Hepatitis B Virus Therapy Research Articles

Antiviral effects of Stichopus japonicus acid mucopolysaccharide on hepatitis B virus transgenic mice

Hepatitis B virus (HBV) is a significant global pathogen and efficient cure for HBV patients is still a challenging goal. We previously reported that acidic mucopolysaccharide from stichopus japonicus selenka (SJAMP) could inhibit HBsAg and HBeAg expression in vitro. However, the potential anti-HBV effects of SJAMP in vivo have not yet been explored. In this study, we show that SJAMP exhibits potent anti-HBV activity in HBV transgenic mice in a dose-dependent manner. Specifically, sixty HBV transgenic male BALB/c mice were randomly selected to receive the treatment of PBS, low dose SJAMP (30 mg kg−1), middle dose SJAMP (40 mg kg−1), high dose SJAMP (50 mg kg−1) and IFN (45 IU kg−1) for 30 d. SJAMP treatment suppressed serum HBV-DNA, and liver HBsAg and HBcAg levels in HBV-transgenic mice. The present study highlights the potential application of SJAMP in HBV therapy.

Core-fucosylation plays a pivotal role in hepatitis B pseudo virus infection: a possible implication for HBV glycotherapy.

The functions of cell surface proteins, such as growth factor receptors and virus/bacteria-entry receptors, can be dynamically regulated by oligosaccharide modifications. In the present study, we investigated the involvement of glycosylation in hepatitis B virus (HBV) entry into hepatoma cells. Infection of oligosaccharide-remodeling hepatoma cells with a pseudo virus of HBV, bio-nanocapsule (BNC), was evaluated by flow cytometry and confocal microscopy. Among various experiments using several hepatoma cells, marked difference was observed between Huh6 cells and HB611 cells, which were established by HBV gene transfection into hepatoma cells. Comprehensive oligosaccharide analysis showed dramatic increases of core fucosylation in HB611 cells, compared with Huh6 cells. Knock down of fucosyltransferase 8 (FUT8) reduced BNC entry into HB611 cells. In contrast, overexpression of FUT8 in Huh6 cells increased BNC entry. Although expression of sodium taurocholate cotransporting polypeptide (NTCP), which is one of HBV receptors was very similar between Huh6 and HB611 cells, proteins coprecipitated with NTCP were dependent on levels of core-fucosylation, suggesting that core-fucosylation regulates BNC entry into hepatoma cells. Our findings demonstrate that core-fucosylation is an important glycosylation for HBV infection of hepatoma cells through HBV-receptor-mediated endocytosis. Down-regulation of core-fucosylation may be a novel target for HBV therapy.

Fatty acid biosynthesis is involved in the production of hepatitis B virus particles

Hepatitis B virus (HBV) proliferates in hepatocytes after infection, but the host factors that contribute to the HBV lifecycle are poorly understood at the molecular level. We investigated whether fatty acid biosynthesis (FABS), which was recently reported to contribute to the genomic replication of hepatitis C virus, plays a role in HBV proliferation. We examined the effects of inhibitors of the enzymes in the FABS pathway on the HBV lifecycle by using recombinant HBV-producing cultured cells and found that the extracellular HBV DNA level, reflecting HBV particle production, was decreased by treatment with inhibitors suppressed the synthesis of long-chain saturated fatty acids with little cytotoxicity. The reduced HBV DNA level was reversed when palmitic acid, which is the product of fatty acid synthase (FAS) during FABS, was used simultaneously with the inhibitor. We also observed that the amount of intracellular HBV DNA in the cells was increased by FAS inhibitor treatment, suggesting that FABS is associated with HBV particle production but not its genome replication. This suggests that FABS might be a potent target for anti-HBV drug with a mode of action different from current HBV therapy.

New therapies for chronic hepatitis B.

