Advanced Strategies for Eliminating the cccDNA of HBV

A study on pregenomic RNA and factors in the pregnant and postpartum women with chronic HBV infection based on real world

Introduction

Most studies have focused on mother-to-child transmission and postpartum hepatitis flares. We aimed to evaluate the expression profile of pregenomic RNA (pgRNA) and its associated factors in patients with chronic HBV infection (CHB) during pregnancy and postpartum.

Methods

A total of 134 pregnant and 100 postpartum CHB patients were enrolled, and serum pgRNA levels were quantified.

Results

Significant differences in clinical characteristics were noted between pregnant and postpartum CHB patients, but there was no significant difference in pgRNA levels between the two groups. When HBV DNA and HBV antigen levels were low, the corresponding pgRNA detection rate decreased. pgRNA was positively correlated with DNA and HBV antigens in the pregnant and postpartum CHB patients. In the pregnant group, antiviral treatment was an independent risk factor for pgRNA levels. In the postpartum period, HBeAg levels and antiviral treatment were independent risk factors for pgRNA levels. Considering that patients receiving antiviral treatment often have a high DNA load or HBeAg positivity, the DNA level and HBeAg essentially affect pgRNA levels.

Conclusion

pgRNA levels differ between pregnant and postpartum patients, and this difference is of great significance for the diagnosis and management of these particular groups.

GalNac-siRNA conjugate delivery technology promotes the treatment of typical chronic liver diseases

INTRODUCTION

Nucleic acid-based therapeutics have become a key pillar of the 'third wave' of modern medicine, following the eras of small molecule inhibitors and antibody drugs. Their rapid progress is heavily dependent on delivery technologies, with the development of N-acetylgalactosamine (GalNAc) conjugates marking a breakthrough in targeting liver diseases. This technology has gained significant attention for its role in addressing chronic conditions like chronic hepatitis B (CHB) and nonalcoholic steatohepatitis (NASH), which are challenging to treat with conventional methods.

AREAS COVERED

This review explores the origins, mechanisms, and advantages of GalNAc-siRNA delivery systems, highlighting their ability to target hepatocytes via the asialoglycoprotein receptor (ASGPR). The literature reviewed covers preclinical and clinical advancements, particularly in CHB and NASH. Key developments in stabilization chemistry and conjugation technologies are examined, emphasizing their impact on enhancing therapeutic efficacy and patient compliance.

EXPERT OPINION

GalNAc-siRNA technology represents a transformative advancement in RNA interference (RNAi) therapies, addressing unmet needs in liver-targeted diseases. While significant progress has been made, challenges remain, including restricted targeting scope and scalability concerns. Continued innovation is expected to expand applications, improve delivery efficiency, and overcome limitations, establishing GalNAc-siRNA as a cornerstone for future nucleic acid-based treatments.

Evaluation of Interfering RNA Efficacy in Treating Hepatitis B: Is It Promising?

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.

The Levels of Serum HBV Pre-Genomic RNA and Its Associated Factors Among HBV-Infected Patients: A Retrospective Cohort Study in Hangzhou, Zhejiang, China

Introduction

This study aimed to explore serum HBV pre-genomic RNA (pgRNA) levels and its associated factors among HBV-infected patients in the real world.

Methods

This retrospective cohort study was conducted from May 10, 2023, to January 15, 2024. Univariate logistic analysis for positive serum HBV pgRNA was performed first, and variables with statistical significance were included in a multivariate logistic model. A decreasing trend of serum HBV pgRNA and HBV DNA levels was also detected first by univariate logistic regression and then by multivariate logistic regression.

Results

482 patients were included in our analysis at baseline, and 191 patients were followed up. Multivariate logistic regression revealed that positive HBV DNA (AOR: 2.63, 95% CI: 1.46-4.75, P=0.001), ≥1000 hBsAg (AOR: 2.29, 95% CI: 1.08-4.89, P=0.03), positive HBeAg (AOR: 28.26, 95% CI: 15.2-52.55, P<0.001), and ALP (AOR: 1.01, 95% CI: 1.001-1.02, P=0.03) were positively correlated with positive HBV pgRNA at baseline. Two independent multivariate logistic regression models were constructed for the decreasing trend of serum HBV pgRNA and HBV DNA for the 191 follow-up patients. Results showed that the decreasing trend of HBV pgRNA was positively correlated with positive baseline HBV DNA (AOR: 4.60, 95% CI: 1.84-11.51, P=0.001), baseline HBsAg ≥1000 IU/mL (AOR: 8.74, 95% CI: 1.09-70.10, P=0.04), and HDL (AOR: 5.01, 95% CI: 1.28-19.66, P=0.02). The decreasing trend of HBV DNA was positively correlated with positive baseline HBV pgRNA (AOR: 3.80, 95% CI: 2.00-8.83, P<0.001) and AST (AOR: 1.06, 95% CI: 1.03-1.08, P<0.001).

