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.

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.

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.

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.

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.

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.

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 β (TGFβ) 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 TGFβ signaling pathway.

[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.

Depletion of T cells via Inducible Caspase 9 Increases Safety of Adoptive T-Cell Therapy Against Chronic Hepatitis B

T-cell therapy with T cells that are re-directed to hepatitis B virus (HBV)-infected cells by virus-specific receptors is a promising therapeutic approach for treatment of chronic hepatitis B and HBV-associated cancer. Due to the high number of target cells, however, side effects such as cytokine release syndrome or hepatotoxicity may limit safety. A safeguard mechanism, which allows depletion of transferred T cells on demand, would thus be an interesting means to increase confidence in this approach. In this study, T cells were generated by retroviral transduction to express either an HBV-specific chimeric antigen receptor (S-CAR) or T-cell receptor (TCR), and in addition either inducible caspase 9 (iC9) or herpes simplex virus thymidine kinase (HSV-TK) as a safety switch. Real-time cytotoxicity assays using HBV-replicating hepatoma cells as targets revealed that activation of both safety switches stopped cytotoxicity of S-CAR- or TCR-transduced T cells within less than one hour. In vivo, induction of iC9 led to a strong and rapid reduction of transferred S-CAR T cells adoptively transferred into AAV-HBV-infected immune incompetent mice. One to six hours after injection of the iC9 dimerizer, over 90% reduction of S-CAR T cells in the blood and the spleen and of over 99% in the liver was observed, thereby limiting hepatotoxicity and stopping cytokine secretion. Simultaneously, however, the antiviral effect of S-CAR T cells was diminished because remaining S-CAR T cells were mostly non-functional and could not be restimulated with HBsAg. A second induction of iC9 was only able to deplete T cells in the liver. In conclusion, T cells co-expressing iC9 and HBV-specific receptors efficiently recognize and kill HBV-replicating cells. Induction of T-cell death via iC9 proved to be an efficient means to deplete transferred T cells in vitro and in vivo containing unwanted hepatotoxicity.

Circ-RNF13, as an oncogene, regulates malignant progression of HBV-associated hepatocellular carcinoma cells and HBV infection through ceRNA pathway of circ-RNF13/miR-424-5p/TGIF2

Circular RNA RNF13 (circ-RNF13; ID: hsa_circ_0067717) is newly identified to be abnormally upregulated in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) patients. However, its role and mechanism remain to be further annotated. First of all, real-time quantitative PCR (RT-qPCR) was utilized to examine RNA expression, and circ-RNF13 was upregulated in HBV-infected human HCC tissues and HBV-expressing cells (Huh7-HBV and Hep3B-HBV), accompanied with TGFβ-induced factor homeobox 2 (TGIF2) upregulation and microRNA (miR)-424-5p downregulation. Loss-of-functional experiments were performed using MTS assay, colony formation assay, flow cytometry, enzyme-linked immunosorbent assay, transwell assay, and xenograft tumor model. As a result, blocking circ-RNF13 enhanced the apoptosis rate of Huh7-HBV and Hep3B-HBV cells, but inhibited cell proliferation, colony formation, migration, and invasion in vitro, along with suppressed tumor growth in vivo. Besides, RT-qPCR data showed that HBV DNA copies and levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were diminished by circ-RNF13 knockdown in Huh7-HBV and Hep3B-HBV cells. Mechanistically, circ-RNF13 and TGIF2 could directly interacting with miR-424-5p according to dual-luciferase reporter assay, suggesting that circ-RNF13 and TGIF2 served as competing endogenous RNAs (ceRNAs) for miR-424-5p. Functionally, overexpressing miR-424-5p mimicked and silencing miR-424-5p counteracted the effects of circ-RNF13 depletion in HBV-expressing HCC cells in vitro; TGIF2 restoration partially abrogated the role of miR-424-5p upregulation. In conclusion, circ-RNF13 might sponge miR-424-5p to suppress HBV-associated HCC cells malignant progression and HBV infection by regulating TGIF2, providing a novel insight into the occurrence and treatment of HBV-associated HCC.

Role of the CXCR3‑mediated TLRs/MyD88 signaling pathway in promoting the development of hepatitis B into cirrhosis and liver cancer

Chronic hepatitis B can lead to liver cirrhosis and primary hepatocellular carcinoma. The present study aimed to investigate whether C‑X‑C motif chemokine receptor 3 (CXCR3) regulates the genes in Toll‑like receptors (TLRs)/myeloid differentiation primary response protein 88 (MyD88) signaling pathway in the development of hepatitis B into cirrhosis and liver cancer in vitro. A hepatitis B virus (HBV) overexpression lentivirus was constructed and infected into a LX‑2 cell line to obtain stable HBV‑overexpressing cells (named HBV‑LX‑2 cells). The CXCR3 gene was knocked down using small interfering RNA in HBV‑LX‑2 cells. Cell Counting Kit‑8 assays, cell scratch tests and flow cytometry were used to detect cell proliferation, migration and apoptosis, respectively. The levels of IL‑1β and IL‑6 in serum samples of patients with liver cancer were measured via ELISA, and the collagen content in liver cancer tissues was detected using Masson staining. Western blotting was used to detect the expression levels of proteins in the TLRs/MyD88 signaling pathway. Excessive fibrosis was identified in the liver cancer tissues, and the serum levels of IL‑6 and IL‑1β were abnormally increased in patients with liver cancer. It was found that interfering with CXCR3 inhibited cell proliferation and migration, as well as promoted the apoptosis of HBV‑LX‑2 cells. Moreover, interfering with CXCR3 inhibited the expression levels of collagen type I α 1 chain and the proteins in the TLRs/MyD88 pathway. In conclusion, CXCR3 knockdown could inhibit the expression levels of proteins in the TLR4/MyD88 signaling pathway, decrease cell proliferation and migration, and promote cell apoptosis, thus inhibiting the development of liver cirrhosis to liver cancer.

Toll-Like Receptor Response to Hepatitis B Virus Infection and Potential of TLR Agonists as Immunomodulators for Treating Chronic Hepatitis B: An Overview

Chronic hepatitis B virus (HBV) infection remains a major global health problem. The immunopathology of the disease, especially the interplay between HBV and host innate immunity, is poorly understood. Moreover, inconsistent literature on HBV and host innate immunity has led to controversies. However, recently, there has been an increase in the number of studies that have highlighted the link between innate immune responses, including Toll-like receptors (TLRs), and chronic HBV infection. TLRs are the key sensing molecules that detect pathogen-associated molecular patterns and regulate the induction of pro- and anti-inflammatory cytokines, thereby shaping the adaptive immunity. The suppression of TLR response has been reported in patients with chronic hepatitis B (CHB), as well as in other models, including tree shrews, suggesting an association of TLR response in HBV chronicity. Additionally, TLR agonists have been reported to improve the host innate immune response against HBV infection, highlighting the potential of these agonists as immunomodulators for enhancing CHB treatment. In this study, we discuss the current understanding of host innate immune responses during HBV infection, particularly focusing on the TLR response and TLR agonists as immunomodulators.

Are Humanized Mouse Models Useful for Basic Research of Hepatocarcinogenesis through Chronic Hepatitis B Virus Infection?

Chronic hepatitis B virus (HBV) infection is a global health problem that can lead to liver dysfunction, including liver cirrhosis and hepatocellular carcinoma (HCC). Current antiviral therapies can control viral replication in patients with chronic HBV infection; however, there is a risk of HCC development. HBV-related proteins may be produced in hepatocytes regardless of antiviral therapies and influence intracellular metabolism and signaling pathways, resulting in liver carcinogenesis. To understand the mechanisms of liver carcinogenesis, the effect of HBV infection in human hepatocytes should be analyzed. HBV infects human hepatocytes through transfer to the sodium taurocholate co-transporting polypeptide (NTCP). Although the NTCP is expressed on the hepatocyte surface in several animals, including mice, HBV infection is limited to human primates. Due to this species-specific liver tropism, suitable animal models for analyzing HBV replication and developing antivirals have been lacking since the discovery of the virus. Recently, a humanized mouse model carrying human hepatocytes in the liver was developed based on several immunodeficient mice; this is useful for analyzing the HBV life cycle, antiviral effects of existing/novel antivirals, and intracellular signaling pathways under HBV infection. Herein, the usefulness of human hepatocyte chimeric mouse models in the analysis of HBV-associated hepatocarcinogenesis is discussed.

