Serum miR-192-5p levels predict the efficacy of pegylated interferon therapy for chronic hepatitis B.

We examined the association between serum miRNA (-192-5p, -122-3p, -320a and -6126-5p) levels and the efficacy of pegylated interferon (Peg-IFN) monotherapy for chronic hepatitis B (CHB) patients. We enrolled 61 CHB patients treated with Peg-IFNα-2a weekly for 48 weeks, of whom 12 had a virological response (VR) and 49 did not VR (non-VR). A VR was defined as HBV DNA < 2,000 IU/ml, hepatitis B e antigen (HBeAg)-negative, and nucleos(t)ide analogue free at 48 weeks after the end of treatment. The non-VR group showed a significantly higher HBeAg-positivity rate, ALT, HBV DNA, and serum miR-192-5p levels at baseline (P = 0.024, P = 0.020, P = 0.007, P = 0.021, respectively). Serum miR-192-5p levels at 24-weeks after the start of treatment were also significantly higher in the non-VR than the VR group (P = 0.011). Multivariate logistic regression analysis for predicting VR showed that miR-192-5p level at baseline was an independent factor (Odds 4.5, P = 0.041). Serum miR-192-5p levels were significantly correlated with the levels of HBV DNA, hepatitis B core-related antigen, and hepatitis B surface antigen (r = 0.484, 0.384 and 0.759, respectively). The serum miR-192-5p level was useful as a biomarker for the therapeutic efficacy of Peg-IFN in CHB treatment.

Complex decay dynamics of HIV virions, intact and defective proviruses, and 2LTR circles following initiation of antiretroviral therapy.

In persons living with HIV-1 (PLWH) who start antiretroviral therapy (ART), plasma virus decays in a biphasic fashion to below the detection limit. The first phase reflects the short half-life (<1 d) of cells that produce most of the plasma virus. The second phase represents the slower turnover (t1/2 = 14 d) of another infected cell population, whose identity is unclear. Using the intact proviral DNA assay (IPDA) to distinguish intact and defective proviruses, we analyzed viral decay in 17 PLWH initiating ART. Circulating CD4+ T cells with intact proviruses include few of the rapidly decaying first-phase cells. Instead, this population initially decays more slowly (t1/2 = 12.9 d) in a process that largely represents death or exit from the circulation rather than transition to latency. This more protracted decay potentially allows for immune selection. After ∼3 mo, the decay slope changes, and CD4+ T cells with intact proviruses decay with a half-life of 19 mo, which is still shorter than that of the latently infected cells that persist on long-term ART. Two-long-terminal repeat (2LTR) circles decay with fast and slow phases paralleling intact proviruses, a finding that precludes their use as a simple marker of ongoing viral replication. Proviruses with defects at the 5' or 3' end of the genome show equivalent monophasic decay at rates that vary among individuals. Understanding these complex early decay processes is important for correct use of reservoir assays and may provide insights into properties of surviving cells that can constitute the stable latent reservoir.

G-Quadruplexes Formation at the Upstream Region of Replication Origin (OriL) of the Pseudorabies Virus: Implications for Antiviral Targets.

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease, which still causes large economic losses for the swine industry. Therefore, it is urgent to find a new strategy to prevent and control PRV infection. Previous studies have proven that guanine (G)-rich DNA or RNA sequences in some other viruses' genomes have the potential to form G-quadruplex (G4), which serve as promising antivirus targets. In this study, we identified two novel G4-forming sequences, OriL-A and OriL-S, which are located at the upstream origin of replication (OriL) in the PRV genome and conserved across 32 PRV strains. Circular dichroism (CD) spectroscopy and a gel electrophoresis assay showed that the two G-rich sequences can fold into parallel G4 structures in vitro. Moreover, fluorescence resonance energy transfer (FRET) melting and a Taq polymerase stop assay indicated that the G4 ligand PhenDC3 has the capacity to bind and stabilize the G4. Notably, the treatment of PRV-infected cells with G4-stabilizer PhenDC3 significantly inhibited PRV DNA replication in host cells but did not affect PRV's attachment and entry. These results not only expand our knowledge about the G4 characteristics in the PRV genome but also suggest that G4 may serve as an innovative therapeutic target against PRV.

