Ivermectin Inhibits HBV Entry into the Nucleus by Suppressing KPNA2.

Hepatitis B virus (HBV) specifically infects human hepatocytes and increases the risks of cirrhosis and liver cancer. Currently, nucleic acid analogs are the main therapeutics for chronic hepatitis caused by HBV infection. Although nucleic acid analogs can eliminate HBV DNA by inhibiting HBV reverse transcriptase, they cannot lead to negative conversion of covalently closed circular DNA (cccDNA) and hepatitis B surface antigen (HBsAg). In this study, we revealed that the antifilarial drug ivermectin suppresses HBV production by a different mechanism from the nucleic acid analog entecavir or Na+ taurocholate co-transporting polypeptide-mediated entry inhibitor cyclosporin A. Ivermectin reduced the levels of several HBV markers, including HBsAg, in HBV-infected human hepatocellular carcinoma cells (HepG2-hNTCP-C4 cells) and humanized mouse hepatocytes (PXB hepatocytes). In addition, ivermectin significantly decreased the expression of HBV core protein and the nuclear transporter karyopherin α2 (KPNA2) in the nuclei of HepG2-hNTCP-C4 cells. Furthermore, depletion of KPNA1-6 suppressed the production of cccDNA. These results suggest that KPNA1-6 is involved in the nuclear import of HBV and that ivermectin suppresses the nuclear import of HBV by inhibiting KPNA2. This study demonstrates the potential of ivermectin as a novel treatment for hepatitis B.

Blocking neddylation elicits antiviral effect against hepatitis B virus replication.

BACKGROUND: Hepatitis B Virus (HBV) is the most common cause of chronic liver disease worldwide. The mechanisms that regulate HBV viral replication remain poorly defined. Here, we show that blocking of the neddylation elicits antiviral effect against HBV replication, indicating that NEDD8 supports viral production. METHODS AND RESULTS: To explore role of neddylation, HBV-replicating HepG2.2.15.7 cells and HBV-infected HepG2-hNTCP-30 cells were treated with siNEDD8 and MLN4924, a potent and selective NEDD8-activating enzyme inhibitor. Cell viability, intracellular and extracellular HBV DNA, covalently closed circular DNA (cccDNA), HBsAg, HBeAg, and HBcrAg were measured to assess the consequences of the various treatments on viral replication. Our data showed that HBV infection increased NEDD8 expression in human liver cell lines. Symmetrically, NEDD8 knockdown by siRNA or MLN4924 treatments decreased HBV replication in HepG2.2.15.7 and HepG2-hNTCP-30 cells. Notably, HBsAg, and HBeAg secretions were strongly suppressed in the culture supernatants, but not the HBcrAg. These results indicate that the suppression of NEDD8 decreases HBV replication. However, cccDNA steady level confirms once again its persistence and longevity in chronic infection. CONCLUSION: The manipulation of the neddylation pathway can thus provide new tools interfering with HBV persistence as well as novel therapeutic strategies against chronic hepatitis B.

A case of child-to-father transmission of hepatitis B virus in Japan: a rare infection route.

This report describes a rare horizontal transmission of hepatitis B virus (HBV) from an unvaccinated 6-year-old boy to his father. The father had been diagnosed with acute hepatitis B 1 month earlier; therefore, when the child visited the clinic with fever, he was screened for HBV markers and diagnosed as an asymptomatic carrier. Neither the child nor his father was vaccinated against HBV, whereas the child's mother and sister, having received the HBV vaccination as they were medical staff and a nursing student, respectively, tested negative for the hepatitis B surface antigen (HBsAg) and positive for anti-HBs. We performed a phylogenetic analysis of HBV in the child and his father, and identified 100% homologous strains of identical genotype C. At diagnosis, the father tested positive for IgM anti-hepatitis B core with a high titer, whereas the child tested negative for this marker. These data strongly indicated a child-to-father transmission. In this case, the HBV infection route was speculated as close contact including saliva-based transmission between the child and father, mainly attributed to their daily food habits. When clinicians diagnose patients with acute or chronic HBV infection, the household members should have been examined for HBV markers immediately. If some household members are susceptible to HBV infection, all members should be vaccinated against HBV.

