HBV-harboring cells. Adoptive transfer of splenocytes from AAV-mIL-33-cured mice was indeed sufficient to engender similar clearance in recipient mice. In vitro, intracellular, instead of extracellular, IL-33 was mainly responsible for repressing viral transcription, protein production and genome replication in Huh7 cells transfected with HBV replicon or rcccDNA. IL-33 was shown to be recruited onto rcccDNA minichromosome accompanied by loss of transcriptional activation epigenetic marks. Finally, transfection of IL-33 into HBV-infected HepG2/NTCP cells resulted in reduced transcription, antigen expression and genome replication, suggesting repression of canonical cccDNA. These data demonstrated diverse inhibitory effects on HBV and HBV-infected cells mediated by IL-33, and suggest IL-33 as an interesting therapeutic candidate.

[The expression of interferon-stimulating gene (STING/TMEM173) in liver tissue and its correlation with liver inflammation in patients with chronic hepatitis B].

Objective To investigate the relationship between the expression and distribution of interferon-stimulating gene/transmembrane protein 173(STING/TMEM173) in liver tissue and the grade of liver inflammation in patients with chronic hepatitis B, and to explore the underlying mechanisms in vitro. Methods The expression of STING/TMEM173 protein in liver tissue of 62 naive patients with chronic hepatitis B was detected by immunohistochemistry. Rank sum test and spearman correlation coefficient were used to analyze the correlation between hepatic STING/TMEM173 expression and liver inflammation grades as well as serum ALT levels. After transient or stable transfection by HBV whole genome plasmid, the expression of STING/TMEM173 in HepG2 cells was determined by Western blot analysis. The peripheral blood mononuclear cells (PBMCs) were stimulated by supernatant of HepG2.2.15 cells containing intact HBV virions, and the expression STING/TMEM173 gene was detected by real-time PCR. Results The results of immunohistochemical showed that STING/TMEM173 protein was higher in liver tissues of CHB patients and mainly expressed in inflammatory cells of liver tissue, and the expression of STING/TMEM173 protein was positively correlated with liver inflammation grade as well as serum ALT level. After transient and stable transfection by HBV whole genome plasmid, the STING/TMEM173 protein decreased significantly in HepG2 cells. In addition, HepG2.2.15 cell supernatant containing intact HBV virions promoted the expression of STING/TMEM173 in PBMC in a dose-dependent manner at RNA level. Conclusion HBV can up-regulate the expression of STING/TMEM173 protein in inflammatory cells of liver tissue, and the number of liver inflammatory cells expressing STING/TMEM173 may reflect the severity of liver inflammation.

Clinical Significance of BTLA and HVEM Expression on Circulating CD4+ T and CD8+ T Cells in Chronic Hepatitis B Virus Infection.

In this study, B and T lymphocyte attenuator (BTLA) and herpesvirus entry mediator (HVEM) expression on the surface of circulating CD4+ T and CD8+ T cells of patients with chronic hepatitis B (CHB) was investigated to explore their relationship with hepatitis B virus (HBV) clinical parameters. Both BTLA and HVEM were significantly upregulated on CD4+ T and CD8+ T cells of CHB patients compared with healthy controls (p < 0.01). Intriguingly, in CHB patients, the percentage of BTLA expression was positively correlated with that of HVEM (CD4+ T cells: r = 0.5461, p < 0.001 and CD8+ T cells: r = 0.4206, p < 0.01). Moreover, the percentage of BTLA expression was positively correlated with the levels of aspartate aminotransferase (AST) (CD4+ T cells: r = 0.3136, p < 0.05 and CD8+ T cells: r = 0.3159, p < 0.05) and alanine aminotransaminase (ALT) (CD4+ T cells: r = 0.3177, p < 0.05 and CD8+ T cells: r = 0.3311, p < 0.05). At the same time, the percentage of HVEM expression was also positively correlated with AST levels (CD4+ T cells: r = 0.3721, p < 0.05 and CD8+ T cells: r = 0.3325, p < 0.05) and ALT (CD4+ T cells: r = 0.3689, p < 0.05 and CD8+ T cells: r = 0.3476, p < 0.05). However, the percentage of BTLA and HVEM expression did not show significant relevance to HBV viral load. Further study demonstrated that BTLA inhibitory signaling could significantly inhibit T cell proliferation, activation, and cytokine production under optimal T cell receptor signaling (p < 0.05). Thereby, our findings indicate that the increased BTLA and HVEM expression on the surface of CD4+ and CD8+ T cells might represent a certain clinical significance and be involved in CHB progression during T cell exhaustion.