Mechanisms of DNA Methylation in Virus-Host Interaction in Hepatitis B Infection: Pathogenesis and Oncogenetic Properties

Hepatitis B virus (HBV), the well-studied oncovirus that contributes to the majority of hepatocellular carcinomas (HCC) worldwide, can cause a severe inflammatory microenvironment leading to genetic and epigenetic changes in hepatocyte clones. HBV replication contributes to the regulation of DNA methyltransferase gene expression, particularly by X protein (HBx), and subsequent methylation changes may lead to abnormal transcription activation of adjacent genes and genomic instability. Undoubtedly, the altered expression of these genes has been known to cause diverse aspects of infected hepatocytes, including apoptosis, proliferation, reactive oxygen species (ROS) accumulation, and immune responses. Additionally, pollutant-induced DNA methylation changes and aberrant methylation of imprinted genes in hepatocytes also complicate the process of tumorigenesis. Meanwhile, hepatocytes also contribute to epigenetic modification of the viral genome to affect HBV replication or viral protein production. Meanwhile, methylation levels of HBV integrants and surrounding host regions also play crucial roles in their ability to produce viral proteins in affected hepatocytes. Both host and viral changes can provide novel insights into tumorigenesis, individualized responses to therapeutic intervention, disease progress, and early diagnosis. As such, DNA methylation-mediated epigenetic silencing of cancer-related genes and viral replication is a compelling therapeutic goal to reduce morbidity and mortality from liver cancer caused by chronic HBV infection. In this review, we summarize the most recent research on aberrant DNA methylation associated with HBV infection, which is involved in HCC development, and provide an outlook on the future direction of the research.

Traditional Chinese medicine Yiqi Huoxue recipe attenuates hepatic fibrosis via YAP/TAZ signaling

BACKGROUND/AIMS

The Yiqi Huoxue (YQHX) recipe has been shown to attenuate liver fibrosis, but precise mechanisms have not yet been elucidated. Recently, Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) signaling has been implicated in liver fibrogenesis. This study investigated whether the YAP/TAZ signaling is involved in the therapeutic effect of YQHX on hepatic fibrosis.

MATERIALS AND METHODS

Wistar rats were used to generate a model of carbon tetrachloride (CCl₄)-induced liver fibrosis. Chronic hepatitis B (CHB) patients with liver fibrosis were enrolled and assigned to receive either nucleoside/nucleotide analogues (NAs) or NAs plus YQHX. Histology, immunohistochemistry, qRT-PCR, and western blotting were conducted to mechanistically assess the therapeutic effects of YQHX on liver fibrosis.

RESULTS

YQHX markedly alleviated morphological alterations in CCl₄-induced liver fibrosis and decreased markers of hepatic fibrosis in rats. Furthermore, YQHX significantly suppressed CCl₄-meidated activation of the transforming growth factor-beta (TGF-β)/Smad signaling pathway. Notably, CCl₄ induced up-regulation of YAP, TAZ, and connective tissue growth factor (CTGF), which were significantly abrogated by YQHX. Consistent with the above major findings in rats, CHB patients treated with NAs plus YQHX had greater improvement in liver fibrosis than those given NAs alone (71.4% vs. 28.6%; P = 0.057). In addition, hepatic and plasma levels of YAP were significantly decreased after YQHX treatment in CHB patients with liver fibrosis.

CONCLUSION

YAP/TAZ signaling plays a role, at least in part, in the anti-fibrotic activity of YQHX. The findings may help to better understand the mechanisms of YQHX in the treatment of liver fibrosis.

HBsAg Dampened STING Associated Activation of NK Cells in HBeAg-Negative CHB Patients

NK cells play crucial roles in defending against persistent HBV. However, NK cells present dysfunction in chronic hepatitis B virus (CHB) infection, and the associated mechanism is still not fully understood. Except for the regulatory receptors, NK cells could also be regulated by the surface and intracellular pattern recognition receptors (PRRs). In the present study, we found that the level of the adaptor of DNA sensor STING in NK cells was significantly decreased in HBeAg-negative CHB patients, and it was positively associated with the degranulation ability of NK cells. Compared to NK cells from healthy donors, NK cells from HBeAg-negative CHB patients displayed a lower responsiveness to cGAMP stimulation. Further investigation showed that HBsAg could inhibit the STING expression in NK cells and suppress the response of NK cells to cGAMP. Significantly, STAT3 was identified to be a transcription factor that directly regulated STING transcription by binding to the promoter. In addition, STAT3 positively regulated the STING associated IFN-α response of NK cells. These findings suggested that STING is an important adaptor in NK cell recognition and activation, while HBsAg disturbs NK cell function by the STAT3-STING axis, providing a new mechanism of NK disability in HBeAg-negative CHB infection.

Hypoxia inducible factors regulate hepatitis B virus replication by activating the basal core promoter

BACKGROUND & AIMS

Hypoxia inducible factors (HIFs) are a hallmark of inflammation and are key regulators of hepatic immunity and metabolism, yet their role in HBV replication is poorly defined. HBV replicates in hepatocytes within the liver, a naturally hypoxic organ, however most studies of viral replication are performed under conditions of atmospheric oxygen, where HIFs are inactive. We therefore investigated the role of HIFs in regulating HBV replication.

METHODS

Using cell culture, animal models, human tissue and pharmacological agents inhibiting the HIF-prolyl hydroxylases, we investigated the impact of hypoxia on the HBV life cycle.

RESULTS

Culturing liver cell-based model systems under low oxygen uncovered a new role for HIFs in binding HBV DNA and activating the basal core promoter, leading to increased pre-genomic RNA and de novo HBV particle secretion. The presence of hypoxia responsive elements among all primate members of the hepadnaviridae highlights an evolutionary conserved role for HIFs in regulating this virus family.

CONCLUSIONS

Identifying a role for this conserved oxygen sensor in regulating HBV transcription suggests that this virus has evolved to exploit the HIF signaling pathway to persist in the low oxygen environment of the liver. Our studies show the importance of considering oxygen availability when studying HBV-host interactions and provide innovative routes to better understand and target chronic HBV infection.

LAY SUMMARY

Viral replication in host cells is defined by the cellular microenvironment and one key factor is local oxygen tension. Hepatitis B virus (HBV) replicates in the liver, a naturally hypoxic organ. Hypoxia inducible factors (HIFs) are the major sensors of low oxygen; herein, we identify a new role for these factors in regulating HBV replication, revealing new therapeutic targets.

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.

Taurocholic acid inhibits the response to interferon-α therapy in patients with HBeAg-positive chronic hepatitis B by impairing CD8+ T and NK cell function

Pegylated interferon-alpha (PegIFNα) therapy has limited effectiveness in hepatitis B e-antigen (HBeAg)-positive chronic hepatitis B (CHB) patients. However, the mechanism underlying this failure is poorly understood. We aimed to investigate the influence of bile acids (BAs), especially taurocholic acid (TCA), on the response to PegIFNα therapy in CHB patients. Here, we used mass spectrometry to determine serum BA profiles in 110 patients with chronic HBV infection and 20 healthy controls (HCs). We found that serum BAs, especially TCA, were significantly elevated in HBeAg-positive CHB patients compared with those in HCs and patients in other phases of chronic HBV infection. Moreover, serum BAs, particularly TCA, inhibited the response to PegIFNα therapy in HBeAg-positive CHB patients. Mechanistically, the expression levels of IFN-γ, TNF-α, granzyme B, and perforin were measured using flow cytometry to assess the effector functions of immune cells in patients with low or high BA levels. We found that BAs reduced the number and proportion and impaired the effector functions of CD3+CD8+ T cells and natural killer (NK) cells in HBeAg-positive CHB patients. TCA in particular reduced the frequency and impaired the effector functions of CD3+CD8+ T and NK cells in vitro and in vivo and inhibited the immunoregulatory activity of IFN-α in vitro. Thus, our results show that BAs, especially TCA, inhibit the response to PegIFNα therapy by impairing the effector functions of CD3+CD8+ T and NK cells in HBeAg-positive CHB patients. Our findings suggest that targeting TCA could be a promising approach for restoring IFN-α responsiveness during CHB treatment.

Metabolic fingerprint of progression of chronic hepatitis B: changes in the metabolome and novel diagnostic possibilities

INTRODUCTION

Chronic hepatitis B (CHB) affects 257 million individuals worldwide with an annual estimated mortality rate of 880,000 individuals. Accurate diagnosis of the stage of disease is difficult, and there is considerable uncertainty concerning the optimal point in time, when treatment should be started.

