Recent progress in potential anti-hepatitis B virus agents: Structural and pharmacological perspectives

Discovery of pentacyclic triterpene conjugates as HBV polymerase/NTCP dual-targeting inhibitors with potent anti-HBV activities

The inhibition of HBV DNA and elimination of HBsAg has already been established as an indicator for HBV clinic cure, and a novel dual-targeting inhibitors of HBV polymerase/entry are designed and synthesized in this study. Pentacyclic triterpenes (PTs) scaffold of exhibiting a high affinity to NTCP, including glycyrrhitinic acid (GA), oleanolic acid (OA), ursolic acid (UA), and betulinic acid (BA) were linked neatly with the nucleoside drug zidovudine (AZT) through a molecular hybrid strategy to synthesize twenty of PTs-AZT conjugates for targeting HBV polymerase as well as sodium taurocholate cotransporting polypeptide (NTCP). The conjugates showed significant inhibitory effects on the secretion of HBsAg and HBeAg in HepG2.2.15 cells, and the activity on HBsAg were better. Moreover, HBV DNA replication was also notably suppressed after incubated with the conjugates. The IC50 value of BA-AZT1 on HBsAg inhibition was 0.65 ± 0.07 μM, and it was 284.2 times and 442.2 times higher comparing to corresponding parent compound BA and AZT. Additionally, the therapeutic index (TI) was also improved by 87.8 times than AZT. And the IC50 value of BA-AZT1 on inhibition of HBV DNA replication was 0.70 ± 0.02 μM, 10.4 times higher than that of AZT besides conspicuous TI. Molecular docking suggested that AZT skeleton of conjugate BA-AZT1 interacted with B region of HBV Polymerase reverse transcription region, and BA structure simultaneously targeted to C region of polymerase via hydrophobic chain, establishing strong binding interactions with the HBV Pol protein. In addition, docked with NTCP, BA-AZT1 with flat pentacyclic structure inserted into the interface and also formed hydrogen bonds, hydrophobic and van der Waals forces with the amino residue 157-165 of NTCP. Further SPR analysis demonstrated the binding affinity of BA-AZT1 to C region of polymerase was 19.55 μM, stronger than 53.21 μM of BA and 31.82 μM of AZT. BA-AZT1 selectively bound to the 157-165 epitopes of NTCP receptors in host cell but not PreS1 of virus. As a result, we deduced that the designed conjugates targeted NTCP and HBV polymerase, not only prevented HBV from entering host cells via selective binding NTCP, but also inhibited HBV DNA replication through obstructing the function of HBV polymerase, and it could potentially serve as a promising dual-functional and dual-target inhibitor with both replication and entry inhibition to exert anti-HBV activity.

Targeting HBV cccDNA Levels: Key to Achieving Complete Cure of Chronic Hepatitis B

Chronic hepatitis B (CHB) caused by HBV infection has brought suffering to numerous people. Due to the stable existence of HBV cccDNA, the original template for HBV replication, chronic hepatitis B (CHB) is difficult to cure completely. Despite current antiviral strategies being able to effectively limit the progression of CHB, complete CHB cure requires directly targeting HBV cccDNA. In this review, we discuss strategies that may achieve a complete cure of CHB, including inhibition of cccDNA de novo synthesis, targeting cccDNA degradation through host factors and small molecules, CRISP-Cas9-based cccDNA editing, and silencing cccDNA epigenetically.

Renal and bone side effects of long-term use of entecavir, tenofovir disoproxil fumarate, and tenofovir alafenamide fumarate in patients with Hepatitis B: a network meta-analysis

BACKGROUND

Nucleoside analogues are currently applied as a first-line treatment for chronic hepatitis B (CHB) patients. However, the long-term effects of this type of treatment on kidney and bone tissue need to be further investigated.

METHODS

We conducted a search of entecavir (ETV), tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide fumarate (TAF) for treatment of CHB patients through October 29, 2023. Side effects of the three drugs were compared. Standardized mean difference (SMD), 95% confidence interval (95%CI), and surface under the cumulative ranking curve (SUCRA) were reported for each outcome. Further subgroup analysis was conducted according to duration of administration.