Conclusion

Our study revealed that HBV DNA, HBsAg, HBeAg, and ALP were significantly correlated with positive HBV pgRNA at baseline. The baseline HBV DNA, HBsAg, and HDL were significantly correlated with decreasing levels of HBV pgRNA. A decreasing trend of HBV DNA significantly correlated with patients' baseline HBV pgRNA and AST.

The significance of detecting HBV pgRNA and HBcrAg in HBV patients treated with NAs

The value of detecting hepatitis B virus (HBV), pregenomic RNA (pgRNA), and hepatitis B core-related antigen (HBcrAg), both separately and jointly, in the management of HBV patients undergoing treatment with Nucleotide Analog was investigated. A total of 149 HBV patients who were being treated with Nucleotide Analog were enrolled in this study. The quantitative levels of HBV pgRNA and HBcrAg in the sera of these patients were determined, aiming to comprehend their replication levels and expression during the course of antiviral therapy. The patients were separated into 3 groups based on treatment duration: treatment time ≤ 12 months, treatment time ranging from 12 months to <60 months, and treatment time ≥ 60 months. Significantly different levels of HBcrAg and HBV pgRNA were observed among 3 groups (P < .05). In the group of patients with positive hepatitis B e antigen, both HBcrAg and pgRNA levels were higher compared to the group with negative hepatitis B e antigen, and this difference between the 2 groups was found to be statistically significant. Stratified analysis based on levels of hepatitis B surface antigen (HBsAg) revealed that the group with HBsAg levels < 100 IU/mL had lower levels of both HBcrAg and pgRNA compared to the group with HBsAg levels ≥ 100 IU/mL (P < .001). Following antiviral therapy, various degrees of transcription of covalently closed circular DNA continue to exist within the liver of HBV patients. The levels of serum HBcrAg and HBV pgRNA vary among patients with different treatment durations, indicating their efficacy in evaluating disease conditions during antiviral therapy.

HBV pregenome RNA as a predictor of spontanous HBeAg seroconversion in HBeAg-positive chronic hepatitis B patients

BACKGROUND

Previous studies have indicated that HBV pregenome RNA (HBV pgRNA) could predict HBeAg seroconversion among the chronic hapatitis B (CHB) patients treated with pegylated interferon (Peg-IFN) or nucleos(t)ide analogues (NAs). However, the data about the prediction of HBV pgRNA for spontaneous HBeAg seroconversion is limited.

METHODS

One hundred thirteen CHB patients with HBeAg-positive in the immune active phase were followed up for 76 weeks without antiviral treatment. Based on the laboratory test results of liver function, HBeAg, anti-HBe, and HBV DNA at week 76, patients were assigned to two groups: spontaneous HBeAg seroconversion (group A, n = 18) and non-spontaneous HBeAg seroconversion group. Among the latter group, 36 patients were selected as controls (group B, n = 36).

RESULTS

At week 12, between group A and group B, there was a significant difference in the level of HBV pgRNA (group A 6.35 ± 1.24 log10 copies/ml and group B 7.52 ± 0.79 log10 copies/ml, P = 0.001), and the difference enlarged at week 28. The receiver operating characteristic curves (AUROCs) of the HBV pgRNA level and the ∆HBV pgRNA at week 28 were 0.912 (P = 0.001, 95% CI: 0.830-0.994), and 0.934 (P = 0.001, 95% CI: 0.872-0.996), respectively. The optimal cutoffs of HBV pgRNA and the reduction from baseline (∆HBV pgRNA) at week 28 for spontaneous HBeAg seroconversion prediction were 5.63 log10 copies/ml and 1.85 log10 copies/ml, respectively. The positive predictive value and negative predictive value of HBV pgRNA and ∆HBV pgRNA at week 28 were 86.7% and 87.2%, 87.5% and 89.5%, respectively. And the combination of the HBV pgRNA level and the HBV pgRNA decreased could provide better prediction.

CONCLUSIONS

HBV pgRNA is a sound predictor for spontaneous HBeAg seroconversion among the CHB patients in immune active phase. Dynamic monitoring of HBV pgRNA is helpful for clinical treatment decision.