Development of an in vivo delivery system for CRISPR/Cas9-mediated targeting of hepatitis B virus cccDNA.

Chronic hepatitis B virus (HBV) infection constitutes a global health issue with limited current therapeutic efficacy owing to the persistence of viral episomal DNA (cccDNA). The CRISPR/Cas9 system, a newly developed, powerful tool for genome editing and potential gene therapy, requires efficient delivery of CRISPR components for successful therapeutic application. Here, we investigated the effects of lentiviral- or adeno-associated virus 2 (AAV2) vector-mediated delivery of 3 guide (g)RNAs/Cas9 selected from 16 gRNAs. These significantly suppressed HBV replication in cells, with WJ11/Cas9 exhibiting highest efficacy and chosen for in vivo study. AAV2/WJ11-Cas9 also significantly inhibited HBV replication and significantly reduced cccDNA in the tested cells. Moreover, AAV2/WJ11-Cas9 enhanced entecavir effects when used in combination, indicative of different modes of action. Notably, in humanized chimeric mice, AAV2/WJ11-Cas9 significantly suppressed HBcAg, HBsAg, and HBV DNA along with cccDNA in the liver tissues without significant cytotoxicity; accordingly, next generation sequencing data showed no significant genomic mutations. To our knowledge, this represents the first evaluation of the CRISPR/Cas9 system using an HBV natural infection mode. Therefore, WJ11/Cas9 delivered by comparatively safer AAV2 vectors may provide a new therapeutic strategy for eliminating HBV infection and serve as an effective platform for curing chronic HBV infection.

7-Deaza-7-fluoro modification confers on 4'-cyano-nucleosides potent activity against entecavir/adefovir-resistant HBV variants and favorable safety.

We designed, synthesized and identified a novel nucleoside derivative, 4'-C-cyano-7-deaza-7-fluoro-2'-deoxyadenosine (CdFA), which exerts potent anti-HBV activity (IC50 ~26 nM) with favorable hepatocytotoxicity (CC50 ~56 µM). Southern blot analysis using wild-type HBV (HBVWT)-encoding-plasmid-transfected HepG2 cells revealed that CdFA efficiently suppresses the production of HBVWT (IC50 = 153.7 nM), entecavir (ETV)-resistant HBV carrying L180M/S202G/M204V substitutions (HBVETVR; IC50 = 373.2 nM), and adefovir dipivoxil (ADV)-resistant HBV carrying A181T/N236T substitutions (HBVADVR; IC50=192.6 nM), whereas ETV and ADV were less potent against HBVETVR and HBVADVR (IC50: >1,000 and 4,022.5 nM, respectively). Once-daily peroral administration of CdFA to human-liver-chimeric mice over 14 days (1 mg/kg/day) comparably blocked HBVWT and HBVETVR viremia by 0.7 and 1.2 logs, respectively, without significant changes in body-weight or serum human-albumin levels, although ETV only slightly suppressed HBVETVR viremia (CdFA vs ETV; p = 0.032). Molecular modeling suggested that ETV-TP has good nonpolar interactions with HBVWT reverse transcriptase (RTWT)'s Met204 and Asp205, while CdFA-TP fails to interact with Met204, in line with the relatively inferior activity against HBVWT of CdFA compared to ETV (IC50: 0.026 versus 0.003 nM). In contrast, the 4'-cyano of CdFA-TP forms good nonpolar contacts with RTWT's Leu180 and RTETVR's Met180, while ETV-TP loses interactions with RTETVR's Met180, explaining in part why ETV is less potent against HBVETVR than CdFA. The present results show that CdFA exerts potent activity against HBVWT, HBVETVR and HBVADVR with enhanced safety and that 7-deaza-7-fluoro modification confers potent activity against drug-resistant HBV variants and favorable safety, shedding light to further design more potent and safer anti-HBV nucleoside analogs.

CMCdG, a Novel Nucleoside Analog with Favorable Safety Features, Exerts Potent Activity against Wild-Type and Entecavir-Resistant Hepatitis B Virus.