OBJECTIVES

By analyzing and comparing the metabolomes of patients at different stages of CHB and comparing them to healthy individuals, we want to determine the metabolic signature of disease progression and develop a more accurate metabolome-based method for diagnosis of disease progression ultimately giving a better basis for treatment decisions.

METHODS

In this study, we used the combination of transient elastography and serum metabolomics of 307 serum samples from a group of 90 patients with CHB before and under treatment (with a follow-up time up to 10 years) at different progression stages over the clinical phases and 43 healthy controls..

RESULTS

Our data show that the metabolomics approach can successfully discover CHB changing from the immune tolerance to the immune clearance phase and show distinctive metabolomes from different medical treatment stages. Perturbations in ammonia detoxification, glutamine and glutamate metabolism, methionine metabolism, dysregulation of branched-chain amino acids, and the tricarboxylic acid (TCA) cycle are the main factors involved in the progression of the disease. Fluctuations increasing in aspartate, glutamate, glutamine, methionine and 13 other metabolites are fingerprints of progression.

CONCLUSIONS

The metabolomics approach may expand the diagnostic armamentarium for patients with CHB. This method can provide a more detailed decision basis for starting medical treatment.

Understanding the antiviral effects of RNAi-based therapy in HBeAg-positive chronic hepatitis B infection

The RNA interference (RNAi) drug ARC-520 was shown to be effective in reducing serum hepatitis B virus (HBV) DNA, hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) in HBeAg-positive patients treated with a single dose of ARC-520 and daily nucleosidic analogue (entecavir). To provide insights into HBV dynamics under ARC-520 treatment and its efficacy in blocking HBV DNA, HBsAg, and HBeAg production we developed a multi-compartmental pharmacokinetic-pharamacodynamic model and calibrated it with frequent measured HBV kinetic data. We showed that the time-dependent single dose ARC-520 efficacies in blocking HBsAg and HBeAg are more than 96% effective around day 1, and slowly wane to 50% in 1-4 months. The combined single dose ARC-520 and entecavir effect on HBV DNA was constant over time, with efficacy of more than 99.8%. The observed continuous HBV DNA decline is entecavir mediated, the strong but transient HBsAg and HBeAg decays are ARC-520 mediated. The modeling framework may help assess ongoing RNAi drug development for hepatitis B virus infection.

Second hits exacerbate alcohol-related organ damage: an update

Chronic and excessive alcohol abuse cause direct and indirect detrimental effects on a wide range of body organs and systems and accounts for ~4% of deaths worldwide. Many factors influence the harmful effects of alcohol. This concise review presents newer insights into the role of select second hits in influencing the progression of alcohol-induced organ damage by synergistically acting to generate a more dramatic downstream biological defect. This review specifically addresses on how a lifestyle factor of high fat intake exacerbates alcoholic liver injury and its progression. This review also provides the mechanistic insights into how increasing matrix stiffness during liver injury promotes alcohol-induced fibrogenesis. It also discusses how hepatotropic viral (HCV, HBV) infections as well as HIV (which is traditionally not known to be hepatotropic), are potentiated by alcohol exposure to promote hepatotoxicity and fibrosis progression. Finally, this review highlights the impact of reactive aldehydes generated during alcohol and cigarette smoke coexposure impair innate antimicrobial defense and increased susceptibility to infections. This review was inspired by the symposium held at the 17th Congress of the European Society for Biomedical research on Alcoholism in Lille, France entitled 'Second hits in alcohol-related organ damage'.

Interleukin 22 is related to development and poor prognosis of hepatocellular carcinoma

BACKGROUND AND AIMS

Immune response against hepatitis B virus (HBV) infection is an important risk factor for the development of hepatocellular carcinoma (HCC). Studies have reported that interleukin 22 (IL-22) exhibits both protective and pathological properties in liver diseases. Our aim was to explore the importance of IL-22 in the development of HCC, and to characterize the relationship between IL-22 levels and the prognosis of HCC.

METHODS

Totally, 136 liver biopsy specimens from 46 patients with chronic hepatitis B (CHB), 37 with atypical hyperplasia (AH), 53 with HCC, patient-matched tumors and peritumoral surgical specimens from 56 HCC patients included in the study. The expression of IL-22 and CD8 was evaluated by immunochemistry. Corresponding serum samples were collected from 30 CHB, 30 AH, and 30 HCC patients. IL-22 expression was determined by an enzyme linked immunosorbent assay.

RESULTS

Liver-infiltrating IL-22+ cells increased in a stepwise manner from CHB to AH and HCC (CHB vs. AH, P=0.002; AH vs. HCC, P=0.010), whereas a decreasing trend was observed for CD8+ T cells (CHB vs. AH, P=0.031; AH vs. HCC, P=0.652). Serum IL-22 levels also increased from CHB to AH and HCC (CHB vs. AH, P=0.024; AH vs. HCC, P=0.026). Tumor-infiltrating IL-22+ cells and serum IL-22 were associated with histologic grade (P=0.024 and P=0.033). Additionally, CD8+ T cells correlated with tumor size (P=0.032). Furthermore, the high intratumoral IL-22+ cell group and high serum IL-22 group showed lower overall survival (OS; P=0.001, P=0.017) and disease-free survival (DFS; P=0.005, P<0.001). Multivariate analysis revealed that intratumoral IL-22+ cells and serum IL-22 levels were independent prognostic factors for both OS and DFS.

CONCLUSIONS

These findings indicate that IL-22 promotes the progression of HCC in CHB patients. High tumor-infiltrating IL-22+ cells and serum IL-22 levels are thought to be unfavorable prognostic indicators for HCC.

Interplay between Cellular Autophagy and Hepatitis B Virus Replication: A Systematic Review

Autophagy, a conserved process in which cells break down and destroy old, damaged, or abnormal proteins and other substances in the cytoplasm through lysosomal degradation, occurs via autophagosome formation and aids in the maintenance of intracellular homeostasis. Autophagy is closely associated with hepatitis B virus (HBV) replication and assembly. Currently, HBV infection is still one of the most serious public health issues worldwide. The unavailability of satisfactory therapeutic strategies for chronic HBV infection indicates an urgent need to elucidate the mechanisms underlying the pathogenesis of HBV infection. Increasing evidence has shown that HBV not only possesses the ability to induce incomplete autophagy but also evades autophagic degradation, indicating that HBV utilizes or hijacks the autophagy machinery for its own replication. Therefore, autophagy might be a crucial target pathway for controlling HBV infection. The definite molecular mechanisms underlying the association between cellular autophagy and HBV replication require further clarification. In this review, we have summarized and discussed the latest findings on the interplay between autophagy and HBV replication.

Hepatitis B Virus Pre-S Mutants as Biomarkers and Targets for the Development and Recurrence of Hepatocellular Carcinoma

Chronic hepatitis B virus (HBV) infection is a major risk factor for the development of hepatocellular carcinoma (HCC), the leading cause of cancer-related death worldwide. Despite progress in the prevention and therapy of HCC, high incidence and recurrence rates of HCC remain big threats, resulting in poor patient survival. Effective biomarkers and targets of HCC are therefore urgently needed for better management and to improve patient outcomes. Pre-S mutants have been well demonstrated as HBV oncoproteins that play important roles in HCC development through activation of multiple oncogenic signal pathways in hepatocytes, in vitro and in vivo. The presence of pre-S mutants in patients with chronic HBV infection and HBV-related HCC has been associated with a significantly higher risk of HCC development and recurrence after curative surgical resection, respectively. In this review, we summarize the roles of pre-S mutants as biomarkers for predicting HBV-related HCC development and recurrence, and highlight the pre-S mutants-activated oncogenic signal pathways as potential targets for preventing HBV-related HCC development.

Final analysis of the international observational S-Collate study of peginterferon alfa-2a in patients with chronic hepatitis B

Background and aims

Sustained off-treatment immune control is achievable in a proportion of patients with chronic hepatitis B treated with peginterferon alfa-2a. We evaluated on-treatment predictors of hepatitis B surface antigen (HBsAg) clearance 3 years after peginterferon alfa-2a treatment and determined the incidence of hepatocellular carcinoma.

Methods

A prospective, international, multicenter, observational study in patients with chronic hepatitis B who have been prescribed peginterferon alfa-2a (40KD) in a real-world setting. The primary endpoint was HBsAg clearance after 3 years’ follow-up.