RESULTS

ETV and TAF exhibited less effect on estimated glomerular filtration rate (eGFR) than TDF (SMD = -3.60 (95%CI: -1.94 ~ -5.26) and SMD = -4.27 (95%CI: -2.62 ~ -5.93)). ETV also exhibited less effect on creatinine rise than TAF and TDF (SMD = -0.55 (95%CI: -0.09 ~ -1.01) and SMD = -0.61 (95%CI: -0.15 ~ -1.06)). Moreover, the effect of TAF on bone mineral density (BMD) was less than that of TDF (SMD = -0.02 (95%CI: -0.01 ~ -0.02)). The probabilities of the three drugs changing relevant indicators exhibited similar patterns: eGFR (TDF (100.0%) > ETV (41.2%) > TAF (8.8%)), creatinine (TDF (94.7%) > TAF (54.7%) > ETV (0.6%)), BMD (TDF (79.7%) > ETV (50.6%) > TAF (19.6%)), and blood phosphorus (TDF (90.6%) > TAF (49.8%) > ETV (9.7%)). After 6 and 24 months of treatment, no statistically significant difference in renal function or bone tissue was observed between ETV and TDF. However, greater adverse effects on renal function were observed for TDF than ETV at 60 months compared to 12 months. TDF also exhibited greater adverse effects on bone tissue than ETV at 36 months than at 12 months.

CONCLUSIONS

Long-term administration of TDF has resulted in stronger adverse effects than TAF and ETV in regard to both renal function and bone tissue in CHB patients. The effect of TAF on creatinine increase was greater than ETV. The difference in side effects between ETV and TDF was independent of treatment duration.

YinQiSanHuang Jiedu decoction for the treatment of hepatitis B-related compensated liver cirrhosis: study protocol for a multi-center randomized controlled trial

INTRODUCTION

Hepatitis B-related compensated liver cirrhosis is related to a higher risk of hepatocellular carcinoma, and antiviral therapy is the preferred method. As the pathological mechanisms of liver fibrosis are complex, drugs developed for a single target are difficult to be effective in clinical practice, so there are no chemical drugs or biological drugs with clear efficacy available for clinical application at present. Traditional Chinese medicine is a kind of medical science that has been gradually formed during thousands of years and continuously enriched by the people of all ethnic groups in China. Traditional Chinese medicine shows curative effects in the treatment of liver diseases, especially in the field of liver fibrosis prevention and treatment. This study aims to test the integrative medicine (Chinese medicine plus antiviral therapy) effective on lowing hepatocellular carcinoma risk among patients with hepatitis-related compensated liver cirrhosis.

METHODS AND ANALYSIS

This is a multi-center randomized controlled trial, and a total of 5 hospitals and 802 patients will be involved in. All the subjects are randomly allocated to the YinQiSanHuang Jiedu decoction (YQSHD) group (n = 401) or the placebo group (n = 401). The YQSHD group receives YQSHD granule with entecavir (ETV), and the placebo group receives YQSHD placebo with ETV. The treatment period will last for 52 weeks, and the follow-up period for 52 ± 2 weeks. The primary outcome measure is the annual incidence of HCC. Outcomes will be assessed at baseline and after treatment. The objective of this trial is "the integrative of YQSHD with ETV reduce the annual incidence of HCC to 1%."

ETHICS AND DISSEMINATION

The protocol has been approved by the Medical Ethics Committee of Guang'anmen Hospital, China (No.2019-006-KY), and the other centers in the trial will not begin recruiting until the local ethical approval has been obtained. Trial final results will be disseminated via publication.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1900021532 . Registered on February 26, 2019.

Pyridine Derivatives-A New Class of Compounds That Are Toxic to E. coli K12, R2-R4 Strains

A preliminary study of 2-amino-4-aryl-3,5-dicarbonitrile-6-thiopyridines as new potential antimicrobial drugs was performed. Special emphasis was placed on the selection of the structure of target pyridine derivatives with the highest biological activity against different types of Gram-stained bacteria by lipopolysaccharide (LPS). Herein, Escherichia coli model strains K12 (without LPS in its structure) and R2–R4 (with different lengths of LPS in its structure) were used. Studied target compounds were provided with yields ranging from 53% to 91% by the lipase-catalyzed one pot multicomponent reaction of various aromatic aldehydes with malononitrile, and thiols. The presented work showed that the antibacterial activity of the studied pyridines depends on their structure and affects the LPS of bacteria. Moreover, the influence of the pyridines on bacteria possessing smooth and rough LPS and oxidative damage to plasmid DNA caused by investigated compounds was indicated. Additionally, the modification of the bacterial DNA with the tested compounds was performed to detect new potential oxidative damages, which are recognized by the Fpg protein. The obtained damage modification values of the analyzed compounds were compared with the modifications after antibiotics were used in this type of research. The presented studies demonstrate that 2-amino-4-aryl-3,5-dicarbonitrile-6-thiopyridines can be used as substitutes for known antibiotics. The observed results are especially important in the case of the increasing resistance of bacteria to various drugs and antibiotics.