Approximately 350 million people worldwide are chronically infected with hepatitis B virus (HBV), representing a significant public health challenge. Nucleos/tide analogues (NUCs) and interferon alpha (IFNα), the current standard of care for chronic infection, aim at preventing progression of the disease to cirrhosis, hepatocellular carcinoma (HCC) and death. However, in contrast to the case of hepatitis C virus infection, in which novel antiviral drugs cure the vast majority of treated patients, in regard to HBV, cure is rare due to the unusual persistence of viral DNA in the form of covalently closed circular DNA (cccDNA) within the nucleus of infected cells. Available therapies for HBV require lifelong treatment and surveillance, as reactivation frequently occurs following medication cessation and the occurrence of HCC is decreased but not eliminated, even after years of successful viral suppression. Progress has been made in the development of new therapeutics, and it is likely that only a combination of immune modulators, inhibitors of gene expression and replication and cccDNA-targeting drugs will eradicate chronic infection. This review aims to summarize the state of the art in HBV drug research highlighting those agents with the greatest potential for success based on in vitro as well as on data from clinical studies.

Clinical, demographic, and epidemiologic characteristics of hepatitis B virus-infected patients at a tertiary public hospital in Presidente Prudente, State of São Paulo, Brazil.

Few studies have addressed the primary characteristics of patients infected with hepatitis B virus (HBV) in the general population, especially those living in small- and medium-sized cities in Brazil. We aimed to determine the clinical, demographic, and epidemiologic characteristics of patients diagnosed with HBV who were followed up at an infectious diseases clinic of a public hospital in State of São Paulo, Brazil. Medical records of patients aged >18 years and diagnosed with HBV infection between January 2000 and December 2013 were reviewed. Seventy-five patients were enrolled with male-female main infection-associated risk factors; 9 (12%) were co-infected with human immunodeficiency virus (HIV), 5 (6.7%) with hepatitis C virus (HCV), and 3 (4%) were co-infected with both HIV and HCV. Antiviral HBV therapy was applied in 21 (28%) patients and tenofovir monotherapy was the most prescribed medication. After approximately 2 years of antiviral treatment, the HBV-DNA viral load was undetectable in 12 (92.3%) patients and lower levels of alanine aminotransferase were found in these patients. Over a 13-year interval, very few individuals infected with HBV were identified, highlighting the barriers for caring for patients with HBV in developing countries. New measures need to be implemented to complement curative practices.

A Tat-conjugated Peptide Nucleic Acid Tat-PNA-DR Inhibits Hepatitis B Virus Replication In Vitro and In Vivo by Targeting LTR Direct Repeats of HBV RNA.

Hepatitis B virus (HBV) infection is a major cause of chronic active hepatitis, cirrhosis, and primary hepatocellular carcinoma, all of which are severe threats to human health. However, current clinical therapies for HBV are limited by potential side effects, toxicity, and drug-resistance. In this study, a cell-penetrating peptide-conjugated peptide nucleic acid (PNA), Tat-PNA-DR, was designed to target the direct repeat (DR) sequences of HBV. Tat-PNA-DR effectively inhibited HBV replication in HepG2.2.15 cells. Its anti-HBV effect relied on the binding of Tat-PNA-DR to the DR, whereby it suppressed the translation of hepatitis B e antigen (HBeAg), HBsAg, HBV core, hepatitis B virus x protein, and HBV reverse transcriptase (RT) and the reverse transcription of the HBV genome. Furthermore, Tat-PNA-DR administered by intravenous injection efficiently cleared HBeAg and HBsAg in an acute hepatitis B mouse model. Importantly, it induced an 80% decline in HBV DNA in mouse serum, which was similar to the effect of the widely used clinical drug Lamivudine (3TC). Additionally, a long-term hydrodynamics HBV mouse model also demonstrated Tat-PNA-DR's antiviral effect. Interestingly, Tat-PNA-DR displayed low cytotoxicity, low mouse acute toxicity, low immunogenicity, and high serum stability. These data indicate that Tat-PNA-DR is a unique PNA and a promising drug candidate against HBV.

Management of hepatitis B reactivation in immunosuppressed patients: An update on current recommendations.