We designed, synthesized, and characterized a novel nucleoside analog, (1S,3S,5S)-3-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-5-hydroxy-1-(hydroxymethyl)-2-methylene-cyclopentanecarbonitrile, or 4'-cyano-methylenecarbocyclic-2'-deoxyguanosine (CMCdG), and evaluated its anti-hepatitis B virus (anti-HBV) activity, safety, and related features. CMCdG's in vitro activity was determined using quantitative PCR and Southern blotting assays, and its cytotoxicity was determined with a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, while its in vivo activity and safety were determined in human liver-chimeric mice infected with wild-type HBV genotype Ce (HBVWTCe) and an entecavir (ETV)-resistant HBV variant containing the amino acid substitutions L180M, S202G, and M204V (HBVETV-RL180M/S202G/M204V). CMCdG potently inhibited HBV production in HepG2.2.15 cells (50% inhibitory concentration [IC50], ∼30 nM) and HBVWTCe plasmid-transfected Huh7 cells (IC50, 206 nM) and efficiently suppressed ETV-resistant HBVETV-RL180M/S202G/M204V (IC50, 2,657 nM), while it showed no or little cytotoxicity (50% cytotoxic concentration, >500 µM in most hepatocytic cells examined). Two-week peroral administration of CMCdG (1 mg/kg of body weight/day once a day [q.d.]) to HBVWTCe-infected human liver-chimeric mice reduced the level of viremia by ∼2 logs. CMCdG also reduced the level of HBVETV-RL180M/S202G/M204V viremia by ∼1 log in HBVETV-RL180M/S202G/M204V-infected human liver-chimeric mice, while ETV (1 mg/kg/day q.d.) completely failed to reduce the viremia. None of the CMCdG-treated mice had significant drug-related changes in body weights or serum human albumin levels. Structural analyses using homology modeling, semiempirical quantum methods, and molecular dynamics revealed that although ETV triphosphate (TP) forms good van der Waals contacts with L180 and M204 of HBVWTCe reverse transcriptase (RT), its contacts with the M180 substitution are totally lost in the HBVETV-RL180M/S202G/M204V RT complex. However, CMCdG-TP retains good contacts with both the HBVWTCe RT and HBVETV-RL180M/S202G/M204V RT complexes. The present data warrant further studies toward the development of CMCdG as a potential therapeutic for patients infected with drug-resistant HBV and shed light on the further development of more potent and safer anti-HBV agents.

An Association Between Core Mutations in Hepatitis B Virus Genotype F1b and Hepatocellular Carcinoma in Alaskan Native People.

Hepatitis B virus (HBV) genotype F1b infection is strongly associated with hepatocellular carcinoma (HCC) in young Alaskan Native (AN) people. However, the mechanisms by which genotype F1b causes HCC are unclear. Here, we analyzed the clinical and virological significance of genotype F1b in long-term serial samples from 20 HCC patients with HBV infection. Complete sequence analyses revealed that all isolates were genotype F1b. In the HCC patients, T1938C and A2051C mutations in the core region had accumulated significantly with A1762T/G1764A mutations in the basal core promoter (BCP) region and G1896A mutation in the precore (PC) region. Several HBV clones containing the core mutations were examined for their replication efficiency and core stability in vitro. Clones containing the A2051C mutation replicated more efficiently than the wild type in association with enhanced stability of core protein dimerization. In chimeric mice with human hepatocytes carrying BCP/PC/2051 mutant but not with wild-type virus, liver fibrosis was induced in association with high levels of serum HBV DNA and hepatitis B surface antigen. Interestingly, microarray analysis and validation study showed that five genes associated with cell proliferation or carcinogenesis, v-myc avian myelocytomatosis viral oncogene homolog, Grb2-associated binding protein 2, bradykinin receptor B2, follistatin, and mitogen-activated protein kinase kinase kinase 8, were significantly up-regulated in human hepatocytes infected with genotype F1b, particularly the BCP/PC/2051 mutant, compared with other genotypes. Conclusion: We have identified an association between Alaska-specific core mutations and HCC development in AN people infected with genotype F1b; accumulation of these core mutations during the course of chronic infection with genotype F1b would contribute to HCC development in AN people earlier in life.

Late Relapse after a Sustained Virologic Response at 24 Weeks after Treatment with Daclatasvir and Asunaprevir Combination Therapy for Chronic Hepatitis C Virus Genotype 1b Infection with Liver Cirrhosis.