Targeting hepatitis B virus cccDNA levels: Recent progress in seeking small molecule drug candidates

Hepatitis B virus (HBV) infection is a major global health problem that puts people at high risk of death from cirrhosis and liver cancer. The presence of covalently closed circular DNA (cccDNA) in infected cells is considered to be the main obstacle to curing chronic hepatitis B. At present, the cccDNA cannot be completely eliminated by standard treatments. There is an urgent need to develop drugs or therapies that can reduce HBV cccDNA levels in infected cells. We summarize the discovery and optimization of small molecules that target cccDNA synthesis and degradation. These compounds are cccDNA synthesis inhibitors, cccDNA reducers, core protein allosteric modulators, ribonuclease H inhibitors, cccDNA transcriptional modulators, HBx inhibitors and other small molecules that reduce cccDNA levels.

Role of epigenetic modification in interferon treatment of hepatitis B virus infection

Human hepatitis B virus (HBV) is a small, enveloped DNA virus that causes acute and chronic hepatitis. Chronic hepatitis B (CHB) is associated with hepatocellular carcinoma pathogenesis. Interferons (IFNs) have been used for the treatment of CHB for a long time, with advantages including less treatment duration and sustained virological response. Presently, various evidence suggests that epigenetic modification of the viral covalently closed circular DNA (cccDNA) and the host genome is crucial for the regulation of viral activity. This modification includes histone acetylation, DNA methylation, N6-methyladenosine, and non-coding RNA modification. IFN treatment for CHB can stimulate multiple IFN-stimulated genes for inhibiting virus replication. IFNs can also affect the HBV life cycle through epigenetic modulation. In this review, we summarized the different mechanisms through which IFN-α inhibits HBV replication, including epigenetic regulation. Moreover, the mechanisms underlying IFN activity are discussed, which indicated its potential as a novel treatment for CHB. It is proposed that epigenetic changes such as histone acetylation, DNA methylation, m6A methylation could be the targets of IFN, which may offer a novel approach to HBV treatment.

Drug Discovery Study Aimed at a Functional Cure for HBV

Hepatitis B virus (HBV) causes acute and, most importantly, chronic hepatitis B worldwide. Antiviral treatments have been developed to reduce viral loads but few patients with chronic hepatitis B (CHB) achieve a functional cure. The development of new therapeutic agents is desirable. Recently, many novel agents have been developed, including drugs targeting HBV-DNA and HBV-RNA. This review provides an overview of the developmental status of these drugs, especially direct acting antiviral agents (DAAs). Serological biomarkers of HBV infection are essential for predicting the clinical course of CHB. It is also important to determine the amount and activity of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. Hepatitis B core-associated antigen (HBcrAg) is a new HBV marker that has an important role in reflecting cccDNA in CHB, because it is associated with hepatic cccDNA, as well as serum HBV DNA. The highly sensitive HBcrAg (iTACT-HBcrAg) assay could be a very sensitive HBV activation marker and an alternative to HBV DNA testing for monitoring reactivation. Many of the drugs currently in clinical trials have shown efficacy in reducing hepatitis B surface antigen (HBsAg) levels. Combination therapies with DAAs and boost immune response are also under development; finding the best combinations will be important for therapeutic development.

A Study on Pregenomic RNA and Factors Related to Hepatitis B Virus Infection Based on Real World

Objective

This article aims to study the influencing factors of pgRNA and its change magnitude based on the real world.

Methods

A total of 421 patients who were tested for pgRNA were selected. According to the baseline data, the subjects were divided into negative and positive groups. The Chi-square test and logistic regression were used to analyze the influencing factors of pgRNA status. Based on the follow-up data, the rank-sum test and linear regression were used to analyze the influencing factors of pgRNA change magnitude.

Results

A total of 153 (36.3%) of the 421 subjects were pgRNA-negative and 268 (63.7%) were pgRNA-positive. Logistic regression analysis showed that positive HBV DNA (OR: 40.51), positive HBeAg (OR: 66.24), tenofovir treatment (OR: 23.47), and entecavir treatment (OR: 14.90) were the independent risk factors for positive pgRNA. Univariate linear regression showed that the pgRNA change magnitude of patients treated with entecavir was higher than that of patients treated with tenofovir. Multivariate linear regression showed that age was an independent factor influencing pgRNA change magnitude.