KSHV-specific antivirals targeting the protein-DNA interaction of the latency-associated nuclear antigen.

The Kaposi sarcoma-associated herpesvirus (KSHV) is an oncogenic human herpesviruses that is responsible for cancer, especially in immunosuppressed people, such as patients with AIDS. So far, there are no KSHV-specifc antiviral agents available. In this review, we provide an overview on one particular target-centered approach toward novel anti-KSHV drugs focusing on interfering with the molecular functions of the latency-associated nuclear antigen (LANA). This review focuses on attempts to interfere with the LANA-DNA interaction mediated by the C-terminal domain. We describe the drug discovery approaches chosen for this endeavor as well as molecular structures that were identified in this innovative concept toward novel and KSHV-specific antiherpesviral agents.

In vitro selection of an RNA aptamer yields an interleukin-6/interleukin-6 receptor interaction inhibitor.

Interleukin-6 (IL-6) binds to the IL-6 receptor (IL-6R) subunit, related to autoimmune diseases and cytokine storm in COVID-19. In this study, we performed systematic evolution of ligands by exponential enrichment and identified a novel RNA aptamer. This RNA aptamer not only bound to IL-6R with a dissociation constant of 200 n m, but also inhibited the interaction of IL-6R with IL-6.

Antiviral Activity of the G-Quadruplex Ligand TMPyP4 against Herpes Simplex Virus-1.

The herpes simplex virus 1 (HSV-1) genome is extremely rich in guanine tracts that fold into G-quadruplexes (G4s), nucleic acid secondary structures implicated in key biological functions. Viral G4s were visualized in HSV-1 infected cells, with massive virus cycle-dependent G4-formation peaking during viral DNA replication. Small molecules that specifically interact with G4s have been shown to inhibit HSV-1 DNA replication. We here investigated the antiviral activity of TMPyP4, a porphyrin known to interact with G4s. The analogue TMPyP2, with lower G4 affinity, was used as control. We showed by biophysical analysis that TMPyP4 interacts with HSV-1 G4s, and inhibits polymerase progression in vitro; in infected cells, it displayed good antiviral activity which, however, was independent of inhibition of virus DNA replication or entry. At low TMPyP4 concentration, the virus released by the cells was almost null, while inside the cell virus amounts were at control levels. TEM analysis showed that virus particles were trapped inside cytoplasmatic vesicles, which could not be ascribed to autophagy, as proven by RT-qPCR, western blot, and immunofluorescence analysis. Our data indicate a unique mechanism of action of TMPyP4 against HSV-1, and suggest the unprecedented involvement of currently unknown G4s in viral or antiviral cellular defense pathways.

Increased Proviral DNA in Circulating Cells Correlates with Plasma Viral Rebound in Simian Immunodeficiency Virus-Infected Rhesus Macaques after Antiretroviral Therapy Interruption.

The human immunodeficiency virus (HIV) reservoir is responsible for persistent viral infection, and a small number of mosaic latent cellular reservoirs promote viral rebound upon antiretroviral therapy interruption, which is the major obstacle to a cure. However, markers that determine effective therapy and viral rebound posttreatment interruption remain unclear. In this study, we comprehensively and longitudinally tracked dynamic decay of cell-associated viral RNA/DNA in systemic and lymphoid tissues in simian immunodeficiency virus (SIV)-infected rhesus macaques on prolonged combined antiretroviral therapy (cART) and evaluated predictors of viral rebound after treatment cessation. The results showed that suppressive ART substantially reduced plasma SIV RNA, cell-associated unspliced, and multiply spliced SIV RNA to undetectable levels, yet viral DNA remained detectable in systemic tissues and lymphoid compartments throughout cART. Intriguingly, a rapid increase of integrated proviral DNA in peripheral mononuclear cells was detected once treatment was withdrawn, accompanied by the emergence of detectable plasma viral load. Notably, the increase of peripheral proviral DNA after treatment interruption correlated with the emergence and degree of viral rebound. These findings suggest that measuring total viral DNA in SIV infection may be a relatively simple surrogate marker of reservoir size and may predict viral rebound after treatment interruption and inform treatment strategies.IMPORTANCE Viral reservoirs are involved in persistent HIV infection, and a small number of mosaic latent cellular reservoirs promote viral rebound upon analytical treatment interruption, which is the major obstacle to a cure. However, early indicators that can predict resurgence of viremia after treatment interruption may aid treatment decisions in people living with HIV. Utilizing the rhesus macaque model, we demonstrated that increased proviral DNA in peripheral cells after treatment interruption, rather than levels of proviral DNA, was a useful marker to predict the emergence and degree of viral rebound after treatment interruption, providing a rapid approach for monitoring HIV rebound and informing decisions.

