Current status of antiviral therapy for hepatitis B

Establishment of a hydrodynamic delivery system in ducks

Chronic hepatitis B virus (HBV) poses a significant global health challenge as it can lead to acute or chronic liver disease and hepatocellular carcinoma (HCC). To establish a safety experimental model, a homolog of HBV-duck HBV (DHBV) is often used for HBV research. Hydrodynamic-based gene delivery (HGD) is an efficient method to introduce exogenous genes into the liver, making it suitable for basic research. In this study, a duck HGD system was first constructed by injecting the reporter plasmid pLIVE-SEAP via the ankle vein. The highest expression of SEAP occurred when ducks were injected with 5 µg/mL plasmid pLIVE-SEAP in 10% bodyweight volume of physiological saline for 6 s. To verify the distribution and expression of exogenous genes in multiple tissues, the relative level of foreign gene DNA and β-galactosidase staining of LacZ were evaluated, which showed the plasmids and their products were located mainly in the liver. Additionally, β-galactosidase staining and fluorescence imaging indicated the delivered exogenous genes could be expressed in a short time. Further, the application of the duck HGD model on DHBV treatment was investigated by transferring representative anti-HBV genes IFNα and IFNγ into DHBV-infected ducks. Delivery of plasmids expressing IFNα and IFNγ inhibited DHBV infection and we established a novel efficient HGD method in ducks, which could be useful for drug screening of new genes, mRNAs and proteins for anti-HBV treatment.

Transcriptomic Analysis of Hepatitis B Infected Liver for Prediction of Hepatocellular Carcinoma

Hepatocellular cancer (HCC) is a leading cause of cancer-related mortality worldwide, and chronic hepatitis B virus infection (CHB) has been a major risk factor for HCC development. The pathogenesis of HBV-related HCC has been a major focus revealing the interplay of a multitude of intracellular signaling pathways, yet the precise mechanisms and their implementations to clinical practice remain to be elucidated. This study utilizes publicly available transcriptomic data from the livers of CHB patients in order to identify a population with a higher risk of malignant transformation. We report the identification of a novel list of genes (PCM1) which can generate clear transcriptomic sub-groups among HBV-infected livers. PCM1 includes genes related to cell cycle activity and liver cancer development. In addition, markers of inflammation, M1 macrophages and gamma delta T cell infiltration are present within the signature. Genes within PCM1 are also able to differentiate HCC from normal liver, and some genes within the signature are associated with poor prognosis of HCC at the mRNA level. The analysis of the immunohistochemical stainings validated that proteins coded by a group of PCM1 genes were overexpressed in liver cancer, while minimal or no expression was detected in normal liver. Altogether, our findings suggest that PCM1 can be developed into a clinically applicable method to identify CHB patients with a higher risk of HCC development.

Hepatocellular Carcinoma in Hepatitis B Virus-Infected Patients and the Role of Hepatitis B Surface Antigen (HBsAg)

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the second leading cause of cancer-related death worldwide. Hepatitis B virus (HBV) infection is among the main risk factors for HCC. The risk of HCC is not eliminated completely after viral suppression, due to HBV DNA integrated into human chromosomes. Cirrhosis, HBV viral DNA levels, age, male gender, the immune response of the host against HBV, and a combination of obesity and diabetes are among the main risk factors for HCC. Active viral replication and long-standing active disease with inflammation are associated with a higher risk of HCC. Treatment of HBV with nucleos(t)ide analogues (NAs) decreased HCC risk by effectively decreasing viral load and inflammation. Similar risk factors have been reported in hepatitis B patients after seroclearance. Studies have reported decreased risk of HCC after seroclearance, but there were also conflicting results from a few studies indicating no difference in risk of developing HCC. The difference in HCC rates could be because of other factors such as coinfection, occult HBV infection, family history, HBV genotype, and other comorbidities. Due to the persistent risk of HCC after seroclearance, HCC surveillance is critical for early detection, especially in high-risk patients. However, long-term studies might be needed to further validate the results.

Humoral Immune Responses and Hepatitis B Infection

BACKGROUND

Chronicity or seroclearance of hepatitis B virus (HBV) antigens is determined by the host immune responses. Current approaches to treat HBV patients are based on inhibition of replication using different antivirals (nucleoside or nucleotide analogs) as monotherapy, or along with immune modulators as combination therapy is being used worldwide for reducing the viral load. Understanding the role of immune cellular therapies with currently available treatments for persistent viral-mediated responses in HBV patients is unexplored. However, the generation of antibodies against a surface (HBs) and envelop (HBe) antigen of hepatitis B remains an issue for future studies and needs to be explored.

