Search Results (76)

Chronic infection with the hepatitis B virus (HBV) results in over 1 million deaths annually. Although currently licensed treatments, including pegylated interferon-α and nucleoside/nucleotide analogs, can inhibit viral replication, they rarely eradicate covalently closed circular DNA (cccDNA) reservoirs. Moreover, vaccination does not offer therapeutic benefit to already infected individuals or non-responders. Consequently, chronic infection is maintained by the persistence of cccDNA in infected hepatocytes. For this reason, novel therapeutic strategies that permanently inactivate cccDNA are a priority. Obligate heterodimeric transcription activator-like effector nucleases (TALENs) provide the precise gene-editing needed to disable cccDNA. To develop this strategy using a therapeutically relevant approach, TALEN-encoding mRNA targeting viral core and surface genes was synthesized using in vitro transcription with co-transcriptional capping. TALENs reduced hepatitis B surface antigen (HBsAg) by 80% in a liver-derived mammalian cell culture model of infection. In a stringent HBV transgenic murine model, a single dose of hepatotropic lipid nanoparticle-encapsulated TALEN mRNA lowered HBsAg by 63% and reduced viral particle equivalents by more than 99%, without evidence of toxicity. A surveyor assay demonstrated mean in vivo HBV DNA mutation rates of approximately 16% and 15% for Core and Surface TALENs, respectively. This study presents the first evidence of the therapeutic potential of TALEN-encoding mRNA to inactivate HBV replication permanently. Full article

Hepatitis B virus (HBV) specifically infects hepatocytes and has a complex life cycle owing to the stabilization and pooling of covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. We previously reported that the suppression of dedicator of cytokinesis 11 (DOCK11) decreases cccDNA and HBV-DNA levels and identified it as a new HBV therapeutic target. The DOCK11-associated gene, Wnt/β-catenin signaling regulator tankyrase (TNKS), was identified using in vitro methods; however, its function in the HBV life cycle remains unknown. Here, we used various inhibitors, antagonists, and short-hairpin RNA treatments related to TNKS signaling in HBV-infected hepatocytes. The role of TNKS-related Wnt/β-catenin signaling in the HBV life cycle was evaluated using immunoprecipitation assays with DOCK11 and bulk RNA sequencing methods. TNKS and Wnt/β-catenin signaling inhibitors significantly repressed cccDNA and HBV-DNA levels. Conversely, certain Wnt/β-catenin signaling agonists enhanced the HBV life cycle. DOCK11 directly binds to β-catenin to regulate HBV using its nuclear transport system. SKL2001, normally used as a Wnt/β-catenin signaling agonist, strongly reduced cccDNA in HBV-infected hepatocytes and in combination with entecavir predominantly eradicated HBV without cytotoxicity. Therefore, DOCK11 and other Wnt/β-catenin signaling molecules may be therapeutic targets to prevent persistent HBV infection. Full article

Background: Hepatitis B core-related antigen (HBcrAg), a novel serum biomarker reflecting the activity of intrahepatic covalently closed circular DNA (cccDNA), has generated conflicting evidence regarding its clinical utility for predicting post-antiviral therapy relapse in chronic hepatitis B (CHB) patients. Methods: We systematically analyzed 13 studies (15 cohorts, n = 1529 patients) from PubMed, Web of Science, Wanfang, and CNKI (through April 2025). A bivariate model evaluated HBcrAg’s predictive performance for relapse outcomes, including virological relapse, clinical relapse, and hepatitis flares. Results: HBcrAg demonstrated a pooled sensitivity of 0.81 (95% CI: 0.75–0.86) and specificity of 0.72 (95% CI: 0.67–0.76) for relapse prediction, with a diagnostic odds ratio of 10.66 (95% CI: 7.36–15.42) and summary AUC of 0.83 (95% CI: 0.80–0.86). Subgroup analysis identified threshold effects as the primary source of heterogeneity, which resolved (I² < 13%) after excluding studies with outlier cutoff values. Meta-regression established that HBcrAg’s predictive value was unaffected by age, sex, hepatitis B e antigen status, or detection methods (p > 0.05). Conclusions: HBcrAg is validated as a robust non-invasive biomarker to optimize treatment cessation strategies, with high sensitivity providing strong negative predictive value in CHB populations. Future research should prioritize multi-marker models to enhance prediction accuracy. Full article