Inactivation of Severe Acute Respiratory Coronavirus Virus 2 (SARS-CoV-2) and Diverse RNA and DNA Viruses on Three-Dimensionally Printed Surgical Mask Materials.

BACKGROUND: Personal protective equipment (PPE) is a critical need during the coronavirus disease 2019 (COVID-19) pandemic. Alternative sources of surgical masks, including 3-dimensionally (3D) printed approaches that may be reused, are urgently needed to prevent PPE shortages. Few data exist identifying decontamination strategies to inactivate viral pathogens and retain 3D-printing material integrity. OBJECTIVE: To test viral disinfection methods on 3D-printing materials. METHODS: The viricidal activity of common disinfectants (10% bleach, quaternary ammonium sanitizer, 3% hydrogen peroxide, or 70% isopropanol and exposure to heat (50°C, and 70°C) were tested on four 3D-printed materials used in the healthcare setting, including a surgical mask design developed by the Veterans' Health Administration. Inactivation was assessed for several clinically relevant RNA and DNA pathogenic viruses, including severe acute respiratory coronavirus virus 2 (SARS-CoV-2) and human immunodeficiency virus 1 (HIV-1). RESULTS: SARS-CoV-2 and all viruses tested were completely inactivated by a single application of bleach, ammonium quaternary compounds, or hydrogen peroxide. Similarly, exposure to dry heat (70°C) for 30 minutes completely inactivated all viruses tested. In contrast, 70% isopropanol reduced viral titers significantly less well following a single application. Inactivation did not interfere with material integrity of the 3D-printed materials. CONCLUSIONS: Several standard decontamination approaches effectively disinfected 3D-printed materials. These approaches were effective in the inactivation SARS-CoV-2, its surrogates, and other clinically relevant viral pathogens. The decontamination of 3D-printed surgical mask materials may be useful during crisis situations in which surgical mask supplies are limited.

Rapid Turnover of Hepatitis B Virus Covalently Closed Circular DNA Indicated by Monitoring Emergence and Reversion of Signature-Mutation in Treated Chronic Hepatitis B Patients.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) plays a pivotal role in the establishment and persistence of HBV infection. Understanding the turnover time of preexisting cccDNA pools would be helpful in designing strategies to clear HBV by fully blocking the de novo generation of cccDNA. APPROACH AND RESULTS: In this study, we retrospectively monitored the emergence and reversion of the rtM204I/V mutant, a signature lamivudine resistance (LAMR ) mutation serving as a biomarker of cccDNA turnover in liver biopsies and longitudinal serum samples from two clinical trials. Methodologies were optimized to differentially isolate and sequence HBV virion DNA, cccDNA, and HBV RNA from clinical samples. A strong correlation was observed between LAMR composition of cccDNA with that of serum and intrahepatic HBV RNA in paired liver and serum samples (r = 0.96 and 0.90, respectively), suggesting that serum HBV RNA can serve as a surrogate marker of cccDNA genetic composition when liver biopsies are unavailable. LAMR mutations emerged and increased from undetectable to 40%-90% within 16-28 weeks in serum HBV RNA from telbivudine-treated patients experiencing virological breakthrough. Similarly, in lamivudine-resistant patients who switched to interferon therapy, serum HBV-RNA population bearing 100% LAMR mutations fully reversed back to wild type within 24-48 weeks. CONCLUSIONS: The genetic composition dynamics of serum HBV RNA and biopsy cccDNA in treated HBV patients indicates that cccDNA turnover occurs relatively rapidly (several months), offering a possibility of HBV cure with finite therapy through completely blocking cccDNA replenishment.

