The covalently closed circular DNA (cccDNA) of the Hepatitis B virus (HBV) serves as a template for producing progeny viruses in virally infected hepatocytes. Promising cccDNA-targeting antiviral agents remain unavailable and unpredictable in the research and development pipelines, making sterile HBV elimination challenging at the current stage. The major challenge of discriminating trace amounts of cccDNA from the abundant HBV relaxed circular DNA (rcDNA), which is nearly identical to cccDNA in sequence, substantially discourages efforts to discover and directly screen cccDNA-targeting drugs. Therefore, an easy cccDNA cell culture system is required for high-throughput drug screening. In this study, we designed an HBV cccDNA self-generating stable cell culture system using a functional complementary concept and successfully generated an HBV cccDNA Gaussia luciferase reporter cell line in HepG2 and Huh7 cells. This design ensures that the Gluc signal is exclusively expressed upon cccDNA formation, allowing for the accurate and easy measurement of cccDNA levels via luminescent signals. Using this system, in conjunction with a firefly luciferase reporter to monitor cell activity, we screened 2074 drugs in the HepG2-HBV-cccDNA/Firefly cell line. Four compounds were selected for further experimentation and their anti-HBV effects were confirmed. Thus, this virus-free hepatitis B cccDNA cell culture system provides a valuable and convenient platform for the high-throughput screening of anti-HBV drugs.

The costimulatory molecules OX40 and OX40L, members of the tumor necrosis factor (receptor) superfamily, play an important role in viral control through the activation of T cells. We speculate that activating the immune checkpoint OX40 may promote the inhibition of hepatitis B virus (HBV) replication.

To test this hypothesis, we investigated the expression dynamics of OX40/OX40L and studied the effects of activation of OX40 on HBV replication, and further explored the possible mechanism.

We found that the percentage of T cells expressing OX40 was lower in adult patients with chronic hepatitis B (CHB) than in healthy adults and was negatively correlated with serum viral load. In contrast, the percentage of B cells and monocytes expressing OX40L was increased in adult patients with CHB and positively correlated with liver inflammatory indicators. The expression of OX40 in T cells and OX40L in monocytes was positively correlated with age in healthy donors. In addition, the levels of serum HBsAg and intrahepatic HBV DNA decreased in an HBV mouse model with an agonistic antibody that activates OX40. This viral inhibition process coincides with changes in liver inflammation, the ratio of T cell subsets, and T cell-related cytokines. Finally, we found that the OX40 activation-mediated inhibition of HBV replication was more dependent on CD8+ T cells than on CD4+ T cells.

The expression levels of the immune checkpoints OX40/OX40L in adult patients with CHB are closely related to virus clearance. The activation of OX40 can suppress HBV replication through a mechanism that is more dependent on CD8+ T cells than on CD4+ T cells. Thus, OX40 is a promising therapeutic target for the treatment of CHB.

The impact of hepatitis B surface antigen (HBsAg) reduction from small interfering RNA (siRNA) treatments on hepatitis B virus (HBV)-specific immunity of individuals with chronic hepatitis B (CHB) has not been adequately analyzed in humans. We conducted a phase 2a study treating CHB participants with nine 4-weekly doses of HBV-targeted siRNA elebsiran (BRII-835), either alone (n = 10) or in combination with a virus-like particle-based therapeutic vaccine (BRII-179) containing Pre-S1, Pre-S2, and S antigens, coadministered with (n = 39) or without (n = 41) interferon alfa.

We analyzed longitudinally for 72 weeks virologic, clinical, and immunologic parameters, including HBsAg, alanine aminotransferase, hepatitis B surface antibody (anti-HBs) antibodies, the neutralizing activity of representative sera, and frequency and cytokine secretion ability of T cells specific for Pre-S1, Pre-S2, and S both directly ex vivo and after in vitro expansion.

Combination therapy with elebsiran and BRII-179 was well tolerated. Although no sustained HBsAg seroclearance or notable difference in mean HBsAg reduction at the group level was observed, we detected marked heterogeneity in immunologic responses among groups. HBsAg reduction mediated by siRNA alone was associated with minimal HBV-specific immune response recovery. In contrast, combination of elebsiran with BRII-179 induced a significant modification of immune responses demonstrated by anti-HBs antibody production and an expansion of interleukin 2-producing cluster of differentiation 4-positive T cells specific for Pre-S1/Pre-S2 antigens only. Importantly, anti-HBs antibodies persisted at ≥100 IU/L in ∼40% of the participants for at least 32 weeks after combined treatment. Moreover, the neutralizing ability of the anti-HBs-positive sera was associated with HBsAg reduction.

siRNA-induced HBsAg reduction may contribute to the persistence and efficacy of the humoral arm of HBV-specific adaptive immunity in CHB participants receiving the therapeutic vaccine BRII-179.

gov number: NCT04749368.

Chronic hepatitis B (CHB) remains a serious global health problem. In our previous investigation, HBV was found to activate a mild ER stress, which facilitated the establishment of persistent HBV infection. However, the role of ER stress manipulation in HBV replication and its underlying mechanisms remain still unclear. Our data showed that mild ER stress inhibited HBV transcription and replication, while severe ER stress enhanced them. Mechanistically, in contrary to the effect on HBV replication, mild ER stress activated whereas severe ER stress inhibited mTOR signaling in HBV-infected cells. Further, mTOR signaling was revealed to be critical for mild ER stress-mediated HBV inhibition. Furthermore, ATF6 but not PERK or IRE1α was found to be involved in mild ER stress-mediated mTOR and the following HBV inhibition. Moreover, ATF6, per se, could inhibit HBV transcription and replication via activating mTOR signaling. Together, ATF6-mediated mild ER stress inhibited HBV transcription and replication through mTOR activation, which might present as an important therapeutic target for CHB patients.

