Oxygen-dependent histone lysine demethylase 4 restricts hepatitis B virus replication

Mammalian cells have evolved strategies to regulate gene expression when oxygen is limited. Hypoxia-inducible factors (HIF) are the major transcriptional regulators of host gene expression. We previously reported that HIFs bind and activate hepatitis B virus (HBV) DNA transcription under low oxygen conditions; however, the global cellular response to low oxygen is mediated by a family of oxygenases that work in concert with HIFs. Recent studies have identified a role for chromatin modifiers in sensing cellular oxygen and orchestrating transcriptional responses, but their role in the HBV life cycle is as yet undefined. We demonstrated that histone lysine demethylase 4 (KDM4) can restrict HBV, and pharmacological or oxygen-mediated inhibition of the demethylase increases viral RNAs derived from both episomal and integrated copies of the viral genome. Sequencing studies demonstrated that KDM4 is a major regulator of the hepatic transcriptome, which defines hepatocellular permissivity to HBV infection. We propose a model where HBV exploits cellular oxygen sensors to replicate and persist in the liver. Understanding oxygen-dependent pathways that regulate HBV infection will facilitate the development of physiologically relevant cell-based models that support efficient HBV replication.

Novel non-HAP class A HBV capsid assembly modulators have distinct in vitro and in vivo profiles

IMPORTANCE

Chronic hepatitis B is the most important cause of liver cancer worldwide and affects more than 290 million people. Current treatments are mostly suppressive and rarely lead to a cure. Therefore, there is a need for novel and curative drugs that target the host or the causative agent, hepatitis B virus itself. Capsid assembly modulators are an interesting class of antiviral molecules that may one day become part of curative treatment regimens for chronic hepatitis B. Here we explore the characteristics of a particularly interesting subclass of capsid assembly modulators. These so-called non-HAP CAM-As have intriguing properties in cell culture but also clear virus-infected cells from the mouse liver in a gradual and sustained way. We believe they represent a considerable improvement over previously reported molecules and may one day be part of curative treatment combinations for chronic hepatitis B.

Conditional replication and secretion of hepatitis B virus genome uncover the truncated 3' terminus of encapsidated viral pregenomic RNA

IMPORTANCE

The biogenesis and clinical application of serum HBV pgRNA have been a research hotspot in recent years. This study further characterized the heterogeneity of the 3' terminus of capsid RNA by utilizing a variety of experimental systems conditionally supporting HBV genome replication and secretion, and reveal that the 3' truncation of capsid pgRNA is catalyzed by cellular ribonuclease(s) and viral RNaseH at positions after and before 3' DR1, respectively, indicating the 3' DR1 as a boundary between the encapsidated portion of pgRNA for reverse transcription and the 3' unprotected terminus, which is independent of pgRNA length and the 3' terminal sequence. Thus, our study provides new insights into the mechanism of pgRNA encapsidation and reverse transcription, as well as the optimization of serum HBV RNA diagnostics.

Phytomedicines to Target Hepatitis B Virus DNA Replication: Current Limitations and Future Approaches

Hepatitis B virus infection (HBV) is one of the most common causes of hepatitis, and may lead to cirrhosis or hepatocellular carcinoma. According to the World Health Organization (WHO), approximately 296 million people worldwide are carriers of the hepatitis B virus. Various nucleos(t)ide analogs, which specifically suppress viral replication, are the main treatment agents for HBV infection. However, the development of drug-resistant HBV strains due to viral genomic mutations in genes encoding the polymerase protein is a major obstacle to HBV treatment. In addition, adverse effects can occur in patients treated with nucleos(t)ide analogs. Thus, alternative anti-HBV drugs of plant origin are being investigated as they exhibit excellent safety profiles and have few or no side effects. In this study, phytomedicines/phytochemicals exerting significant inhibitory effects on HBV by interfering with its replication were reviewed based on different compound groups. In addition, the chemical structures of these compounds were developed. This will facilitate their commercial synthesis and further investigation of the molecular mechanisms underlying their effects. The limitations of compounds previously screened for their anti-HBV effect, as well as future approaches to anti-HBV research, have also been discussed.

The Functional and Antiviral Activity of Interferon Alpha-Inducible IFI6 Against Hepatitis B Virus Replication and Gene Expression

Hepatitis B virus is an enveloped DNA virus, that infects more than three hundred and sixty million people worldwide and leads to severe chronic liver diseases. Interferon-alpha inducible protein 6 (IFI6) is an IFN-stimulated gene (ISG) whose expression is highly regulated by the stimulation of type I IFN-alpha that restricts various kinds of virus infections by targeting different stages of the viral life cycle. This study aims to investigate the antiviral activity of IFI6 against HBV replication and gene expression. The IFI6 was highly induced by the stimulation of IFN-α in hepatoma cells. The overexpression of IFI6 inhibited while knockdown of IFI6 elevated replication and gene expression of HBV in HepG2 cells. Further study determined that IFI6 inhibited HBV replication by reducing EnhII/Cp of the HBV without affecting liver enriched transcription factors that have significant importance in regulating HBV enhancer activity. Furthermore, deletion mutation of EnhII/Cp and CHIP analysis revealed 100 bps (1715-1815 nt) putative sites involved in IFI6 mediated inhibition of HBV. Detailed analysis with EMSA demonstrated that 1715-1770 nt of EnhII/Cp was specifically involved in binding with IFI6 and restricted EnhII/Cp promoter activity. Moreover, IFI6 was localized mainly inside the nucleus to involve in the anti-HBV activity of IFI6. In vivo analysis based on the hydrodynamic injection of IFI6 expression plasmid along with HBV revealed significant inhibition of HBV DNA replication and gene expression. Overall, our results suggested a novel mechanism of IFI6 mediated HBV regulation that could develop potential therapeutics for efficient HBV infection treatment.

Curcumin and Photobiomodulation in Chronic Viral Hepatitis and Hepatocellular Carcinoma

Immune modulation is a very modern medical field for targeting viral infections. In the race to develop the best immune modulator against viruses, curcumin, as a natural product, is inexpensive, without side effects, and can stimulate very well certain areas of the human immune system. As a bright yellow component of turmeric spice, curcumin has been the subject of thousands of scientific and clinical studies in recent decades to prove its powerful antioxidant properties and anticancer effects. Curcumin has been shown to influence inter- and intracellular signaling pathways, with direct effects on gene expression of the antioxidant proteins and those that regulate the immunity. Experimental studies have shown that curcumin modulates several enzyme systems, reduces nitrosative stress, increases the antioxidant capacity, and decreases the lipid peroxidation, protecting against fatty liver pathogenesis and fibrotic changes. Hepatitis B virus (HBV) affects millions of people worldwide, having sometimes a dramatic evolution to chronic aggressive infection, cirrhosis, and hepatocellular carcinoma. All up-to-date treatments are limited, there is still a gap in the scientific knowledge, and a sterilization cure may not yet be possible with the removal of both covalently closed circular DNA (cccDNA) and the embedded HBV DNA. With a maximum light absorption at 420 nm, the cytotoxicity of curcumin as photosensitizer could be expanded by the intravenous blue laser blood irradiation (IVBLBI) or photobiomodulation in patients with chronic hepatitis B infection, Hepatitis B e-antigen (HBeAg)-positive, noncirrhotic, but nonresponsive to classical therapy. Photobiomodulation increases DNA repair by the biosynthesis of complex molecules with antioxidant properties, the outset of repairing enzyme systems and new phospholipids for regenerating the cell membranes. UltraBioavailable Curcumin and blue laser photobiomodulation could suppress the virus and control better the disease by reducing inflammation/fibrosis and stopping the progression of chronic hepatitis, reversing fibrosis, and diminishing the progression of cirrhosis, and decreasing the incidence of hepatocellular carcinoma. Photodynamic therapy with blue light and curcumin opens new avenues for the effective prevention and cure of chronic liver infections and hepatocellular carcinoma. Blue laser light and UltraBioavailable Curcumin could be a new valuable alternative for medical applications in chronic B viral hepatitis and hepatocarcinoma, saving millions of lives.

Characterization of the antiviral effects of REP 2139 on the HBV lifecycle in vitro

During hepatitis B virus (HBV) infection, HBV subviral particles (SVP) are produced in large excess in comparison to infectious virions and account for the major source of HBV surface antigen (HBsAg) in the blood. This abundant circulating HBsAg has been postulated to promote HBV chronicity by inducing immune exhaustion against HBsAg. Nucleic acid polymers (NAPs) such as REP 2139 display promising antiviral activity against both HBV and hepatitis Delta virus (HDV) in clinical trials. REP 2139 is accompanied by clearance of HBsAg from blood with concomitant reappearance of anti-HBsAg antibodies. To decipher the mechanism-of-action of NAPs, a recently developed cell-based assay in human HepG2.2.15 cells was used (Blanchet et al., 2019). This assay recapitulates the HBsAg secretion inhibition observed in treated patients. In the present study, we analysed the antiviral effect of REP 2139 on the HBV lifecycle. Importantly, we confirm here the potent inhibitory activity of the compound on HBsAg secretion, and report minor or no effect on other viral markers such as intracellular DNA and RNA, and HBeAg or Dane particle secretion. Notably, intracellular HBsAg accumulation is prevented by proteasomal and lysosomal degradation.