There have been few studies on relapse after a sustained virological response in hepatitis C virus (HCV) patients treated with interferon-free regimens. Thus, the risk of late relapse in patients treated with interferon-free therapy remains unclear. A 67-year-old woman with HCV genotype 1b and liver cirrhosis received oral daclatasvir and asunaprevir. Combination therapy was stopped after 4 weeks because of an episode of encephalopathy. Nonetheless, an HCV polymerase chain reaction at 24 weeks posttreatment was negative. However, HCV ribonucleic acid was detectable at approximately 62 weeks posttreatment. Very late HCV relapses may occur in patients with liver cirrhosis who receive an interferon-free regimen when the treatment period is insufficient.

High levels of serum Mac-2-binding protein glycosylation isomer (M2BPGi) predict the development of hepatocellular carcinoma in hepatitis B patients treated with nucleot(s)ide analogues.

BACKGROUND: Nucleot(s)ide analogues (NA) can reduce the risk of hepatocellular carcinoma (HCC), but not completely prevent its development. METHODS: Two hundred and thirty-four chronic hepatitis B patients virologically well controlled with entecavir or tenofovir disoproxil fumarate for more than 1 year were enrolled in this study. Over the median observation period of 51 (12-142) months, 24 of 234 patients developed HCC. We quantified HBV markers, alpha-fetoprotein (AFP) and Mac-2-binding protein glycosylation isomer (M2BPGi) at baseline and 48 weeks after therapy. RESULTS: Serum AFP and M2BPGi tended to decline from baseline to 48 weeks after treatment both in patients who did and those who did not develop HCC. Univariate Cox regression analysis indicated that serum M2BPGi levels ≥ 1.215 COI at 48 weeks were associated with HCC development [hazard ratio (HR) 5.73; p ≤ 0.001]. Multivariate analysis showed that male sex (HR 5.6; p = 0.01), AFP ≥ 9.65 ng/ml (HR 22.01; p ≤ 0.001), M2BPGi ≥ 1.215 (HR 5.07; p = 0.004) at 48 weeks were significant independent predictive factors for HCC development. Based on a scoring system consisting of three factors above described, Kaplan-Meier analysis for four groups (score 0, 1, 2, ≥ 3), revealed significant differences in cumulative HCC occurrence for each group within 2 years. The rate of incidence of HCC was 0, 5.4, 23.4, and 75% in each group, respectively. CONCLUSIONS: In patients receiving NA therapy, higher M2BPGi at 48 weeks, as well as male sex and higher AFP at 48 weeks were independent risk factors for HCC development.

Interferon-ß response is impaired by hepatitis B virus infection in Tupaia belangeri.

To date, the chimpanzee has been used as the natural infection model for hepatitis B virus (HBV). However, as this model is very costly and difficult to use because of ethical and animal welfare issues, we aimed to establish the tupaia (Tupaia belangeri) as a new model for HBV infection and characterized its intrahepatic innate immune response upon HBV infection. First, we compared the propagation of HBV genotypes A2 and C in vivo in tupaia hepatocytes. At 8-10days post infection (dpi), the level of HBV-A2 propagation in the tupaia liver was found to be higher than that of HBV-C. Abnormal architecture of liver cell cords and mitotic figures were also observed at 8 dpi with HBV-A2. Moreover, we found that HBV-A2 established chronic infection in some tupaias. We then aimed to characterize the intrahepatic innate immune response in this model. First, we infected six tupaias with HBV-A2 (strains JP1 and JP4). At 28 dpi, intrahepatic HBV-DNA and serum hepatitis B surface antigens (HBsAg) were detected in all tupaias. The levels of interferon (IFN)-ß were found to be significantly suppressed in the three tupaias infected with HBV A2_JP4, while no significant change was observed in the three infected with HBV A2_JP1. Expression of toll-like receptor (TLR) 1 was suppressed, while that of TLR3 and TLR9 were induced, in HBV A2_JP1-infected tupaias. Expression of TLR8 was induced in all tupaias. Next, we infected nine tupaias with HBV-A2 (JP1, JP2, and JP4), and characterized the infected animals after 31 weeks. Serum HBsAg levels were detected at 31 weeks post-infection (wpi) and IFN-ß was found to be significantly suppressed in all tupaias. TLR3 was not induced, except in tupaia #93 and #96. Suppression of TLR9 was observed in all tupaias, except tupaia #93. Also, we investigated the expression levels of cyclic GMP-AMP synthase, which was found to be induced in all tupaias at 28 dpi and in four tupaias at 31 wpi. Additionally, we evaluated the expression levels of sodium-taurocholate cotransporting polypeptide, which was found to be suppressed during chronic HBV infection. Thus, the tupaia infection model of HBV clearly indicated the suppression of IFN-ß at 31 wpi, which might have contributed to the establishment of chronic HBV infection.

