scholarly journals Recent Progress and Future Prospective in HBV Cure by CRISPR/Cas

Viruses ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 4
Author(s):  
Yu-Chan Yang ◽  
Hung-Chih Yang
Keyword(s):  
Hepatitis B ◽  
Antiviral Therapy ◽  
Hbv Infection ◽  
Host Genome ◽  
Attractive Potential ◽  
Major Barrier ◽  
Base Editing ◽  
Promising Therapeutic Approach ◽  
In Vivo Delivery

Hepatitis B virus (HBV) infection remains an important issue of global public health. Although current antiviral therapy has dramatically reduced the mortality and morbidity of chronic hepatitis B (CHB), it fails to cure it. Rebound viremia often occurs after stopping antiviral therapy. Persistent HBV covalently closed circular DNA (cccDNA) and integrated DNA under antiviral therapy form the major barrier to eradication of HBV infection. CRISPR-mediated genome editing has emerged as a promising therapeutic approach to specifically destroy persistent HBV genomes, both cccDNA and integrated DNA, for HBV cure. However, the cleavage of integrated HBV DNA by CRISPR-Cas9 will cause double-strand break (DSB) of host genome, raising a serious safety concern about genome instability and carcinogenesis. The newly developed CRISPR-derived base editors (BEs), which fuse a catalytically disabled nuclease with a nucleobase deaminase enzyme, can be used to permanently inactivate HBV genome by introducing irreversible point mutations for generation of premature stop codons without DSBs of host genome. Although promising, CRISPR-mediated base editing still faces daunting challenges before its clinical application, including the base-editing efficacy, the off-target effect, the difficulty in finding conserved target HBV sequences, and in vivo delivery efficiency. Several strategies have been adopted to optimize the efficiency and specificity of CRISPR-BEs and to improve in vivo delivery efficacy through novel viral and non-viral delivery approaches. Particularly, the non-viral delivery of Cas9 mRNA and ribonucleoprotein by lipid nanoparticles exhibits attractive potential for liver-targeted delivery in clinical. Along with all progress above, the CRISPR-mediated gene therapy will ultimately achieve HBV cure.

scholarly journals In Vivo Bioluminescence Imaging of HBV Replicating Hepatocytes Allows for the Monitoring of Anti-Viral Immunity

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2273
Author(s):  
Katrin Manske ◽  
Annika Schneider ◽  
Chunkyu Ko ◽  
Percy A. Knolle ◽  
Katja Steiger ◽  
...  
Keyword(s):  
T Cells ◽  
Chronic Hepatitis ◽  
Hepatitis B ◽  
Chronic Hepatitis B ◽  
Cd8 T Cells ◽  
Recombinant Adenovirus ◽  
Hbv Infection ◽  
High Dose ◽  
Viral Immunity

Immunity against hepatitis B virus (HBV) infection is complex and not entirely understood so far, including the decisive factors leading to the development of chronic hepatitis B. This lack of a mechanistic understanding of HBV-specific immunity is also caused by a limited number of suitable animal models. Here, we describe the generation of a recombinant adenovirus expressing an HBV 1.3-overlength genome linked to luciferase (Ad-HBV-Luc) allowing for precise analysis of the quantity of infected hepatocytes. This enables sensitive and close-meshed monitoring of HBV-specific CD8 T cells and the onset of anti-viral immunity in mice. A high dose of Ad-HBV-Luc developed into chronic hepatitis B accompanied by dysfunctional CD8 T cells characterized by high expression of PD1 and TOX and low expression of KLRG1 and GzmB. In contrast, a low dose of Ad-HBV-Luc infection resulted in acute hepatitis with CD8 T cell-mediated elimination of HBV-replicating hepatocytes associated with elevated sALT levels and increased numbers of cytotoxic HBV-specific CD8 T cells. Thus, the infectious dose was a critical factor to induce either acute self-limited or chronic HBV infection in mice. Taken together, the new Ad-HBV-Luc vector will allow for highly sensitive and time-resolved analysis of HBV-specific immune responses during acute and chronic infection.

scholarly journals Hepatitis B virus reactivation during hepatitis C direct-acting antiviral therapy in patients with previous HBV infection