Presence of Precore (C)/C Promoter Mutants in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B (CHB) Carriers During Pregnancy Does Not Correlate with Increased Risk of Liver Disease in 4 Years of Follow-Up

PURPOSE

HBV precore (PC) and basal core promoter (BCP) mutants are associated with liver disease severity, yet have been suggested to protect against HBV vertical transmission. HBV within peripheral blood mononuclear cells (PBMC) has been reported in association with intrauterine HBV infection. We analyzed HBV replication status in PBMC and PC/BCP mutants in PBMC from pregnant chronic hepatitis B (CHB) patients.

METHODS

Pregnant CHB carriers were assessed for HBeAg, HBV-DNA, ALT in second-third trimester and liver stiffness measurement (LSM) postpartum. HBV-DNA, HBV-cccDNA, and HBV-mRNA were tested in PBMC by in-house PCR. BCP/PC variants were determined by Sanger sequencing and analyzed using MEGA7.

RESULTS

In 37 CHB pregnant carriers, median age 32 years, 53% Asian, median ALT 19 versus 26 U/L, median HBV-DNA 2.6 versus 8.1 logIU/mL (untreated vs. treated), eight HBeAg⁺, with genotype 10%A, 29%B, 21%C, 10%D, 19%E, eight received tenofovir in pregnancy to reduce vertical transmission risk. HBV-DNA was detected in ~ 55% (25/45) PBMC, and PC/BCP mutations were found in 36% (9/25) and 4% (1/25), respectively. All infants received HBV immunoprophylaxis and tested HBV surface antigen negative at 9-12 months of age. During a median 4 years (IQR 3-5), follow-up all mothers showed normal LSM, with no significant change in ALT, HBeAg status, or HBV-DNA levels compared to baseline in untreated CHB carriers.

CONCLUSION

In this multiethnic cohort of pregnant CHB carriers, HBV replicative intermediates and PC/BCP mutants were found in significant proportion of PBMC, but were not associated with increased risk of HBV immunoprophylaxis failure or liver disease severity over long-term follow-up.

ATM and ATR Expression Potentiates HBV Replication and Contributes to Reactivation of HBV Infection upon DNA Damage

Chronic hepatitis B virus infection (CHB) caused by the hepatitis B virus (HBV) is one of the most common viral infections in the world. Reactivation of HBV infection is a life-threatening condition observed in patients with CHB receiving chemotherapy or other medications. Although HBV reactivation is commonly attributed to immune suppression, other factors have long been suspected to play a role, including intracellular signaling activated in response to DNA damage. We investigated the effects of DNA-damaging factors (doxorubicin and hydrogen peroxide) on HBV reactivation/replication and the consequent DNA-damage response. Dose-dependent activation of HBV replication was observed in response to doxorubicin and hydrogen peroxide which was associated with a marked elevation in the mRNA levels of ataxia-telangiectasia mutated (ATM) and ATM- and RAD3-related (ATR) kinases. Downregulation of ATM or ATR expression by shRNAs substantially reduced the levels of HBV RNAs and DNA. In contrast, transcriptional activation of ATM or ATR using CRISPRa significantly increased HBV replication. We conclude that ATM and ATR are essential for HBV replication. Furthermore, DNA damage leading to the activation of ATM and ATR transcription, results in the reactivation of HBV replication.

Inhibition of replication of hepatitis B virus using transcriptional repressors that target the viral DNA

BACKGROUND

Chronic infection with hepatitis B virus (HBV) is a serious global health problem. Persistence of the virus occurs as a result of stability of the replication intermediate comprising covalently closed circular DNA (cccDNA). Development of drugs that are capable of disabling this cccDNA is vital.

METHODS

To investigate an epigenetic approach to inactivating viral DNA, we engineered transcriptional repressors that comprise an HBV DNA-binding domain of transcription activator like effectors (TALEs) and a fused Krüppel Associated Box (KRAB). These repressor TALEs (rTALEs) targeted the viral surface open reading frame and were placed under transcription control of constitutively active or liver-specific promoters.

RESULTS

Evaluation in cultured cells and following hydrodynamic injection of mice revealed that the rTALEs significantly inhibited production of markers of HBV replication without evidence of hepatotoxicity. Increased methylation of HBV DNA at CpG island II showed that the rTALEs caused intended epigenetic modification.

CONCLUSIONS

Epigenetic modification of HBV DNA is a new and effective means of inactivating the virus in vivo. The approach has therapeutic potential and avoids potentially problematic unintended mutagenesis of gene editing.

Platelet count is associated with sustained virological response rates in treatments for chronic hepatitis C

BACKGROUND/AIMS

This study was conducted to clarify the sustained virological response (SVR) prediction ability of baseline and treatment-related factors in patients with chronic hepatitis C virus (HCV) infection.

METHODS

This retrospective study collected data at four tertiary referral hospitals between June 2004 and July 2012. Out of 476 patients, 330 treatment-naïve patients with chronic HCV infection were recruited. Pegylated interferon α-2a/- 2b plus ribavirin was administered for either 24 or 48 weeks depending on the HCV genotype. The baseline and treatment-related predictive factors of SVR were evaluated by analyzing data measured before treatment (i.e., baseline) and during treatment.

RESULTS

SVR rates for genotypes 1 and 2 were 63% (97/154) and 79.5% (140/176), respectively (p = 0.001). Multivariate analysis for baseline factors revealed that young age (p = 0.009), genotype 2 (p = 0.001), HCV RNA level of < 800,000 IU/mL (p < 0.001), and a baseline platelet count of > 150 × 103 /µL (p < 0.001) were significant SVR predictors, regardless of the genotype. In particular, predictive accuracy for achievement of SVR was 87.3% for a baseline platelet count of > 150 × 103 /µL. In multivariate analysis for treatment-related factors, SVR was associated with achievement of a rapid virological response (RVR; p < 0.001), treatment adherence of ≥ 80/80/80 (p < 0.001).

CONCLUSION

Young age, genotype 2, low HCV RNA level, RVR, and treatment adherence were significantly associated with SVR. In addition, platelet count was an independent predictive factor for SVR. Therefore, platelet count could be used to develop individualized treatment regimens and to optimize treatment outcomes in patients with chronic HCV infection.

Orthologous CRISPR/Cas9 systems for specific and efficient degradation of covalently closed circular DNA of hepatitis B virus

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the major cause of viral persistence and chronic hepatitis B. CRISPR/Cas9 nucleases can specifically target HBV cccDNA for decay, but off-target effects of nucleases in the human genome limit their clinical utility. CRISPR/Cas9 systems from four different species were co-expressed in cell lines with guide RNAs targeting conserved regions of the HBV genome. CRISPR/Cas9 systems from Streptococcus pyogenes (Sp) and Streptococcus thermophilus (St) targeting conserved regions of the HBV genome blocked HBV replication and, most importantly, resulted in degradation of over 90% of HBV cccDNA by 6 days post-transfection. Degradation of HBV cccDNA was impaired by inhibition of non-homologous end-joining pathway and resulted in an erroneous repair of HBV cccDNA. HBV cccDNA methylation also affected antiviral activity of CRISPR/Cas9. Single-nucleotide HBV genetic variants did not impact anti-HBV activity of St CRISPR/Cas9, suggesting its utility in targeting many HBV variants. However, two or more mismatches impaired or blocked CRISPR/Cas9 activity, indicating that host DNA will not likely be targeted. Deep sequencing revealed that Sp CRISPR/Cas9 induced off-target mutagenesis, whereas St CRISPR/Cas9 had no effect on the host genome. St CRISPR/Cas9 system represents the safest system with high anti-HBV activity.

BATF Interference Blocks Th17 Cell Differentiation and Inflammatory Response in Hepatitis B Virus Transgenic Mice

BACKGROUND

B cell-activating transcription factor (BATF) contributes to Th17 cell differentiation and pathological inflammatory responses.

AIMS

This study explored BATF as a regulator of Th17 differentiation in normal and hepatitis B virus (HBV) transgenic mice.