Human viral infections remain a significant global health challenge, contributing to a substantial number of cancer cases worldwide. Among them, infections with oncoviruses such as hepatitis B virus (HBV) and hepatitis C virus (HCV) are key drivers of hepatocellular carcinoma (HCC). Despite the availability of an effective HBV vaccine since the 1980s, millions remain chronically infected due to the persistence of covalently closed circular DNA (cccDNA) as a reservoir in hepatocytes. Current antiviral therapies, including nucleos(t)ide analogs and interferon, effectively suppress viral replication but fail to eliminate cccDNA, underscoring the urgent need for innovative therapeutic strategies. Direct-acting antiviral agents (DAAs), which have revolutionized HCV treatment with high cure rates, offer a promising model for HBV therapy. A particularly attractive target is the intrinsically disordered region (IDR) of the HBx protein, which regulates cccDNA transcription, viral replication, and oncogenesis by interacting with key host proteins. DAAs targeting these interactions could inhibit viral persistence, suppress oncogenic signaling, and overcome treatment resistance. This review highlights the potential of HBx-directed DAAs to complement existing therapies, offering renewed hope for a functional HBV cure and reduced cancer risk. Full article

Hepatitis B virus (HBV) is an important global public health issue. The World Health Organization (WHO) 2024 Global Hepatitis Report estimated that the global prevalence of people living with HBV infection is 254 million, with an estimated prevalence incidence of 1.2 million new HBV infections yearly. Previous studies have shown that natural compounds have antiviral inhibition potentials. In silico methods such as molecular docking, virtual screening, pharmacophore modeling, quantitative structure–activity relationship (QSAR), and molecular dynamic simulations have been successfully applied in identifying bioactive compounds with strong binding energies in HBV treatment targets. The COVID-19 pandemic necessitated the importance of repurposing already approved drugs using in silico methods. This study is aimed at unveiling the benefits of in silico techniques as a potential alternative in natural compounds’ drug discovery and repurposing for HBV therapy. Relevant articles from PubMed, Google Scholar, and Web of Science were retrieved and analyzed. Furthermore, this study comprehensively reviewed the literature containing identified bioactive compounds with strong inhibition of essential HBV proteins. Notably, hesperidin, quercetin, kaempferol, myricetin, and flavonoids have shown strong binding energies for hepatitis B surface antigen (HBsAg). The investigation reveals that in silico drug discovery methods offer an understanding of the mechanisms of action, reveal previously overlooked viral targets (including PreS1 Domain of HBsAg and cccDNA (Covalently Closed Circular DNA) regulators, and facilitate the creation of specific inhibitors. The integration of in silico, in vitro, and in vivo techniques is essential for the discovery of new drugs for HBV therapy. The insights further highlight the importance of natural compounds and in silico methods as targets in drug discovery for HBV therapy. Moreover, the combination of natural compounds, an in silico approach, and drug repurposing improves the chances of personalized and precision medicine in HBV treatment. Therefore, we recommend drug repurposing strategies that combine in vitro, in vivo, and in silico approaches to facilitate the discovery of effective HBV drugs. Full article

Hepatitis B virus (HBV) is a major global health issue, with an estimated 254 million people living with chronic HBV infection worldwide as of 2022. Chronic HBV infection is the leading cause of cirrhosis and liver cancer. Current treatment with nucleos(t)ide analogs is effective in the suppression of viral activity but generally requires lifelong treatment. They fail to eradicate the HBV viral reservoir, called covalently closed circular DNA (cccDNA), which replicates in the nucleus of liver cells. The cccDNA serves as the sole template for viral replication, as it generates the pregenomic RNA (pgRNA) necessary for producing new viral genomes. This stable form of viral DNA can reactivate the virus when treatment is stopped. HBV cccDNA is therefore one of the main challenges in curing chronic HBV infections. By targeting steps such as cccDNA formation, capsid assembly, or particle secretion, researchers continue to seek ways to interfere with HBV replication and to reduce its persistence, ultimately to eradicate HBV as a global health problem. This review provides an overview of what is currently known about cccDNA formation and biogenesis and the ongoing efforts to target and eradicate it to cure chronic HBV infections. Full article

Hepatitis B virus (HBV) can cause chronic infections, significantly increasing the risk of death from cirrhosis and hepatocellular carcinoma (HCC). A key player in chronic HBV infection is covalently closed circular DNA (cccDNA), a stable episomal form of viral DNA that acts as a persistent reservoir in infected hepatocytes and drives continuous viral replication. Despite the development of several animal models, few adequately replicate cccDNA formation and maintenance, limiting our understanding of its dynamics and the evaluation of potential therapeutic interventions targeting cccDNA. In this study, we aimed to develop a mouse model to investigate cccDNA formation and maintenance. We infected C57BL/6 mice with recombinant adeno-associated virus (rAAV) carrying a 1.3-overlength HBV genome (genotype C) and collected liver tissue at various time points to assess cccDNA levels and viral replication. Our results demonstrated the successful establishment of a chronic hepatitis B mouse model using rAAV-HBV1.3, which supported persistent HBV infection with sustained cccDNA expression in hepatocytes. Serum levels of HBsAg and HBeAg were elevated for up to 12 weeks, while alanine transaminase (ALT) levels remained within the normal range, indicating limited liver damage during this period. We confirmed HBV DNA expression in hepatocytes, and importantly, cccDNA was detected using qPCR after Plasmid-Safe ATP-Dependent DNase treatment, which selectively removes non-cccDNA forms. Additionally, Southern blot analysis confirmed the presence of cccDNA isolated using the Hirt extraction method. This established model provides a valuable platform for studying the long-term maintenance of cccDNA in chronic HBV infection and offers an important tool for testing novel therapeutic strategies aimed at targeting cccDNA. Full article