Discovery of Phthalazinone Derivatives as Novel Hepatitis B Virus Capsid Inhibitors

HBV capsid assembly has been viewed as an attractive target for new antiviral therapies against HBV. On the basis of a lead compound 4r, we further investigated this target to identify novel active compounds with appropriate anti-HBV potencies and improved pharmacokinetic (PK) properties. Structure-activity relationship studies based on metabolic pathways of 4r led to the identification of a phthalazinone derivative 19f with appropriate anti-HBV potencies (IC₅₀ = 0.014 ± 0.004 μM in vitro), which demonstrated high oral bioavailability and liver exposure. In the AAV-HBV/mouse model, administration of 19f resulted in a 2.67 log reduction of the HBV DNA viral load during a 4-week treatment with 150 mg/kg dosing twice daily.

Efficacy and safety of YinQiSanHuang-antiviral decoction in chronic hepatitis B: study protocol for a randomized, placebo-controlled, double-blinded trial

Introduction

Chronic hepatitis B (CHB) is a global public health problem. Antiviral therapy is the primary treatment. Studies have shown that a combined therapy of traditional Chinese medicine (TCM) and conventional antiviral drugs has better efficacy than conventional antiviral for treatment of CHB. YinQiSanHuang-antiviral decoction (YQSH) is a TCM compound preparation that has shown an effect on anti-hepatitis B virus and on slowing progression of hepatitis B-related liver diseases. To evaluate the efficacy and safety of YQSH combined with entecavir and its preventive effect on hepatitis B cirrhosis, we designed this randomized, double-blind and placebo-controlled trial. The objective is that the combination of YinQiSanHuang-antiviral decoction with entecavir will reduce the annual incidence of liver fibrosis/cirrhosis to 1%.

Methods

This is a multicenter, randomized, placebo-controlled, double-blinded trial involving five hospitals. A total of 802 patients are randomly allocated to two groups: the YQSH group (n = 401) or the placebo group (n = 401). The YQSH group receives YQSH with entecavir; the placebo group receives granules of placebo with entecavir. Patients receive treatment for 52 weeks and then are followed up for 52 ± 2 weeks. The primary outcome measure is the annual incidence of cirrhosis. The secondary outcome measures are hepatitis B virus DNA negative rate, hepatitis B surface antigen negative rate, hepatitis B e antigen seroconversion rate, liver function (alanine aminotransferase, aspartate aminotransferase , gamma-glutamyl transferase , alkaline phosphatase , serum albumin, and total bilirubin), spleen thickness, evaluation scores of patients’ clinical symptoms, and safety assessment. Outcomes will be assessed at baseline and after treatment.

Discussion

Combination therapy could become a trend for treatment of CHB, and this trial expects to provide credible clinical evidence for the future combination of TCM and conventional antiviral drugs for the treatment of CHB.

Trial registration

Chinese Clinical Trial Registry: ChiCTR1900021521. Registered on 25 February 2019.

Codon usage pattern and its influencing factors in different genomes of hepadnaviruses

Codon usage bias (CUB) arises from the preference for a codon over codons for the same amino acid. The major factors contributing to CUB are evolutionary forces, compositional properties, gene expression, and protein properties. The present analysis was performed to investigate the compositional properties and the extent of CUB across the genomes of members of the family Hepadnaviridae, as previously no work using bioinformatic tools has been reported. The viral genes were found to be AT rich with low CUB. Analysis of relative synonymous codon usage (RSCU) was used to identify overrepresented and underrepresented codons for each amino acid. Correlation analysis of overall nucleotide composition and its composition at the third codon position suggested that mutation pressure might influence the CUB. A highly significant correlation was observed between GC12 and GC3 (r = 0.910, p < 0.01), indicating that directional mutation affected all three codon positions across the genome. Translational selection (P2) and mutational responsive index (MRI) values of genes suggested that mutation plays a more important role than translational selection in members of the family Hepadnaviridae.