Results

The modified intention-to-treat population comprised 844 hepatitis B e antigen (HBeAg)-positive patients (540 [64%] completed 3 years’ follow-up), and 872 HBeAg-negative patients (614 [70%] completed 3 years’ follow-up). At 3 years’ follow-up, HBsAg clearance rates in HBeAg-positive and HBeAg-negative populations, respectively, were 2% (16/844) and 5% (41/872) in the modified intention-to-treat population and 5% [16/328] and 10% [41/394] in those with available data. In HBeAg-positive patients with data, Week 12 HBsAg levels <1500, 1500–20,000, and >20,000 IU/mL were associated with HBsAg clearance rates at 3 years’ follow-up of 11%, 1%, and 5%, respectively (Week 24 predictability was similar). In HBeAg-negative patients with available data, a ≥10% decline vs a <10% decline in HBsAg at Week 12 was associated with HBsAg clearance rates of 16% vs 4%. Hepatocellular carcinoma incidence was lower than REACH-B (Risk Estimation for Hepatocellular Carcinoma in Chronic Hepatitis B) model predictions.

Conclusions

Sustained off-treatment immune control is achieved with peginterferon alfa-2a in a real-world setting. HBsAg clearance 3 years after completion of peginterferon alfa-2a can be predicted on the basis of on-treatment HBsAg kinetics.

Peroxisome proliferator-activated receptor γ inhibits hepatic stellate cell activation regulated by miR-942 in chronic hepatitis B liver fibrosis

AIMS

Liver fibrosis is a chronic liver disease characterized by hepatic stellate cell (HSC) activation. Peroxisome proliferator-activated receptor gamma (PPARγ) play an important role in HSC activation. This study aimed to investigate the role of PPARγ in the progression of human hepatic fibrosis and the mechanism by which microRNA-942 regulates HSC activation.

METHODS

70 chronic hepatitis B (CHB) patients liver tissues were used to assess PPARγ, α-SMA and miR-942 levels by immunoblot and real-time PCR. Human primary HSCs or LX2 cells were used to perform multiple molecular experiments based on the transfection of small interfering RNA (siRNA) or co-transfection of microRNA inhibitor. Site-directed mutagenesis and luciferase reporter assays were used to identify miR-942 targets. miR-942 expression and localization in hepatic fibrosis and co-localization between α-SMA were determined by fluorescence in situ hybridization (FISH).

KEY FINDINGS

The mRNA expression of PPARγ was decreased in activated HSCs and CHB patients with liver fibrosis, which was negatively correlated with F stage and α-SMA. miR-942 negatively regulates PPARγ expression via targeting the PPARγ 3'UTR. Inhibiting PPARγ promoted TGFβ1 induced HSC activation, and this effect was blocked after inhibiting the miR-942. Moreover, miR-942 was mainly expressed in fibrous septa and negatively correlated with PPARγ in liver fibrosis.

SIGNIFICANCE

PPARγ targeting by miR-942 and decreasing HSC activation in human hepatic fibrosis. Hence, regulating PPARγ may be a promising therapeutic strategy for hepatic fibrosis.

Relation Between Immunohistochemical Expression of Hippo Pathway Effectors and Chronic Hepatitis Induced Fibrosis in Egyptian Patients

OBJECTIVE

Chronic hepatitis is a global health problem especially in Egypt. Hepatic fibrosis is a common end clinical manifestation of many chronic liver diseases. Although it is a wound-healing process, excessive accumulation of fibrillary collagen leads to architectural damage, cirrhosis and liver failure. Recently, a few studies have linked Hippo pathway effectors of yes-associated protein (YAP) and its paralog transcriptional coactivator with PDZ-binding motif (TAZ) to extracellular matrix deposition and ongoing fibrosis.

MATERIAL AND METHOD

Immunohistochemical expression of YAP and TAZ were analyzed in 121 liver needle core biopsies (91 core biopsies of chronic viral hepatitis, 20 biopsies of autoimmune hepatitis and 10 normal liver cores).

RESULTS

YAP and TAZ nuclear localization was absent in all normal liver cores. Autoimmune hepatitis cases showed higher nuclear expression of both YAP and TAZ in comparison to chronic viral cases. YAP and TAZ expression were correlated with severity of hepatocyte injury together with fibrosis in chronic viral cases but these correlations were absent in AIH cases despite the pronounced increase of YAP and TAZ nuclear localization.

CONCLUSION

The correlation between Hippo effectors activation and fibrosis in chronic viral hepatitis patients emphasize their role in the development and advancement of hepatic scarring and highlight the use of both YAP and TAZ as novel targets to ameliorate liver fibrosis.

Effects of radiofrequency ablation combined with transarterial chemoembolization and antiviral therapy on the prognosis and quality of life in primary chronic HBV-related liver cancer

PURPOSE

To investigate the effects of radiofrequency ablation (RFA) combined with transarterial chemoembolization (TACE) and antiviral therapy on the prognosis and quality of life in primary chronic hepatitis B virus (HBV)-related liver cancer.

METHODS

A total of 80 hepatitis B patients complicated with hepatocellular carcinoma treated in our hospital from March 2016 to February 2018 were selected and divided into the control group (n=40) and the observation group (n=40) using a random number table. The patients in the control group were treated with RFA combined with TACE, while those in the observation group were additionally treated with entecavir. The HBV-DNA load and alpha fetoprotein (AFP) level during intervention and the liver function before and after intervention were compared between the two groups. The patients were followed up for 2 years after treatment, the clinical therapeutic effects in both groups were recorded, and the correlations of HBV-DNA load, AFP level and alanine aminotransferase (ALT) level with the survival time of patients were analyzed.

RESULTS

At 1 and 3 months after intervention, the HBV-DNA load in the observation group was significantly lower than that before intervention (p<0.05), and it was also significantly lower than in the control group (p<0.05). At 1 and 3 months after intervention, the AFP level was lowered in both groups compared with that before the intervention (p<0.05), and it was also lower in the observation group than in the control group (p<0.05). After intervention, the levels of total bilirubin (Tbil), aspartate aminotransferase (AST) and ALT in the observation group were lower than those before the intervention (p<0.05), and they were also lower than those in the control group (p<0.05). Moreover, the disease progression in the observation group was significantly lower than in the control group, and the 1-year and 2-year survival in the observation group was longer compared with the control group. The HBV-DNA load, AFP level and ALT level were negatively correlated with the survival of patients (p<0.05).

CONCLUSIONS

The RFA combined with TACE and regular antiviral therapy for HBV-related liver cancer is of significance in reducing the HBV-DNA load and tumor markers, improving the liver function, promoting the overall clinical therapeutic effect and prolonging the survival of patients.

Hepatitis B virus X protein: The X factor in chronic hepatitis B virus disease progression

Introduction

Hepatitis B virus (HBV) is the most common aetiological factor causing hepatocellular carcinoma (HCC). HBx gene plays an enigmatic role in HBV-related HCC. In this study we have analysed amino acid substitutions in HBx from HBV-infected individuals of different clinical stages.

Materials and Methods

HBV-infected individuals (n = 93) were recruited in the study. DNA was extracted from plasma, amplified, and DNA sequencing was performed using specific primers targeting HBx gene (540 bp).

Results

Among the study participants, 57% had chronic HBV infection, 30% had chronic liver disease (CLD) and 13% had HBV related HCC. Genotypes such as D1, D2, D3, A1, C2 and B2 were identified of which genotype D2 was predominant (78%). HBxC-terminal deletion was observed in four hepatitis B e antigen (HBeAg) negative participants with CLD. The frequency of aminoacid substitution in proapoptotic domain was higher in HBeAg negative participants including I127V (34%), K130M (34%), V131I (40%). The frequency of double mutation (K130M+V131I) and triple mutation (I127V+K130M+V131I) were found to be higher (32% and 36%) in HBeAg negative participants. Also, we identified L5M substitution (4.3%) in HBeAg positive participants with advanced liver disease.

Conclusion

In HBx gene, aminoacid substitutions at positions 127, 130, 131 are associated with poor expression of HBeAg. We suggest screening for HBx aminoacid substitutions especially in patients with HBeAg negative chronic HBV infection to predict the clinical outcome and enable early treatment to prevent disease progression.