The proportion of hepatitis B virus (HBV) previously exposed patients who receive immunosuppressive treatment is usually very small. However, if these individuals are exposed to potent immunosuppressive compounds, the risk of HBV reactivation (HBVr) increases with the presence of hepatitis B surface antigen (HBsAg) in the serum. Chronic HBsAg carriers have a higher risk than those who have a total IgG anticore as the only marker of resolved/occult HBV disease. The loss of immune control in these patients may results in the reactivation of HBV replication within hepatocytes. Upon reconstitution of the immune system, infected hepatocytes are once again targeted and damaged by immune surveillance in an effort to clear the virus. There are different virological scenarios, and a wide spectrum of associated drugs with specific and stratified risk for the development of HBVr. Some of this agents can trigger a severe degree of hepatocellular damage, including hepatitis, acute liver failure, and even death despite employment of effective antiviral therapies. Currently, HBVr incidence seems to be increasing around the world; a fact mainly related to the incessant appearance of more powerful immunosuppressive drugs launched to the market. Moreover, there is no consensus on the length of prophylactic treatment before the patients are treated with immunosuppressive therapy, and for how long this therapy should be extended once treatment is completed. Therefore, this review article will focus on when to treat, when to monitor, what patients should receive HBV therapy, and what drugs should be selected for each scenario. Lastly, we will update the definition, risk factors, screening, and treatment recommendations based on both current and different HBV management guidelines.

Application of CRISPR/Cas9 Technology to HBV.

More than 240 million people around the world are chronically infected with hepatitis B virus (HBV). Nucleos(t)ide analogs and interferon are the only two families of drugs to treat HBV currently. However, none of these anti-virals directly target the stable nuclear covalently closed circular DNA (cccDNA), which acts as a transcription template for viral mRNA and pre-genomic RNA synthesis and secures virus persistence. Thus, the fact that only a small number of patients treated achieve sustained viral response (SVR) or cure, highlights the need for new therapies against HBV. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing system can specifically target the conserved regions of the HBV genome. This results in robust viral suppression and provides a promising tool for eradicating the virus. In this review, we discuss the function and application of the CRISPR/Cas9 system as a novel therapy for HBV.

Present and future therapies of hepatitis B: From discovery to cure.

Hepatitis B virus (HBV) is a significant global pathogen, infecting more than 240 million people worldwide. While treatment for HBV has improved, HBV patients often require lifelong therapies and cure is still a challenging goal. Recent advances in technologies and pharmaceutical sciences have heralded a new horizon of innovative therapeutic approaches that are bringing us closer to the possibility of a functional cure of chronic HBV infection. In this article, we review the current state of science in HBV therapy and highlight new and exciting therapeutic strategies spurred by recent scientific advances. Some of these therapies have already entered into clinical phase, and we will likely see more of them moving along the development pipeline. With growing interest in developing and efforts to develop more effective therapies for HBV, the challenging goal of a cure may be well within reach in the near future.

118. Inhibition of Hepatitis B Virus Replication In Vivo Following Delivery of Antiviral TALENs With Recombinant Adeno-Associated Viral Vectors

Hepatitis B virus (HBV) is hyperendemic to sub-Saharan Africa where there are approximately 600 000 deaths per year associated with chronic HBV infection. HBV may have long periods of dormancy in carriers of the virus, which is dependent on persistence of the nuclear replication intermediate covalently closed DNA (cccDNA). Current HBV therapies, including nucleot(s)ide analogs, target the actively transcribed virus. The cccDNA is not cleared and may act as a reservoir for re-initiation of viral replication following treatment withdrawal. This poses a significant challenge for the successful treatment of chronic HBV sufferers, and makes the cccDNA intermediate an important target for novel HBV treatments. Employing gene editing technology to disable cccDNA has emerged as a promising novel therapeutic strategy. TALENs targeting the surface and the core viral open reading frames, previously described by our group, demonstrated efficacy against HBV targets. To advance this technology to therapeutic application, efficient delivery and evaluation of the TALENs’ safety and target specificity in vivo and in vitro need to be established. This study aimed to evaluate the safety and efficacy of TALENs delivered by adeno-associated viral (AAV) vectors in vivo and in vitro. The HBV-infectable HepG2-hNTCP-C4 cell line was used to establish that the TALENs could disable cccDNA. Capacity for capsid modification, low immunogenicity and good hepatotropic transduction efficiency are favorable features that were considered in selecting these vectors. However, the delivery of TALENs by AAVs is technically complicated, as sequences encoding the two subunits of the complete TALENs exceed the capacity of single stranded AAVs. Consequently, we generated AAVs that encode each of the TALEN subunits. To constitute the complete TALENs, pairs of vectors were thus administered to mice or cultured cells. In vitro testing of AAV-TALENs was undertaken using the HepG2-hNTCP-C4 cell line. These cells present a novel tool for testing anti-HBV therapeutics as they overexpress the human sodium taurocholate co-transporting polypeptide (hNTCP) gene allowing them to be infected by HBV. The viral life-cycle is accurately recapitulated and enables assessment of effects of therapeutic agents on cccDNA. Since viral gene expression is dependent on transcription from the cccDNA intermediate in these cells, measurement of markers of HBV replication may be used as an indicator of cccDNA function. This study evaluated the potential of AAV delivered TALENs in vivo and in vitro by testing their activity and evaluating off-target activity, immunogenicity and liver toxicity. The results provide evidence for the utility of applying AAVs to the delivery of anti-HBV TALENs and offers further support for the feasibility of employing TALENs to treat chronic HBV infection.