As a highly complex organ with digestive, endocrine, and immune-regulatory functions, the liver is pivotal in maintaining physiological homeostasis through its roles in metabolism, detoxification, and immune response. Various factors including viruses, alcohol, metabolites, toxins, and other pathogenic agents can compromise liver function, leading to acute or chronic injury that may progress to end-stage liver diseases. While sharing common features, liver diseases exhibit distinct pathophysiological, clinical, and therapeutic profiles. Currently, liver diseases contribute to approximately 2 million deaths globally each year, imposing significant economic and social burdens worldwide. However, there is no cure for many kinds of liver diseases, partly due to a lack of thorough understanding of the development of these liver diseases. Therefore, this review provides a comprehensive examination of the epidemiology and characteristics of liver diseases, covering a spectrum from acute and chronic conditions to end-stage manifestations. We also highlight the multifaceted mechanisms underlying the initiation and progression of liver diseases, spanning molecular and cellular levels to organ networks. Additionally, this review offers updates on innovative diagnostic techniques, current treatments, and potential therapeutic targets presently under clinical evaluation. Recent advances in understanding the pathogenesis of liver diseases hold critical implications and translational value for the development of novel therapeutic strategies.

Hepatitis B is a liver infection caused by HBV. Infected individuals who fail to control the viral infection develop chronic hepatitis B and are at risk of developing life-threatening liver diseases, such as cirrhosis or liver cancer. Dendritic cells (DCs) play important roles in the immune response against HBV but are functionally impaired in patients with chronic hepatitis B. The underlying mechanisms involved in HBV-induced DC dysfunctions remain to be elucidated.

We explored DC modulations by HBV and HBsAg by exposing blood-derived cDC1s, cDC2s, and plasmacytoid DCs from healthy donors to HBV or HBsAg and stimulating them with toll-like receptor ligand. Their phenotypic and functional features, as well as their metabolic profile, were analyzed through multiparametric flow cytometry and multiplex assays and further explored on patients' samples.

We found that HBV deeply reshaped the DC secretome in response to toll-like receptor ligand. Strikingly, we observed that HBV-exposed DCs secrete high levels of CX3CL1 (fractalkine), a chemokine responsible for attracting antiviral effectors to the site of infection. HBsAg exposure favored DC activation while drastically altering TRAIL expression in response to toll-like receptor ligand and increasing the secretion of cytokines/chemokines involved in immune tolerance. HBsAg further dampened the metabolism of DC subsets while driving metabolic switches. Notably, the relevance of the CX3CL1/CX3CR1 axis, TGF-β, and metabolic disturbances was demonstrated within intrahepatic DC subsets in patients according to disease stage.

Our work brings new insights into the immunomodulation induced by HBV on DCs, which contribute to impaired antiviral responses and progression toward chronicity.

Hepatitis B virus (HBV) relaxed circular DNA (rcDNA) possesses an 8-9 nucleotide-long terminal redundancy (TR, or r) on the negative (-) strand DNA derived from the reverse transcription of viral pregenomic RNA (pgRNA). It remains unclear whether the TR forms a 5' or 3' flap structure on HBV rcDNA and which TR copy is removed during covalently closed circular DNA (cccDNA) formation. To address these questions, a mutant HBV cell line HepDES-C1822G was established with a C1822G mutation in the pgRNA coding sequence, altering the sequence of 3' TR of (-) strand DNA while the 5' TR remained wild type (wt). The production of HBV rcDNA and cccDNA in HepDES-C1822G cells was comparable to wt levels. Next-generation sequencing (NGS) analysis revealed that the positive (+) strand DNA of rcDNA and both strands of cccDNA predominantly carried the wt nt1822 residue, indicating that the 5' TR of (-) strand DNA serves as the template during rcDNA replication, forming a duplex with the (+) strand DNA, while the 3' TR forms a flap-like structure, which is subsequently removed during cccDNA formation. In a survey of known cellular flap endonucleases using a loss-of-function study, we found that the 3' flap endonuclease Mus81 plays a critical role in cccDNA formation in wild-type HBV replicating cells, alongside the 5' flap endonuclease FEN1. Additionally, we have mapped the potential Mus81 and FEN1 cleavage sites within the TR of nuclear DP-rcDNA by RACE-NGS analyses. The overlapping function between Mus81 and FEN1 in cccDNA formation indicates that the putative 5' and 3' flap formed by TR are dynamically interchangeable on rcDNA precursor. These findings shed light on HBV rcDNA structure and cccDNA formation mechanisms, contributing to our understanding of HBV replication cycle.

Hepatitis B virus (HBV) ribonuclease H (RNaseH) inhibitors are a potent class of antivirals that prevent degradation of the viral pregenomic RNA during reverse transcription and block formation of mature HBV DNAs. Development of HBV RNaseH inhibitors is entering advanced preclinical analyses. To ensure the mechanism of action was fully understood, we defined the effects of RNaseH inhibitors on other steps of HBV replication. Some N-hydroxypyridinedione (HPD) HBV RNaseH inhibitors significantly reduced accumulation of capsids in HBV-replicating cells. A representative HPD 1466, with a 50% effective concentration against HBV replication of 0.25 µM, decreased capsid and core protein accumulation by 50-90% in HepDES19 and HepG2.2.15 cells. Surprisingly, 1466 did not affect pregenomic RNA encapsidation, demonstrating a specific effect on empty capsids. HBV genomic replication was not necessary for 1466's inhibitory effect as it decreased capsid accumulation in cells transfected with replication-deficient mutants blocking pgRNA encapsidation (Δ-bulge), DNA synthesis (YMHA), and RNaseH (D702A) activities. 1466 also decreased capsid and core protein accumulation in cells transfected with a core protein expression plasmid, indicating that other HBV products are unneeded. 1466 reduced initial capsid assembly rates in biochemical assembly reactions employing purified core protein (Cp149), demonstrating a specific effect on HBV core protein. We conclude that the bimodal HPD HBV RNaseH inhibitor 1466 is the prototypic member of a new class of capsid assembly modulators (CAM) that inhibits capsid assembly rather than accelerating it, as all other CAM classes do. We propose that this class be called CAM-I, for CAM-inhibitor. These results lay the foundation for identifying bimodal HBV antivirals targeting the RNaseH and capsid assembly.