METHODS

Normal mice were divided into control, short hairpin RNA (shRNA) scramble, and shRNA BATF groups. HBV transgenic mice were divided into control, entecavir, shRNA scramble, entecavir + vector control, entecavir + shRNA scramble, shRNA BATF, and entecavir + shRNA BATF groups. Serum concentrations of AST, ALT, HBV-DNA, BATF, IL-17, and IL-22 and Th17 cell frequencies in the liver were compared among the groups. Correlations of serum HBV surface antigen (HBsAg), e-antigen (HBeAg), and core antigen (HBcAg) concentrations with BATF mRNA expression and the proportion of Th17 cells in the livers of HBV transgenic mice were also analyzed.

RESULTS

Serum AST, ALT, BATF, IL-17, and IL-22 concentrations and Th17 cell proportions were higher in HBV transgenic mice relative to normal controls. Positive correlations of the HBcAg concentration with BATF mRNA and the proportion of Th17 cells were observed in HBV transgenic mice. BATF interference reduced the proportion of Th17 cells and serum IL-17 and IL-22 concentrations and led to obvious downregulation of AST, ALT, BATF, IL-17, and IL-22 expression and a reduced proportion of Th17 cells when combined with entecavir.

CONCLUSION

HBV markedly upregulated BATF expression and promoted Th17 cell activation. By contrast, BATF interference significantly impeded the proliferation of Th17 cells and secretion of IL-17 and IL-22 while alleviating hepatic lesions.

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.

Hepatitis B Infection among Parturient Women in Peri-Urban Ghana

Global evidence suggests that hepatitis B viral (HBV) infection is endemic in Africa and perinatal transmission remains one of the most important modes of HBV transmission in this area. This cross-sectional survey examined the seroprevalence and knowledge of hepatitis B among pregnant women attending antenatal clinic (ANC) in a mission hospital in Ghana. Systematic sampling technique was used to recruit 196 pregnant women. The level of statistical significance was set at 0.05 alpha level. The hepatitis B prevalence estimate (hepatitis B surface antigen) was 10.2% (N = 20) and all of the participants were aware of HBV infection. Majority cited media (radio) as their main source of information. Approximately 86% of the participants (N = 168) associated HBV infection with a curse and 88.8% (N = 174) indicated witches and wizards as possible causes of the infection. Those with higher level of school education had high hepatitis B knowledge score (P < 0.01). Implementation of a health education program on the route of hepatitis B transmission is required in the study setting. Also, inclusion of hepatitis B education as part of ANC activities will enable HBV-positive pregnant women to appreciate the need for hepatitis B vaccination of their newborns at birth.

Trends in hepatitis B virus resistance to nucleoside/nucleotide analogues in North China from 2009-2016: A retrospective study

Nucleos(t)ide analogues (NAs) are widely used in anti-hepatitis B virus (anti-HBV) therapy for effective inhibition of HBV replication. However, HBV resistance to NAs has emerged, resulting in virus reactivation and disease recurrence. Data on the current dynamics of HBV resistance are still rare in China. This study analysed 4491 plasma samples with HBV primary genotypic resistance mutations representative of the general HBV resistance situation in northern China from 2009-2016. We found that entecavir (ETV), representing 57.6% (12 713/22 060) of NA users in North China in 2016, has become the major NA for treating Chinese patients infected with HBV. Despite >50% of M204I/V±L180M among all HBV resistance cases annually and extensive exposure of patients to lamivudine (LAM), telbivudine (LdT) and adefovir dipivoxil (ADV), ETV resistance also showed a dramatically increased incidence, which rose to 17.1% in 2016. Moreover, A181T/V, ETV resistance mutations and multidrug resistance mutations were found more frequently in HBV genotype C compared with genotype B (21.2% vs. 8.5%, 12.4% vs. 7.9% and 5.9% vs. 3.0%, respectively), whereas M204I and N236T were more predominant in genotype B than genotype C (40.3% vs. 20.8% and 11.3% vs. 1.8%, respectively). In conclusion, we report the dynamic changes of HBV NA resistance mutation patterns and the current NA usage profile for anti-HBV treatment in North China over the past 8 years. These data provide valuable information on HBV NA resistance that is an important reference for clinicians to devise more effective treatment regimens for individual patients.

Pre-S2 Start Codon Mutation of Hepatitis B Virus Subgenotype B3 Effects on NF-κB Expression and Activation in Huh7 Cell Lines

A cross-sectional study on hepatitis B patients in Indonesia showed association of pre-S2 start codon mutation (M120 V) with cirrhosis and hepatocellular carcinoma (HCC), which was dissimilar from studies from other populations where pre-S2 deletion mutation was more prevalent. Different mutation patterns were attributed to different hepatitis B virus (HBV) subgenotypes in each population study. HBV surface proteins are reported to induce the activation of NF-κB, a transcriptional factor known to play an important role in the development of liver disease. This study aimed to see the effects of HBs variants in HBV subgenotype B3 on the expression and activation of NF-κB as one of the mechanisms in inducing advanced liver disease. HBV subgenotypes B3, each carrying wild-type (wt) HBs, M120 V, and pre-S2 deletion mutation were isolated from three HCC patients. HBs genes were amplified and cloned into pcDNA3.1 and were transfected using Lipofectamine into a Huh7 cell line. NF-κB activation was measured through IκB-α expression, which is regulated by NF-κB. RNA expressions for HBs, IκB-α, and NF-κB subunit (p50) were evaluated using real-time PCR. M120 V mutant had a significantly higher mRNA level compared with wt and pre-S2 deletion mutant; however, there were no significant differences in HBs protein expressions. The transcription level of p50 was higher in M120 V mutation compared with HBs wild-type and pre-S2 deletion mutant. NF-κB activation was higher in HBs wild-type compared with the two mutant variants. Pre-S2 mutations had no effect on the increment of NF-κB activation. However, M120 V mutation may utilize a different pathway in liver disease progression that involves high expression of NF-κB subunit, p50.

Discovery of Oxime Ethers as Hepatitis B Virus (HBV) Inhibitors by Docking, Screening and In Vitro Investigation

A series of oxime ethers with C₆-C₄ fragment was designed and virtually bioactively screened by docking with a target, then provided by a Friedel–Crafts reaction, esterification (or amidation), and oximation from p-substituted phenyl derivatives (Methylbenzene, Methoxybenzene, Chlorobenzene). Anti-hepatitis B virus (HBV) activities of all synthesized compounds were evaluated with HepG2.2.15 cells in vitro. Results showed that most of compounds exhibited low cytotoxicity on HepG2.2.15 cells and significant inhibition on the secretion of HBsAg and HBeAg. Among them, compound 5c-1 showed the most potent activity on inhibiting HBsAg secretion (IC₅₀ = 39.93 μM, SI = 28.51). Results of the bioactive screening showed that stronger the compounds bound to target human leukocyte antigen A protein in docking, the more active they were in anti-HBV activities in vitro.

Relationship between PK2 and number of Kupffer cells during the progression of liver fibrosis in patients with HBV

Background/aim: This study aimed to investigate the potential regulatory role of prokineticin 2 (PK2) in modulation of the number and function of Kupffer cells (KCs) during the progression of liver fibrosis in patients with hepatitis B virus (HBV). Materials and methods: We obtained liver tissue sections from 200 patients with HBV undergoing surgical resection in our hospital between January 2013 and July 2016. Of these 200 tissue sections, 150 were fibrosis tissues and 50 were hepatocellular carcinoma tissues. Immunohistochemical evaluations were performed to assess the expression levels of CD68 and PK2 in the sections. The clinical parameters of these 200 patients were also analyzed. Results: As a potential cytokine, PK2 was commonly expressed in KCs. In addition, a close correlation between PK2 and the number of KCs during the progression of liver fibrosis in patients with HBV was found in this study. Conclusion: PK2 is expressed in KCs and participates in the progression of liver fibrosis after HBV infection. As a potential cytokine, PK2 modulates the number of KCs during fibrosis. Thus, PK2 most likely adjusts the number of M1 cells to modulate the role of KCs in the progression of liver fibrosis after HBV infection.

Advances with using CRISPR/Cas-mediated gene editing to treat infections with hepatitis B virus and hepatitis C virus

Chronic infections with hepatitis B and hepatitis C viruses (HBV and HCV) account for the majority of cases of cirrhosis and hepatocellular carcinoma. Current therapies for the infections have limitations and improved efficacy is necessary to prevent complications in carriers of the viruses. In the case of HBV persistence, the replication intermediate comprising covalently closed circular DNA (cccDNA) is particularly problematic. Licensed therapies have little effect on cccDNA and HBV replication relapses following treatment withdrawal. Disabling cccDNA is thus key to curing HBV infections and application of gene editing technology, such as harnessing the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system, has curative potential. Several studies have reported good efficacy when employing CRISPR/Cas technologies to disable HBV replication in cultured cells and in hydrodynamically injected mice. Recent advances with HCV drug development have revolutionized treatment of the infection. Nevertheless, individuals may be refractory to treatment. Targeting RNA from HCV with CRISPR/Cas isolated from Francisella novicida may have therapeutic utility. Although preclinical work shows that CRISPR/Cas technology has potential to overcome infection with HBV and HCV, significant challenges need to be met. Ensuring specificity for viral targets and efficient delivery of the gene editing sequences to virus-infected cells are particularly important. The field is at an interesting stage and the future of curative antiviral drug regimens, particularly for treatment of chronic HBV infection, may well entail use of combinations that include derivatives of CRISPR/Cas.