Immunological aspects of antiviral therapy of chronic hepatitis B virus and hepatitis C virus infections.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) cause a large proportion of acute and chronic liver disease worldwide. Over the past decades many immunological studies defined host immune responses that mediate spontaneous clearance of acute HBV and HCV infection. However, host immune responses are also relevant in the context of treatment-induced clearance of chronic HBV and HCV infection. First, the pretreatment level of interferon-stimulated genes as well as genetic determinants of innate immune responses, such as single nucleotide polymorphisms near the IFNL3 gene, are strong predictors of the response to interferon-alpha (IFN-α)-based therapy. Second, IFN-α, which has been a mainstay of HBV and HCV therapy over decades, and ribavirin, which has also been included in interferon-free direct antiviral therapy for HCV, modulate host immune responses. Third, both IFN-α-based and IFN-α-free treatment regimens of HBV and HCV infection alter the short-term and long-term adaptive immune response against these viruses. Finally, treatment studies have not just improved the clinical outcomes, but also provided opportunities to study virus-host interaction. This review summarizes our current knowledge on how a patient's immune response affects the treatment outcome of HBV and HCV infection and how innate and adaptive immune responses themselves are altered by the different treatment regimens.

Hepatitis B virus therapy: What's the future holding for us?

Hepatitis B is one of the leading causes of liver cancer worldwide and unfortunately the number of people affected with hepatitis B virus (HBV) infection is still on the rise. Although the HBV has been known to cause fatal illness since decades but the population effected by this lethal virus have still only a few options for its management. The major treatment strategies include interferons and nucleos(t)ide analogues. These agents have so far produced unsatisfactory results in terms of complete virus eradication. Interferons cannot be used for long term therapy because of their potential side effects. Prolong treatment with nucleos(t)ide analogues has also been reported to cause serious side effects besides the increasing resistance by the virus. The need for new innovative solutions for treatment of HBV has been realized by global research institutes and pharmaceutical industry. Present review focuses in detail on the new ideas that are being transformed into therapeutic tools for use as future therapies in HBV infection. Modern drug designing and screening methods have made the drug discovery process shorter and more reliable. HBV therapeutics will take a new turn in coming years owing to these intelligent drug designing and screening methods. Future therapy of HBV is aiming to include the use of vaccines (both prophylactic and therapeutic), immunomodulators such as antibodies, non-nucleoside antivirals such as RNAi and inhibitors of viral life cycle.

Post-Autotransplant Hepatitis B Virus (HBV) Reactivation in Lymphoma and Multiple Myeloma Patients with Hepatitis B Surface Antigen-Positive or Resolved HBV Infection