A dendritic cell receptor-targeted chimeric immunotherapeutic protein (C-HBV) for the treatment of chronic hepatitis B

In chronic Hepatitis B Virus (HBV) infections HBV-specific T cells are functionally impaired. Immunotherapy may restore HBV-specific T cell responses essential for sustained disease remission off-treatment and induction of a functional cure. Chimigen® Molecules are fusion proteins of antigen(s) with the Fc fragment of a xenotypic antibody designed to target specific receptors on dendritic cells (DCs). Here we describe the production and pre-clinical evaluation of Chimigen® HBV (C-HBV), containing HBV PreS1 and PreS2 peptide fragments, HBV core and murine Fc, produced in insect cells. C-HBV binding to immature DCs and internalization by endocytosis was FcγRII (CD32) and mannose receptor (CD206) dependent and led to increased MHC I and MHC II surface expression. Upon exposure of human T cells isolated from HBV un-infected healthy and chronically HBV-infected donors to C-HBV-pulsed mature DCs ex vivo, C-HBV induced vigorous T cell proliferation and enhanced expression of IFN-γ, TNF-α, perforin and granzyme B in both CD4⁺ and CD8⁺ T cell subsets. Re-stimulation of C-HBV-activated T cells from chronically infected donors with HBV PreS1/PreS2 and core overlapping peptides induced IFN-γ production in both CD4⁺ and CD8⁺ populations. C-HBV-activation of peripheral blood mononuclear cells (PBMCs) from chronically HBV-infected patients stimulated granzyme B production by CD4⁺CD25^- T responder (Tresp) cells, accompanied by an increase in Annexin V staining on CD4⁺CD25⁺ T regulatory (Treg) cell phenotype, consistent with apoptosis. The observed HBV-specific cellular responses induced by C-HBV ex vivo suggest that C-HBV is a promising immunotherapeutic candidate for the treatment of chronic HBV infections.

A dendritic cell-targeted chimeric hepatitis B virus immunotherapeutic vaccine induces both cellular and humoral immune responses in vivo

Chimigen® HBV Immunotherapeutic Vaccine (C-HBV), a recombinant chimeric fusion protein comprising hepatitis B virus (HBV) S1 and S2 surface antigen fragments, Core antigen and a murine monoclonal antibody heavy chain fragment (Fc), was designed and produced in Sf9 insect cells. C-HBV targets the host immune system through specific receptors present on dendritic cells (DCs) which facilitates antigen internalization, processing, and presentation on MHC class I and II to induce both cellular and humoral immune responses against HBV antigens. T cell responses, previously assessed by ex vivo antigen presentation assays using human peripheral blood mononuclear cell (PBMC)-derived DCs and T cells from uninfected and HBV chronic-infected donors, demonstrated that C-HBV was highly immunogenic. A vaccine dose response study was performed in sheep to analyze the immunogenicity of C-HBV in vivo. Sheep (n = 8/group) received three consecutive subcutaneous injections of each dose of C-HBV at four-week intervals. Analysis of serum antibody levels confirmed C-HBV induced a dose-dependent antibody response to C-HBV and S1/S2-Core. Kinetics of the S1/S2-Core specific antibody response was similar to hepatitis B surface antigen (HBsAg)-specific antibody responses induced by ENGERIX-B. Analysis of cell-mediated immune responses (CMI) confirmed C-HBV induced both dose-dependent S1/S2-Core-specific lymphocyte proliferative responses and IFN-γ secretion. These responses were stronger with blood lymphocytes than with cells isolated from the lymph node draining the vaccination site. No correlation was seen between antibody titers and CMI. The results confirm C-HBV is an effective delivery vehicle for the induction of T cell responses and may be an appropriate candidate for immunotherapy for chronic HBV infections.

A Newly Established Murine Cell Line as a Model for Hepatocellular Cancer in Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) has become a major risk factor for hepatocellular cancer (HCC) due to the worldwide increasing prevalence of obesity. However, the pathophysiology of NASH and its progression to HCC is incompletely understood. Thus, the aim of this study was to generate a model specific NASH-derived HCC cell line. A murine NASH-HCC model was conducted and the obtained cancer cells (N-HCC25) were investigated towards chromosomal aberrations, the expression of cell type-specific markers, dependency on nutrients, and functional importance of mTOR. N-HCC25 exhibited several chromosomal aberrations as compared to healthy hepatocytes. Hepatocytic (HNF4), EMT (Twist, Snail), and cancer stem cell markers (CD44, EpCAM, CK19, Sox9) were simultaneously expressed in these cells. Proliferation highly depended on the supply of glucose and FBS, but not glutamine. Treatment with a second generation mTOR inhibitor (KU-0063794) resulted in a strong decrease of cell growth in a dose-dependent manner. In contrast, a first generation mTOR inhibitor (Everolimus) only slightly reduced cell proliferation. Cell cycle analyses revealed that the observed growth reduction was most likely due to G₁/G₀ cell cycle arrest. These results indicate that N-HCC25 is a highly proliferative HCC cell line from a NASH background, which might serve as a suitable in vitro model for future investigations of NASH-derived HCC.