Hepatitis B virus (HBV) is a major cause of acute and chronic liver disease and represents a major public health problem worldwide. Current antiviral therapies with nucleos(t)ide analogues can effectively suppressing viremia but are not curative, and have little or no impact upon the HBV cccDNA minichromosome or the portions of integrated HBV DNA. Several alternative therapeutic strategies targeted at viral components and life cycle are under intense investigation. This article highlights the reasons for considering HBx as a therapeutic target as this may allow targeting of both virus and disease. Recent studies focused at HBx have led to the identification of several new pharmacological agents and development of some novel therapeutic approaches that now deserve to be taken to the next level for better management of hepatitis B. Besides, new therapies could be combined with other established therapies, to provide a functional cure from hepatitis B infection.

Chronic hepatitis B virus (HBV) infection is still a widespread global health issue. HuaganJiedu Decoction (HGJDD) is a common prescription for treating HBV in China, which has the effect of enhancing antiviral efficacy and improving clinical efficacy. However, its precise mechanism of action remains unclear, warranting further investigation to elucidate its therapeutic potential and integration into standard medical practices.

This study aims to explore the therapeutic mechanism of HuaganJiedu Decoction (HGJDD) in HBV.

We investigated the therapeutic potential of HGJDD, and LC-MS analysis characterized the chemical profile of HGJDD. In vitro, we utilized HepG2.2.15 cell line to assess cytotoxicity and treatment efficacy of HGJDD compared to Entecavir controls. In vivo, assessments included monitoring HBV-related biomarkers and viral load. Network pharmacology and RNA-seq analyses identified molecular pathways and targets influenced by HGJDD treatment. Immunofluorescence and Western blotting provided further insights into the therapeutic mechanisms underlying HGJDD for HBV.

HGJDD showed no toxicity on HepG2.2.15 cells at 10%, 20%, 40%, and 80% serum concentrations. In vitro, HGJDD reduced HBsAg, HBeAg, and HBV DNA levels by dose-dependently and time-dependently. HGJDD can decrease the levels of HBsAg, HBeAg, and HBV DNA in serum and liver levels, meanwhile the therapeutic effect of high-dose HGJDD approach to EVT's in HBV Tg mice. According to intersection of network pharmacology and transcriptome, FOXO signal pathway was highlighted as potential targets and Immunofluorescence find that FOXO4D protein expression lever was increased in three HGJDD group, especially in high-dose HGJDD group. Western blotting confirmed increased level of FOXO4, ERK, and p-ERK and decreased levels of HNF4α, which reflected that the therapeutic effect was closely to FOXO4/ERK/HNF4α signal pathway.

Traditional Chinese medicine (TCM) offers diverse herbal treatments for HBV, with HGJDD showing efficacy in reducing HBsAg, HBeAg, and HBV DNA levels at cellular and animal levels. This study identified that FOXO4/ERK/HNF4α signal pathway played an important role in HGJDD's therapeutic effects. These findings support HGJDD's potential in HBV treatment, providing a scientific basis for clinical use.

Although pegylated interferon α-2b (PEG-IFN α-2b) therapy for chronic hepatitis B has received increasing attention, determining the optimal treatment course remains challenging. This research aimed to develop an efficient model for predicting interferon (IFN) treatment course.

Patients with chronic hepatitis B, undergoing PEG-IFN α-2b monotherapy or combined with NAs (Nucleoside Analogs), were recruited from January 2018 to December 2023 at Tianjin Third Central Hospital. All patients achieved hepatitis B surface antigen (HBsAg) clearance post-treatment.

The study enrolled 176 patients with chronic hepatitis B, with the median IFN treatment course of 35.23 ± 25.22 weeks. They were randomly divided into two cohorts in a ratio of 7:3. And there were 123 patients in the training cohort and 53 patients in the validation cohort. Univariable and multivariable analyses demonstrated that baseline HBsAg, 12 weeks HBsAg and the presence of cirrhosis significantly influenced IFN treatment course, and both are risk factors (β=7.27,4.27,10.91; p<0.05). After adjusting for confounding factors, HBsAg remained a significant predictor (β=6.99, 95%CI: 3.59,10.40; p<0.05), which was finally included to establish the model. The actual and predicted values in the validation cohort were highly matched, meanwhile the mean absolute percentage error (MAPE), root mean square error (RMSE) and accuracy (ACC) of the validation cohort were calculated. External validation also suggests that the model can be used as a tool for initial assessment.

Baseline HBsAg in chronic hepatitis B patients were a risk factor for prolonged IFN treatment course with a positive correlation. Ultimately, a personalized model based on baseline HBsAg levels can be established to roughly estimate the duration of interferon therapy prior to treatment initiation, thereby guiding clinical decision-making.

Quantification of intrahepatic covalently closed circular DNA (cccDNA) is a key for evaluating an elimination of hepatitis B virus (HBV) in infected patients. However, quantifying cccDNA requires invasive methods such as a liver biopsy, which makes it impractical to access the dynamics of cccDNA in patients. Although HBV RNA and HBV core-related antigens (HBcrAg) have been proposed as surrogate markers for evaluating cccDNA activity, they do not necessarily estimate the amount of cccDNA. Here, we employed a recently developed multiscale mathematical model describing intra- and intercellular viral propagation and applied it in HBV-infected patients under treatment. We developed a model that can predict intracellular HBV dynamics by use of extracellular viral markers, including HBsAg, HBV DNA, and HBcrAg in peripheral blood. Importantly, the model prediction of the amount of cccDNA in patients over time was confirmed to be well correlated with the data for quantified cccDNA by paired liver biopsy. Thus, our method combining classic and emerging surrogate markers enables us to predict the decay dynamics of cccDNA in patients undergoing treatment.