Genomic analysis of Hepatitis B virus and its association with disease manifestations in Bangladesh

The direct cytopathic effects of the hepatitis B virus (HBV) on subsequent liver damage are not fully understood in HBV-infected patients. However, associations between the prevalence of various HBV genotypes and the extent of liver damage have been reported from different parts of the world. The purpose of this study was to determine the distribution of HBV genotypes in patients with chronic HBV infection in Bangladesh, a country of 160 million people, of which approximately 3–6 million are chronically infected HBV patients. In addition, whole and partial genome sequencing of HBV was performed to evaluate the relationship between HBV mutations and genotypes. We found that 42% of the patients with low HBV DNA and normal levels of alanine aminotransferase (ALT) had HBV genotype D. In contrast, the HBV genotype C was dominant among patients with high HBV DNA levels (>2000 IU/ml) and elevated ALT and in patients with liver cirrhosis (LC) and hepatocellular carcinomas (HCC). Whole and partial genome sequences of HBV revealed that most patients with LC and HCC had HBV genotype C with mutations at the T1762/A1764 positions. It seems that Bangladesh represents a borderline country, situated within East Asia, which mainly consists of individuals with HBV genotypes B and C, whereas in the western parts of Asia, HBV genotypes A and D are prevalent. Bangladesh is, therefore, an excellent model for the comparison of the pathophysiology of three major HBV genotypes in a single population. The findings of this study suggest a possible association between HBV viral factors and the extent of liver damage in chronic HBV-infected patients.

DNA Polymerase alpha is essential for intracellular amplification of hepatitis B virus covalently closed circular DNA

Persistent hepatitis B virus (HBV) infection relies on the establishment and maintenance of covalently closed circular (ccc) DNA, a 3.2 kb episome that serves as a viral transcription template, in the nucleus of an infected hepatocyte. Although evidence suggests that cccDNA is the repair product of nucleocapsid associated relaxed circular (rc) DNA, the cellular DNA polymerases involving in repairing the discontinuity in both strands of rcDNA as well as the underlying mechanism remain to be fully understood. Taking a chemical genetics approach, we found that DNA polymerase alpha (Pol α) is essential for cccDNA intracellular amplification, a genome recycling pathway that maintains a stable cccDNA pool in infected hepatocytes. Specifically, inhibition of Pol α by small molecule inhibitors aphidicolin or CD437 as well as silencing of Pol α expression by siRNA led to suppression of cccDNA amplification in human hepatoma cells. CRISPR-Cas9 knock-in of a CD437-resistant mutation into Pol α genes completely abolished the effect of CD437 on cccDNA formation, indicating that CD437 directly targets Pol α to disrupt cccDNA biosynthesis. Mechanistically, Pol α is recruited to HBV rcDNA and required for the generation of minus strand covalently closed circular rcDNA, suggesting that Pol α is involved in the repair of the minus strand DNA nick in cccDNA synthesis. Our study thus reveals that the distinct host DNA polymerases are hijacked by HBV to support the biosynthesis of cccDNA from intracellular amplification pathway compared to that from de novo viral infection, which requires Pol κ and Pol λ.

CCC DNA is the most refractory HBV replication intermediate under long-term antiviral therapies and is responsible for the viral rebound after treatment cessation. Therefore, understanding the biosynthesis and maintenance of cccDNA minichromosome is crucial for the development of novel antiviral therapeutics to cure chronic HBV infection. Although it has been clearly demonstrated that cccDNA biosynthesis relies on host cellular DNA repair machinery, the molecular pathways that convert rcDNA into cccDNA remain to be identified. Here we report that DNA polymerase alpha (Pol α) as well as Pol δ and ɛ are required for converting rcDNA into cccDNA through intracellular cccDNA amplification. This finding adds novel molecular insights on cccDNA biosynthesis. Further understanding the mechanism of cccDNA synthesis should reveal molecular targets for developing therapeutic agents to eradicate cccDNA and cure chronic hepatitis B.

Hepatitis B e antigen induces the expansion of monocytic myeloid-derived suppressor cells to dampen T-cell function in chronic hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is associated with functionally impaired virus-specific T cell responses. Although the myeloid-derived suppressor cells (MDSCs) are known to play a critical role in impairing antiviral T cell responses, viral factors responsible for the expansion of MDSCs in chronic hepatitis B (CHB) remain obscure. In order to elucidate the mechanism of monocytic MDSCs (mMDSCs) expansion and T cell function suppression during persistent HBV infection, we analyzed the circulation frequency of mMDSCs in 164 CHB patients and 70 healthy donors, and found that the proportion of mMDSCs in HBeAg (+) CHB patients was significantly increased compared to that in HBeAg (-) patients, which positively correlated with the level of HBeAg. Furthermore, exposure of peripheral blood mononuclear cells (PBMCs) isolated from healthy donors to HBeAg led to mMDSCs expansion and significant upregulation of IL-1β, IL-6 and indoleamine-2, 3-dioxygenase (IDO), and depletion of the cytokines abrogated HBeAg-induced mMDSCs expansion. Moreover, HBeAg-induced mMDSCs suppressed the autologous T-cell proliferation in vitro, and the purified mMDSCs from HBeAg (+) subjects markedly reduced the proliferation of CD4⁺ and CD8⁺ T cells and IFN-γ production, which could be efficiently restored by inhibiting IDO. In summary, HBeAg-induced mMDSCs expansion impairs T cell function through IDO pathway and favors the establishment of a persistent HBV infection, suggesting a mechanism behind the development of HBeAg-induced immune tolerance.

HBeAg is not a structural component of HBV and is not essential for viral DNA replication, however, HBeAg positivity is associated with high levels of viremia in patients. HBeAg may represent a viral strategy to establish persistent infection, but the mechanism remains largely ambiguous. Growing evidence suggests that chronic HBV infection may be shaped by MDSCs-mediated T-cell exhaustion. Here, we report that the frequency of circulating mMDSCs in HBeAg (+) patients is higher than HBeAg (-) patients and positively correlates with serum HBeAg levels. The correlation is further demonstrated by in vitro HBeAg stimulation of PBMCs, which induced mMDSCs expansion. Furthermore, HBeAg-induced expansion of mMDSCs is dependent upon cytokine IL-6 and IL-1β, and the indoleamine-2, 3-dioxynase (IDO) plays a critical role in the suppression of T cell proliferation and IFN-γ production by HBeAg-activated mMDSCs. Therefore, our findings demonstrate a novel mechanism responsible for mMDSCs expansion in HBeAg (+) patients, and suggest that the HBeAg-mMDSC-IDO axis may serve as an immunotherapeutic target of chronic hepatitis B.

Suppressing the NHEJ pathway by DNA-PKcs inhibitor NU7026 prevents degradation of HBV cccDNA cleaved by CRISPR/Cas9

Chronic hepatitis B is a severe liver disease caused by hepatitis B virus (HBV) infection. Covalently closed circular DNA (cccDNA), a super-spiralized, double-stranded form of the HBV genome, is the major determinant of viral persistence. CRISPR/Cas9 nucleases have been recently shown to introduce double-stranded DNA breaks into HBV cccDNA. The inflicted damage results predominantly in erroneous repair of cccDNA by non-homologous end-joining (NHEJ). NHEJ has been suggested to enhance anti-HBV activity of CRISPR/Cas9 and increase cccDNA mutation. In this study, we assessed anti-HBV activity of CRISPR/Cas9 and cccDNA repair outcomes in an altered NHEJ/HR environment. NU7026, a strong inhibitor of NHEJ, prevented CRISPR/Cas9-mediated degradation of cccDNA and resulted in frequent on-target deletions. We conclude that CRISPR/Cas9 is a highly effective tool to degrade cccDNA and first demonstrate that inhibiting NHEJ impairs cccDNA degradation.

Cisplatin induces autophagy to enhance hepatitis B virus replication via activation of ROS/JNK and inhibition of the Akt/mTOR pathway

Chronic hepatitis B virus (HBV) infection remains a serious global health concern. Cisplatin is a chemotherapeutic agent commonly used to treat various cancers. However, HBV-infected patients receiving chemotherapy are at risk of HBV reactivation via unknown mechanisms, which we aimed to elucidate in this study. We found that autophagy plays a central role in cisplatin-induced HBV replication. Cisplatin treatment induced autophagy in both HBV-replicating cells and an HBV-transgenic mouse model as evident from marked upregulation of microtubule-associated protein 1 light chain 3 (LC3)-II and the accumulation of red fluorescent protein (RFP)-LC3 puncta. Cisplatin induced complete autophagic flux, which was detected via monitoring of p62 degradation and RFP-GFP-LC3 expression. Inhibition of autophagy by chloroquine, 3-methyladenine, or Atg5 knockdown significantly attenuated cisplatin-induced HBV replication. Additionally, cisplatin-induced autophagy could be significantly attenuated by using the ROS scavenger N-acetyl-l-cysteine. Mechanically, cisplatin promoted HBV replication and autophagy through ROS/JNK and AKT/mTOR signaling. Inhibition of JNK or activation of Akt/mTOR signaling reversed cisplatin-mediated autophagy and HBV replication promotion. In contrast, suppression of Akt/mTOR signaling further promoted cisplatin-induced HBV replication. Finally, pharmacotherapeutic inhibition of autophagy or ROS production impaired HBV production induced by cisplatin in vivo. Together, our results indicate that ROS/JNK and mTOR/AKT-mediated autophagy plays an important role in cisplatin-induced HBV reactivation.