Efficacy of Nucleotide/Nucleoside Analogues and Hepatitis B Immunoglobulin Therapy in Blocking Mother-to-Child Transmission of Hepatitis B in an Eastern Chinese Group.

The objective of this study was to investigate the efficacy and potential side-effects of nucleotide/nucleoside analogues and hepatitis B immunoglobulin injection of newborns in blocking mother-to-child transmission of hepatitis B virus in the middle and late pregnancy period. 238 cases of enrolled pregnant women were divided into the Telbivudine group, the Tenofovir group, the Lamivudine group, and the hepatitis B immunoglobulin (HBIG) group. Enrolled patients received corresponding therapies. Clinical and laboratory data were collected. Results showed that the levels of HBV DNA of the enrolled pregnant women in the Telbivudine, Tenofovir, and Lamivudine groups decreased rapidly after 12 weeks of drug intervention compared with those in the control. HBsAg positive rate in newborns and in children 24 weeks after birth was 0/60, 0/60, 0/60, 3/30, and 11/28 in the Telbivudine, Tenofovir, Lamivudine, HBIG, and control groups, respectively. No significant side-effects were identified after following up to 12 months after birth. Our results show that routine HBV vaccine plus HBIG injections is insufficient in blocking mother-to-child HBV transmission. Administration of nucleotide/nucleoside analogues or HBIG at pregnancy is suggested to maximize the blocking of vertical HBV transmission.

Interrogating Host Antiviral Environments Driven by Nuclear DNA Sensing: A Multiomic Perspective.

Nuclear DNA sensors are critical components of the mammalian innate immune system, recognizing the presence of pathogens and initiating immune signaling. These proteins act in the nuclei of infected cells by binding to foreign DNA, such as the viral genomes of nuclear-replicating DNA viruses herpes simplex virus type 1 (HSV-1) and human cytomegalovirus (HCMV). Upon binding to pathogenic DNA, the nuclear DNA sensors were shown to initiate antiviral cytokines, as well as to suppress viral gene expression. These host defense responses involve complex signaling processes that, through protein-protein interactions (PPIs) and post-translational modifications (PTMs), drive extensive remodeling of the cellular transcriptome, proteome, and secretome to generate an antiviral environment. As such, a holistic understanding of these changes is required to understand the mechanisms through which nuclear DNA sensors act. The advent of omics techniques has revolutionized the speed and scale at which biological research is conducted and has been used to make great strides in uncovering the molecular underpinnings of DNA sensing. Here, we review the contribution of proteomics approaches to characterizing nuclear DNA sensors via the discovery of functional PPIs and PTMs, as well as proteome and secretome changes that define a host antiviral environment. We also highlight the value of and future need for integrative multiomic efforts to gain a systems-level understanding of DNA sensors and their influence on epigenetic and transcriptomic alterations during infection.

Significance of Hepatitis B Recurrence in Liver Transplantation Recipients.