MicroRNA-802 induces hepatitis B virus replication and replication through regulating SMARCE1 expression in hepatocellular carcinoma

Growing evidences have indicated that microRNAs (miRNAs) can regulate hepatitis B virus (HBV) expression and replication, playing crucial roles in the development of HBV infection. Until now, the functional role and mechanism of miR-802 in HBV replication and expression remain unknown. We indicated that miR-802 expression was upregulated in the HBV-associated hepatocellular carcinoma (HCC) tissues compared with the adjacent noncancerous samples. In addition, we showed that the SMARCE1 expression level was downregulated in the HBV-associated HCC tissues compared with the adjacent noncancerous samples. miR-802 expression was negatively related with MARCE1 expression in HBV-associated HCC tissues. Moreover, miR-802 expression was upregulated, and SMARCE1 expression was downregulated in the HBV-infected HepG2.2.15 cells. Ectopic expression of miR-802 significantly enhanced HBV DNA replication, while knockdown of miR-802 significantly decreased HBV DNA replication. We showed that overexpression of miR-802 promoted HbsAg and HbeAg expression, while inhibition of miR-802 decreased HbsAg and HbeAg expression. Furthermore, we indicated that ectopic expression of SMARCE1 suppressed HBV DNA replication and decreased the expression level of HbsAg and HbeAg. Finally, we showed that overexpression of miR-802 promoted HBV DNA replication through regulating SMARCE1 expression. These results suggested the important roles of miR-802 on HBV expression and replication, which may shed new light on the development of treatment for HBV.

Prolonged inhibition of hepatocellular carcinoma cell proliferation by combinatorial expression of defined transcription factors

Hepatocellular carcinoma (HCC) accounts for a large proportion of liver cancer cases and has an extremely poor prognosis. Therefore, novel innovative therapies for HCC are strongly desired. As gene therapy tools for HCC, 2 hepatic transcription factors (TF), HNF4A and HNF1A, have been used to suppress proliferation and to extinguish cancer‐specific characteristics of target cells. However, our present data demonstrated that single transduction of HNF4A or HNF1A had only a limited effect on suppression of HCC cell proliferation. Thus, in this study, we examined whether combinations of TF could show more effective antitumor activity, and found that combinatorial transduction of 3 hepatic TF, HNF4A, HNF1A and FOXA3, suppressed HCC cell proliferation more stably than single transduction of these TF. The combinatorial transduction also suppressed cancer‐specific phenotypes, such as anchorage‐independent growth in culture and tumorigenicity after transplantation into mice. HCC cell lines transduced with the 3 TF did not recover their proliferative property after withdrawal of anticancer drugs, indicating that combinatorial expression of the 3 TF suppressed the growth of all cell subtypes within the HCC cell lines, including cancer stem‐like cells. Transcriptome analyses revealed that the expression levels of a specific gene set involved in cell proliferation were only decreased in HCC cells overexpressing all 3 TF. Moreover, combined transduction of the 3 TF could facilitate hepatic differentiation of HCC cell lines. Our strategy for inducing stable inhibition and functional differentiation of tumor cells using a defined set of TF will become an effective therapeutic strategy for various types of cancers.

ABPP and Host-Virus Interactions

Successful viral infection, as well as any resultant antiviral response, relies on numerous sequential interactions between host and viral factors. These interactions can take the form of affinity-based interactions between viral and host macromolecules or active, enzyme-based interactions, consisting both of direct enzyme activity performed by viral enzymes and indirect modulation of the activity of the host cell's enzymes via viral interference. This activity has the potential to transform the local microenvironment to the benefit or detriment of both the virus and the host, favouring either the continuation of the viral life cycle or the host's antiviral response. Comprehensive characterisation of enzymatic activity during viral infection is therefore necessary for the understanding of virally induced diseases. Activity-based protein profiling techniques have been established as effective and practicable tools with which to interrogate the regulation of enzymes' catalytic activity and the roles played by these enzymes in various cell processes. This paper will review the contributions of these techniques in characterising the roles of both host and viral enzymes during viral infection in humans.