Endoplasmic reticulum stress promotes HBV production by enhancing use of the autophagosome/multivesicular body axis.

BACKGROUND AND AIMS: HBV infection has been reported to trigger endoplasmic reticulum (ER) stress and initiate autophagy. However, how ER stress and autophagy influence HBV production remains elusive. Here, we studied the effect of tunicamycin (TM), an N-glycosylation inhibitor and ER stress inducer, on HBV replication and secretion and examined the underlying mechanisms. APPROACH AND RESULTS: Protein disulfide isomerase (an ER marker), microtubule-associated protein 1 light chain 3 beta (an autophagosome [AP] marker), and sequestosome-1 (a typical cargo for autophagic degradation) expression were tested in liver tissues of patients with chronic HBV infection and hepatoma cell lines. The role of TM treatment in HBV production and trafficking was examined in hepatoma cell lines. TM treatment that mimics HBV infection triggered ER stress and increased AP formation, resulting in enhanced HBV replication and secretion of subviral particles (SVPs) and naked capsids. Additionally, TM reduced the number of early endosomes and HBsAg localization in this compartment, causing HBsAg/SVPs to accumulate in the ER. Thus, TM-induced AP formation serves as an alternative pathway for HBsAg/SVP trafficking. Importantly, TM inhibited AP-lysosome fusion, accompanied by enhanced AP/late endosome (LE)/multivesicular body fusion, to release HBsAg/SVPs through, or along with, exosome release. Notably, TM treatment inhibited HBsAg glycosylation, resulting in impairment of HBV virions' envelopment and secretion, but it was not critical for HBsAg/SVP trafficking in our cell systems. CONCLUSIONS: TM-induced ER stress and autophagic flux promoted HBV replication and the release of SVPs and naked capsids through the AP-LE/MVB axis.

Urine miR-93-5p is a promising biomarker for early detection of HBV-related hepatocellular carcinoma.

INTRODUCTION: The mortality rate of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC)continues to increase because sensitive, early and readily available diagnostic tools are lacking. To address this problem, we aimed to identify diagnosticbio markers to be used for early detection of HCC. MATERIALS AND METHODS: miR-93-5p was selected as a candidate biomarker based on the analyses of relevant Gene Expression Omnibus (GEO) datasets; it was validated using qPCR to quantify its expression levels in tissue, plasma and saliva sample sets. RESULTS: miR-93-5p was significantly upregulated in HBV-related HCC tissue. Notably, miR-93-5p in plasma and urine was also significantly increased in patients with early HBV-related HCC. The expression of miR-93-5p was significantly and positively correlated in pairwise comparisons of samples (tissue vs. plasma, tissue vs. urine, plasma vs. urine). Moreover, after curative hepatectomy,miR-93-5p in plasma and urine decreased significantly over one month after the curative hepatectomy and returned to normal levels. Furthermore, receiver operating characteristic (ROC) analysis indicated that both plasma and urine miR-39-5p could detect be used to early, advanced and overall HBV-related HCC cases with more than 85% sensitivities and 93% of specificities. Finally, urine miR-93-5p could be used to predict progress-free survival for early HCC patients who received curative hepatectomy and overall survival for advanced HCC patients without curative treatments. CONCLUSIONS: Plasma and urine miR-93-5p show great promise as potential novel biomarkers for early detection of HBV-related HCC. Moreover, urine miR-93-5p could be used to predict the prognosis of patients with HBV-related HCC.