Background: Despite an existing safe and effective vaccine for hepatitis B virus (HBV), it is still a major public health concern. Nowadays, several drugs are used to treat chronic hepatitis B; however, full healing remains controversial. The viral covalently closed circular DNA (cccDNA) formed by HBV forms a major challenge in its treatment, as does the ability of HBV to integrate itself into the host genome, which enables infection reactivation. Interfering RNA (RNAi) is a gene-silencing post-transcriptional mechanism which forms as a promising alternative to treat chronic hepatitis B. The aim of the present review is to assess the evolution of hepatitis B treatment approaches based on using RNA interference. Methods: Data published between 2016 and 2023 in scientific databases (PubMed, PMC, LILACS, and Bireme) were assessed. Results: In total, 76,949 articles were initially identified and quality-checked, and 226 eligible reports were analyzed in depth. The main genomic targets, delivery systems, and major HBV therapy innovations are discussed in this review. This review reinforces the therapeutic potential of RNAi and identifies the need for conducting further studies to fill the remaining gaps between bench and clinical practice. Full article

Cells have developed various mechanisms to counteract viral infections. In an evolutionary arms race, cells mobilize cellular restriction factors to fight off viruses, targeted by viral factors to facilitate their own replication. The hepatitis B virus (HBV) is a small dsDNA virus that causes acute and chronic infections of the liver. Its genome persists in the nuclei of infected hepatocytes as a covalently closed circular DNA (cccDNA) minichromosome, thus building up an episomal persistence reservoir. The chromosomal maintenance complex SMC5/6 acts as a restriction factor hindering cccDNA transcription, whereas the viral regulatory protein HBx targets SMC5/6 for proteasomal degradation, thus relieving transcriptional suppression of the HBV minichromosome. To date, no curative therapies are available for chronic HBV carriers. Knowledge of the factors regulating the cccDNA and the development of therapies involving silencing the minichromosome or specifically interfering with the HBx-SMC5/6 axis holds promise in achieving sustained viral control. Here, we summarize the current knowledge of the mechanism of SMC5/6-mediated HBV restriction. We also give an overview of SMC5/6 cellular functions and how this compares to the restriction of other DNA viruses. We further discuss the therapeutic potential of available and investigational drugs interfering with the HBx-SMC5/6 axis. Full article

Hepatitis B virus (HBV) infection remains a significant global health challenge, leading to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Covalently closed circular DNA (cccDNA) and integrated HBV DNA are pivotal in maintaining viral persistence. Recent advances in CRISPR/Cas technology offer innovative strategies to inhibit HBV by directly targeting both cccDNA and integrated HBV DNA or indirectly by degrading HBV RNAs or targeting host proteins. This review provides a comprehensive overview of the latest advancements in using CRISPR/Cas to inhibit HBV, with a special highlight on newer non-double-strand (non-DSB) break approaches. Beyond the canonical use of CRISPR/Cas for target inhibition, we discuss additional applications, including HBV diagnosis and developing models to understand cccDNA biology, highlighting the diverse use of this technology in the HBV field. Full article

Hepatitis B core-related antigen (HBcrAg) reflects the activity of intrahepatic covalently closed circular DNA. HBcrAg can be detected even in chronic hepatitis B patients in whom serum HBV DNA or hepatitis B surface antigen is undetectable. The HBcrAg measurement system was developed based on two concepts. One is a fully-automated and highly-sensitive HBcrAg assay (iTACT-HBcrAg) and the other is a point-of-care testing (POCT) that can be used in in resource-limited areas. iTACT-HBcrAg is an alternative to HBV DNA for monitoring HBV reactivation and predicting the development of hepatocellular carcinoma. This validated biomarker is available in routine clinical practice in Japan. Currently, international guidelines for the prevention of mother-to-child transmission recommend anti-HBV prophylaxis for pregnant women with high viral loads. However, over 95% of HBV-infected individuals live in countries where HBV DNA quantification is widely unavailable. Given this situation, a rapid and simple HBcrAg assay for POCT would be highly effective. Long-term anti-HBV therapy may have potential side effects and appropriate treatment should be provided to eligible patients. Therefore, a simple method of determining the indication for anti-HBV treatment would be ideal. This review provides up-to-date information regarding the clinical value of HBcrAg in HBV management, based on iTACT-HBcrAg or POCT. Full article