SUMMARY

Humoral immunity, specifically T follicular helper (TFh) cells, may serve as a target for therapy for HBsAg seroconversion. In this review, we have been engrossed in the importance and role of the humoral immune responses in CHBV infection and vertical transmission. Key Message: TFh cells have been suggested as the potential target of immunotherapy which lead to seroconversion of HBe and HBs antigens of HBV. HBsAg seroconversion and eradication of covalently closed circular DNA are the main challenges for existing and forthcoming therapies in HBV infection.

Comprehensive Proteomics Identification of IFN-λ3-regulated Antiviral Proteins in HBV-transfected Cells

Interferon lambda (IFN-λ) is a relatively unexplored, yet promising antiviral agent. IFN-λ has recently been tested in clinical trials of chronic hepatitis B virus infection (CHB), with the advantage that side effects may be limited compared with IFN-α, as IFN-λ receptors are found only in epithelial cells. To date, IFN-λ's downstream signaling pathway remains largely unelucidated, particularly via proteomics methods. Here, we report that IFN-λ3 inhibits HBV replication in HepG2.2.15 cells, reducing levels of both HBV transcripts and intracellular HBV DNA. Quantitative proteomic analysis of HBV-transfected cells was performed following 24-hour IFN-λ3 treatment, with parallel IFN-α2a and PBS treatments for comparison using a dimethyl labeling method. The depth of the study allowed us to map the induction of antiviral proteins to multiple points of the viral life cycle, as well as facilitating the identification of antiviral proteins not previously known to be elicited upon HBV infection (e.g. IFITM3, XRN2, and NT5C3A). This study also shows up-regulation of many effectors involved in antigen processing/presentation indicating that this cytokine exerted immunomodulatory effects through several essential molecules for these processes. Interestingly, the 2 subunits of the immunoproteasome cap (PSME1 and PSME2) were up-regulated whereas cap components of the constitutive proteasome were down-regulated upon both IFN treatments, suggesting coordinated modulation toward the antigen processing/presentation mode. Furthermore, in addition to confirming canonical activation of interferon-stimulated gene (ISG) transcription through the JAK-STAT pathway, we reveal that IFN-λ3 restored levels of RIG-I and RIG-G, proteins known to be suppressed by HBV. Enrichment analysis demonstrated that several biological processes including RNA metabolism, translation, and ER-targeting were differentially regulated upon treatment with IFN-λ3 versus IFN-α2a. Our proteomic data suggests that IFN-λ3 regulates an array of cellular processes to control HBV replication.

Identification of anti-HBV activities in Paeonia suffruticosa Andr. using GRP78 as a drug target on Herbochip®

Background

Herbochip^® technology is a high throughput drug screening platform in a reverse screening manner, in which potential chemical leads in herbal extracts are immobilized and drug target proteins can be used as probes for screening process [BMC Complementary and Alternative Medicine (2015) 15:146]. While herbal medicines represent an ideal reservoir for drug screenings, here a molecular chaperone GRP78 is demonstrated to serve as a potential target for antiviral drug discovery.

Methods

We cloned and expressed a truncated but fully functional form of human GRP78 (hGRP78^1-508) and used it as a probe for anti-HBV drug screening on herbochips. In vitro cytotoxicity and in vitro anti-HBV activity of the herbal extracts were evaluated by MTT and ELISA assays, respectively. Finally, anti-HBV activity was confirmed by in vivo assay using DHBV DNA levels in DHBV-infected ducklings as a model.

Results

Primary screenings using GRP78 on 40 herbochips revealed 11 positives. Four of the positives, namely Dioscorea bulbifera, Lasiosphaera fenzlii, Paeonia suffruticosa and Polygonum cuspidatum were subjected to subsequent assays. None of the above extracts was cytotoxic to AML12 cells, but P. cuspidatum extract (PCE) was found to be cytotoxic to HepG2 2.2.15 cells. Both PCE and P. suffruticosa extract (PSE) suppressed secretion of HBsAg and HBeAg in HepG2 2.2.15 cells. The anti-HBV activity of PSE was further confirmed in vivo.

Conclusion

We have demonstrated that GRP78 is a valid probe for anti-HBV drug screening on herbochips. We have also shown that PSE, while being non-cytotoxic, possesses in vitro and in vivo anti-HBV activities. Taken together, our data suggest that PSE may be a potential anti-HBV agent for therapeutic use.

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-017-0132-2) contains supplementary material, which is available to authorized users.