Hepatitis B virus (HBV) X protein (HBx) is a key factor for regulating viral transcription and replication. We recently characterized homeobox protein MSX-1 (MSX1) as a host restriction factor that inhibits HBV gene expression and genome replication by directly binding to HBV enhancer II/core promoter (EnII/Cp) and suppressing its promoter and enhancer activities. Notably, HBx expression was observed to be repressed more drastically by MSX1 compared to other viral antigens. In this work, we report that in addition to transcriptional repression, MSX1 also post-transcriptionally downregulates HBx protein stability. Mechanistically, MSX1 induces ubiquitin-independent proteasomal degradation of HBx, which is mediated through HBx C-terminal domain. Furthermore, this effect on HBx degradation correlates with MSX1-induced upregulation of DNAJA4 and CRYAB expression. Similar to MSX1, both DNAJA4 and CRYAB promote HBx degradation and repress HBV gene expression and genome replication. In chronic hepatitis B (CHB) patients, immune active phase (IA) is associated with higher intrahepatic expression of MSX1, DNAJA4 and CRYAB, and lower serum HBV markers compared to immune tolerant (IT) phase. Finally, HBV infection is significantly suppressed by MSX1 overexpression in both NTCP-overexpressing cell and humanized liver mouse models. These results demonstrate additional and novel mechanisms of MSX1-mediated repression of HBV, and establish MSX1 as a multi-functional HBV restriction factor with therapeutic potential.

In preclinical studies, GST-HG141, a novel hepatitis B virus (HBV) capsid assembly modulator displayed potent anti-HBV activity in vitro and strong efficacy in HBV animal models. A randomized, double-blind, ascending phase 1b trial assessed the pharmacokinetics, safety, and efficacy of GST-HG141 in chronic hepatitis B (CHB) individuals. Thirty treatment-naïve CHB patients were enrolled in three cohorts (25, 50, and 100 mg twice orally after meals daily) over 28 days, with 10 subjects per cohort (8:2 ratio for GST-HG141 and placebo). Dose-related safety and tolerability, pharmacokinetic profiles, and drug responses were evaluated. GST-HG141 exhibited a generally favorable safety profile across all doses with predominantly mild adverse reactions, including three cases of grade 1 transaminase elevations. Significant reductions in HBV DNA and pregenomic RNA (pgRNA) levels were observed across all doses of (25, 50, and 100 mg of GST-HG141, twice-daily) after 28 days of treatment. Pharmacokinetic analysis showed a consistent linear trend in GST-HG141 concentrations, with mean trough concentrations ranging from 75 to 240 ng/mL. These concentrations adequately covered the protein binding-adjusted EC50 (16.89 ng/mL) by factors of 4.4, 11.1, and 14.6 for doses of 25, 50, and 100 mg, respectively. Our study demonstrated GST-HG141's well-tolerated profile up to 100 mg over 4 weeks, alongside robust antiviral activity in CHB patients, supporting its progression into further clinical investigation for CHB management.

The gut microbiota (GM) plays a major role in the progression and treatment response of liver diseases, with diverse compositions based on different etiologies. In China, hepatitis B virus (HBV) infection is the leading cause of cirrhosis and affects the GM composition in patients with cirrhosis-related portal hypertension (PH). However, a few studies have been conducted on GM alterations after transjugular intrahepatic portosystemic shunt (TIPS) in patients with HBV-related PH. A recent study investigated the changes in the GM in these patients after TIPS. This study found an increase in potentially pathogenic bacteria and a decrease in beneficial bacteria post-TIPS, particularly in patients with hepatic encephalopathy (HE), indicating the potential role of the GM in HE prediction and management post-TIPS. Nevertheless, the study had several limitations, including a small sample size, limited follow-up, a single time point for sample collection, and inadequate analysis of the correlation between intestinal flora, HBV infection status, and clinical parameters. Future research should address these limitations by expanding the sample size, prolonging the follow-up duration, collecting samples at multiple time points, and conducting comprehensive analyses to confirm the findings and evaluate the effectiveness of individualized microbiome-based therapies.

Xalnesiran, a small interfering RNA molecule that targets a conserved region of the hepatitis B virus (HBV) genome and silences multiple HBV transcripts, may have efficacy, with or without an immunomodulator, in patients with chronic HBV infection.

We conducted a phase 2, multicenter, randomized, controlled, adaptive, open-label platform trial that included the evaluation of 48 weeks of treatment with xalnesiran at a dose of 100 mg (group 1), xalnesiran at a dose of 200 mg (group 2), xalnesiran at a dose of 200 mg plus 150 mg of ruzotolimod (group 3), xalnesiran at a dose of 200 mg plus 180 μg of pegylated interferon alfa-2a (group 4), or a nucleoside or nucleotide analogue (NA) alone (group 5) in participants with chronic HBV infection who had virologic suppression with NA therapy. The primary efficacy end point was hepatitis B surface antigen (HBsAg) loss (HBsAg level, <0.05 IU per milliliter) at 24 weeks after the end of treatment. Safety was also assessed.

Among 159 participants (30, 30, 34, 30, and 35 in groups 1 through 5, respectively), the primary end-point event occurred in 7% (95% confidence interval [CI], 1 to 22) of those in group 1, in 3% (95% CI, 0 to 17) of those in group 2, in 12% (95% CI, 3 to 28) of those in group 3, in 23% (95% CI, 10 to 42) of those in group 4, and in none (95% CI, 0 to 10) of those in group 5. In groups 1 through 5, respectively, HBsAg seroconversion occurred in 3%, none, 3%, 20%, and none of the participants at 24 weeks after the end of treatment. HBsAg loss with or without seroconversion occurred only in participants with a screening HBsAg level below 1000 IU per milliliter. In groups 1 through 5, respectively, grade 3 or 4 adverse events occurred in 17%, 10%, 18%, 50%, and 6% of the participants, with the most frequent event being an elevated alanine aminotransferase level.