2017 ◽  
Vol 67 (5) ◽  
pp. 1106-1108 ◽  
Author(s):  
Naoki Kawagishi ◽  
Goki Suda ◽  
Masahiro Onozawa ◽  
Megumi Kimura ◽  
Osamu Maehara ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Therapy ◽  
Hbv Infection ◽  
Virus Reactivation ◽  
Hepatitis B Virus Reactivation ◽  
Direct Acting Antiviral ◽  
B Virus ◽  
Direct Acting

scholarly journals Establishment of a monoclonal antibody against human NTCP that blocks HBV infection

2022 ◽  
Author(s):  
Toshitada Takemori ◽  
Akiko Sugimoto-Ishige ◽  
Hironori Nishitsuji ◽  
Yushi Futamura ◽  
Michishige Harada ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Chronic Hepatitis ◽  
Bile Acid ◽  
Hepatitis B ◽  
Inhibitory Effect ◽  
Hbv Infection ◽  
Current Therapy ◽  
Entry Inhibitors ◽  
Hdv Infection

Hepatitis B virus (HBV) infects 240 million people worldwide. Current therapy profoundly suppresses HBV replication but requires long-term maintenance therapy. Therefore there is still a medical need for an efficient HBV cure. HBV enters host cells by binding via the preS1-domain of the viral L protein to the Na + /Taurocholate Cotransporting Polypeptide (NTCP). Thus, NTCP should be a key target for the development of anti-HBV therapeutics. Indeed, Myrcludex B, a synthetic form of the myristoylated preS1 peptide, effectively reduces HBV/HDV infection and has been approved as Hepcludex® in Europe for the treatment of patients with chronic hepatitis D virus (HDV) infection. We established a monoclonal antibody (mAb) N6HB426-20 that recognizes the extracellular domain of human NTCP and blocks HBV entry in vitro into human liver cells but has much less of an inhibitory effect on bile acid uptake. In vivo , administration of the N6HB426-20 mAb prevented HBV viremia for an extended period of time after HBV inoculation in a mouse model system without strongly inhibiting bile acid absorption. Among the extracellular loops (ECLs) of NTCP, regions of amino acids (aa) 84-87 in ECL1 and aa 157-165 near ECL2 of transmembrane domain 5 are critically important for HBV/HDV infection. Epitope-mapping and the 3D model of the NTCP structure suggested that the N6HB426-20 mAb may recognize aa 276/277 at the tip of ECL4 and interfere with an binding of HBV to the aa 84-87 region. In summary, we identified an in vivo neutralizing NTCP-targeting antibody capable of preventing HBV infection. Further improvements in efficacy of this drug will pave the way for its clinical applications. IMPORTANCE A number of entry inhibitors are being developed to enhance the treatment of HBV patients with oral nucleos(t)ide analogues (NA). To amplify the effectiveness of NA therapy, several efforts have been made to develop therapeutic mAbs with neutralizing activity against HBs antigens. However, the neutralizing effect of these mAbs may be muted by a large excess of HBsAg-positive noninfectious particles in the blood of infected patients. The advantage of NTCP-targeted HBV entry inhibitors is that they remain effective regardless of viral genotype, viral mutations and the presence of subviral particles. Although N6HB426-20 requires a higher dose than Myrcludex to obtain equivalent suppression of HBV in a model mouse system, it maintained the inhibitory effect for a long time post administration in proportion to the half-life of an IgG mAb. We believe that further improvements will make this antibody a promising treatment option for patients with chronic hepatitis B.

scholarly journals The Epigenetic Modulation of Cancer and Immune Pathways in Hepatitis B Virus-Associated Hepatocellular Carcinoma: The Influence of HBx and miRNA Dysregulation

2021 ◽  
Vol 12 ◽  
Author(s):  
Kurt Sartorius ◽  
Ping An ◽  
Cheryl Winkler ◽  
Anil Chuturgoon ◽  
Xiaodong Li ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Immune System ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hbv Infection ◽  
Host Genome ◽  
Epigenetic Changes ◽  
Epigenetic Change ◽  
Genome Expression ◽  
B Virus