Conclusions

The pgRNA of patients who were young, female, HBV DNA-positive, high-HBsAg, HBeAg-positive is higher than the detection line. HBV DNA and HBeAg are the independent risk factors of positive pgRNA. Different antiviral regimens and disease stages have significantly different effects on pgRNA status. There was a significant correlation between pgRNA and FIB-4, suggesting that pgRNA is related to liver fibrosis. The decrease in pgRNA was greater in young patients than in non-young patients. The decrease in pgRNA was greater in patients treated with tenofovir than in patients treated with entecavir.

Inhaled siRNA Formulations for Respiratory Diseases: From Basic Research to Clinical Application

The development of siRNA technology has provided new opportunities for gene-specific inhibition and knockdown, as well as new ideas for the treatment of disease. Four siRNA drugs have already been approved for marketing. However, the instability of siRNA in vivo makes systemic delivery ineffective. Inhaled siRNA formulations can deliver drugs directly to the lung, showing great potential for treating respiratory diseases. The clinical applications of inhaled siRNA formulations still face challenges because effective delivery of siRNA to the lung requires overcoming the pulmonary and cellular barriers. This paper reviews the research progress for siRNA inhalation formulations for the treatment of various respiratory diseases and summarizes the chemical structural modifications and the various delivery systems for siRNA. Finally, we conclude the latest clinical application research for inhaled siRNA formulations and discuss the potential difficulty in efficient clinical application.

Higher titer hepatitis B core antibody predicts a higher risk of liver metastases and worse survival in patients with colorectal cancer

BACKGROUND

There have been controversial voices on if hepatitis B virus infection decreases the risk of colorectal liver metastases or not. This study aims to the find the association between HBV infection and postoperative survival of colorectal cancer and the risk of liver metastases in colorectal cancer patients.

METHODS

Patients who underwent curative surgical resection for colorectal cancer between January 2011 and December 2012 were included. Patients were grouped according to anti-HBc. Differences in overall survival, time to progress, and hepatic metastasis-free survival between groups and significant predictors were analyzed.

RESULTS

Three hundred twenty-seven colorectal cancer patients were comprised of 202 anti-HBc negative cases and 125 anti-HBc positive cases, and anti-HBc positive cases were further divided into high-titer anti-HBc group (39) and low-titer anti-HBc group (86). The high-titer anti-HBc group had significantly worse overall survival (5-Yr, 65.45% vs. 80.06%; P < .001), time to progress (5-Yr, 44.26% vs. 84.73%; P < .001), and hepatic metastasis-free survival (5-Yr, 82.44% vs. 94.58%; P = .029) than the low-titer group. Multivariate model showed anti-HBc ≥ 8.8 S/CO was correlated with poor overall survival (HR, 3.510; 95% CI, 1.718-7.17; P < .001), time to progress (HR, 5.747; 95% CI, 2.789-11.842; P < .001), and hepatic metastasis-free survival (HR, 3.754; 95% CI, 1.054-13.369; P = .041) in the anti-HBc positive cases.

CONCLUSIONS

Higher titer anti-HBc predicts a potential higher risk of liver metastases and a worse survival in anti-HBc positive colorectal cancer patients.

Recent developments with advancing gene therapy to treat chronic infection with hepatitis B virus

PURPOSE OF REVIEW

The available vaccine and therapies against hepatitis B virus (HBV) rarely eliminate chronic infection with the virus. High mortality resulting from complicating cirrhosis and hepatocellular carcinoma makes improving anti-HBV therapy an important priority. Recent advances with using gene therapy to counter HBV have potential and are the focus of this review.

RECENT FINDINGS

The stable replication-competent HBV intermediate comprising covalently closed circular DNA (cccDNA) is the template for expression of all viral genes. Inactivating cccDNA has thus been a focus of research aimed at achieving cure for HBV infection. Many studies have reported profound inhibition of replication of the virus using silencing and editing techniques. Therapeutic gene silencing with synthetic short interfering RNA is now in clinical trials. Ability to mutate and permanently inactivate cccDNA with engineered gene editors, such as those derived from CRISPR/Cas or TALENs, is particularly appealing but has not yet reached clinical evaluation.

SUMMARY

Gene silencing and gene editing potentially provide the means to cure HBV infection. However, achieving efficient delivery of therapeutic sequences, ensuring their specificity of action and progress with other antiviral strategies are likely to determine utility of gene therapy for chronic HBV infection.