Among participants with chronic HBV infection who had virologic suppression with NA therapy, treatment with xalnesiran plus an immunomodulator resulted in HBsAg loss at 24 weeks after the end of treatment in a substantial percentage of participants. Grade 3 or 4 adverse events were not uncommon. (Funded by F. Hoffmann-La Roche; Piranga ClinicalTrials.gov number, NCT04225715.).

Hepatitis B virus (HBV) is a hepatotropic DNA virus that can cause acute or chronic hepatitis, representing a significant global health concern. By 2019, approximately 296 million individuals were chronically infected with HBV, with 1.5 million new cases annually and 820,000 deaths due to HBV-related cirrhosis and liver cancer. Current treatments for chronic hepatitis B include nucleotide analogs (NAs) and interferons (IFNs), particularly IFN-α. NAs, such as entecavir and tenofovir, inhibit viral reverse transcription, while IFN-α exerts antiviral effects by directly suppressing viral replication, modulating viral genome epigenetics, degrading cccDNA, and activating immune responses. Despite its potential, IFN-α shows limited clinical efficacy, partly due to HBV's interference with the IFN signaling pathway. HBV encodes proteins like HBc, Pol, HBsAg, and HBx that disrupt IFN-α function. For example, HBV Pol inhibits STAT1 phosphorylation, HBsAg suppresses STAT3 phosphorylation, and HBx interferes with IFN-α efficacy through multiple mechanisms. Additionally, HBV downregulates key genes in the IFN signaling pathway, further diminishing IFN-α's antiviral effects. Understanding these interactions is crucial for improving IFN-α-based therapies. Future research may focus on overcoming HBV resistance by targeting viral proteins or optimizing IFN-α delivery. In summary, HBV's ability to resist IFN-α limits its therapeutic effectiveness, highlighting the need for new strategies to enhance treatment outcomes.

The persistence of HBV covalently closed circular DNA (cccDNA) and HBV integration into the host genome in infected hepatocytes pose significant challenges to the cure of chronic HBV infection. Although CRISPR/Cas9-mediated genome editing shows promise for targeted clearance of viral genomes, a safe and efficient delivery method is currently lacking. Here, we developed a novel approach by combining light-induced heterodimerization and protein acylation to enhance the loading efficiency of Cas9 protein into extracellular vesicles (EVs). Moreover, vesicular stomatitis virus-glycoprotein (VSV-G) was incorporated onto the EVs membrane, significantly facilitating the endosomal escape of Cas9 protein and increasing its gene editing activity in recipient cells. Our results demonstrated that engineered EVs containing Cas9/gRNA and VSV-G can effectively reduce viral antigens and cccDNA levels in the HBV-replicating and infected cell models. Notably, we also confirmed the antiviral activity and high safety of the engineered EVs in the HBV-replicating mouse model generated by hydrodynamic injection and the HBV transgenic mouse model. In conclusion, engineered EVs could successfully mediate functional CRISPR/Cas9 delivery both in vitro and in vivo, leading to the clearance of episomal cccDNA and integrated viral DNA fragments, and providing a novel therapeutic approach for curing chronic HBV infection.

Hepatitis B virus (HBV) is an ancient virus that has evolved unique strategies to persist as a chronic infection in humans. Here, I summarize the innate and adaptive features of the HBV-host interaction, and I discuss how different profiles of antiviral immunity cannot be predicted only on the basis of virological and clinical parameters.

Type I interferons (IFN-Is) have key roles in immune defense and treatments for various diseases, including chronic hepatitis B virus (HBV) infection. All IFN-Is signal through a shared IFN-I heterodimeric receptor complex comprising IFN-α receptor 1 (IFNAR1) and IFNAR2 subunits, but differences in antiviral and immunomodulatory responses among IFN-I subtypes remain largely unknown. Because the IFN-IFNAR interactions are species-specific, mice exhibit weak responses to human IFN-I. To more fully characterize the actions of human IFN-α and its subtypes in vivo, a gene targeting strategy was employed to generate gene knock-in mice with extracellular-humanized IFNAR1/2 (IFNAR-hEC) in the C57BL/6N strain. IFNAR-hEC mice actively responded to human IFN-I, and endogenous mouse IFN-I signalling remained active in heterozygous mice (IfnarhEC/+). Analyses of IFNAR-hEC mice and isolated cells showed that human IFN-α2 and α14 subtypes exerted differential effect on the activation of JAK-STAT signalling and immune responses. Compared with IFN-α2, IFN-α14 induced greater activation of STAT1/2 and IFN-stimulated genes, synergistically elicited IFN-α and -γ signalling, and induced higher numbers of antigen-specific CD8+ T cells. Moreover, IFNAR-hEC mice with HBV replication displayed long-term viral suppression upon treatment with the clinically-used PEGylated hIFN-α2. These results indicate that IFNAR-hEC mice may be useful for elucidating antiviral and immunomodulatory functions of human IFN-Is and for conducting preclinical studies. A better understanding of the distinct activities of IFN-α subtypes can provide insights concerning the development of improved IFN-based therapy.