Chronic hepatitis B: Immunological profile and current therapeutic vaccines in clinical trials

More than 250million people worldwide are chronically infected with hepatitis B virus (CHB), and over half a million die each year due to CHB-associated liver complications such as cirrhosis and hepatocellular carcinoma. The translation of immunological knowledge about CHB into therapeutic strategies aiming to a sustainable hepatitis B virus (HBV) clearance has been challenging. In recent years, however, the understanding on the immune effectors required to overcome chronicity has notably increased thanks to preclinical and clinical research. Therapeutic vaccination may prove to be useful for treating CHB patients when coupled with current antiviral agents and other immunomodulatory strategies. This review summarizes current data and future perspectives on therapeutic vaccination. Other treatment alternatives that could be combined with vaccines for a complete cure from hepatitis B virus infection are also discussed.

Subtle presentation of active primary biliary cirrhosis in chronic hepatitis B: a case report

We are describing an interesting case of two chronic liver diseases in a 48-year-old Chinese woman. While chronic hepatitis B is a common entity in Asia, the patient was later found to have active, asymptomatic primary biliary cirrhosis due to a persistently elevated alkaline phosphatase level after optimal hepatitis B virus DNA suppression on antiviral therapy. This report emphasizes the importance of keeping a high index of suspicion for another potential liver disease process even after a patient has been successfully treated for a primary liver condition. Clinical vigilance, especially in atypical clinical presentations, can result in early accurate diagnosis and prompt treatment.

Current and future antiviral drug therapies of hepatitis B chronic infection

Despite significant improvement in the management of chronic hepatitis B virus (HBV) it remains a public health problem, affecting more than 350 million people worldwide. The natural course of the infection is dynamic and involves a complex interplay between the virus and the host’s immune system. Currently the approved therapeutic regimens include pegylated-interferon (IFN)-α and monotherapy with five nucleos(t)ide analogues (NAs). Both antiviral treatments are not capable to eliminate the virus and do not establish long-term control of infection after treatment withdrawal. IFN therapy is of finite duration and associates with low response rates, liver decompensating and numerous side effects. NAs are well-tolerated therapies but have a high risk of drug resistance development that limits their prolonged use. The imperative for the development of new approaches for the treatment of chronic HBV infection is a challenging issue that cannot be over-sided. Research efforts are focusing on the identification and evaluation of various viral replication inhibitors that target viral replication and a number of immunomodulators that aim to restore the HBV specific immune hyporesponsiveness without inducing liver damage. This review brings together our current knowledge on the available treatment and discusses potential therapeutic approaches in the battle against chronic HBV infection.

Hepatitis B surface antigen (HBsAg) and core antigen (HBcAg) combine CpG oligodeoxynucletides as a novel therapeutic vaccine for chronic hepatitis B infection

Hepatitis B virus infection is a non-cytopathic hepatotropic virus which can lead to chronic liver disease and hepatocellular carcinoma. Traditional therapies fail to provide sustained control of viral replication and liver damage in most patients. As an alternative strategy, immunotherapeutic approaches have shown promising efficacy in the treatment of chronic hepatitis B patients. Here, we investigated the efficacy of a novel therapeutic vaccine formulation consisting of two HBV antigens, HBsAg and HBcAg, and CpG adjuvant. This vaccine formulation elicits forceful humoral responses directed against HBsAg/HBcAg, and promotes a Th1/Th2 balance response against HBsAg and a Th1-biased response against HBcAg in both C57BL/6 and HBV transgenic mice. Vigorous cellular immune response was also detected in HBV transgenic mice, for a significantly higher number of HBs/HBc-specific IFN-γ secreting CD4+ and CD8+ T cells was generated. Moreover, vaccinated mice elicited significantly intense in vivo CTL attack, reduced serum HBsAg level without causing liver damage in HBV transgenic mice. In summary, this study demonstrates a novel therapeutic vaccine with the potential to elicit vigorous humoral and cellular response, overcoming tolerance in HBV transgenic mice.

Serum microRNA-125a-5p, a useful biomarker in liver diseases, correlates with disease progression

It has been demonstrated that liver microRNA-125a-5p (miR-125a-5p) is correlated with disease progression in different liver diseases, including liver fibrosis and hepatocellular carcinoma (HCC). The present study investigated whether serum miR-125a-5p correlated with the progression of different liver diseases. Serum samples were obtained from healthy individuals, patients with chronic hepatitis B who had undergone a liver biopsy, and patients with HCC and were analyzed for the levels of miR-125a-5p. Compared with the healthy controls, the serum levels of miR-125a-5p were significantly higher in the liver fibrosis serum, and were reduced in HCC. With the development of liver fibrosis, there was a significant increase in the expression of miR-125a-5p (P<0.05). In comparing histological activity index (HAI) scores, higher expression levels of miR125a-5p were observed in the high HAI score group (P<0.05). Furthermore, correlation between serum miR-125a-5p and viral replication (P<0.001) was observed. Notably, miR-125a-5p demonstrated significant correlation with other markers in the liver fibrosis group (P<0.001). In the patients with HCC, lower serum levels of miR-125a-5p were correlated with a poor prognosis, determined by Kaplan-Meier curve analysis (P=0.009). In the liver fibrosis and HCC groups, different expression levels of serum miR-125a-5p were observed, and were correlated with disease progression. The results of the present study suggested that serum miR-125a-5p may be used as a non-invasive biomarker for monitoring disease progression in liver diseases.