Background: Although hepatitis B virus (HBV) reactivation in patients with hepatitis B surface antigen (HBsAg)-positive or resolved HBV infection (HBsAg-negative and hepatitis B core antibody [anti-HBc]-positive) undergoing anticancer therapy with or without rituximab has been frequently reported, few studies have evaluated the risk of HBV reactivation in patients receiving autologous stem cell transplantation (ASCT). We studied the rate of hepatitis and HBV reactivation after ASCT in lymphoma and multiple myeloma (MM) patients with HBsAg-positive or resolved HBV infection.Methods & Materials: Medical records of patients who diagnosed with lymphoma or MM and received ASCT between November 2005 and April 2014 in Severance hospital were retrospectively analyzed. HBV status was screened routinely at ASCT and when viral-related hepatitis was suspected after ASCT. Hepatitis was defined as a 3-fold or greater increase in serum alanine transaminase (ALT) that exceeded the reference range (>46 IU/L) or an absolute increase of ALT to more than 100 IU/L. HBV reactivation was defined as elevation of serum HBV-DNA level more than 1 log IU/L from baseline in HBsAg(+) patients. In case of resolved HBV patients, positive conversion of HBsAg (reverse seroconversion) with or without increase of ALT was defined as HBV reactivation. Hepatitis and HBV reactivation occurred before 1 year after ASCT was considered ASCT-related in this study.Result: A total of 297 patients (196 lymphoma and 101 MM) were studied. Median age at diagnosis was 47 years (range 16-64). A male to female ratio was 1.36:1. Most common subtype of lymphoma was diffuse large B-cell lymphoma (DLBCL, n=111). The median duration from diagnosis to ASCT was 475 days (range 105-5230) and 175 days (range 39-5400) in lymphoma and MM patients, respectively. Busulfan-based (n= 161, 82.1%) conditioning regimens were commonly used in lymphoma patients and melphalan-based (n=101, 100%) conditioning regimens were used in MM patients. The patients with HBsAg(-) did not received a routine anti-HBV prophylaxis regardless of the presence of anti-HBc. Nine patients did not tested for HBV at ASCT.Among 274 patients with HBsAg(-), 110 patients were anti-HBc(+) (resolved HBV infection) and 161 patients were anti-HBc(-). Within 1 year after ASCT, 48 of anti-HBc(+) and 71 of anti-HBc(-) patients experienced hepatitis (43.6% vs. 44.1%, p>0.999). The most common cause of hepatitis was drug-related (n= 81, 66.9%). There was no HBsAg reverse seroconversion within 1 year after ASCT. After 1 year, Only one patient with anti-HBc(+) experienced HBV reactivation at days 763 after ASCT and 3 patients with anti-HBc(-) showed HBsAg reverse seroconversion at days 406, 457 and 1172 post-transplant.In the subset of 178 lymphoma patients with HBsAg(-), 90 patients had a history of previous use of anti-CD20 monoclonal antibody, of whom 37 patients were anti-HBc(+). Twelve of anti-HBc(+) and 24 of anti-HBc(-) patients experienced hepatitis (32.4% vs. 45.3%, p=0.276) but there was no HBV reactivation related hepatitis within 1 year after ASCT.Among 14 patients with HBsAg(+) at ASCT, 13 patients received rituximab-containing chemotherapy before ASCT. They had received prophylactic HBV therapy with lamivudine (n=6), telbivudine (n=4), clevudine (n=2), adefovir (n=1) and tenofovir (n=1). Among them, 3 patients with telbivudine (n=1, 25%), clevudine (n=1, 50%) and lamivudine (n=1, 16.7%) experienced HBV reactivation at days 36, 161 and 204 after ASCT.Conclusion: Our data suggest that ASCT-related HBV reactivation is rare in lymphoma and MM patients with resolved HBV infection regardless of previous anti-CD20 therapy. Routine anti-HBV prophylaxis is not necessary for patients with resolved HBV infection. In case of HBsAg(+) patients, antiviral prophylaxis with lamivudine, clevudine, or telbivudine may not be sufficient to prevent HBV reactivation after ASCT. More potent antiviral agents such as adefovir or tenofovir should be considered. [Display omitted] Characteristics of 7 patients with HBV reactivation or HBsAg reverse seroconversion after ASCT. DisclosuresNo relevant conflicts of interest to declare.

In silico single cell dynamics of hepatitis B virus infection and clearance.

The progression of acute hepatitis B virus (HBV) to chronic infection or clearance is highly dependent on the host immune response composed of cytolytic (CTL) and non-cytolytic (non-CTL) effects. Cytolytic processes induce hepatocyte killing while non-CTL processes inhibit intracellular replication. Both effects are widely recognized and accepted. However, there are uncertainties about the assistance provided by either the loss of covalently circular closed DNA (cccDNA) during cell proliferation or the emergence of refractory cells to immune mediated clearance. We developed an agent-based mathematical model and tested the relative roles of different mechanisms of the immune system in the clearance of acute HBV infection. HBV viremia clearance time and hepatocyte turnover (HT) were used as the two major criteria in determining reasonable outcomes. Modelling results in 90% of cells containing between 1 and 17 cccDNA copies and normally distributed at the peak of infection. Variations in p36 levels, responsible for determining export of virions or recirculation to amplify cccDNA numbers, have a much greater impact on mean cccDNA level/cell at peak viremia than virus infectivity and cccDNA half-life. A strong CTL effect alone failed to clear infection with HT ≈ 10. Acute infection clearance was possible with combined CTL and non-CTL effects along with complete loss of intracellular viral components during cell proliferation resulting in the desired range of HT (0.7-1). The emergence of cells refractory to infection can reduce HT by up to 90%. However their impact was less effective than complete loss of intracellular viral components during cell proliferation. the existence of refractory cells is not necessary when there is complete loss of intracellular quantities during cell proliferation but is essential with only partial clearance.