It is well established that humoral immunity targeting hepatitis B virus surface antigen (HBsAg) plays a critical role in viral clearance and clinical cure. However, the functional changes in HBsAg-specific B cells before and after achieving functional cure remain poorly understood. In this study, we characterized circulating HBsAg-specific B cells and identified functional shifts and B-cell epitopes directly associated with HBsAg loss. The phenotypes and functions of HBV-specific B cells in patients with chronic HBV infection were investigated using a dual staining method and the ELISpot assay. Epitope mapping was performed to identify B cell epitopes associated with functional cure. Hyperactivated HBsAg-specific B cells in patients who achieved HBsAg loss were composed of enriched resting memory and contracted atypical memory fractions, accompanied by sustained co-expression of multiple inhibitory receptors and increased IL-6 secretion. The frequency of HBsAb-secreting B cells was significantly increased after achieving a functional cure. The rHBsAg displayed a weaker immunomodulatory effect on B cells than rHBeAg and rHBcAg in vitro. Notably, sera from patients with HBsAg loss reacted mainly with peptides S60, S61, and S76, suggesting that these are dominant linear B-cell epitopes relevant for functional cure. Intriguingly, patients reactive with S76 showed a higher frequency of the HLA class II DQB1*05:01 allele. Taken together, HBsAg-specific B cells were partially restored in patients after achieving a functional cure. Functional cure-related epitopes may be promising targets for developing therapeutic vaccines to treat HBV infection and promote functional cure.

The changes in HBV-specific B cells in patients with chronic hepatitis B (CHB) undergoing pegylated interferon-α (PEG-IFNα) treatment and achieving functional cure remain unclear. We aimed to evaluate the alterations in HBV-specific B cells during treatment and therefore explored the mechanism of functional recovery of HBsAg-specific B cells.

We included 39 nucleos(t)ide analogue-treated patients with CHB who received sequential combination therapy with PEG-IFNα and eight treatment-naïve patients. HBV-specific B cells were characterized ex vivo using fluorescently labeled hepatitis B surface and core antigens (HBsAg and HBcAg). The frequency, phenotype, and subsets of HBV-specific B cells and follicular helper T cells (Tfh cells) were detected using flow cytometry. The functionality of HBV-specific B cells was quantified through ELISpot assays.

During treatment, the fraction of activated memory B cells (MBCs) among HBsAg-specific B cells and the expression of IgG, CXCR3, and CD38 increased. The antibody-secretion capacity of HBsAg-specific B cells was only restored in patients achieving a functional cure after treatment and it positively correlated with serum hepatitis B surface antibody levels. The phenotype and function of HBsAg-specific B cells differed between patients with and without functional cure. Patients with functional cure exhibited IgG+ classical MBCs and plasmablasts among HBsAg-specific B cells. HBcAg-specific B cells displayed both attenuated antibody secretion with reduced IgG expression and an IgM+ atypical type of MBC after treatment, irrespective of functional cure. The number of CD40L+ Tfh cells increased after PEG-IFNα treatment and positively correlated with HBsAg-specific B-cell activation.

After PEG-IFNα treatment, HBsAg- and HBcAg-specific B cells exhibit various changes in antibody secretion. Their functional differences are reflected in the alterations in phenotypes and subtypes. The presence of CD40L+ Tfh cells is associated with the active recovery of HBsAg-specific B cells.

HBV-related complications and hepatocellular carcinoma remain the leading causes of mortality from chronic liver disease worldwide, and a cure is rarely achieved with antiviral therapies. Elucidating the immunological mechanisms underlying the functional cure of patients with chronic hepatitis B offers a promising therapeutic strategy for viral clearance, e.g. via therapeutic vaccination. We analyzed the alterations in HBV-specific B cells in patients treated with pegylated interferon-α and identified novel pathways for immunotherapeutic boosting of B cell immunity.

Dysbiosis of oral microbiota has been reported in late stage of chronic hepatitis B (CHB) infection with cirrhosis. CHB is characterized by the constant virus-induced liver injury which may lead to liver cirrhosis and hepatocellular carcinoma (HCC). However, some patients show normal liver function without antiviral treatment, associating with favourable prognosis. The oral microbiota composition and oral health status in these patients is unidentified.

The study focuses on the composition of oral microbiota and oral health status in individuals with CHB and HBV vaccinees as controls. The CHB patients were hepatitis B 'e' antigen (HBeAg)-negative, with or without elevated liver enzyme increase at time of sampling, The 16S rRNA high-throughput sequencing and bioinformatic analysis were applied to investigate oral bacterial diversity, and oral examination including decay-missing-filled teeth (DMFT) index, probing depth (PD) and mucosal status was performed, along with oral health questionnaire, to assess the oral health status in CHB patients and healthy controls.

Our results indicate that their oral microbiome compositions are not significantly different though some have increased ALT/AST liver enzyme levels at the time of sampling, compared to the healthy control participants who are vaccinated e.g. protected from this viral disease. CHB patients here bore a good oral health status and life-style habits as comparing to healthy controls.

These findings suggest that a health-associated salivary microflora is present in CHB without severe liver injury. Continued regular dental health and lifestyle support in liver disease patients is therefore justified.

Hepatitis B virus (HBV) infection is a major health problem, causing thousands of deaths each year worldwide. Although current medications can often inhibit viral replication and reduce the risk of liver carcinoma, several obstacles still hinder their effectiveness. These include viral resistance, prolonged treatment duration, and low efficacy in clearing viral antigens. To address these challenges in current HBV treatment, numerous approaches have been developed with remarkable success. Among these strategies, small-interfering RNA (siRNA) stands out as one of the most promising therapies for hepatitis B. However, naked siRNAs are vulnerable to enzymatic digestion, easily eliminated by renal filtration, and unable to cross the cell membrane due to their large, anionic structure. Therefore, effective delivery systems are required to protect siRNAs and maintain their functionality. In this review, we have discussed the promises of siRNA therapy in treating HBV, milestones in their delivery systems, and products that have entered clinical trials. Finally, we have outlined the future perspectives of siRNA-based therapy for HBV treatment.

Whether patients with compensated cirrhosis and low-level viremia (LLV) of hepatitis B should receive antiviral therapy (AVT) is still controversial, and published results are inconsistent.

To investigate the link between LLV in compensated cirrhosis and prognosis concerning hepatocellular carcinoma (HCC), decompensation, and liver-related events.