The potential and challenges of CRISPR-Cas in eradication of hepatitis B virus covalently closed circular DNA

Current antiviral therapy fails to cure chronic hepatitis B virus (HBV) infection, primarily because of the persistence of covalently closed circular DNA (cccDNA). Although nucleos(t)ide analogues (NAs) can inhibit the reverse transcriptase of HBV and suppress its replication to levels below the detection limit, viremia often rebounds after cessation of therapy. Nuclear cccDNA serves as the HBV replicative template and exhibits extraordinary stability, and is not affected by NAs. Therefore, curing chronic hepatitis B (CHB) requires novel therapy for purging cccDNA from patients. The CRISPR/Cas9 system is a newly developed programmable genome-editing tool and allows for sequence-specific cleavage of DNA. Compared to other genome-editing tools, the CRIPSR/Cas9 system is advantageous for its simplicity and flexibility of design. Theoretically, Cas9 can be redirected to specifically cleave any desired genome sequences simply by designing guide RNAs with about 20 nucleotides that match the particular sequences of genomes with downstream protospacer adjacent motifs. Recently, it has been demonstrated that the CRIPSR/Cas9 system can specifically destruct HBV genomes in vitro and in vivo. Although promising, the CRISPR/Cas9 system faces several challenges that need to be overcome for the clinical application, namely, off-target cleavage and the in vivo delivery efficiency. Cutting integrated HBV genomes by CRISPR/Cas9 also raises serious concern because this has the risk of genome instability. In summary, the CRISPR/Cas9 system bears the potential for curing CHB as long as several challenging issues can be successfully solved.

A new hepatitis B virus e antigen-negative strain gene used as a reference sequence in an animal model

Infection with hepatitis B virus (HBV) e-antigen (HBeAg)-negative strains is increasingly prevalent. Currently, detailed information of the obtained natural HBV strain is not available except for the B genotype and HBeAg-negative. The aim of the present study was to characterize the natural genetic variation of the HBeAg-negative strain and investigate its function. The genic sequence was determined using Sanger sequencing, and compared to related sequences using alignment and phylogenetic analysis. In vivo, virus-specific serum markers were investigated in CBA/CaJ mice. The sequence had a full genome length of 3215 nucleotides. Sites 122, 125, 127, and 160 in S regions were identified as lysine, threonine, proline, and lysine respectively. The main four point variants including A1762T, G1764A, G1896A, and G1899A were detected in the full-length genome. The genotype of the sequence was B, with sub-genotype B2 and serological subtype adw2. The characterize of the natural genetic variation strain showed no reported drug-resistant variant in P region and no reported immune escape site in S region. The strain will increase viral replication and infection for mutations A1762T and G1764A in the basal core promoter region, and mutations G1896A and G1899A in the pre-core region. The G1896A variant resulted in a premature stop codon and abolished HBeAg expression. HBsAg persisted for 26 weeks and HBeAg was still negative in CBA/CaJ mice. The present sequence is representative of the HBeAg-negative genome and may serve as a valuable reference for studying HBeAg-negative strains. The present findings were successfully verified in CBA/CaJ mice, demonstrating good applicability of the sequence.

IFNA2 p.Ala120Thr impairs the inhibitory activity of Interferon-α2 against the hepatitis B virus through altering its binding to the receptor

BACKGROUND

Our previous study found that a rare genetic mutation IFNA2p.Ala120Thr affects the structure of IFN-α2 and contributes to increased host susceptibility to CHB. However, the way in which the single amino acid residue mutation affects IFN-α2 activity is unclear. The purpose of this research was to investigate the effects and mechanisms of IFNA2p.Ala120Thr on IFN-α2 activity.

METHODS

Plasmid transfection of BL-21 was used to construct both wild type IFNA2 (wt) and p.Ala120Thr IFNA2 (mut) proteins. The HepG2-NTCP model was established using a lentiviral vector (LV003). Anti-HBV activity of wt and mut were tested on HepG2-NTCP infected cells with HBV, through the detection of HBsAg and HBcAg using immunohistochemistry and by detecting HBV DNA with RT PCR. IF and Co-IP were performed in order to investigate the binding of the IFNA2 protein and its receptor. The changes in IFNAR density and signal molecule phosphorylation were measured with western blotting. We used qPCR to further explore anti-HBV protein expression including APOBEC3, MxA, OAS1, and PKR.

RESULTS

Cell model experiments confirmed that IFNA2p.Ala120Thr impairs anti-HBV activity of IFN-α2. Co-IP tests indicated that the binding of mut-IFNα to IFNR was weaker in the mut-treated group. IFNR density on the cells surface increased after treatment with wt-IFN-α2. Obvious differences in the STAT phosphorylation profiles were seen between the mut-treated and wt-treated groups. The expression of four main kinds of anti-HBV proteins induced by mut was higher in the HepG2-NTCP cells. Thus, IFNA2p.Ala120Thr affects anti-HBV activity of IFN-α2.

CONCLUSION

IFNA2p.Ala120Thr impairs the anti-HBV ability of IFN-a2, mainly by reducing its binding to the IFN receptor. Mut IFN-a2 has a very weak binding, barely inducing STAT phosphorylation, and induces the expression of only a low level of related anti-HBV ISG. This is quite different from the effects of wt IFN-a2, implying that modifying the key structural position of IFNa may lead to the modulation of targeted gene expression.

Viral-Associated GN: Hepatitis B and Other Viral Infections

By definition, viral-associated GN indicates the direct pathogenic relationship between active viral replication and the development of acute GN. This definition is in sharp contrast to the semantic label and pathophysiologic foundation behind postinfectious GN that uniquely develops only during a period of resolved and absent active infection. The primary example of postinfectious GN are the glomerular lesions described after a pharyngeal or cutaneous streptococcal infection and do not represent the clinical or immunologic pattern seen with viral-associated GN. Hepatitis B (HBV) is the most common chronic viral infection in the world affecting >400 million people which is more than double the prevalence of chronic HIV and hepatitis C carriers combined. In addition, 10%-20% of HBV patients may be coinfected with hepatitis C and 5%-10% will have coinfection with HIV. Being able to distinguish the different types of GN seen with each viral infection is essential for the practicing clinician as each virus requires its own specific antiviral therapy. HBV-induced immune complex disease with renal injury lies on one end of the spectrum of disorders that occurs after a prolonged chronic carrier state. On the opposite end of the spectrum are renal diseases that develop from acute or subacute viral infections. One important glomerular lesion in this category is the association of collapsing FSGS with acute active cytomegalovirus, Epstein-Barr virus, and parvovirus B19 infection. The data supporting or disproving this relationship for each of these viruses will be discussed. A second renal manifestation of acute viral infections often occurs with many different sporadic or epidemic infections such as dengue and hantavirus and can lead to a transient proliferative GN that resolves upon viral clearance. The complex interplay of HBV and all viruses with the immune system provides conceptual lessons on the pathophysiology of immune complex GN that can be applied to all infection-related renal disease and plays an integral role in developing an approach to therapeutic intervention.

Establishment of a human hepatocellular cell line capable of maintaining long-term replication of hepatitis B virus

Hepatitis B virus (HBV) is a virus whose replication cycle cannot be completely reproduced using cultured cell lines. Here, we report an engineered cell line capable of supporting the complete HBV life cycle. We generated HepG2 cells over-expressing the HBV entry receptor human NTCP (sodium taurocholate cotransporting polypeptide), and defective in RIG-I (retinoic acid-inducible gene-I)-like receptor signaling, by knocking down the IPS-1 (IFNβ-promoter stimulator-1) adaptor molecule. The resultant NtG20.i7 cells were susceptible to HBV, and its replication was detectable at 14 days post-infection and persisted for at least 35 days with a gradual increase of HBV core expression. The cells produced infectious HBV in the culture supernatant, and the addition of preS1 peptide myr47-WT, which blocks HBV entry, impaired the persistence of the infection. These findings suggest that the persistence of the infection was maintained by continuous release of infectious HBV virions and their re-infection. This system is useful for expanding our basic understanding of the HBV replication cycle and for screening of anti-HBV chemicals.