HBV covalently closed circular DNA minichromosomes in distinct epigenetic transcriptional states differ in their vulnerability to damage.

BACKGROUND AND AIMS: HBV covalently closed circular DNA (cccDNA) is a major obstacle for a cure of chronic hepatitis B. Accumulating evidence suggests that epigenetic modifications regulate the transcriptional activity of cccDNA minichromosomes. However, it remains unclear how the epigenetic state of cccDNA affects its stability. APPROACHES AND RESULTS: By using HBV infection cell models and in vitro and in vivo recombinant cccDNA (rcccDNA) and HBVcircle models, the reduction rate of HBV cccDNA and the efficacy of apolipoprotein B mRNA editing enzyme catalytic subunit 3A (APOBEC3A)-mediated and CRISPR/CRISPR-associated 9 (Cas9)-mediated cccDNA targeting were compared between cccDNAs with distinct transcriptional activities. Interferon-α treatment and hepatitis B x protein (HBx) deletion were applied as two strategies for cccDNA repression. Chromatin immunoprecipitation and micrococcal nuclease assays were performed to determine the epigenetic pattern of cccDNA. HBV cccDNA levels remained stable in nondividing hepatocytes; however, they were significantly reduced during cell division, and the reduction rate was similar between cccDNAs in transcriptionally active and transcriptionally repressed states. Strikingly, HBV rcccDNA without HBx expression exhibited a significantly longer persistence in mice. The cccDNA with low transcriptional activity exhibited an epigenetically inactive pattern and was more difficult to access by APOBEC3A and engineered CRISPR-Cas9. The epigenetic regulator activating cccDNA increased its vulnerability to APOBEC3A. CONCLUSIONS: HBV cccDNA minichromosomes in distinct epigenetic transcriptional states showed a similar reduction rate during cell division but significantly differed in their accessibility and vulnerability to targeted nucleases and antiviral agents. Epigenetic sensitization of cccDNA makes it more susceptible to damage and may potentially contribute to an HBV cure.

Therapeutic shutdown of HBV transcripts promotes reappearance of the SMC5/6 complex and silencing of the viral genome in vivo.

OBJECTIVE: Therapeutic strategies silencing and reducing the hepatitis B virus (HBV) reservoir, the covalently closed circular DNA (cccDNA), have the potential to cure chronic HBV infection. We aimed to investigate the impact of small interferring RNA (siRNA) targeting all HBV transcripts or pegylated interferon-α (peg-IFNα) on the viral regulatory HBx protein and the structural maintenance of chromosome 5/6 complex (SMC5/6), a host factor suppressing cccDNA transcription. In particular, we assessed whether interventions lowering HBV transcripts can achieve and maintain silencing of cccDNA transcription in vivo. DESIGN: HBV-infected human liver chimeric mice were treated with siRNA or peg-IFNα. Virological and host changes were analysed at the end of treatment and during the rebound phase by qualitative PCR, ELISA, immunoblotting and chromatin immunoprecipitation. RNA in situ hybridisation was combined with immunofluorescence to detect SMC6 and HBV RNAs at single cell level. The entry inhibitor myrcludex-B was used during the rebound phase to avoid new infection events. RESULTS: Both siRNA and peg-IFNα strongly reduced all HBV markers, including HBx levels, thus enabling the reappearance of SMC5/6 in hepatocytes that achieved HBV-RNA negativisation and SMC5/6 association with the cccDNA. Only IFN reduced cccDNA loads and enhanced IFN-stimulated genes. However, the antiviral effects did not persist off treatment and SMC5/6 was again degraded. Remarkably, the blockade of viral entry that started at the end of treatment hindered renewed degradation of SMC5/6. CONCLUSION: These results reveal that therapeutics abrogating all HBV transcripts including HBx promote epigenetic suppression of the HBV minichromosome, whereas strategies protecting the human hepatocytes from reinfection are needed to maintain cccDNA silencing.