The PubMed, EMBASE, and Cochrane Library databases were searched up to March 5, 2023. Outcomes of interest were assessed by pooled hazard ratios (HRs). The study was registered with PROSPERO (CRD42023405345).

Six cohort studies representing 3155 patients were included. Compared with patients with undetectable HBV DNA, patients with LLV was associated with increased risk of HCC (HR: 2.06, 95%CI: 1.36-3.13; Q-statistic-P = 0.07, I 2 = 51%) regardless of receiving AVT or not (AVT group: HR: 3.14; 95%CI: 1.73-5.69; Q-statistic-P = 0.60, I 2 = 0%; un-AVT group: HR: 1.73, 95%CI: 1.09-2.76; Q-statistic-P = 0.11, I 2 = 50%). The pooled results showed no statistical association between LLV and decompensation of cirrhosis (HR: 2.06, 95%CI: 0.89-4.76; Q-statistic-P = 0.04, I 2 = 69%), and liver-related events (HR: 1.84, 95%CI: 0.92-3.67; Q-statistic-P = 0.03, I 2 = 72%), respectively. Grading of Recommendations Assessment, Development and Evaluation assessment indicated moderate certainty for HCC, very low certainty for decompensation of cirrhosis and liver-related clinical events.

LLV in compensated cirrhotic patients is associated with increased risk of HCC, higher tendency for hepatic decompensation and liver-related events. Closer screening of HCC should be conducted in this population.

In the hepatis B virus (HBV) transgenic mouse model of chronic infection, the forkhead box protein A/hepatocyte nuclear factor 3 (Foxa/HNF3) family of pioneer transcription factors are required to support postnatal viral demethylation and subsequent HBV transcription and replication. Liver-specific Foxa-deficient mice with hepatic expression of only Foxa3 do not support HBV replication but display biliary epithelial hyperplasia with bridging fibrosis. However, liver-specific Foxa-deficient mice with hepatic expression of only Foxa1 or Foxa2 also successfully restrict viral transcription and replication but display only minimal alterations in liver physiology. These observations suggest that the level of Foxa activity, rather than the combination of specific Foxa genes, is a key determinant of HBV biosynthesis. Together, these findings suggest that targeting Foxa activity could lead to HBV DNA methylation and transcriptional inactivation, resulting in the resolution of chronic HBV infections that are responsible for approximately one million deaths annually worldwide.

The current absence of curative therapies capable of resolving chronic hepatis B virus (HBV) infection is a major clinical problem associated with considerable morbidity and mortality. The small viral genome limits molecular targets for drug development, suggesting that the identification of cellular factors essential for HBV biosynthesis may represent alternative targets for therapeutic intervention. Genetic Foxa deficiency in the neonatal liver of HBV transgenic mice leads to the transcriptional silencing of viral DNA by CpG methylation without affecting viability or displaying an obvious phenotype. Therefore, limiting liver Foxa activity therapeutically may lead to the methylation of viral covalently closed circular DNA (cccDNA), resulting in its transcriptional silencing and ultimately the resolution of chronic HBV infection.

Extracellular vesicles (EVs) are bilayer vesicles released by cells in the microenvironment of the liver including parenchymal and non-parenchymal cells. They are the third important mechanism in the communications between cells, besides the secretion of cytokines and chemokines and the direct cell-to-cell contact. The aim of this review is to discuss the important role of EVs in viral liver disease, as there is increasing evidence that the transportation of viral proteins, all types of RNA, and viral particles including complete virions is implicated in the pathogenesis of both viral cirrhosis and viral-related hepatocellular carcinoma. The biogenesis of EVs is discussed and their role in the pathogenesis of viral liver diseases is presented. Their use as diagnostic and prognostic biomarkers is also analyzed. Most importantly, the significance of possible novel treatment strategies for liver fibrosis and hepatocellular carcinoma is presented, although available data are based on experimental evidence and clinical trials have not been reported.

Targeted protein degradation (TPD) represents a revolutionary therapeutic strategy in disease management, providing a stark contrast to traditional therapeutic approaches like small molecule inhibitors that primarily focus on inhibiting protein function. This advanced technology capitalizes on the cell's intrinsic proteolytic systems, including the proteasome and lysosomal pathways, to selectively eliminate disease-causing proteins. TPD not only enhances the efficacy of treatments but also expands the scope of protein degradation applications. Despite its considerable potential, TPD faces challenges related to the properties of the drugs and their rational design. This review thoroughly explores the mechanisms and clinical advancements of TPD, from its initial conceptualization to practical implementation, with a particular focus on proteolysis-targeting chimeras and molecular glues. In addition, the review delves into emerging technologies and methodologies aimed at addressing these challenges and enhancing therapeutic efficacy. We also discuss the significant clinical trials and highlight the promising therapeutic outcomes associated with TPD drugs, illustrating their potential to transform the treatment landscape. Furthermore, the review considers the benefits of combining TPD with other therapies to enhance overall treatment effectiveness and overcome drug resistance. The future directions of TPD applications are also explored, presenting an optimistic perspective on further innovations. By offering a comprehensive overview of the current innovations and the challenges faced, this review assesses the transformative potential of TPD in revolutionizing drug development and disease management, setting the stage for a new era in medical therapy.