Hepatitis B and D viruses replication interference: Influence of hepatitis B genotype

AIM: To study the hepatitis B virus (HBV) and hepatitis D virus (HDV) replication interferences in patients with chronic hepatitis delta infected with different HBV genotypes.

METHODS: We conducted a transversal study including 68 chronic hepatitis delta (CHD) (37 HIV-positive) patients and a control group of 49 chronic hepatitis B (CHB) (22 HIV-positive) patients. In addition, a dynamic follow-up was performed in 16 CHD patients. In all the samples, the surface antigen of hepatitis B (HBsAg) serum titers were analyzed with the Monolisa HBsAg Ultra system (Bio-Rad), using as quantification standard a serial dilution curve of an international HBsAg standard. Serum HBV-DNA titers were analyzed using the Roche Cobas TaqMan (Roche, Barcelona, Spain), and the serum HDV-RNA using an in-house real-time qRT-PCR method, with TaqMan probes. HBV genotype was determined with the line immunoassay LiPA HBV genotyping system (Innogenetics, Ghent, Belgium). In those patients negative for LiPA assay, a nested PCR method of complete HBsAg coding region, followed by sequence analysis was applied.

RESULTS: No differences in the HBV-DNA levels were found in CHB patients infected with different HBV genotypes. However, in CHD patients the HBV-DNA levels were lower in those infected with HBV-A than in those with HBV-D, both in HIV negative [median (IQR): 1.25 (1.00-1.35) vs 2.95 (2.07-3.93) log₁₀ (copies/mL), P = 0.013] and HIV positive patients [2.63 (1.24-2.69) vs 7.25 (4.61-7.55) log₁₀ (copies/mL), P < 0.001]. This was confirmed in the dynamic study of the HBV/HDV patients. These differences induce an under-estimation of HBV-A incidence in patients with CHD analyzed with LiPA assay. Finally, the HBsAg titers reflected no significant differences in CHD patients infected with HBV-A or D.

CONCLUSION: Viral replication interference between HBV and HDV is HBV-genotype dependent, and more evident in patients infected with HBV-genotype A, than with HBV-D or E.

Stable Human Hepatoma Cell Lines for Efficient Regulated Expression of Nucleoside/Nucleotide Analog Resistant and Vaccine Escape Hepatitis B Virus Variants and Woolly Monkey Hepatitis B Virus

Hepatitis B virus (HBV) causes acute and chronic hepatitis B (CHB). Due to its error-prone replication via reverse transcription, HBV can rapidly evolve variants that escape vaccination and/or become resistant to CHB treatment with nucleoside/nucleotide analogs (NAs). This is particularly problematic for the first generation NAs lamivudine and adefovir. Though now superseded by more potent NAs, both are still widely used. Furthermore, resistance against the older NAs can contribute to cross-resistance against more advanced NAs. For lack of feasible HBV infection systems, the biology of such variants is not well understood. From the recent discovery of Na⁺-taurocholate cotransporting polypeptide (NTCP) as an HBV receptor new in vitro infection systems are emerging, yet access to the required large amounts of virions, in particular variants, remains a limiting factor. Stably HBV producing cell lines address both issues by allowing to study intracellular viral replication and as a permanent source of defined virions. Accordingly, we generated a panel of new tetracycline regulated TetOFF HepG2 hepatoma cell lines which produce six lamivudine and adefovir resistance-associated and two vaccine escape variants of HBV as well as the model virus woolly monkey HBV (WMHBV). The cell line-borne viruses reproduced the expected NA resistance profiles and all were equally sensitive against a non-NA drug. The new cell lines should be valuable to investigate under standardized conditions HBV resistance and cross-resistance. With titers of secreted virions reaching >3x10⁷ viral genome equivalents per ml they should also facilitate exploitation of the new in vitro infection systems.

Management of hepatitis B virus infection after liver transplantation

Chronic hepatitis B virus (HBV) infection is responsible for up to 30% of cases of liver cirrhosis and up to 53% of cases of hepatocellular carcinoma. Liver transplantation (LT) is the best therapeutic option for patients with end-stage liver failure caused by HBV. The success of transplantation, though, depends on receiving prophylactic treatment against post-transplant viral reactivation. In the absence of prophylaxis, liver transplantation due to chronic hepatitis B (CHB) is associated with high rates of viral recurrence and poor survival. The introduction of treatment with hepatitis B immunoglobulins (HBIG) during the 1990s and later the incorporation of oral antiviral drugs have improved the prognosis of these patients. Thus, LT for CHB is now a universally accepted option, with an estimated 5 years survival of around 85% vs the 45% survival seen prior to the introduction of HBIG. The combination of lamivudine plus HBIG has for many years been the most widely used prophylactic regimen. However, with the appearance of new more potent oral antiviral agents associated with less resistance (e.g., entecavir and tenofovir) for the treatment of CHB, new prophylactic strategies are being designed, either in combination with HBIG or alone as a monotherapy. These advances have allowed for more personalized prophylaxis based on the individual risk profile of a given patient. In addition, the small pool of donors has required the use of anti-HBc-positive donors (with the resulting possibility of transmitting HBV from these organs), which has been made possible by suitable prophylactic regimens.

Application of nucleoside analogues to liver transplant recipients with hepatitis B

Hepatitis B is a common yet serious infectious disease of the liver, affecting millions of people worldwide. Liver transplantation is the only possible treatment for those who advance to end-stage liver disease. Donors positive for hepatitis B virus (HBV) core antibody (HBcAb) have previously been considered unsuitable for transplants. However, those who test negative for the more serious hepatitis B surface antigen can now be used as liver donors, thereby reducing organ shortages. Remarkable improvements have been made in the treatment against HBV, most notably with the development of nucleoside analogues (NAs), which markedly lessen cirrhosis and reduce post-transplantation HBV recurrence. However, HBV recurrence still occurs in many patients following liver transplantation due to the development of drug resistance and poor compliance with therapy. Optimized prophylactic treatment with appropriate NA usage is crucial prior to liver transplantation, and undetectable HBV DNA at the time of transplantation should be achieved. NA-based and hepatitis B immune globulin-based treatment regimens can differ between patients depending on the patients’ condition, virus status, and presence of drug resistance. This review focuses on the current progress in applying NAs during the perioperative period of liver transplantation and the prophylactic strategies using NAs to prevent de novo HBV infection in recipients of HBcAb-positive liver grafts.

Dual gRNAs guided CRISPR/Cas9 system inhibits hepatitis B virus replication

AIM

To screen and investigate the effective gRNAs against hepatitis B virus (HBV) of genotypes A-D.

METHODS

A total of 15 gRNAs against HBV of genotypes A-D were designed. Eleven combinations of two above gRNAs (dual-gRNAs) covering the regulatory region of HBV were chosen. The efficiency of each gRNA and 11 dual-gRNAs on the suppression of HBV (genotypes A-D) replication was examined by the measurement of HBV surface antigen (HBsAg) or e antigen (HBeAg) in the culture supernatant. The destruction of HBV-expressing vector was examined in HuH7 cells co-transfected with dual-gRNAs and HBV-expressing vector using polymerase chain reaction (PCR) and sequencing method, and the destruction of cccDNA was examined in HepAD38 cells using KCl precipitation, plasmid-safe ATP-dependent DNase (PSAD) digestion, rolling circle amplification and quantitative PCR combined method. The cytotoxicity of these gRNAs was assessed by a mitochondrial tetrazolium assay.

RESULTS

All of gRNAs could significantly reduce HBsAg or HBeAg production in the culture supernatant, which was dependent on the region in which gRNA against. All of dual gRNAs could efficiently suppress HBsAg and/or HBeAg production for HBV of genotypes A-D, and the efficacy of dual gRNAs in suppressing HBsAg and/or HBeAg production was significantly increased when compared to the single gRNA used alone. Furthermore, by PCR direct sequencing we confirmed that these dual gRNAs could specifically destroy HBV expressing template by removing the fragment between the cleavage sites of the two used gRNAs. Most importantly, gRNA-5 and gRNA-12 combination not only could efficiently suppressing HBsAg and/or HBeAg production, but also destroy the cccDNA reservoirs in HepAD38 cells.

CONCLUSION

These results suggested that CRISPR/Cas9 system could efficiently destroy HBV expressing templates (genotypes A-D) without apparent cytotoxicity. It may be a potential approach for eradication of persistent HBV cccDNA in chronic HBV infection patients.