BACKGROUND: A combination of antihepatitis B immunoglobulin and antiviral agents is the most common regimen for prophylaxis of hepatitis B recurrence after liver transplantation. However, hepatitis B recurrence still happens. The significance of hepatitis B recurrence is less mentioned. MATERIALS: Forty-eight of the 313 hepatitis B liver transplant recipients having hepatitis B recurrence were included in this study. The patients were divided into group A, the patients transplanted for hepatitis B-related liver failure, and group B, the patients transplanted for hepatitis B-related cirrhosis and HCC. The clinical manifestations after hepatitis B recurrence were recorded. RESULTS: Among the 48 patients with hepatitis B recurrence, 23 patients were in group A and 25 patients in group B. The age was 51.6 ± 9.4 years in group A and 52.8 ± 6.4 in group B (p = 0.869). The MELD score prior to transplantation was 23.1 ± 9.9 in group A patients and 12.9 ± 5.6 in group B patients (p < 0.001). The median (interquartile) interval from transplantation to hepatitis B recurrence was 10 (2-19) months for group A patients and 13 (8.5-35) months for group B patients (p = 0.051). After hepatitis B recurrence, the liver function was almost normal in both groups. In group B patients, 10 patients had HCC recurrence with 7 of 10 patients having hepatitis B recurrence earlier than HCC recurrence. The interval between hepatitis B and HCC recurrence was 1 to 15 months. The 1-, 3-, and 5-year survival rates were 82.6%, 73.9%, and 69.0%, respectively, for group A patients and 96%, 76%, and 68%, respectively, for group B patients (p = 0.713). CONCLUSION: The patients have uneventful liver function under antiviral agent while hepatitis B recurred. For the patients having HCC prior to transplantation, close monitoring of HCC recurrence is necessary if hepatitis B recurs.

Efficacy and safety of tenofovir alafenamide fumarate for preventing mother-to-child transmission of hepatitis B virus: a national cohort study.

BACKGROUND: Data on tenofovir alafenamide fumarate (TAF) for preventing mother-to-child transmission of hepatitis B virus (HBV) are lacking. AIMS: To investigate the efficacy and safety of TAF therapy for preventing hepatitis B mother-to-child transmission. METHODS: Mothers with chronic HBV infection, positive for hepatitis B e-antigen and with HBV DNA >200 000 IU/mL received TAF for preventing mother-to-child transmission were enrolled retrospectively from multiple centres with data collection on mother-infant dyads up to postpartum week 24-28. Primary measurements were the mother-to-child transmission rate and infants' malformation rate. Secondary assessments included maternal HBV DNA reduction at delivery, and maternal or infant adverse events during follow up. RESULTS: Among 71 mothers enrolled, the mean (±SD) age was 30.3 (±2.2) years. TAF was initiated during the second or third trimester and continued to delivery with a mean (±SD) duration of 12.8 (±4.0) weeks. At delivery, 85.9% (61/71) of the mothers achieved HBV DNA <200 000 IU/L. Seventy-three infants (two sets of twins) were born from mothers treated with TAF and none had congenital defects or malformations. All infants received HBV immunoglobulin and vaccine at birth with additional HBV vaccinations at one and six months. At age 24-28 weeks, all infants had negative hepatitis B surface antigen and undetectable levels of HBV DNA (<100 IU/mL). Body weight, height, and head circumferences were comparable to national standards for physical development. No severe adverse effects were reported in either mothers or infants. CONCLUSIONS: TAF for highly viraemic mothers effectively prevented mother-to-child transmission of hepatitis B. There were no safety concerns for either mothers or infants with 24-28 weeks of follow up.

Hit-to-lead optimization of a latency-associated nuclear antigen inhibitor against Kaposi's sarcoma-associated herpesvirus infections.

The Latency-associated nuclear antigen (LANA) plays a central role for the latent persistence of the Kaposi's Sarcoma Herpesvirus (KSHV) in the human host and helps to establish lifelong infections. Herein, we report our efforts towards hit-to-lead generation starting from a previously discovered LANA-DNA inhibitor. By tethering the viral genome to the host nucleosomes, LANA ensures the segregation and persistence of the viral DNA during mitosis. LANA is also required for the replication of the latent viral episome during the S phase of the cell cycle. We aim to inhibit the interaction between LANA and the viral genome to prevent the latent persistence of KSHV in the host organism. Medicinal chemistry-driven optimization studies and structure-activity-relationship investigation led to the discovery of an improved LANA inhibitor. The functional activity of our compounds was evaluated using a fluorescence polarization (FP)-based interaction inhibition assay and electrophoretic mobility shift assay (EMSA). Even though a crystal structure of the ligand protein complex was not available, we successfully conducted hit optimization toward a low micromolar protein-nucleic acid-interaction inhibitor. Additionally, we applied STD-NMR studies to corroborate target binding and to gain insights into the binding orientation of our most potent inhibitor, providing opportunities for further rational design of more efficient LANA-targeting anti KSHV agents in future studies.