Characteristics of escape mutations from occult hepatitis B virus infected patients with hematological malignancies in South Egypt.

AIM: To investigate the prevalence and virological characteristics of occult hepatitis B virus (HBV) infections in patients with hematological malignancies in South Egypt. METHODS: Serum samples were collected from 165 patients with hematological malignancies to monitor titers of HBV DNA, hepatitis B surface antigen (HBsAg), and antibodies to HBV core (anti-HBc) and surface antigens. Serum samples negative for HBsAg and positive for anti-HBc were subjected to nucleic acid extraction and HBV DNA detection by real-time polymerase chain reaction. DNA sequences spanning the S region were analyzed in cases with occult HBV infection. In vitro comparative study of constructed 1.24-fold wild type and S protein mutant HBV genotype D clones was further performed. RESULTS: HBV DNA was detected in 23 (42.6%) of 54 patients with hematological malignancies who were HBsAg negative, but anti-HBc positive, suggesting the presence of occult HBV infection. The complete HBV genome was retrieved from 6 occult HBV patients, and P120T and S143L were detected in 3 and 2 cases, respectively. Site directed mutagenesis was done to produce 1.24-fold genotype D clones with amino acid mutations T120 and L143. The in vitro analyses revealed that a lower level of extracellular HBsAg was detected by chemiluminescence enzyme immunoassay (CLEIA) with the clone containing T120 mutation, compared with the wild type or the clone with S143L mutation despite the similar levels of extracellular and intracellular HBsAg detected by Western blot. Southern blot experiments showed that the levels of intracellular HBV DNA were not different between these clones. CONCLUSION: Occult HBV infection is common in patients with hematological malignancies and associated with P120T and S143L mutations. 120T mutation impairs the detection of HBsAg by CLEIA.

Molecular epidemiology of co-infection with hepatitis B virus and human immunodeficiency virus (HIV) among adult patients in Harare, Zimbabwe.

The objective of this study was to determine the prevalence of co-infection with hepatitis B virus (HBV) and human immunodeficiency virus (HIV) and the genetic characteristics of both viruses among pre-HIV-treatment patients in Harare, Zimbabwe. This cross-sectional survey involved 176 remnant plasma samples collected from consenting HIV patients (median age 35 [18-74]) between June and September 2014. HBV seromarkers were determined by high-sensitivity chemiluminescence assays. Molecular evolutionary analyses were conducted on the basal core promoter/precore (BCP/PC) and S regions of HBV, as well as part of the HIV pol region. Of the 176 participants (65.7% female), 19 (10.8%) were positive for HBsAg (median 0.033 IU/ml (IQR 0.01-415). The HBsAg incidence was higher in men than women (P = 0.009). HBsAg-positive subjects had lower median CD4 counts (P = 0.016). HBV DNA was detectable in 12 HBsAg-positive samples (median 3.36 log cp/ml (2.86-4.51), seven being amplified and sequenced. All isolates were subgenotype A1 without HBV drug resistance mutations but each had at least one BCP/PC mutation. PreS deletion mutants and small S antigen variants M133I/T and D144G were identified. Of the 164 HIV isolates successfully genotyped, 163 (99.4%) were HIV-1 subtype C and only one was HIV-1 subtype F1. Sixteen (9.8%) had at least one drug resistance mutation, predominantly non-nucleoside reverse transcriptase inhibitor-related mutations, observed mostly among female participants. This study shows that co-infection with HBV is present among HIV patients enrolling into HIV care in Zimbabwe, suggesting that HBV screening and monitoring programmes be strengthened in this context. J. Med. Virol. 89:257-266, 2017. © 2016 Wiley Periodicals, Inc.