Management of hepatitis B virus infection during treatment for hepatitis B virus-related hepatocellular carcinoma

Although liver resection is considered the most effective treatment for hepatocellular carcinoma (HCC), treatment outcomes are unsatisfactory because of the high rate of HCC recurrence. Since we reported hepatitis B e-antigen positivity and high serum hepatitis B virus (HBV) DNA concentrations are strong risk factors for HCC recurrence after curative resection of HBV-related HCC in the early 2000s, many investigators have demonstrated the effects of viral status on HCC recurrence and post-treatment outcomes. These findings suggest controlling viral status is important to prevent HCC recurrence and improve survival after curative treatment for HBV-related HCC. Antiviral therapy after curative treatment aims to improve prognosis by preventing HCC recurrence and maintaining liver function. Therapy with interferon and nucleos(t)ide analogs may be useful for preventing HCC recurrence and improving overall survival in patients who have undergone curative resection for HBV-related HCC. In addition, reactivation of viral replication can occur after liver resection for HBV-related HCC. Antiviral therapy can be recommended for patients to prevent HBV reactivation. Nevertheless, further studies are required to establish treatment guidelines for patients with HBV-related HCC.

Hepatitis B virus and microRNAs: Complex interactions affecting hepatitis B virus replication and hepatitis B virus-associated diseases

Chronic infection with the hepatitis B virus (HBV) is the leading risk factor for the development of hepatocellular carcinoma (HCC). With nearly 750000 deaths yearly, hepatocellular carcinoma is the second highest cause of cancer-related death in the world. Unfortunately, the molecular mechanisms that contribute to the development of HBV-associated HCC remain incompletely understood. Recently, microRNAs (miRNAs), a family of small non-coding RNAs that play a role primarily in post-transcriptional gene regulation, have been recognized as important regulators of cellular homeostasis, and altered regulation of miRNA expression has been suggested to play a significant role in virus-associated diseases and the development of many cancers. With this in mind, many groups have begun to investigate the relationship between miRNAs and HBV replication and HBV-associated disease. Multiple findings suggest that some miRNAs, such as miR-122, and miR-125 and miR-199 family members, are playing a role in HBV replication and HBV-associated disease, including the development of HBV-associated HCC. In this review, we discuss the current state of our understanding of the relationship between HBV and miRNAs, including how HBV affects cellular miRNAs, how these miRNAs impact HBV replication, and the relationship between HBV-mediated miRNA regulation and HCC development. We also address the impact of challenges in studying HBV, such as the lack of an effective model system for infectivity and a reliance on transformed cell lines, on our understanding of the relationship between HBV and miRNAs, and propose potential applications of miRNA-related techniques that could enhance our understanding of the role miRNAs play in HBV replication and HBV-associated disease, ultimately leading to new therapeutic options and improved patient outcomes.

Novel therapeutic approaches for hepatitis B virus covalently closed circular DNA

Hepatitis B virus (HBV) infection is a major global health problem. Although current therapies, such as the use of nucleos(t)ide analogs, inhibit HBV replication efficiently, they do not eliminate covalently closed circular DNA (cccDNA), which persists in hepatocyte nuclei. As HBV cccDNA is a viral transcription template, novel therapeutic approaches to directly target HBV cccDNA are necessary to completely eradicate persistent HBV infections. HBV cccDNA levels in HBV-infected human liver cells are extremely low; thus, more reliable and simple measurement methods are needed to correctly monitor their levels during therapeutic treatment. Although reverse transcription-polymerase chain reaction or Southern blot procedures are currently used in research studies, these methods are not completely reliable and are also time-consuming and labor-intensive. Genome editing technologies, such as zinc finger nucleases, transcription activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system, which are designed to target specific DNA sequences, represent highly promising potential therapeutic tools. In particular, the CRISPR/Cas9 system is an easily customizable sequence-specific nuclease with high flexibility and may be the most feasible approach to target HBV cccDNA. Further research to develop easier, safer, and more effective protocols should be pursued.

Precore/basal core promoter mutants quantification throughout phases of hepatitis B virus infection by Simpleprobe

AIM: To investigate precore/basal core promoter (PC/BCP) mutants throughout hepatitis B virus (HBV) infection and to determine their relationship to hepatitis B early antigen (HBeAg) titers.

METHODS: We enrolled 191 patients in various stages of HBV infection at the Huashan Hospital and the Taizhou Municipal Hospital from 2010 to 2012. None of the patients received antiviral therapy. HBV DNA from serum, was quantified by real-time PCR. The HBV genotype was determined by direct sequencing of the S gene. We used the Simpleprobe ultrasensitive quantitative method to detect PC/BCP mutants in each patient. We compared the strain number, percentage, and the changes in PC/BCP mutants in different phases, and analyzed the relationship between PC/BCP mutants and HBeAg by multiple linear regression and logistic regression.

RESULTS: Patients with HBV infection (n = 191) were assigned to groups by phase: Immune tolerance (IT) = 55, Immune clearance (IC) = 67, Low-replicative (LR) = 49, and HBeAg-negative hepatitis (ENH) = 20. Of the patients (male, 112; female, 79) enrolled, 122 were HBeAg-positive and 69 were HBeAg-negative. The median age was 33 years (range: 18-78 years). PC and BCP mutation detection rates were 84.82% (162/191) and 96.86% (185/191), respectively. In five HBeAg-negative cases, we detected double mutation G1896A/G1899A. The logarithm value of PC mutant quantities (log₁₀ PC) significantly differed in IT, IC, and LR phases, as well as in the ENH phase (F = 49.350, P < 0.001). The logarithm value of BCP mutant quantities (log₁₀ BCP) also differed during the four phases (F = 25.530, P < 0.001). Log₁₀ PC and log₁₀ BCP values were high in the IT and IC phases, decreased in the LR phase, and increased in the ENH phase, although the absolute value at this point remained lower than that in the IT and IC phases. PC mutant quantity per total viral load (PC%) and BCP mutant quantity per total viral load (BCP%) differed between phases (F = 20.040, P < 0.001; F = 10.830, P < 0.001), with PC% and BCP% gradually increasing in successive phases. HBeAg titers negatively correlated with PC% (Spearman’s rho = -0.354, P < 0.001) and BCP% (Spearman’s rho = -0.395, P < 0.001). The negative correlation between PC% and HBeAg status was significant (B = -5.281, P = 0.001), but there was no such correlation between BCP% and HBeAg status (B = -0.523, P = 0.552).

CONCLUSION: PC/BCP mutants become predominant in a dynamic and continuous process. Log₁₀ PC, log₁₀ BCP, PC% and BCP% might be combined to evaluate disease progression. PC% determines HBeAg status.

Epigallocatechin-3-gallate opposes HBV-induced incomplete autophagy by enhancing lysosomal acidification, which is unfavorable for HBV replication

Epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, exhibits diverse beneficial properties, including antiviral activity. Autophagy is a cellular process that is involved in the degradation of long-lived proteins and damaged organelles. Recent evidence indicates that modulation of autophagy is a potential therapeutic strategy for various viral diseases. In the present study, we investigated the effect of EGCG on hepatitis B virus (HBV) replication and the possible involvement of autophagy in this process. Our results showed that HBV induced autophagosome formation, which was required for replication of itself. However, although EGCG efficiently inhibited HBV replication, it enhanced, but not inhibited, autophagosome formation in hepatoma cells. Further study showed that HBV induced an incomplete autophagy, while EGCG, similar to starvation, was able to induce a complete autophagic process, which appeared to be unfavorable for HBV replication. Furthermore, it was found that HBV induced an incomplete autophagy by impairing lysosomal acidification, while it lost this ability in the presence of EGCG. Taken together, these data demonstrated that EGCG treatment opposed HBV-induced incomplete autophagy via enhancing lysosomal acidification, which was unfavorable for HBV replication.

Antiviral therapies for hepatitis B virus-related hepatocellular carcinoma

Chronic hepatitis B virus (HBV) infection is a critical risk factor for the carcinogenesis and progression of hepatocellular carcinoma (HCC). It promotes HCC development by inducing liver fibrogenesis, genetic and epigenetic alterations, and the expression of active viral-coded proteins. Effective antiviral treatments inhibit the replication of HBV, reduce serum viral load and accelerate hepatitis B e antigen serum conversion. Timely initiation of antiviral treatment is not only essential for preventing the incidence of HCC in chronic hepatitis B patients, but also important for reducing HBV reactivation, improving liver function, reducing or delaying HCC recurrence, and prolonging overall survival of HBV-related HCC patients after curative and palliative therapies. The selection of antiviral drugs, monitoring of indicators such as HBV DNA and hepatitis B surface antigen, and timely rescue treatment when necessary, are essential in antiviral therapies for HBV-related HCC.

Pegylated-interferon alpha therapy for treatment-experienced chronic hepatitis B patients

Background

Studies are limited on pegylated interferon (Peg-IFN) therapy for chronic hepatitis B (CHB) patients who failed or relapsed on previous antiviral therapy.