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HBV-HCC) pathogenesis is fueled by persistent HBV infection that stealthily maintains a delicate balance between viral replication and evasion of the host immune system. HBV is remarkably adept at using a combination of both its own, as well as host machinery to ensure its own replication and survival. A key tool in its arsenal, is the HBx protein which can manipulate the epigenetic landscape to decrease its own viral load and enhance persistence, as well as manage host genome epigenetic responses to the presence of viral infection. The HBx protein can initiate epigenetic modifications to dysregulate miRNA expression which, in turn, can regulate downstream epigenetic changes in HBV-HCC pathogenesis. We attempt to link the HBx and miRNA induced epigenetic modulations that influence both the HBV and host genome expression in HBV-HCC pathogenesis. In particular, the review investigates the interplay between CHB infection, the silencing role of miRNA, epigenetic change, immune system expression and HBV-HCC pathogenesis. The review demonstrates exactly how HBx-dysregulated miRNA in HBV-HCC pathogenesis influence and are influenced by epigenetic changes to modulate both viral and host genome expression. In particular, the review identifies a specific subset of HBx induced epigenetic miRNA pathways in HBV-HCC pathogenesis demonstrating the complex interplay between HBV infection, epigenetic change, disease and immune response. The wide-ranging influence of epigenetic change and miRNA modulation offers considerable potential as a therapeutic option in HBV-HCC.

scholarly journals Innovative HBV Animal Models Based on the Entry Receptor NTCP

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 828 ◽  
Author(s):  
Jochen M. Wettengel ◽  
Benjamin J. Burwitz
Keyword(s):  
Amino Acid ◽  
Animal Models ◽  
Hepatitis B ◽  
Amino Acid Sequence ◽  
Sodium Taurocholate ◽  
Hbv Infection ◽  
Species Barrier ◽  
Bile Acid Transporter

Hepatitis B is a major global health problem, with an estimated 257 million chronically infected patients and almost 1 million deaths per year. The causative agent is hepatitis B virus (HBV), a small, enveloped, partially double-stranded DNA virus. HBV has a strict species specificity, naturally infecting only humans and chimpanzees. Sodium taurocholate co-transporting polypeptide (NTCP), a bile acid transporter expressed on hepatocytes, has been shown to be one of the key factors in HBV infection, playing a crucial role in the HBV entry process in vitro and in vivo. Variations in the amino acid sequence of NTCP can inhibit HBV infection and, therefore, contributes, in part, to the species barrier. This discovery has revolutionized the search for novel animal models of HBV. Indeed, it was recently shown that variations in the amino acid sequence of NTCP represent the sole species barrier for HBV infection in macaques. Here, we review what is known about HBV entry through the NTCP receptor and highlight how this knowledge has been harnessed to build new animal models for the study of HBV pathogenesis and curative therapies.

Hepatitis B reactivation after therapy for non-Hodgkin lymphoma: A case report with review of literature

2013 ◽  
Vol 21 (3-4) ◽  
pp. 151-154 ◽  
Author(s):  
Gorana Matovina-Brko ◽  
Maja Ruzic ◽  
Milotka Fabri ◽  
Lazar Popovic ◽  
Ivana Kolarov-Bjelobrk ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Antiviral Therapy ◽  
Cancer Patients ◽  
Malignant Disease ◽  
Liver Enzymes ◽  
Antiviral Treatment ◽  
Immunosuppressive Treatment ◽  
Hbv Dna ◽  
Hbv Infection ◽  
Anticancer Treatment

The natural course of hepatitis B virus (HBV) infection depends on the immune status of the host. In cancer patients, as the consequence of immune suppression due to chemotherapy and malignant disease itself, the balance between replicative potential of the virus and immune response of the host is disrupted leading to acute HBV infection or reactivation. We present a case of HBsAg positive, diffuse large B cell gastric lymphoma patient CD20+ staged IB, treated with six cycles of R-CHOP protocol and two cycles with rituximab monotherapy. Five months after the successful anticancer treatment, patient developed reactivation of chronic HBV infection (ten-fold increase in liver enzymes, HBsAg+, IgM antiHBc+, HBeAg(-), and HBV DNA 5?106 copies/ml). Antiviral therapy with lamivudine was started. Four weeks after the antiviral therapy initiation liver enzymes were in normal ranges. One year after the start of antiviral treatment HBV DNA PCR test did not detect any viral particles. The patient is in complete remission of malignant disease, and still receiving therapy with lamivudine. HBV screening in cancer patients is necessary in order to provide a prompt antiviral therapy and to prevent postponement or even cessation of planned anticancer treatment. HBsAg positive patients should start prophylactic antiviral treatment before the start of immunosuppressive treatment. Chemotherapy protocols consisting rituximab and corticosteroids significantly increase the risk of reactivation. If reactivation is diagnosed in course of chemotherapy, the therapy should be stopped and antiviral treatment should be applied as soon as possible. Treatment with lamivudine is continued at least 6 months after the chemotherapy end.