Hepatitis B virus-host interactions and novel targets for viral cure

Chronic infection with HBV is a major cause of advanced liver disease and hepatocellular carcinoma. Nucleos(t)ide analogues effectively control HBV replication but viral cure is rare. Hence treatment has often to be administered for an indefinite duration, increasing the risk for selection of drug resistant virus variants. PEG-interferon-α-based therapies can sometimes cure infection but suffer from a low response rate and severe side-effects. CHB is characterized by the persistence of a nuclear covalently closed circular DNA (cccDNA), which is not targeted by approved drugs. Targeting host factors which contribute to the viral life cycle provides new opportunities for the development of innovative therapeutic strategies aiming at HBV cure. An improved understanding of the host immune system has resulted in new potentially curative candidate approaches. Here, we review the recent advances in understanding HBV-host interactions and highlight how this knowledge contributes to exploiting host-targeting strategies for a viral cure.

Dicoumarol, an NQO1 inhibitor, blocks cccDNA transcription by promoting degradation of HBx

BACKGROUND & AIMS

Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx.

METHODS

We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model.

RESULTS

Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells.

CONCLUSIONS

Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability.

LAY SUMMARY

Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.

Lipid nanoparticles loaded with ribonucleoprotein-oligonucleotide complexes synthesized using a microfluidic device exhibit robust genome editing and hepatitis B virus inhibition

The clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system has considerable therapeutic potential for use in treating a wide range of intractable genetic and infectious diseases including hepatitis B virus (HBV) infections. While non-viral delivery technologies for the CRISPR/Cas system are expected to have clinical applications, difficulties associated with the clinically relevant synthesis of formulations and the poor efficiency of delivery severely hinder therapeutic genome editing. We report herein on the production of a lipid nanoparticle (LNP)-based CRISPR/Cas ribonucleoprotein (RNP) delivery nanoplatform synthesized using a clinically relevant mixer-equipped microfluidic device. DNA cleavage activity and the aggregation of Cas enzymes was completely avoided under the optimized synthetic conditions. The optimized formulation, which was identified through 2 steps of design of experiments, exhibited excellent gene disruption (up to 97%) and base substitution (up to 23%) without any apparent cytotoxicity. The addition of negative charges to the RNPs by complexing single-stranded oligonucleotide (ssON) significantly enhanced the delivery of both Cas9 and Cpf1 RNPs. The optimized formulation significantly suppressed both HBV DNA and covalently closed circular DNA (cccDNA) in HBV-infected human liver cells compared to adeno-associated virus type 2 (AAV2). These findings represent a significant contribution to the development of CRISPR/Cas RNP delivery technology and its practical applications in genome editing therapy.

Recent Advances in Understanding, Diagnosing, and Treating Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection affects 292 million people worldwide and is associated with a broad range of clinical manifestations including cirrhosis, liver failure, and hepatocellular carcinoma (HCC). Despite the availability of an effective vaccine HBV still causes nearly 900,000 deaths every year. Current treatment options keep HBV under control, but they do not offer a cure as they cannot completely clear HBV from infected hepatocytes. The recent development of reliable cell culture systems allowed for a better understanding of the host and viral mechanisms affecting HBV replication and persistence. Recent advances into the understanding of HBV biology, new potential diagnostic markers of hepatitis B infection, as well as novel antivirals targeting different steps in the HBV replication cycle are summarized in this review article.

Host-Directed Antiviral Therapy

Antiviral drugs have traditionally been developed by directly targeting essential viral components. However, this strategy often fails due to the rapid generation of drug-resistant viruses. Recent genome-wide approaches, such as those employing small interfering RNA (siRNA) or clustered regularly interspaced short palindromic repeats (CRISPR) or those using small molecule chemical inhibitors targeting the cellular "kinome," have been used successfully to identify cellular factors that can support virus replication. Since some of these cellular factors are critical for virus replication, but are dispensable for the host, they can serve as novel targets for antiviral drug development. In addition, potentiation of immune responses, regulation of cytokine storms, and modulation of epigenetic changes upon virus infections are also feasible approaches to control infections. Because it is less likely that viruses will mutate to replace missing cellular functions, the chance of generating drug-resistant mutants with host-targeted inhibitor approaches is minimized. However, drug resistance against some host-directed agents can, in fact, occur under certain circumstances, such as long-term selection pressure of a host-directed antiviral agent that can allow the virus the opportunity to adapt to use an alternate host factor or to alter its affinity toward the target that confers resistance. This review describes novel approaches for antiviral drug development with a focus on host-directed therapies and the potential mechanisms that may account for the acquisition of antiviral drug resistance against host-directed agents.