Chronic hepatitis B and metabolic risk factors: A call for rigorous longitudinal studies

Long-term nucleos(t)ide analogue therapy in chronic hepatitis B virus (HBV) infection is effective in suppressing viral replication and reducing liver-related complications. However, HBV-related liver events can still occur in different patient sub-groups. There is emerging evidence that, similar to chronic hepatitis C virus infection, metabolic risk factors may play a role in the disease process of chronic HBV. While the mechanistic nature of metabolic-HBV interactions remains uncertain, studies in different HBV-infected populations have demonstrated that hepatic steatosis, increased body-mass index, diabetes, or a combination of different metabolic risk factors are associated with an increased risk of hepatocellular carcinoma and cirrhosis. The impact of metabolic risk factors is especially prominent in patients with quiescent virological activity, including on-treatment patients with effective viral suppression. As the proportion of on-treatment chronic HBV patients increases worldwide, longitudinal studies determining the relative risks of different metabolic parameters with respect to clinical outcomes are needed. Future studies should also determine if metabolic-directed interventions can improve disease outcomes in chronic HBV.

Type 3 innate lymphoid cell: a new player in liver fibrosis progression

Type 3 innate lymphoid cell (ILC3) has recently emerged as a crucial effector in inflammatory and fibrotic diseases. The present study was designed to determine the roles of ILC3 in liver fibrosis. By flow cytometry, we documented increased frequencies of peripheral ILC3 (Lin-CD127+CD117+CD294- lymphocytes) in patients, especially at the advanced stage of hepatitis B virus (HBV)-related chronic liver diseases, and demonstrated their correlations with disease progression. The in vitro fibrogenic effects by ILC3 were determined by co-culture experiments with LX-2 (a human hepatic stellate cell (HSC) line). The data indicate that pathogenic ILC3 can directly promote LX-2 fibrogenesis in non-contact manners by producing interleukin (IL)-17A and IL-22. Additionally, they had indirect fibrogenic effects by producing IL-22 to suppress interferon (IFN)-γ (a well-known anti-fibrotic cytokine) production by other immune cells. In carbon tetrachloride (CCl4)-induced wild-type mouse liver fibrosis models, we also documented significantly increased frequencies of both non-natural killer (NK) ILC (Lin-CD127+ lymphocytes) and ILC3 (Lin-CD127+RORγt+ lymphocytes) in liver and spleen specimens. Furthermore, the ILC3 from fibrotic mice contained more IL-17A+ILC3 and IL-22+ILC3 subsets than those from normal and less-fibrotic mice. The in vivo effects of ILC3 in liver fibrogenesis were further determined using RAG-1-/- mice with ILC depletion and further adoptive transfer of ILC3 from wild-type mice. The immunohistochemical staining of liver specimens showed the beneficial effects by ILC depletion and the detrimental effects by ILC3 transfer in CCl4-induced mouse liver fibrosis models. Collectively, ILC3 plays a pro-fibrotic role in liver fibrosis progression.

Interferon alpha receptors and STAT1 as therapy predictors of a sustained virological response in hepatitis C/B co-infection

OBJECTIVE

: To determine the expression of interferon alpha receptors 1 and 2 along with signal transducer and activator of transcription-1 in peripheral blood mononuclear cells of both hepatitis C mono-infected and hepatitis C and B co-infected patients, and to assess whether these targeted genes predict sustained virological response to interferon therapy.

METHODS

This cross-sectional study was carried out at the Army Medical College, Rawalpindi, Pakistan, from January 2012 to December 2015, and comprised hepatitis C mono-infected and hepatitis C and B co-infected patients. The patients were divided into groups 1 and 2. Group-1a and group-2a consisted of mono-infected and co-infected sustained responders, while group-1b and group-2b had mono-infected and co-infected non sustained responders. Peripheral blood mononuclear cells from healthy controls were also quantified for these subunits. Target gene expressions were studied by retro-transcription of respective messenger ribonuclieic acid extracted from the cells followed by polymerase chain reaction amplification.

RESULTS

Of the 191 subjects, there were 20(10.5%) in group-1a, 35(18.3%) in group-2a, 65(34%) in group-1b and 51(26.7%) in group-2b. The remaining 20(10.5%) were controls. Overall, 106 (55.5%) were males and 85 (44.5%) were females. Interferon alpha receptor 1 expression in groups 1a and 2a was significantly higher compared to groups 1b (p=0.018) and 2b (p 0.031). Signal transducer and activator of transcription-1 protein expression showed no significant difference (p=0.062 and p=0.519). No difference in expression was measured between the two sets of groups with regard to interferon alpha receptor 2 expression (p=0.278 and p=0.590).

CONCLUSIONS

Our results show that levels of IFNAR-1 mRNA expression may be a good predictor for IFN-related anti-viral activity in both HCV mono infected and HCV/HBV co-infected patients.

Altered oral microbiota in chronic hepatitis B patients with different tongue coatings

AIM

To elucidate tongue coating microbiota and metabolic differences in chronic hepatitis B (CHB) patients with yellow or white tongue coatings.

METHODS

Tongue coating samples were collected from 53 CHB patients (28 CHB yellow tongue coating patients and 25 CHB white tongue coating patients) and 22 healthy controls. Microbial DNA was extracted from the tongue samples, and the bacterial 16S ribosomal RNA gene V3 region was amplified from all samples and sequenced with the Ion Torrent PGM™ sequencing platform according to the standard protocols. The metabolites in the tongue coatings were evaluated using a liquid chromatography-mass spectrometry (LC-MS) platform. Statistical analyses were then performed.

RESULTS

The relative compositions of the tongue coating microbiotas and metabolites in the CHB patients were significantly different from those of the healthy controls, but the tongue coating microbiota abundances and diversity levels were not significantly different. Compared with the CHB white tongue coating patients, the CHB yellow tongue coating patients had higher hepatitis B viral DNA (HBV-DNA) titers (median 21210 vs 500, respectively, P = 0.03) and a significantly lower level of Bacteroidetes (20.14% vs 27.93%, respectively, P = 0.013) and higher level of Proteobacteria (25.99% vs 18.17%, respectively, P = 0.045) in the microbial compositions at the phylum level. The inferred metagenomic pathways enriched in the CHB yellow tongue coating patients were mainly those involved in amino acid metabolism, which was consistent with the metabolic disorder. The abundances of bacteria from Bacteroidales at the order level were higher in the CHB white tongue coating patients (19.2% vs 27.22%, respectively, P = 0.011), whereas Neisseriales were enriched in the yellow tongue coating patients (21.85% vs 13.83%, respectively, P = 0.029). At the family level, the abundance of Neisseriaceae in the yellow tongue patients was positively correlated with the HBV-DNA level but negatively correlated with the S-adenosyl-L-methionine level.

CONCLUSION

This research illustrates specific clinical features and bacterial structures in CHB patients with different tongue coatings, which facilitates understanding of the traditional tongue diagnosis.

Prediction model of the progression of patients with acute deterioration of hepatitis B virus-related chronic liver disease to acute-on-chronic liver failure

This study aimed to establish a new model for predicting acute-on-chronic liver failure (ACLF) (defined by the Chinese Medical Association), which potentially occurs among patients with acute deterioration (AD) of hepatitis B virus (HBV)-related chronic liver disease (CLD).A total of 754 patients with AD of HBV-related CLD (total bilirubin (TBIL) > 51.3 μmol/L and prothrombin activity (PTA) < 60%, 40% < PTA < 60% when TBIL ≥ 171.1 μmol/L) were retrospectively analyzed and divided into a training cohort (580 patients) and a validation cohort (174 patients). The ACLF occurrence probability of these patients was statistically analyzed within 4 weeks. In the training cohort, multivariate logistic regression analysis was performed to determine the independent predictors of ACLF occurrence and to develop a new prediction model. The validation cohort was utilized to verify and evaluate the value of the new prediction model.Within 4 weeks, 9.9% of the patients progressed to ACLF (12.0 ± 6.7 days). The new prediction model was characterized by R = 3.090 + 0.035 × Age (years) - 0.050 × PTA (%) + 0.005 × TBIL (μmol/L) + 0.044 × D/T (%) - 0.072 × Na (mmol/L) + 0.180 × HBV DNA (log10IU/mL). The areas under the receiver operating characteristic curves of the training and validation cohorts in the new model were higher than those in the model for end-stage liver disease.The new prediction model could be used by clinicians to recognize patients with AD of HBV-related CLD with high risks of progressing to ACLF.