scholarly journals Immunogenicity and Tolerogenicity of Hepatitis B Virus Structural and Nonstructural Proteins: Implications for Immunotherapy of Persistent Viral Infections

2002 ◽  
Vol 76 (17) ◽  
pp. 8609-8620 ◽  
Author(s):  
Kazuhiro Kakimi ◽  
Masanori Isogawa ◽  
JoSan Chung ◽  
Alessandro Sette ◽  
Francis V. Chisari
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Viral Infections ◽  
Cytotoxic T Lymphocyte ◽  
T Cell Response ◽  
Hbv Infection ◽  
Peripheral Tolerance ◽  
Specific Ctls ◽  
B Virus

ABSTRACT Persistent hepatitis B virus (HBV) infection is characterized by a weak and narrowly focused CD8+ T-cell response to HBV that is thought to reflect the induction of central and/or peripheral tolerance to HBV proteins in neonatal and adult onset infections, respectively. Immunotherapeutic strategies that overcome tolerance and boost these suboptimal responses may lead to viral clearance in chronically infected individuals. The present study was performed to compare the relative immunogenicities and tolerogenicities of HBV structural (envelope [ENV]) and nonstructural (polymerase [POL]) proteins at the CD8+ cytotoxic T lymphocyte (CTL) level in transgenic mice that replicate HBV in the liver and secrete infectious virus into the blood, thus representing an excellent model of persistent HBV infection. Interestingly, the mice were tolerant to the ENV but not to the POL proteins at the CTL level. Furthermore, the POL-specific CTLs had no impact on HBV replication or liver function in vivo, even though they were readily induced and reached the liver after DNA immunization, reflecting their relatively low avidity and the low level at which the POL protein is expressed by the hepatocyte. Collectively, these results suggest that the factors that make POL less tolerogenic also make POL-specific CTLs relatively inefficient effector cells when they reach the target organ. Immunotherapeutic strategies to control HBV infection by inducing virus-specific CTL responses in chronically infected subjects should be evaluated in light of this observation.

scholarly journals Chronic Hepatitis B in Canada

2001 ◽  
Vol 12 (6) ◽  
pp. 351-356 ◽  
Author(s):  
GY Minuk ◽  
J Uhanova
Keyword(s):  
General Population ◽  
Hepatitis B ◽  
Antiviral Therapy ◽  
Public Health Problem ◽  
Risk Groups ◽  
Hbv Infection ◽  
Serological Evidence ◽  
Important Public Health Problem ◽  
Treatment And Prevention ◽  
Chronic Hbv

Recent developments in the treatment and prevention of hepatitis B virus (HBV) infections warrant revisiting important epidemiological questions, such as how prevalent is chronic HBV infection in Canada, in which Canadian subpopulations are HBV prevalence rates the highest, in what percentage of infected individuals is the virus actively replicating, and how many infected Canadians are candidates for antiviral therapy? Currently available data suggest the overall prevalence of HBV-infected individuals in the general population is approximately 2%, with 5% to 10% having serological evidence of previous HBV infection. In high risk groups, such as street-connected individuals, Aboriginals and immigrants from endemic areas, these rates of viral prevalence and serological evidence of previous HBV infection are approximately two to 10 and five to 10 times higher, respectively, than in the general population. Candidates for antiviral therapy range from less than 1% of infected Aboriginals to 15% to 30% of Asians with chronic HBV. From these data, it is clear that chronic HBV remains an important public health problem in this country. Hence, resources must be identified to enhance Canadians' awareness of HBV infection, maintain, if not expand, efforts to identify and implement safe and effective antiviral therapy for HBV-infected individuals, and continue programs for universal vaccination to prevent new HBV infections.

scholarly journals Evaluation of Single and Combination Therapies with Tenofovir Disoproxil Fumarate and EmtricitabineIn Vitroand in a Robust Mouse Model Supporting High Levels of Hepatitis B Virus Replication