Possible role of tocopherols in the modulation of host microRNA with potential antiviral activity in patients with hepatitis B virus-related persistent infection: a systematic review.

Hepatitis B virus (HBV) infection represents a serious global health problem and persistent HBV infection is associated with an increased risk of cirrhosis, hepatocellular carcinoma and liver failure. Recently, the study of the role of microRNA (miRNA) in the pathogenesis of HBV has gained considerable interest as well as new treatments against this pathogen have been approved. A few studies have investigated the antiviral activity of vitamin E (VE) in chronic HBV carriers. Herein, we review the possible role of tocopherols in the modulation of host miRNA with potential anti-HBV activity. A systematic research of the scientific literature was performed by searching the MEDLINE, Cochrane Library and EMBASE databases. The keywords used were 'HBV therapy', 'HBV treatment', 'VE antiviral effects', 'tocopherol antiviral activity', 'miRNA antiviral activity' and 'VE microRNA'. Reports describing the role of miRNA in the regulation of HBV life cycle, in vitro and in vivo available studies reporting the effects of VE on miRNA expression profiles and epigenetic networks, and clinical trials reporting the use of VE in patients with HBV-related chronic hepatitis were identified and examined. Based on the clinical results obtained in VE-treated chronic HBV carriers, we provide a reliable hypothesis for the possible role of this vitamin in the modulation of host miRNA profiles perturbed by this viral pathogen and in the regulation of some cellular miRNA with a suggested potential anti-HBV activity. This approach may contribute to the improvement of our understanding of pathogenetic mechanisms involved in HBV infection and increase the possibility of its management and treatment.

In silico analysis and experimental validation of azelastine hydrochloride (N4) targeting sodium taurocholate co-transporting polypeptide (NTCP) in HBV therapy.

The aim of this study was to explore sodium taurocholate co-transporting polypeptide (NTCP) exerting its function with hepatitis B virus (HBV) and its targeted candidate compounds, in HBV therapy. Identification of NTCP as a novel HBV target for screening candidate small molecules, was used by phylogenetic analysis, network construction, molecular modelling, molecular docking and molecular dynamics (MD) simulation. In vitro virological examination, q-PCR, western blotting and cytotoxicity studies were used for validating efficacy of the candidate compound. We used the phylogenetic analysis of NTCP and constructed its protein-protein network. Also, we screened compounds from Drugbank and ZINC, among which five were validated for their authentication in HepG 2.2.15 cells. Then, we selected compound N4 (azelastine hydrochloride) as the most potent of them. This showed good inhibitory activity against HBsAg (IC50 = 7.5 μm) and HBeAg (IC50 = 3.7 μm), as well as high SI value (SI = 4.68). Further MD simulation results supported good interaction between compound N4 and NTCP. In silico analysis and experimental validation together demonstrated that compound N4 can target NTCP in HepG2.2.15 cells, which may shed light on exploring it as a potential anti-HBV drug.

A rational study for identification of highly effective siRNAs against hepatitis B virus

RNA interference (RNAi) is a powerful gene knockdown technique used for study gene function. It also potentially provides effective agents for inhibiting infectious and genetic diseases. Most of RNAi studies employ a single siRNA designing program and then require large-scale screening experiments to identify functional siRNAs. In this study, we demonstrate that an assembly of results generated from different siRNA designing programs could provide clusters of predicting sites that aided selection of potent siRNAs. Based on the clusters, three siRNA target sites were selected on a conserved RNA region of hepatitis B virus (HBV), known as HBV post-transcriptional regulatory element (HBV PRE) at nucleotide positions 1317–1337, 1357–1377 and 1644–1664. All three chosen siRNAs driven by H1 promoter were highly effective and could drastically decrease expression of HBV transcripts (core, surface and X) and surface protein without induction of interferon response and cell cytotoxicity in liver cancer cell line (HepG2). Based on prediction of secondary structures, the silencing effects of siRNAs were less effective against a loop sequence of the mRNA target with hairpin structure. In summary, we demonstrate an effectual approach for identification of functional siRNAs. Moreover, highly potent siRNAs identified here may serve as novel agents for development of nucleic acid-based HBV therapy.