Intrahepatic hepatitis B virus large surface antigen induces hepatocyte hyperploidy via failure of cytokinesis

Hepatitis B virus (HBV) is an aetiological factor for liver cirrhosis and hepatocellular carcinoma (HCC). Despite current antiviral therapies that successfully reduce the viral load in patients with chronic hepatitis B, persistent hepatitis B surface antigen (HBsAg) remains a risk factor for HCC. To explore whether intrahepatic viral antigens contribute directly to hepatocarcinogenesis, we monitored the mitotic progression of HBV-positive cells. Cytokinesis failure was increased in HBV-positive HepG2.2.15 and 1.3ES2 cells, as well as in HuH-7 cells transfected with a wild-type or X-deficient HBV construct, but not in cells transfected with an HBsAg-deficient construct. We show that expression of viral large surface antigen (LHBS) was sufficient to induce cytokinesis failure of immortalized hepatocytes. Premitotic defects with DNA damage and G2 /M checkpoint attenuation preceded cytokinesis in LHBS-positive cells, and ultimately resulted in hyperploidy. Inhibition of polo-like kinase-1 (Plk1) not only restored the G2 /M checkpoint in these cells, but also suppressed LHBS-mediated in vivo tumourigenesis. Finally, a positive correlation between intrahepatic LHBS expression and hepatocyte hyperploidy was detected in >70% of patients with chronic hepatitis B. We conclude that HBV LHBS provokes hyperploidy by inducing DNA damage and upregulation of Plk1; the former results in atypical chromatin structures, and the latter attenuates the function of the G2 /M DNA damage checkpoint. Our data uncover a mechanism by which genomic integrity of hepatocytes is disrupted by viral LHBS. These findings highlight the role of intrahepatic surface antigen as an oncogenic risk factor in the development of HCC. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Drugs in Development for Hepatitis B

With high morbidity and mortality worldwide, there is great interest in effective therapies for chronic hepatitis B (CHB) virus. There are currently several dozen investigational agents being developed for treatment of CHB. They can be broadly divided into two categories: (1) direct-acting antivirals (DAAs) that interfere with a specific step in viral replication; and (2) host-targeting agents that inhibit viral replication by modifying host cell function, with the latter group further divided into the subcategories of immune modulators and agents that target other host functions. Included among the DAAs being developed are RNA interference therapies, covalently closed circular DNA (cccDNA) formation and transcription inhibitors, core/capsid inhibitors, reverse transcriptase inhibitors, hepatitis B surface antigen (HBsAg) release inhibitors, antisense oligonucleotides, and helioxanthin analogues. Included among the host-targeting agents are entry inhibitors, cyclophilin inhibitors, and multiple immunomodulatory agents, including Toll-like receptor agonists, immune checkpoint inhibitors, therapeutic vaccines, engineered T cells, and several cytokine agents, including recombinant human interleukin-7 (CYT107) and SB 9200, a novel therapy that is believed to both have direct antiviral properties and to induce endogenous interferon. In this review we discuss agents that are currently in the clinical stage of development for CHB treatment as well as strategies and agents currently at the evaluation and discovery phase and potential future targets. Effective approaches to CHB may require suppression of viral replication combined with one or more host-targeting agents. Some of the recent research advances have led to the hope that with such a combined approach we may have a functional cure for CHB in the not distant future.

IFI16 is involved in HBV-associated acute-on-chronic liver failure inflammation

BACKGROUND

Hepatitis B virus (HBV) is a hepatotropic DNA virus, and its DNA may be a potent inflammatory molecule. Interferon-inducible protein 16 (IFI16), a newly discovered DNA sensor, plays an important role in the process of inflammation in viral infections. Our study sought to identify a correlation between IFI16 expression and inflammation in patients with chronic hepatitis B (CHB) and HBV-associated acute-on-chronic liver failure (HBV-ACLF).

METHODS

We performed flow cytometry to measure IFI16 levels in peripheral blood mononuclear cells (PBMC) and used immunohistochemistry and western blotting to measure IFI16 protein levels in liver tissues. The cellular source of IFI16 was detected using double immunofluorescence. All datum were analyzed using SPSS 13.0 and GraphPad Prism 6.

RESULTS

The number of IFI16+ cells was significantly associated with the degree of inflammation. In detail, the number of IFI16+ cells was higher in livers but lower in PBMCs in HBV-ACLF patients than those in CHB patients and healthy controls. There was no significant difference between CHB patients and healthy controls in numbers of IFI6+ cells in livers and PBMCs. There was no significant relationship between IFI16 expression levels and HBV parameters. Furthermore, IFI16 was expressed in the nucleus of Kupffer cells (KCs), endothelial cells, natural killer cells, dendritic cells, and hepatic stellate cells in healthy donors and CHB patients, but only in the cytoplasm of KCs in the livers of HBV-ACLF patients.

CONCLUSIONS

IFI16 was closely related to the degree of inflammation in CHB and HBV-ACLF patients and may serve as a vital contributor to the pathogeneses of liver damage in HBV-ACLF.

The Study of Immune Response in PBMC of CHB Patients treated with IFN-α and 3-TC in vitro

BACKGROUND

The primary aim of this study is to measure the JAK-STAT signaling in HBV infected peripheral blood mononuclear cells (PBMCs) stimulated by IFN-α and 3-TC and explore the influence of HBV to the JAKSTAT signaling pathways.

METHODS

PBMCs were separated from healthy volunteers and patients who had not received any treatment with chronic hepatitis B. PBMCs were divided into the control group, IFN-α stimulation group, Lamivudine stimulation group, and combined treatment group. The expression of molecules of JAK-STAT signal transduction pathway (STAT1, STAT2, IRF9) and the antiviral protein (MxA) were detected by RT-qPCR and Western blot method.

RESULTS

The majority of IFN-α inducible genes were expressed. The molecules of JAK-STAT signal transduction pathway (STAT1, STAT2, IRF9) and the antiviral protein (MxA) were highly expressed in IFN-α stimulation group and the combined treatment group. Compared to healthy controls, the expression levels of molecules (STAT1, IRF9) and the antiviral protein (MxA) are significantly lower in the control group, IFN-α stimulation group, and the combined treatment group of the CHB patients.

CONCLUSIONS

IFN-α could activate JAK-STAT signaling transduction pathway in PBMCs of HBV-infected patients and HBV might process the activity to antagonize the antiviral activity in HBV infected PBMCs.

Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is associated with immune phases of patients with chronic hepatitis B

Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is a newly negative immune regulator but its role in different immune phases of patients with chronic hepatitis B (CHB) is unknown. We determined the mRNA levels of TIPE2, interleukin-6, interleukin-10, tumor necrosis factors-α and interferon-γ in peripheral blood mononuclear cells from 205 naïve treated CHB patients and 15 healthy controls by quantitative real time polymerase chain reaction. Intrahepatic TIPE2 protein was also determined using immunohistochemistry staining. The TIPE2 mRNA level in CHB patients was significantly higher than that in healthy controls. Moreover, the TIPE2 mRNA level in immune clearance (IC) phases was significantly higher than that in immune tolerance (IT) phase; whereas TIPE2 mRNA in HBeAg negative hepatitis (ENH) was obviously higher than low replication (LR) phase. Furthermore, the optional cut off values of 2.02 and 1.59 for TIPE2 mRNA level have strong power in identifying IC and ENH from IT and LR. In addition, intrahepatic TIPE2 protein was predominantly located in hepatocyte plasma and correlated with hepatic inflammatory and fibrosis. Multivariate analysis showed tumor necrosis factors-α, interferon-γ and HBV DNA load were independently correlated with TIPE2 level. In conclusion, TIPE2 might be associated to the immune clearance of patients with chronic hepatitis B.

Frequency and role of NKp46 and NKG2A in hepatitis B virus infection

Background and Aim

Natural Killer (NK) cells are involved in the control of viral infection. However, the role of NK cells in chronic hepatitis B (CHB) remains unclear. This study investigated the frequencies and roles of NK cells in CHB, with a focus on activating receptor NKp46 and inhibitory receptor NKG2A.