Novel monitoring of hepatitis B reactivation based on ultra-high sensitive hepatitis B surface antigen assay.

BACKGROUND & AIMS: Occult hepatitis B virus (HBV) infection should be evaluated before systemic chemotherapy to prevent HBV reactivation-related hepatitis. We investigated HBV reactivation using high sensitivity HB surface antigen (HBsAg) chemiluminescent enzyme immunoassay (HBsAg-HQ) and ultra-high sensitive HBsAg assay employing a semi-automated immune complex transfer chemiluminescence enzyme technique (ICT-CLEIA). METHODS: Of 120 HBV-resolved patients with haematological malignancy receiving systemic chemotherapy from 2012 to 2015 in our hospital, 13 patients had HBV DNA reactivation (in 12/13 patients HBV DNA became quantifiable) according to HBV DNA monitoring. These patients were applied for Architect HBsAg-QT (detection limit:50 mIU/mL), HBsAg-HQ (5 mIU/mL) and ICT-CLEIA (0.5 mIU/mL) using stored samples. RESULTS: When HBV DNA was firstly quantifiable by regular HBV DNA monitoring, HBsAg-QT was detected in 1/12 patients (8%), HBsAg-HQ was detected in 4/12 patients (33%) and ICT-CLEIA was detected in all 12 patients (100%), suggesting that the sensitivity of ICT-CLEIA was comparable to that of HBV DNA quantification. Interestingly, two patients were HBsAg positive by ICT-CLEIA before HBV DNA became detectable. Median difference of detectable point between HBV DNA and ICT-CLEIA was zero (range from -28 to 56 days), while median delay by HBsAg-QT or HBsAg-HQ was 52.5 days after HBV DNA became detectable. Although anti-HBs titres were high (131.9 mIU, 80.4 mIU) in two patients with escape mutations (Saa126V, Saa145R), HBsAg by ICT-CLEIA and HBV DNA were detectable concurrently. CONCLUSIONS: ICT-CLEIA is a novel assay for HBV monitoring to prevent hepatitis caused by HBV reactivation.

Inhibitory effect of CDK9 inhibitor FIT-039 on hepatitis B virus propagation.

Current therapies for hepatitis B virus (HBV) cannot completely eliminate the HBV genome because of the stable population of covalently closed circular DNA (cccDNA) and so on. FIT-039, which is a cyclin-dependent kinase (CDK) 9 inhibitor, is known to suppress the replication of several DNA viruses including HSV, HPV and human adenovirus. In this study, we investigated the antiviral effect of FIT-039 on HBV infection. HepG2 cells expressing human sodium taurocholate cotransporting polypeptide (HepG2/NTCP cells) were infected with HBV in the presence of FIT-039. FIT-039 dose-dependently reduced intracellular viral RNA, nucleocapsid-associated viral DNA, and supernatant viral antigens without cytotoxicity in the infected cells (IC50 = 0.33 µM, CC50 > 50 µM). The antiviral activity of FIT-039 was prominent at an early phase of viral infection, although the compound did not inhibit preS1-binding to HepG2/NTCP cells. FIT-039 reduced cccDNA in HBV-replicating or HBV-infected cells. Furthermore, the antiviral activity of entecavir was significantly enhanced by the combination with FIT-039 in the chimeric mice having human hepatocytes infected with HBV. None of the mice had significant drug-related body weight or serum human-albumin concentration changes. These data suggest that CDK9 inhibitor FIT-039 is a promising antiviral candidate for HBV infection.

Novel pH-sensitive multifunctional envelope-type nanodevice for siRNA-based treatments for chronic HBV infection.