Objectives

We aimed to investigate the effect of Peg-IFN therapy in treatment-experienced CHB patients.

Study Design

A total of 57 treatment-experienced CHB patients at two medical centers were enrolled. All of the patients were treated with Peg-IFN α-2a at 180 μg weekly for 24 or 48 weeks. The hepatitis B serological markers and viral loads were tested every 3 months until 1 year after stopping Peg-IFN therapy. The endpoints were HBV DNA <2000IU/mL, hepatitis B e antigen (HBeAg) seroconversion, and a hepatitis B surface antigen (HBsAg) loss at 12 months post-treatment.

Results

In HBeAg-positive patients, 25.0%, 29.2%, and 12.5% of the patients achieved HBeAg seroconversion, HBV DNA <2000 IU/mL and a combined response, respectively, at 12 months post-treatment. Prior IFN therapy, a high baseline ALT level, a low creatinine level, undetectable HBV DNA at 12 weeks and a decline in HBV DNA >2 log₁₀ IU/mL at 12 weeks of therapy were factors associated with treatment response. In HBeAg-negative patients, 9.1%, 15.2%, and 6.1% of the patients achieved undetectable HBV DNA, HBV DNA <2000 IU/mL, and an HBsAg loss, respectively, at 12 months post-treatment. No factor was significantly associated with the treatment response in the HBeAg-negative patients. The median HBsAg level declined from 3.4 to 2.6 log₁₀ IU/mL in all the patients, and the 5-year cumulative rate of the HBsAg loss was 9.8% in the HBeAg-negative patients. Overall, none of the patients prematurely discontinued the Peg-IFN therapy.

Conclusions

Peg-IFN re-treatment is effective for a proportion of HBeAg-positive treatment-experienced patients; it has limited efficacy for HBeAg-negative treatment-experienced patients. Peg-IFN might facilitate HBsAg loss in HBeAg-negative treatment-experienced patients.

Efficacy and safety of lamivudine or tenofovir plus intramuscular hepatitis B immunoglobulin in prevention of hepatitis B virus reinfection after liver transplant

OBJECTIVES

Hepatitis B immunoglobulin prophylaxis in combination with antiviral drugs is recommended for prevention of hepatitis B virus reinfection after liver transplant. However, there is no consensus on a standard prophylactic method, and controversy exists over the duration, dose, and route of administration. We conducted a prospective study to evaluate the safety and effectiveness of intramuscular hepatitis B immunoglobulin in combination with lamivudine and/or tenofovir and discontinuation of hepatitis B immunoglobulin after 1 year for prevention of hepatitis B virus reinfection.

MATERIALS AND METHODS

Patients with hepatitis Brelated liver cirrhosis who had undergone primary liver transplants were enrolled. The prophylactic protocol involved intraoperative intramuscular hepatitis B immunoglobulin at 10 000 IU, tapering to 5000 IU daily for the first 6 days, weekly for a month, every 2 weeks for the next month, and monthly for a year after liver transplant, in combination with antiviral drugs.

RESULTS

From January 2002 until March 2014, two hundred sixty-eight liver transplants were performed. Forty-four patients (16.4%) who underwent liver transplants due to hepatitis B-related liver failure were enrolled. Five patients had hepatocellular carcinoma; 20 had both hepatitis D and hepatitis B virus infection. The median age was 47 years (range, 26-59 y) with a median model for end stage liver disease score of 20. Thirty-three patients were men (76%). Sixty-one percent of patients were negative for hepatitis B virus DNA at the time of transplant. The median follow-up was 13.6 months (range, 0-142 mo). Only 1 patient (2.3%) experienced hepatitis B virus reinfection (at 44.7 months posttransplant), which was successfully treated with tenofovir. Five patients died (11.4%) during the follow-up from nonhepatitis B causes.

CONCLUSIONS

Intramuscular hepatitis B immunoglobulin in combination with lamivudine or tenofovir and discontinuation of hepatitis B immunoglobulin after 1 year posttransplant may provide safe and cost-effective protection against posttransplant hepatitis B reinfection.

Long-term virological outcome in chronic hepatitis B patients with a partial virological response to entecavir

BACKGROUND/AIMS

The clinical outcome of patients with a partial virological response (PVR) to entecavir (ETV), in particular nucloes(t)ide analogue (NA)-experienced patients, has not been thoroughly investigated. The aim of the present study was to assess long-term outcomes in NA-naive and NA-experienced chronic hepatitis B patients with a PVR to ETV.

METHODS

Chronic hepatitis B patients treated with ETV (0.5 mg/day) for at least 1 year were enrolled retrospectively. PVR was defined as a decrease in hepatitis B virus (HBV) DNA titer of more than 2 log10 IU/mL, yet with residual serum HBV DNA, as determined by real time-polymerase chain reaction, at week 48 of ETV therapy.

RESULTS

A total of 202 patients (127 NA-naive and 75 NA-experienced, male 70.8%, antigen positive 53.2%, baseline serum HBV DNA 6.2 ± 1.5 log10 IU/mL) were analyzed. Twenty-eight patients demonstrated a PVR. The PVR was associated with a high serum HBV DNA titer at baseline and at week 24. Virological response (< 60 IU/mL) was achieved in 46.2%, 61.5%, 77.6%, and 85% of patients with PVR at week 72, 96, 144, and 192, respectively. Resistance to antivirals developed in two NA-experienced patients. Failure of virological response (VR) in patients with PVR was associated with high levels of serum HBV DNA at week 48.

CONCLUSIONS

Patients with PVR to ETV had favorable long-term virological outcomes. The low serum level of HBV DNA (< 200 IU/mL) at week 48 was associated with subsequent development of a VR in patients with PVR to ETV.

Effect of adjuvant interferon therapy on hepatitis b/c virus-related hepatocellular carcinoma after curative therapy - meta-analysis

BACKGROUND

Hepatocellular carcinoma is the fifth most common malignant cancer in the world. Liver resection and local ablation are the most effective therapeutic approaches for most HCC patients. Recurrence after curative therapy is very common. Some studies reveal that IFNs have an effect on recurrence. While the opinion is disagreement.

OBJECTIVES

The aim of this meta-analysis was to evaluate whether interferon therapy could reduce the recurrence of patients of hepatitis B/C virus-related hepatocellular carcinoma after curative therapy.

MATERIAL AND METHODS

All randomized controlled trials about interferon on recurrence of hepatitis B/C virus-related hepatocellular carcinoma patients after curative surgery treatment were searched from PubMed, Embase, Cochrane library (all from 1977 to January 2014). Two reviewers independently assessed the quality of each included study and extracted data. RevMan 5.1 was used for meta-analysis.

RESULTS

Pooled data analysis revealed that the interferon group had no statistical significance on the recurrence of hepatitis-related hepatocellular carcinoma compared to the control group (RR=0.91, 95% CI, 0.82 to 1.00; p=0.11). While from the subgroup analysis of adjuvant interferon can reduce the recurrence of the median tumor size below 3 cm (RR 0.50, 95% CI 0.35-0.72; p=0.00002).

CONCLUSIONS

Adjuvant IFN after curative treatment of hepatitis-related HCC can improve the survival of HCC patients. In addition, IFN could decrease the recurrence rate of HCC patient with median tumor size below 3 cm but not exceeding 3 cm.

S-phase arrest after vincristine treatment may promote hepatitis B virus replication

AIM: To observe the effect of vincristine on hepatitis B virus (HBV) replication in vitro and to study its possible mechanisms.

METHODS: Vincristine was added to the cultures of two cell lines stably expressing HBV. Then, the levels of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B core antigen (HBcAg) in the supernatants or cytoplasm were examined using by enzyme-linked immunosorbent assay and Western blot. The HBV pregenome RNA (pgRNA) was detected using reverse transcription-PCR and real-time fluorescent quantitative PCR (RT-qPCR), and viral DNA was detected using Southern blot and RT-qPCR. Cell proliferation after drug treatment was detected using the BrdU incorporation test and the trypan blue exclusion assay. Cell cycle and cell apoptosis were examined using flow cytometry and Western blot.

RESULTS: Vincristine up-regulated HBV replication directly in vitro in a dose-dependent manner, and 24-h exposure to 0.1 μmol/L vincristine induced more than 4-fold and 3-fold increases in intracellular HBV DNA and the secretion of viral DNA, respectively. The expression of HBV pgRNA, intracellular HBsAg and HBcAg, and the secretion of HBeAg were also increased significantly after drug treatment. Most importantly, vincristine promoted the cell excretion of HBV nucleocapsids instead of HBV Dane particles, and the nucleocapsids are closely related to the HBV pathogenesis. Furthermore, vincristine inhibited the proliferation of cells stably expressing HBV. The higher the concentration of the drug, the more significant the inhibition of the cell proliferation and the stronger the HBV replication ability in cells. Flow cytometry indicated that cell cycle arrest at S-phase was responsible for the cell proliferation inhibition.