Patients/Method

Peripheral blood lymphocytes were obtained from 71 CHB patients and 37 healthy subjects (HS). The expressions of NKp46 and NKG2A were analyzed using flow cytometry. The role of NKp46-ligand was assessed using an in vitro co-culture system. Cytotoxicity and IFN-γ production in NK cells were evaluated using RT-PCR and flow cytometry.

Results

CHB patients were classified into treatment-naïve patients with low HBV DNA titer (CHB-L; n = 28), high HBV DNA titer (CHB-H; n = 24) by the cut-off level of serum HBV DNA 4 log copies/ml, and patients receiving nucleos(t)ide analogue (CHB-NA; n = 19). The expressions of NKp46 and NKG2A were higher in CHB-H than in HS/CHB-L/CHB-NA. HepG2.2.15 had higher NKp46-ligand expression than HepG2. When NK cells from HS were co-cultured with HepG2.2.15, inhibition of the NKp46 and NKp46-ligand interaction by anti-NKp46 antibody significantly reduced cytolysis of HepG2.2.15 and IFN-γ production. However, those reductions were not observed in co-culture with HepG2. Additionally, NK cells that highly expressed NKp46 also highly expressed NKG2A (NKp46^highNKG2A^high subset). The frequencies of NKp46^highNKG2A^high subset in CHB-H were higher than those in HS/CHB-L/CHB-NA. Among treatment-naïve CHB patients, the frequencies of NKp46^highNKG2A^high subset were positively correlated with serum ALT (P<0.01, r = 0.45) and HBV DNA (P<0.01, r = 0.59) levels. The expressions of Fas-L, STAT1, TRAIL and CD107a were higher and IFN-γ expression was lower in the NKp46^highNKG2A^high subset than in the other subsets.

Conclusion

The NKp46 and NKp46-ligand interaction contributes to NK cell activation. A novel NK cell subset, the NKp46^highNKG2A^high subset, may be associated with liver injury and HBV replication.

NKG2D modulates aggravation of liver inflammation by activating NK cells in HBV infection

Hepatitis B virus (HBV) infection is thought to be an immune-mediated liver disease. The mechanisms underlying natural killer (NK) cell group 2D receptor (NKG2D) that activates NK cells and participates in anti-HBV immunity and immunopathology has not been thoroughly elucidated. Peripheral NKG2D⁺ and IFN-γ⁺ NK cells frequencies and intrahepatic NKG2D and IFN-γ mRNA and protein expressions were determined in HBV-infected patients. Levels of NKG2D and IFN-γ mRNA and protein in NK cells, co-cultured with HBV-replicating HepG2 cells with or without NKG2D blockade, were analyzed. Serum and supernatant IFN-γ, TNF-α, perforin and granzyme B were measured. In results, peripheral NKG2D⁺ and IFN-γ⁺ NK cells frequencies, intrahepatic NKG2D and IFN-γ mRNA and protein levels, and serum IFN-γ, TNF-α, perforin and granzyme B levels were all highest in HBV-related acute-on-chronic liver failure group, followed by chronic hepatitis B and chronic HBV carrier groups. In vitro, NKG2D and IFN-γ mRNA and protein levels were higher in NK cells with IFN-α stimulation than without stimulation. Supernatant IFN-γ, TNF-α, perforin and granzyme B levels were increased under co-culture or IFN-α stimulating conditions, but were partially blocked by NKG2DmAb. In conclusion, NKG2D regulates immune inflammation and anti-viral response partly through activation of NK cells during HBV infection.

Decreased S100B expression in chronic liver diseases

BACKGROUND/AIMS

Hepatic innervation in liver diseases is not fully understood. We here evaluated S100B expression as a marker of hepatic nerves in patients with various chronic liver diseases, topographically and semi-quantitatively.

METHODS

Liver specimens were obtained from 70 subjects (three controls, and 32 chronic hepatitis B, 14 chronic hepatitis C, 14 liver cirrhosis, and seven hepatocellular carcinoma patients). The hepatic nerve density was calculated based on immunohistochemical staining of S100B protein in the portal tracts and hepatic lobules. S100B mRNA levels were semi-quantitatively assessed as the S100B/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA ratio.

RESULTS

The densities of the hepatic nerves in portal tracts of chronic liver diseases were not significantly different from those of normal controls but the hepatic nerve densities in lobular areas of liver cirrhosis were significantly decreased (p = 0.025). Compared to the control, the S100B/GAPDH mRNA ratio was significantly decreased in chronic liver diseases (p = 0.006) and most decreased in chronic hepatitis C patients (p = 0.023). In chronic liver diseases, The S100B/GAPDH mRNA ratio tended to decrease as the fibrosis score > 0 (p = 0.453) but the overall correlation between the S100B/GAPDH mRNA ratio and fibrosis score was not statistically significant (r = 0.061, p = 0.657).

CONCLUSIONS

Hepatic innervation is decreased in cirrhotic regenerating nodules compared to the control group and seems to decrease in early stages of fibrosis progression. Further studies are needed to clarify the association between changes of hepatic innervation and chronic liver disease progression.

Phosphorylation-specific status of RNAi triggers in pharmacokinetic and biodistribution analyses

The RNA interference (RNAi)-based therapeutic ARC-520 for chronic hepatitis B virus (HBV) infection consists of a melittin-derived peptide conjugated to N-acetylgalactosamine for hepatocyte targeting and endosomal escape, and cholesterol-conjugated RNAi triggers, which together result in HBV gene silencing. To characterize the kinetics of RNAi trigger delivery and 5΄-phosphorylation of guide strands correlating with gene knockdown, we employed a peptide-nucleic acid (PNA) hybridization assay. A fluorescent sense strand PNA probe binding to RNAi duplex guide strands was coupled with anion exchange high performance liquid chromatography to quantitate guide strands and metabolites. Compared to PCR- or ELISA-based methods, this assay enables separate quantitation of non-phosphorylated full-length guide strands from 5΄-phosphorylated forms that may associate with RNA-induced silencing complexes (RISC). Biodistribution studies in mice indicated that ARC-520 guide strands predominantly accumulated in liver. 5΄-phosphorylation of guide strands was observed within 5 min after ARC-520 injection, and was detected for at least 4 weeks corresponding to the duration of HBV mRNA silencing. Guide strands detected in RISC by AGO2 immuno-isolation represented 16% of total 5΄-phosphorylated guide strands in liver, correlating with a 2.7 log10 reduction of HBsAg. The PNA method enables pharmacokinetic analysis of RNAi triggers, elucidates potential metabolic processing events and defines pharmacokinetic-pharmacodynamic relationships.

Hepatitis B virus modulates store-operated calcium entry to enhance viral replication in primary hepatocytes

Many viruses modulate calcium (Ca²⁺) signaling to create a cellular environment that is more permissive to viral replication, but for most viruses that regulate Ca²⁺ signaling, the mechanism underlying this regulation is not well understood. The hepatitis B virus (HBV) HBx protein modulates cytosolic Ca²⁺ levels to stimulate HBV replication in some liver cell lines. A chronic HBV infection is associated with life-threatening liver diseases, including hepatocellular carcinoma (HCC), and HBx modulation of cytosolic Ca²⁺ levels could have an important role in HBV pathogenesis. Whether HBx affects cytosolic Ca²⁺ in a normal hepatocyte, the natural site of an HBV infection, has not been addressed. Here, we report that HBx alters cytosolic Ca²⁺ signaling in cultured primary hepatocytes. We used single cell Ca²⁺ imaging of cultured primary rat hepatocytes to demonstrate that HBx elevates the cytosolic Ca²⁺ level in hepatocytes following an IP₃-linked Ca²⁺ response; HBx effects were similar when expressed alone or in the context of replicating HBV. HBx elevation of the cytosolic Ca²⁺ level required extracellular Ca²⁺ influx and store-operated Ca²⁺ (SOC) entry and stimulated HBV replication in hepatocytes. We used both targeted RT-qPCR and transcriptome-wide RNAseq analyses to compare levels of SOC channel components and other Ca²⁺ signaling regulators in HBV-expressing and control hepatocytes and show that the transcript levels of these various proteins are not affected by HBV. We also show that HBx regulation of SOC-regulated Ca²⁺ accumulation is likely the consequence of HBV modulation of a SOC channel regulatory mechanism. In support of this, we link HBx enhancement of SOC-regulated Ca²⁺ accumulation to Ca²⁺ uptake by mitochondria and demonstrate that HBx stimulates mitochondrial Ca²⁺ uptake in primary hepatocytes. The results of our study may provide insights into viral mechanisms that affect Ca²⁺ signaling to regulate viral replication and virus-associated diseases.