HBV infection is challenging to cure due to the persistence of viral covalently closed circular viral DNA (cccDNA). The dedicator of cytokinesis 11 (DOCK11) is recognized as a guanine nucleotide exchange factor (GEF) for CDC42 that has been reported to be required for HBV persistence. DOCK11 is expressed in both the cytoplasm and nucleus of human hepatocytes and is functionally associated with retrograde trafficking proteins Arf-GAP with GTPase domain, ankyrin repeat, and pleckstrin homology domain-containing protein 2 (AGAP2), and ADP-ribosylation factor 1 (ARF1), together with the HBV capsid, in the trans-Golgi network (TGN). This opens an alternative retrograde trafficking route for HBV from early endosomes (EEs) to the TGN and then to the endoplasmic reticulum (ER), thereby avoiding lysosomal degradation. DOCK11 also facilitates the association of cccDNA with H3K4me3 and RNA Pol II for activating cccDNA transcription. In addition, DOCK11 plays a crucial role in the host DNA repair system, being essential for cccDNA synthesis. This function can be inhibited by 10M-D42AN, a novel DOCK11-binding peptide, leading to the suppression of HBV replication both in vitro and in vivo. Treatment with a combination of 10M-D42AN and entecavir may represent a promising therapeutic strategy for patients with chronic hepatitis B (CHB). Consequently, DOCK11 may be seen as a potential candidate molecule in the development of molecularly targeted drugs against CHB. Full article

Chronic hepatitis B (CHB) virus infection is a major public health burden and the leading cause of hepatocellular carcinoma. Despite the efficacy of current treatments, hepatitis B virus (HBV) cannot be fully eradicated due to the persistence of its minichromosome, or covalently closed circular DNA (cccDNA). The HBV community is investing large human and financial resources to develop new therapeutic strategies that either silence or ideally degrade cccDNA, to cure HBV completely or functionally. cccDNA transcription is considered to be the key step for HBV replication. Transcription not only influences the levels of viral RNA produced, but also directly impacts their quality, generating multiple variants. Growing evidence advocates for the role of the co-transcriptional regulation of HBV RNAs during CHB and viral replication, paving the way for the development of novel therapies targeting these processes. This review focuses on the mechanisms controlling the different co-transcriptional processes that HBV RNAs undergo, and their contribution to both viral replication and HBV-induced liver pathogenesis. Full article

Hepatitis B virus (HBV) is the etiologic agent of chronic hepatitis B, which puts at least 300 million patients at risk of developing fibrosis, cirrhosis, and hepatocellular carcinoma. HBV is a partially double-stranded DNA virus of the Hepadnaviridae family. While HBV was discovered more than 50 years ago, many aspects of its replicative cycle remain incompletely understood. Central to HBV persistence is the formation of covalently closed circular DNA (cccDNA) from the incoming relaxed circular DNA (rcDNA) genome. cccDNA persists as a chromatinized minichromosome and is the major template for HBV gene transcription. Here, we review how cccDNA and the viral minichromosome are formed and how viral gene transcription is regulated and highlight open questions in this area of research. Full article

Chronic hepatitis B virus (HBV) infection is the largest global cause of hepatocellular carcinoma (HCC). Current HBV treatment options include pegylated interferon-alpha and nucleos(t)ide analogues (NAs), which have been shown to be effective in reducing HBV DNA levels to become undetectable. However, the literature has shown that some patients have persistent risk of developing HCC. The mechanism in which this occurs has not been fully elucidated. However, it has been discovered that HBV’s covalently closed circular DNA (cccDNA) integrates into the critical HCC driver genes in hepatocytes upon initial infection; additionally, these are not targets of current NA therapies. Some studies suggest that HBV undergoes compartmentalization in peripheral blood mononuclear cells that serve as a sanctuary for replication during antiviral therapy. The aim of this review is to expand on how patients with HBV may develop HCC despite years of HBV viral suppression and carry worse prognosis than treatment-naive HBV patients who develop HCC. Furthermore, HCC recurrence after initial surgical or locoregional treatment in this setting may cause carcinogenic cells to behave more aggressively during treatment. Curative novel therapies which target the life cycle of HBV, modulate host immune response, and inhibit HBV RNA translation are being investigated. Full article