NLR family member X1 (NLRX1) is an important member of the NOD-like receptor (NLR) family and plays unique roles in immune system regulation. Patients with hepatitis B virus (HBV) infection are more likely to have the NLRX1 mutation p.Arg707Cys than healthy individuals. It has been reported that NLRX1 increases the infection rate of HBV in HepG2 cells expressing sodium taurocholate cotransporting polypeptide (NTCP). However, the role of NLRX1 mutation (p.Arg707Cys) in hepatitis remains unclear. We constructed Huh7 cells that stably overexpressed NTCP, using LV003 lentivirus. First, wild-type (WT) and mutant (MT) NLRX1 overexpression plasmids were constructed. The MT plasmid contained a point mutation at position 707 of the WT overexpression plasmid. Then, Huh7-NTCP cells were transfected with the WT or MT NLRX1 overexpression plasmid, and subsequent NLRX1 expression was analyzed using real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. HBV RNA levels were determined using RT-qPCR. HBsAg and HBcAg levels were confirmed immunohistochemically. Interferon alpha (IFN-α), interleukin 6 (IL-6), and type I interferon beta (IFN-β) levels were determined using enzyme-linked immunosorbent assay kits. p-p65, p-interferon regulatory factor (IRF) 3, and p-IRF7 expression levels were examined using western blot. The interaction of NLRX1 and retinoic acid-inducible gene (RIG)-1/mitochondrial antiviral signaling (MAVS) protein was confirmed by coimmunoprecipitation. The interaction of NLRX1 with IFN-α, IL-6, or IFN-β was analyzed by dual luciferase reporter gene assay. The levels of HBV RNA, HBsAg, and HBcAg in infected cells transfected with the WT NLRX1 or MT NLRX1 expression plasmid were higher than those in the untransfected control group; and these levels were lower in the cells transfected with MT NLRX1 than in those transfected with WT NLRX1. The levels of IFN-α, IFN-β, IL-6, p-p65, p-IRF3, and p-IRF7 were lower in cells transfected with WT NLRX1 or MT NLRX1 than in control cells. The levels of IFN-β, p-p65, p-IRF3, and p-IRF7 were higher in cells transfected with MT NLRX1 than in those transfected with WT NLRX1. Moreover, NLRX1 competitively inhibited RIG1 binding to MAVS, but the mutation in MT NLRX1 reduced this inhibitory effect. In addition, NLRX1 decreased the promoter activity of IFN-α, IFN-β, and IL-6. Our findings revealed that NLRX1 is a regulatory factor that inhibits the anti-HBV ability of hepatocytes and that the mutation p.Arg707Cys in NLRX1 suppresses HBV infection and activates the IFN/nuclear factor κB pathway.

Due to the limitations of current anti-HBV therapies, the HBV core (HBc or HBcAg) protein assembly modulators (CpAMs) are believed to be potential anti-HBV agents. Therefore, discovering safe and efficient CpAMs is of great value. In this study, we established a HiBiT-based high-throughput screening system targeting HBc and screened novel CpAMs from an in-house marine chemicals library. A novel lead compound 8a, a derivative of the marine natural product naamidine J, has been successfully screened for potential anti-HBV activity. Bioactivity-driven synthesis was then conducted, and the structure‒activity relationship was analyzed, resulting in the discovery of the most effective compound 11a (IC50 = 0.24 μmol/L). Furthermore, 11a was found to significantly inhibit HBV replication in multiple cell models and exhibit a synergistic effect with tenofovir disoproxil fumarate (TDF) and IFNa2 in vitro for anti-HBV activity. Treatment with 11a in a hydrodynamic-injection mouse model demonstrated significant anti-HBV activity without apparent hepatotoxicity. These findings suggest that the naamidine J derivative 11a could be used as the HBV core protein assembly modulator to develop safe and effective anti-HBV therapies.

Chronic hepatitis B virus (HBV) infection is a global issue and can lead to cirrhosis and hepatocellular carcinoma (HCC). Hepatitis B surface antigen (HBsAg) is an important marker of HBV infection and HBsAg quantification could be a useful tool in clinical practice. This systematic literature review aimed to explore the association between HBsAg titres and long-term disease outcomes and evaluate the relationship between HBsAg titres, or changes in HBsAg titres, and clinical and treatment characteristics in patients with chronic HBV infection. Structured searches were performed in MEDLINE and Embase (January 2000 to 31 March 2023). Eighty-two studies were included, comprising 51% retrospective cohort studies, mostly conducted in Asia (85%). HBsAg levels were shown to predict the long-term development of cirrhosis and HCC in patients who were untreated prior to and during follow-up; however, these data were inconclusive in mixed and treated populations. HBsAg titres were significantly associated with various virological markers including serum HBV DNA, HBcrAg, HBeAg, HBV RNA levels, intrahepatic covalently closed circular DNA (cccDNA) and intrahepatic HBsAg expression. HBsAg titres generally declined over time; this decline was more pronounced in early (HBeAg-positive) than later disease phases (HBeAg-negative). Higher decline in HBsAg levels was consistently associated with subsequent HBsAg seroclearance and a greater decline in total intrahepatic HBV DNA and cccDNA levels. In conclusion, this review showed that HBsAg levels and rates of decline could inform assessment, management and prediction of outcomes in chronic HBV infection. Further studies in broader, more diverse populations and treated patients are needed.

Hepatitis B virus (HBV) is a globally prevalent human DNA virus responsible for over 250 million cases of chronic liver infections, leading to conditions such as liver inflammation, cirrhosis and hepatocellular carcinoma (HCC). Sodium taurocholate co-transporting polypeptide (NTCP) is a transmembrane protein highly expressed in human hepatocytes and functions as a bile acid (BA) transporter. NTCP has been identified as the receptor that HBV and its satellite virus, hepatitis delta virus (HDV), use to enter hepatocytes. HBV entry into hepatocytes is tightly regulated by various signaling pathways, and NTCP plays an important role as the initial stage of HBV infection. NTCP acts as an initiation signal, causing metabolic changes in hepatocytes and facilitating the entry of HBV into hepatocytes. Thus, a comprehensive understanding of NTCP's role is crucial. In this review, we will examine the regulatory mechanisms governing HBV pre-S1 binding to liver membrane NTCP, the role of NTCP in HBV internalization, and the transcriptional and translational regulation of NTCP expression. Additionally, we will discuss clinical drugs targeting NTCP, including combination therapies involving NTCP inhibitors, and consider the safety of NTCP as a therapeutic target.