Retrospective analysis of total direct medical costs associated with hepatitis B patients with oral antiviral versus pegylated interferon therapy in Turkey

To explore healthcare costs associated with antiviral treatment of hepatitis B virus (HBV) in Turkey. Research-identified data from a claims processing system for all Turkish health insurance funds were analysed. Adult patients prescribed oral antiviral and pegylated interferon treatment were identified between 1 January 2010 and 31 December 2010. The first prescription date was defined as the index date. Patients were required to have HBV diagnosis within the 6-month pre-index period. Pharmacy, outpatient and inpatient claims were compiled over the study period for the selected patients, and risk-adjusted 1-year healthcare costs of patients with oral antiviral and pegylated interferon treatment were compared. Risk adjustment was carried out using propensity score matching, controlling for baseline demographic and clinical characteristics. A total of 9618 patients were identified, of which 9074 were treated with oral antiviral medication and 544 with pegylated interferon medication. The oral antiviral treatment group was older (45.28 vs 42.19, P < 0.001), less likely to be female (32.17% vs 39.71%, P < 0.001) and to reside in Southeastern Anatolia (8.29% vs 13.97%, P < 0.001) or Mediterranean region (8.90% vs 11.76%, P < 0.03) and had higher Elixhauser comorbidity index scores (60.22% vs 74.08%, P < 0.001) than the pegylated interferon group. After adjusting for confounding factors, total medical costs for pegylated interferon patients were €2771 higher than for oral antiviral patients (P < 0.001), due to higher outpatient and prescription costs. For annual healthcare costs for antiviral treatment options for HBV patients in Turkey, after adjusting for age, gender, region and comorbid condition differences, oral antiviral treatment is more costly than pegylated interferon treatment.

A review of non-nucleoside anti-hepatitis B virus agents

Hepatitis B Virus is the most common cause of chronic liver disease worldwide. Currently approved agents of chronic HBV infection treatment include interferon and nucleoside analogues. However, the side effects of interferon and the viral resistance of nucleoside analogues make the current treatment far from satisfactory. Therefore, new drugs with novel structures and mechanisms are needed. Recently, a number of non-nucleoside HBV inhibitors have been obtained from natural sources or prepared by synthesis/semi-synthesis. Some of them exhibited potent anti-HBV activity with novel mechanisms. These compounds provide useful information for the medicinal chemist to develop novel non-nucleoside compounds as anti-HBV agents.

Expression of hepatitis B virus 1.3-fold genome plasmid in an SV40 T-antigen-immortalized mouse hepatic cell line

AIM: To investigate the expression of the hepatitis B virus (HBV) 1.3-fold genome plasmid (pHBV1.3) in an immortalized mouse hepatic cell line induced by SV40 T-antigen (SV40T) expression.

METHODS: Mouse hepatic cells were isolated from mouse liver tissue fragments from 3-5 d old Kunming mice by the direct collagenase digestion method and cultured in vitro. The pRSV-T plasmid was transfected into mouse hepatic cells to establish an SV40LT-immortalized mouse hepatic cell line. The SV40LT-immortalized mouse hepatic cells were identified and transfected with the pHBV1.3 plasmid. The levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in the supernatant were determined by an electrochemiluminescence immunoassay at 24, 48, 72 and 96 h after transfection. The expressions of HBsAg and hepatitis B c antigen (HBcAg) in the cells were investigated by indirect immunofluorescence analysis. The presence of HBV DNA replication intermediates in the transfected cells and viral particles in the supernatant of the transfected cell cultures was monitored using the Southern hybridization assay and transmission electronic microscopy, respectively.