CONCLUSION: Vincristine has a strong stimulatory effect on HBV replication and induces cell cycle arrest, and cell proliferation inhibition may be conducive to viral replication.

Recent advances in micro/nanotechnologies for global control of hepatitis B infection

The control of hepatitis B virus (HBV) infection is a challenging task, specifically in developing countries there is limited access to diagnostics and antiviral treatment mainly due to high costs and insufficient healthcare infrastructure. Although the current diagnostic technologies can reliably detect HBV, they are relatively laborious, impractical and require expensive resources that are not suitable for resource-limited settings. Advances in micro/nanotechnology are pioneering the development of new generation methodologies in diagnosis and screening of HBV. Owing to combination of nanomaterials (metal/inorganic nanoparticles, carbon nanotubes, etc.) with microfabrication technologies, utilization of miniaturized sensors detecting HBV and other viruses from ultra-low volume of blood, serum and plasma is realized. The state-of-the-art microfluidic devices with integrated nanotechnologies potentially allow for inexpensive HBV screening at low cost. This review aims to highlight recent advances in nanotechnology and microfabrication processes that are employed for developing point-of-care (POC) HBV assays.

Targeted in vivo delivery of siRNA and an endosome-releasing agent to hepatocytes

The discoveries of RNA interference (RNAi) and short interfering RNAs (siRNAs) have provided the opportunity to treat diseases in a fundamentally new way: by co-opting a natural process to inhibit gene expression at the mRNA level. Given that siRNAs must interact with the cells' natural RNAi machinery in order to exert their silencing effect, one of the most fundamental requirements for their use is efficient delivery to the desired cell type and, specifically, into the cytoplasm of those cells. Numerous research efforts involving the testing of a large number of delivery approaches using various carrier molecules and inventing several distinct formulation technologies during the past decade illustrate the difficulty and complexity of this task. We have developed synthetic polymer formulations for in vivo siRNA delivery named Dynamic PolyConjugates™ (DPCs) that are designed to mimic the features viruses possess for efficient delivery of their nucleic acids. These include small size, long half-life in circulation, capability of displaying distinct host cell tropism, efficient receptor binding and cell entry, disassembly in the endosome and subsequent release of the nucleic acid cargo to the cytoplasm. Here we present an example of this delivery platform composed of a hepatocyte-targeted endosome-releasing agent and a cholesterol-conjugated siRNA (chol-siRNA). This delivery platform forms the basis of ARC-520, an siRNA-based therapeutic for the treatment of chronic hepatitis B virus (HBV) infection. In this chapter, we provide a general overview of the steps in developing ARC-520 and detailed protocols for two critical stages of the discovery process: (1) verifying targeted in vivo delivery to hepatocytes and (2) evaluating in vivo drug efficacy using a mouse model of chronic HBV infection.

Immunopathogenesis of chronic hepatitis B

Chronic hepatitis B (CHB) is a widespread infectious disease with unfavorable outcomes and life-threatening consequences for patients, in spite of modern vaccination and antiviral treatment modalities. Cutting-edge experimental approaches have demonstrated key pathways that involve cross-talk between viral particles and host immune cells. All events, including penetration of hepatitis B virus (HBV) particles into host cells, establishing persistence, and chronization of CHB infection, and possibility of complete elimination of HBV particles are controlled by the immune system. Researchers have paid special attention to the replication capacity of HBV in host cells, which is associated with cellular changes that reflect presentation of viral antigens and variability of HBV antigen features. In addition, specific HBV proteins have an immune-modulating ability to initiate molecular mechanisms that “avoid” control by the immune system. The relationship between immunological shifts and chronic infection stages has been intensively studied since it was recognized that the immune system is a direct participant in the recurrent (cyclic) nature of CHB. Understanding the wide diversity of molecular pathways and the crosstalk between innate and adaptive immune system components will provide fresh insight into CHB immune pathogenesis and the possibilities of developing new treatment strategies for this disease.

Genotype F of hepatitis B: response to interferon

BACKGROUND

The relevance of HBV genotype diversity on interferon (IFN) therapy outcome in chronic hepatitis B patients has recently been highlighted. Data available for genotype F is poor. The aim of this work was to analyse the response of HBV genotype F to treatment with IFN. Additionally, response was analysed according to the role of single nucleotide polymorphisms (SNPs) near to the IL28B gene.

METHODS

A total of 29 HBeAg-positive patients with chronic infection were included with a median age 47 (18-68) years. Of them, 27 were male. One patient was treated with standard IFN-α for 16 weeks, 6 patients received PEG-IFN-α2a 180 μg weekly for 24 weeks and 22 patients for 48 weeks. Response to treatment was defined as loss of HBeAg, anti-HBe seroconversion and decline of HBV DNA level to below 3 log of baseline (IU/ml) at the 6-month of follow-up. The SNPs rs12979860, rs12980275 and rs8099917 were studied by PCR-RFLP.

RESULTS

The overall response was obtained in 18 (62%) patients, including one patient who was treated with standard IFN. Additionally, a total of 9 (31%) patients cleared HBsAg, with appearance of anti-HBs. The viral load was undetectable in all of these patients. The same IL28B variants associated with IFN response in HCV infections were also more frequently found in HBV patients compared with non-responders.

CONCLUSIONS

Our study indicates that treatment with IFN is effective in patients with HBV genotype F.

Control of hepatitis B virus replication by interferons and Toll-like receptor signaling pathways

Hepatitis B virus (HBV) infection is one of the major causes of liver diseases, affecting more than 350 million people worldwide. The interferon (IFN)-mediated innate immune responses could restrict HBV replication at the different steps of viral life cycle. Indeed, IFN-α has been successfully used for treatment of patients with chronic hepatitis B. However, the role of the innate immune response in HBV replication and the mechanism of the anti-HBV effect of IFN-α are not completely explored. In this review, we summarized the currently available knowledge about the IFN-mediated anti-HBV effect in the HBV life cycle and the possible effectors downstream the IFN signaling pathway. The antiviral effect of Toll-like receptors (TLRs) in HBV replication is briefly discussed. The strategies exploited by HBV to evade the IFN- and TLR-mediated antiviral actions are summarized.

Management of antiviral drug resistance in chronic hepatitis B

Rescue antiviral treatment for patients with resistance to preexisting nucleos(t)ide analogues remains a clinical challenge. The correct choice of a first-line treatment of high potency and with a high genetic barrier to achieve sustained long-term suppression of viral replication provides the best chance of preventing treatment failure and the emergence of drug resistance. The management of treatment failure and drug resistance requires a precise and accurate clinical and virologic monitoring. Combination treatment with antiviral drugs that belong to different groups is associated with a lower chance of developing resistance to rescue drugs. To guarantee better control of viral replication in patients with drug resistance, the addition of another drug without a cross resistance profile should be given as early as possible, preferably at the time when genotypic resistance emerges. Long-term surveillance for treatment efficacy and possible emergence of drug resistance should be continued to prevent the emergence of multidrug-resistant strains.

Prospects for inhibiting the post-transcriptional regulation of gene expression in hepatitis B virus

There is a continuing need for novel antivirals to treat hepatitis B virus (HBV) infection, as it remains a major health problem worldwide. Ideally new classes of antivirals would target multiple steps in the viral lifecycle. In this review, we consider the steps in which HBV RNAs are processed, exported from the nucleus and translated. These are often overlooked steps in the HBV life-cycle. HBV, like retroviruses, incorporates a number of unusual steps in these processes, which use a combination of viral and host cellular machinery. Some of these unusual steps deserve a closer scrutiny. They may provide alternative targets to existing antiviral therapies, which are associated with increasing drug resistance. The RNA post-transcriptional regulatory element identified 20 years ago promotes nucleocytoplasmic export of all unspliced HBV RNAs. There is evidence that inhibition of this step is part of the antiviral action of interferon. Similarly, the structured RNA epsilon element situated at the 5’ end of the polycistronic HBV pregenomic RNA also performs key roles during HBV replication. The pregenomic RNA, which is the template for translation of both the viral core and polymerase proteins, is also encapsidated and used in replication. This complex process, regulated at the epsilon element, also presents an attractive antiviral target. These RNA elements that mediate and regulate gene expression are highly conserved and could be targeted using novel strategies employing RNAi, miRNAs or aptamers. Such approaches targeting these functionally constrained genomic regions should avoid escape mutations. Therefore understanding these regulatory elements, along with providing potential targets, may also facilitate the development of other new classes of antiviral drugs.

HBeAg negative variants and their role in the natural history of chronic hepatitis B virus infection

Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.