Pressurized DNA state inside herpes capsids-A novel antiviral target.

Drug resistance in viruses represents one of the major challenges of healthcare. As part of an effort to provide a treatment that avoids the possibility of drug resistance, we discovered a novel mechanism of action (MOA) and specific compounds to treat all nine human herpesviruses and animal herpesviruses. The novel MOA targets the pressurized genome state in a viral capsid, "turns off" capsid pressure, and blocks viral genome ejection into a cell nucleus, preventing viral replication. This work serves as a proof-of-concept to demonstrate the feasibility of a new antiviral target-suppressing pressure-driven viral genome ejection-that is likely impervious to developing drug resistance. This pivotal finding presents a platform for discovery of a new class of broad-spectrum treatments for herpesviruses and other viral infections with genome-pressure-dependent replication. A biophysical approach to antiviral treatment such as this is also a vital strategy to prevent the spread of emerging viruses where vaccine development is challenged by high mutation rates or other evasion mechanisms.

Anti-hepatitis B virus activity of swertisin isolated from Iris tectorum Maxim.

ETHNOPHARMACOLOGICAL RELEVANCE: Iris tectorum Maxim (I. tectorum, Yuan Wei in Chinese) is a common and traditional Chinese medicinal herb that be used to treat liver-related diseases. However, the anti-HBV activity of I. tectorum and its isolates has not been systemically studied. AIM OF THE STUDY: To screen the active part of I. tectorum and systemically evaluate their anti-HBV activity. MATERIALS AND METHODS: In this study, a series of compounds from I. tectorum were evaluated for their ability to inhibit HBV replication. Swertisin showed a significant inhibitory function on HBV replication. Then, the suppression effect of different concentrations of swertisin in HBsAg, HBeAg and HBV DNA level in HepG2.2.15 cells and HBV-infected HepG2-NTCP cells were comprehensive evaluated, respectively. Moreover, the anti-HBV effects of swertisin were confirmed in HBV transgenic mice model. RESULTS: Among these compounds, swertisin strongly inhibited the HBsAg, HBeAg and HBV DNA level in a dose-dependent manner in HepG2.2.15 cells and HBV-infected HepG2-NTCP cells. Furthermore, swertisin showed a significant inhibition role on HBV replication in HBV transgenic mice model, the inhibition effect of which was enhanced when combined with ETV. CONCLUSIONS: We have identified that swertisin can inhibit HBeAg and HBsAg production, as well as HBV DNA in vitro and in vivo. This study show that we may found a novel compound isolated from traditional Chinese medicines with potent anti-HBV function.

Antiviral activity of a polysaccharide from Radix Isatidis (Isatis indigotica Fortune) against hepatitis B virus (HBV) in vitro via activation of JAK/STAT signal pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Hepatitis B virus (HBV) infection frequently results in both acute and chronic hepatitis and poses serious threats to human health worldwide. Despite the availability of effective HBV vaccine and anti-HBV drugs, apparently inevitable side effects and resistance have limited its efficiency, thus prompt the search for new anti-HBV agents. The traditional Chinese medicine Radix Isatidis has been used for thousands of years, mainly for the treatment of viral and bacterial infection diseases including hepatitis. AIM OF THE STUDY: In this study, antiviral activities of a Radix Isatidis (Isatis indigotica Fortune) polysaccharide (RIP) were evaluated in vitro model using the HepG2.2.15 cell line and the underlying mechanism was elucidated with the aim of developing a novel anti-HBV therapeutic agent. MATERIALS AND METHODS: Structure features of the purified polysaccharide RIP were investigated by a combination of chemical and instrumental analysis. Drug cytotoxicity was assessed using the MTT assay. The contents of HBsAg, HBeAg, intracellular and extracellular IFN-α level were measured using respective commercially available ELISA kit. The HBV DNA expression was evaluated by real-time quantitative polymerase chain reaction (PCR) and the relevant proteins involved in TFN/JAK/STAT signaling pathways were examined by western blot assay. RESULTS: MTT assay showed that RIP had no toxicity on HepG2.2.15 cell line below the concentration 400 µg/ml at Day 3, 6 and 9. Furthermore, RIP at the concentration of 50, 100 and 200 µg/ml significantly reduced extracellular and intracellular level of HBsAg, HBeAg and HBV DNA in HepG2.2.15 cells in a time and dose-dependent manner. Moreover, RIP also enhanced the production of IFN-α in HepG2.2.15 cell via activation of JAK/STAT signal pathway and induction of antiviral proteins, as evidenced by the increased protein expression of p-STAT-1, p-STAT-2, p-JAK1, p-TYK2, OAS1, and Mx in HepG2.2.15 cells. In addition, the over expression of SOCS-1 and SOCS-3 was significantly abolished under same conditions. CONCLUSIONS: These results suggested that the HBV inhibitory effect of RIP was possibly due to the activation of IFN-α-dependent JAK/STAT signal pathway and induction of the anti-HBV protein expression.