RESULTS: The pRSV-T plasmid was used to immortalize mouse hepatocytes and an SV40LT-immortalized mouse hepatic cell line was successfully established. SV40LT-immortalized mouse hepatic cells have the same morphology and growth characteristics as primary mouse hepatic cells can be subcultured and produce albumin and cytokeratin-18 in vitro. Immortalized mouse hepatic cells did not show the characteristics of tumor cells, as alpha-fetoprotein levels were comparable (0.58 ± 0.37 vs 0.61 ± 0.31, P = 0.37). SV40LT-immortalized mouse hepatic cells were then transfected with the pHBV1.3 plasmid, and it was found that the HBV genome replicated in SV40LT-immortalized mouse hepatic cells. The levels of HBsAg and HBeAg continuously increased in the supernatant after the transfection of pHBV1.3, and began to decrease 72 h after transfection. The expressions of HBsAg and HBcAg were observed in the pHBV1.3-transfected cells. HBV DNA replication intermediates were also observed at 72 h after transfection, including relaxed circular DNA, double-stranded DNA and single-stranded DNA. Furthermore, a few 42 nm Dane particles, as well as many 22 nm subviral particles with a spherical or filamentous shape, were detected in the supernatant.

CONCLUSION: SV40T expression can immortalize mouse hepatic cells, and the pHBV1.3-transfected SV40T-immortalized mouse hepatic cell line can be a new in vitro cell model.

Anti-hepatitis B virus activities of α-DDB-FNC, a novel nucleoside-biphenyldicarboxylate compound in cells and ducks, and its anti-immunological liver injury effect in mice

Infection with hepatitis B virus (HBV) continues to be a major global cause of acute and chronic liver disease with high mortality. Herein, we examined both the anti-HBV and hepatoprotective activity of α-DDB-FNC. In human HBV-transfected liver cell line HepG2.2.15, α-DDB-FNC effectively suppressed the secretion of HBV antigens in a time and dose-dependent manner with 25.11% inhibition on HBeAg and 43.68% on HBsAg at 2.5 μM on day 9. Consistent with the HBV antigen reduction, α-DDB-FNC (2.5 μM) also reduced HBV DNA level by 77.74% extracellularly and 78.94% intracellularly on day 9. In the duck hepatitis B virus (DHBV) infected ducks, after α-DDB-FNC was given once daily for 10 days, the serum and liver DHBV DNA levels were reduced markedly with 96.81% and 97.21% at 10 mgkg(-1) on day 10, respectively. In Con A-induced immunological liver-injury mice, α-DDB-FNC significantly inhibited the elevation of serum ALT, AST, TBiL and liver MDA, NO levels. Furthermore, significant improvement of the liver was observed after α-DDB-FNC treatment both in ducks and mice, as evaluated by the histopathological analysis. In conclusion, our results demonstrated that α-DDB-FNC possesses both antiviral activity against HBV and hepatoprotective effect to Con A-induced liver-injury mice.

Golgi protein 73(GP73), a useful serum marker in liver diseases

BACKGROUND

This study was performed to quantify the expression of Golgi protein-73 (GP73) in healthy controls and in patients with liver disease, and to evaluate the correlations between GP73 and other serum markers in different liver diseases.

METHODS

Serum GP73 was measured in 478 healthy controls and 296 patients with different types of liver disease. Quantitative hepatitis B virus (HBV) DNA was determined in two chronic hepatitis B (CHB) groups. Other serum liver fibrosis markers were measured in the liver fibrosis group and α-fetoprotein (AFP) was measured in hepatocellular carcinoma (HCC) group. The correlations between GP73 and these markers were evaluated.

RESULTS

The GP73 value in hepatitis B e antigen (HBeAg)-positive CHB group, HBeAg-negative CHB group, liver fibrosis group and HCC group was significantly higher (p<0.001) than that in healthy controls. GP73 showed significant correlation with other markers in the liver fibrosis group and with AFP in the HCC group.

CONCLUSIONS

Compared with healthy controls, GP73 in patients with liver disease was significantly increased. With the progression of liver disease, GP73 showed a significantly increasing trend. These results suggest that GP73 might be used as a serum marker for the diagnosis of liver diseases and for monitoring disease progression.

Synthesis and in vitro anti-hepatitis B virus activity of 6H-[1]benzothiopyrano[4,3-b]quinolin-9-ols

A series of novel 6H-[1]benzothiopyrano[4,3-b]quinoline derivatives were prepared and evaluated for their anti-hepatitis B virus (HBV) activity and cytotoxicity in human hepatoblastoma-derived liver Hep-G2 cells. Compounds 10g, 10h, 10j, 10l and 10o were found to be potent anti-HBV compounds with IC(50) values less than 50 microM. The most promising compound was 10l, with an IC(50) value of 14.7 microM and a SI value of 12.4. This is the first report of the anti-HBV effects of 6H-[1]benzothiopyrano[4,3-b] quinolin-9-ols.