2012 ◽  
Vol 56 (12) ◽  
pp. 6186-6191 ◽  
Author(s):  
Raymond F. Schinazi ◽  
Leda Bassit ◽  
Marcia M. Clayton ◽  
Bill Sun ◽  
James J. Kohler ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Combination Therapy ◽  
Virus Replication ◽  
Tenofovir Disoproxil Fumarate ◽  
Hbv Infection ◽  
Experimental Drugs ◽  
Chronic Hepatitis B Virus ◽  
B Virus

ABSTRACTNext-generation therapies for chronic hepatitis B virus (HBV) infection will involve combinations of established and/or experimental drugs. The current study investigated thein vitroandin vivoefficacy of tenofovir disoproxil fumarate (TDF) and/or emtricitabine [(−)-FTC] alone and in combination therapy for HBV infection utilizing the HepAD38 system (human hepatoblastoma cells transfected with HBV). Cellular pharmacology studies demonstrated increased levels of (−)-FTC triphosphate with coincubation of increasing concentrations of TDF, while (−)-FTC had no effect on intracellular tenofovir (TFV) diphosphate levels. Quantification of extracellular HBV by real-time PCR from hepatocytes demonstrated the anti-HBV activity with TDF, (−)-FTC, and their combination. Combination of (−)-FTC with TDF or TFV (ratio, 1:1) had a weighted average combination index of 0.7 for both combination sets, indicating synergistic antiviral effects. No cytotoxic effects were observed with any regimens. Using anin vivomurine model which develops robust HBV viremia in nude mice subcutaneously injected with HepAD38 cells, TDF (33 to 300 mg/kg of body weight/day) suppressed virus replication for up to 10 days posttreatment. At 300 mg/kg/day, (−)-FTC strongly suppressed virus titers to up to 14 days posttreatment. Combination therapy (33 mg/kg/day each drug) sustained suppression of virus titer/ml serum (<1 log10unit from pretreatment levels) at 14 days posttreatment, while single-drug treatments yielded virus titers 1.5 to 2 log units above the initial virus titers. There was no difference in mean alanine aminotransferase values or mean wet tumor weights for any of the groups, suggesting a lack of drug toxicity. TDF–(−)-FTC combination therapy provides more effective HBV suppression than therapy with each drug alone.

scholarly journals Hepatitis B Core-related Antigen: An Alternative to Hepatitis B Virus DNA to Assess Treatment Eligibility in Africa

2019 ◽  
Author(s):  
Yusuke Shimakawa ◽  
Gibril Ndow ◽  
Ramou Njie ◽  
Harr Freeya Njai ◽  
Kazuaki Takahashi ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Antiviral Therapy ◽  
Characteristic Curve ◽  
Scale Up ◽  
Treatment Algorithm ◽  
Hbv Dna ◽  
Hbv Infection ◽  
B Virus ◽  
Treatment Naïve

Abstract Background To eliminate hepatitis B virus (HBV) infection, it is essential to scale up testing and treatment. However, conventional tools to assess treatment eligibility, particularly nucleic acid testing (NAT) to quantify HBV DNA, are hardly available and affordable in resource-limited countries. We therefore assessed the performance of a novel immunoassay, hepatitis B core-related antigen (HBcrAg), as an inexpensive (US$ <15/assay) alternative to NAT to diagnose clinically important HBV DNA thresholds (≥2000, ≥20 000, and ≥200 000 IU/mL) and to select patients for antiviral therapy in Africa. Methods Using a well-characterized cohort of treatment-naive patients with chronic HBV infection in The Gambia, we evaluated the accuracy of serum HBcrAg to diagnose HBV DNA levels and to indicate treatment eligibility determined by the American Association for the Study of Liver Diseases, based on reference tests (HBV DNA, hepatitis B e antigen, alanine aminotransferase, liver histopathology, and/or FibroScan). Results A total of 284 treatment-naive patients were included in the analysis. The area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity of serum HBcrAg were 0.88 (95% confidence interval [CI], .82–.93), 83.3%, and 83.9%, respectively, to diagnose HBV DNA ≥2000 IU/mL; and 0.94 (95% CI, .88–.99), 91.4%, and 93.2% for ≥200 000 IU/mL. A simplified treatment algorithm using HBcrAg without HBV DNA showed high AUROC (0.91 [95% CI, .88–.95]) with a sensitivity of 96.6% and specificity of 85.8%. Conclusions HBcrAg might be an accurate alternative to HBV DNA quantification as a simple and inexpensive tool to identify HBV-infected patients in need of antiviral therapy in low- and middle-income countries.

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