Diagnostic Value of Detection of Pregenomic RNA in Sera of Hepatitis B Virus-Infected Patients with Different Clinical Outcomes

Pregenomic RNA (pgRNA) is a direct transcription product of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), and it plays important roles in viral genome amplification and replication. This study was designed to investigate whether serum pgRNA is a strong alternative marker for reflecting HBV cccDNA levels and to analyze the correlation between serum pgRNA, serum HBV DNA, and hepatitis B surface antigen (HBsAg). A total of 400 HBV-infected patients who received nucleos(t)ide analog (NA) therapy with different clinical outcomes were involved in this research. Case groups included asymptomatic hepatitis B virus carrier (ASC), chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC) patients, with 100 patients in each group. The results showed that the levels of HBV pgRNA had significant differences between these 4 groups. Serum pgRNA levels correlated well with serum HBV DNA and HBsAg levels (HBV pgRNA levels versus HBV DNA levels, r = 0.58, P < 0.001; HBV pgRNA levels versus HBsAg levels, r = 0.47, P < 0.001). In addition, we focused on the 108 HBV-infected patients with HBV DNA levels of <500 IU/ml; it was surprising to find that in 17.57% (13/74) of cases, HBV pgRNA could be detected even when the HBV DNA level was below 20 IU/ml. In conclusion, HBV pgRNA levels in serum can be a surrogate marker for intrahepatic HBV cccDNA compared with serum HBV DNA and HBsAg. The detection of serum HBV pgRNA levels may provide a reference for clinical monitoring of cccDNA levels and the selection of appropriate timing for discontinuing antiviral therapy, especially when HBV DNA levels are below the detection limit.

Mapping the Interactions of HBV cccDNA with Host Factors

Hepatitis B virus (HBV) infection is a major health problem affecting about 300 million people globally. Although successful administration of a prophylactic vaccine has reduced new infections, a cure for chronic hepatitis B (CHB) is still unavailable. Current anti-HBV therapies slow down disease progression but are not curative as they cannot eliminate or permanently silence HBV covalently closed circular DNA (cccDNA). The cccDNA minichromosome persists in the nuclei of infected hepatocytes where it forms the template for all viral transcription. Interactions between host factors and cccDNA are crucial for its formation, stability, and transcriptional activity. Here, we summarize the reported interactions between HBV cccDNA and various host factors and their implications on HBV replication. While the virus hijacks certain cellular processes to complete its life cycle, there are also host factors that restrict HBV infection. Therefore, we review both positive and negative regulation of HBV cccDNA by host factors and the use of small molecule drugs or sequence-specific nucleases to target these interactions or cccDNA directly. We also discuss several reporter-based surrogate systems that mimic cccDNA biology which can be used for drug library screening of cccDNA-targeting compounds as well as identification of cccDNA-related targets.

Factors associated with disease progression and viral replication in patients with chronic hepatitis B virus infection

Hepatitis B virus (HBV) infection remains a severe clinical concern in China. Of note, the progression of HBV infection varies between different populations. To identify the factors that influence the disease progression and prognosis, a total of 478 chronic HBV-infected patients were enrolled, and liver function parameters, HBV DNA levels and hepatic fibrosis indices were analyzed. First, the results demonstrated a significant difference in hepatitis B e antigen (HBeAg) expression between male and female patients (χ²=4.061, P=0.044). Furthermore, when comparing either HBeAg-negative or -positive male and female patients, males exhibited a greater variation in HBV DNA levels. Although significant differences between male and female patients in certain abnormal ratios of liver function parameters were identified, a trend in the differences was observed in the HBeAg-negative and -positive groups. When considering age, the results of the present study confirmed that HBV DNA levels decreased with advanced age, and the values of the majority of biomarkers exhibited an evident decreasing trend with increasing age. In addition, it was demonstrated that all HBeAg seropositive patients had higher levels of hepatic fibrosis indexes and higher abnormal ratios of hepatic fibrosis values in their serum when compared with those of HBeAg seronegative patients, particularly with regard to serum IV collagen. The present results revealed that HBV DNA replication was closely associated with liver function; however, it was notable that in HBeAg-negative patients, the association between HBV DNA levels and liver function was particularly significant among subjects aged <61. Furthermore, this result was not observed in HBeAg-positive patients. In conclusion, the present study indicated the importance of host factors (including sex and age) and viral factors (including HBeAg expression pattern and HBV DNA levels) in the progression of chronic HBV infection, and its influence regarding prognosis and treatment. The present results provide a foundation for clinical management strategies for chronic HBV infection, particularly in individual schemes.