Molecular epidemiology and genotyping of hepatitis B virus of HBsAg-positive patients in Oman.

BackgroundHepatitis B virus (HBV) infection is a major global health burden with distinct geographic public health significance. Oman is a country with intermediate HBV carrier prevalence; however, little is known about the incidence of HBV variants in circulation. We investigated the HBV genotype distribution, the occurrence of antiviral resistance, and HBV surface antigen (HBsAg) escape mutations in HBsAg-positive patients in Oman.MethodsSerum samples were collected from 179 chronically HBV-infected patients enrolled in various gastroenterology clinics in Oman. HBV genotypes were determined by sequencing and phylogenetic analysis. Mutations in the HBV polymerase and the HBsAg gene were characterized by mutational analysis.ResultsHBV genotypes D (130/170; 76.47%) and A (32/170; 18.28%) are predominant in Oman. The HBV genotypes C and E were less frequent (each 1.18%), while the HBV genotypes B, G, F, and H were not detected. Four patients revealed HBV genotype mixtures (HBV-A/D and D/C). The analyses of vaccine escape mutations yield that 148/170 (87.06%) HBV sequences were wild type. 22/170 (12.94%) HBV sequences showed mutations in the “a” determinant of the HBsAg domain. Two patients showed the described HBV vaccine escape mutation sP120T. 8/146 (5.48%) HBV isolates harbored mutations in the HBV polymerase known to confer resistance against antiviral therapy. Especially the lamivudine resistance mutations rtL180M/rtM204V and rtM204I were detected.ConclusionThis study shows the distribution of HBV genotypes, therapy resistance, and vaccine escape mutations in HBV-infected patients in Oman. Our findings will have a major impact on therapy management and diagnostics of chronic HBV infections in Oman to control HBV infection in this intermediate HBV-endemic country.

AAV-Mediated Delivery of Zinc Finger Nucleases Targeting Hepatitis B Virus Inhibits Active Replication

Despite an existing effective vaccine, hepatitis B virus (HBV) remains a major public health concern. There are effective suppressive therapies for HBV, but they remain expensive and inaccessible to many, and not all patients respond well. Furthermore, HBV can persist as genomic covalently closed circular DNA (cccDNA) that remains in hepatocytes even during otherwise effective therapy and facilitates rebound in patients after treatment has stopped. Therefore, the need for an effective treatment that targets active and persistent HBV infections remains. As a novel approach to treat HBV, we have targeted the HBV genome for disruption to prevent viral reactivation and replication. We generated 3 zinc finger nucleases (ZFNs) that target sequences within the HBV polymerase, core and X genes. Upon the formation of ZFN-induced DNA double strand breaks (DSB), imprecise repair by non-homologous end joining leads to mutations that inactivate HBV genes. We delivered HBV-specific ZFNs using self-complementary adeno-associated virus (scAAV) vectors and tested their anti-HBV activity in HepAD38 cells. HBV-ZFNs efficiently disrupted HBV target sites by inducing site-specific mutations. Cytotoxicity was seen with one of the ZFNs. scAAV-mediated delivery of a ZFN targeting HBV polymerase resulted in complete inhibition of HBV DNA replication and production of infectious HBV virions in HepAD38 cells. This effect was sustained for at least 2 weeks following only a single treatment. Furthermore, high specificity was observed for all ZFNs, as negligible off-target cleavage was seen via high-throughput sequencing of 7 closely matched potential off-target sites. These results show that HBV-targeted ZFNs can efficiently inhibit active HBV replication and suppress the cellular template for HBV persistence, making them promising candidates for eradication therapy.

Insight into the Effect of Tenofovir in Patients with HBV/HIV Coinfection

Hepatitis B virus (HBV) coinfection is common in HIV-infected patients. Current HBV therapies suppress HBV replication and can improve clinical