Antiviral Properties and Mechanism of Action Studies of the Hepatitis B Virus Capsid Assembly Modulator JNJ-56136379.

Capsid assembly is a critical step in the hepatitis B virus (HBV) life cycle, mediated by the core protein. Core is a potential target for new antiviral therapies, the capsid assembly modulators (CAMs). JNJ-56136379 (JNJ-6379) is a novel and potent CAM currently in phase II trials. We evaluated the mechanisms of action (MOAs) and antiviral properties of JNJ-6379 in vitro Size exclusion chromatography and electron microscopy studies demonstrated that JNJ-6379 induced the formation of morphologically intact viral capsids devoid of genomic material (primary MOA). JNJ-6379 accelerated the rate and extent of HBV capsid assembly in vitro JNJ-6379 specifically and potently inhibited HBV replication; its median 50% effective concentration (EC50) was 54 nM (HepG2.117 cells). In HBV-infected primary human hepatocytes (PHHs), JNJ-6379, when added with the viral inoculum, dose-dependently reduced extracellular HBV DNA levels (median EC50 of 93 nM) and prevented covalently closed circular DNA (cccDNA) formation, leading to a dose-dependent reduction of intracellular HBV RNA levels (median EC50 of 876 nM) and reduced antigen levels (secondary MOA). Adding JNJ-6379 to PHHs 4 or 5 days postinfection reduced extracellular HBV DNA and did not prevent cccDNA formation. Time-of-addition PHH studies revealed that JNJ-6379 most likely interfered with postentry processes. Collectively, these data demonstrate that JNJ-6379 has dual MOAs in the early and late steps of the HBV life cycle, which is different from the MOA of nucleos(t)ide analogues. JNJ-6379 is in development for chronic hepatitis B treatment and may translate into higher HBV functional cure rates.

Design, synthesis and anti-HBV activity evaluation of new substituted imidazo[4,5-b]pyridines.

The design and synthesis of a number of new imidazo[4,5-b]pyridines is described. The heterocyclic scaffold possesses 6-chloro- or 5,6-dichloro-substitution and bears various 2-alkylamino-methyl or ethyl groups. The corresponding N1 and N3-tosylates are also presented. The anti-HBV activity of the compounds was evaluated in HBV infectious system at the level of HBV rcDNA secretion and CC50, EC50 and selectivity index values were determined. The tosylates showed low antiviral potency and relatively high cytotoxicity, on the contrary, a number of 2,5 and/or-6-substituted imidazopyridines, mainly those belonging to the 6-chloroimidazo[4,5-b]pyridine series, were endowed with a very interesting profile and were further investigated. The most promising among them, along with the reduction of the secreted HBV rcDNA, also caused a reduction in HBV cccDNA and pgRNA levels, with a concomitant accumulation of the intracellular encapsidated rcDNA. Surprisingly, the most active 2-diethylaminoethyl-substituted derivative (21d), was highly competitive to interferon.