BACKGROUND & AIMS: Antiviral agents including entecavir (ETV) suppress the replication of the hepatitis B virus (HBV) genome in human hepatocytes, but they do not reduce the abundance of viral proteins. The present study focused on effectively reducing viral protein levels. METHODS: We designed siRNAs (HBV-siRNA) that target consensus sequences in HBV genomes. To prevent the emergence of escaped mutant virus, we mixed three HBV-siRNAs (HBV-siRNAmix); the mixture was encapsulated in a novel pH-sensitive multifunctional envelope-type nanodevice (MEND), a hepatocyte-specific drug delivery system. Coagulation factor 7 siRNA was used to assess delivery and knockdown efficiencies of MEND/siRNA treatments in mice. The potency of MEND/HBV-siRNAmix was evaluated in primary human hepatocytes and in chimeric mice with humanized liver persistently infected with HBV. RESULTS: Effective knockdown of targets, efficient delivery of siRNA, and liver-specific delivery were each observed with MEND. MEND/HBV-siRNA caused efficient reduction of HBsAg and HBeAg in vitro and in vivo. However, ETV treatment did not efficiently reduce HBsAg or HBeAg when compared with a single MEND/HBV-siRNAmix treatment. Furthermore, the suppressive effects of a single dose of MEND/HBV-siRNAmix persisted for 14days in vitro and in vivo. CONCLUSION: We demonstrated that MEND/HBV-siRNA controlled HBV more efficiently than did ETV. Furthermore, the effect of a single dose of MEND/HBV-siRNA persisted for a long time. These results indicated that MEND/HBV-siRNA may be a promising novel HBV treatment that is more effective than reverse transcriptase inhibitors.

Property of hepatitis B virus replication in Tupaia belangeri hepatocytes.

The northern treeshrew (Tupaia belangeri) has been reported to be an effective candidate for animal infection model with hepatitis B virus (HBV). The objective of our study was to analyze the growth characteristics of HBV in tupaia hepatocytes and the host response to HBV infection. We established primary tupaia hepatocytes (3-6-week old tupaia) and infected them with HBV genotypes A, B and C, and all the genotypes proliferated as well as those in human primary hepatocytes (>10(5) copies/ml in culture supernatant). We next generated a chimeric mouse with tupaia liver by transplantation of tupaia primary hepatocytes to urokinase-type plasminogen activator cDNA (cDNA-uPA)/severe combined immunodeficient (SCID) mice and the replacement ratio with tupaia hepatocytes was found to be more than 95%. Infection of chimeric mice with HBV (genotypes B, C, and D) resulted in HBV-DNA level of 10(4)-10(6) copies/ml after 8 weeks of infection, which were almost similar to that in humanized chimeric mouse. In contrast, serum HBV level in adult tupaia (1-year-old tupaia) was quite low (<10(3) copies/ml). Understanding the differences in the response to HBV infection in primary tupaia hepatocytes, chimeric mouse, and adult tupaia will contribute to elucidating the mechanism of persistent HBV infection and viral eradication. Thus, T. belangeri was found to be efficient for studying the host response to HBV infection, thereby providing novel insight into the pathogenesis of HBV.

Hepatitis B surface gene variants isolated from blood donors with overt and occult HBV infection in north eastern Egypt.

BACKGROUND: Major hydrophilic region in genomic HBV extending from aa99 to aa169, clustered with a highly conformational epitope, is critical to the antigenicity of hepatitis B surface antigen (HBsAg) and may affect the diagnosis of HBV in HBV screening test. So, this study aimed to characterize variants of S gene product of hepatitis B virus (HBV) isolated from patients with overt or occult HBV infection in north-eastern Egypt. METHODS: The study included sera of two different groups of volunteer blood donors (VBDs), 82 with overt HBV that were positive for HBsAg and anti-HBc and 343 donors negative for HBsAg eligible for donation. Of the latter group, only 44 were positive for anti-HBc. All anti-HBc positive sera were subjected to HBV DNA detection and partial sequence analysis targeting the HBV S gene. RESULTS: HBV DNA was detected in 22.7 % of HBsAg-/anti-HBc + (10/44 patients) and in 90 % of HBsAg + donors (74/82 patients) with significant statistical difference (P = 0.0001). Phylogenetic analysis showed that HBV strains retrieved from both groups were of genotype D. Amino acid escape mutation T125M was detected in only 2 samples of the occult infection group and in none of the overt group (P = 0.01). Different amino acid substitutions were identified in overt infection group: S143L/T (16.2 %, 12/74) and P120T/S (2.7 %, 2/74). Q129R was significantly more frequent in cases with occult HBV infection (40 %, 4/10) than overt group (6.8 %, 5/74) (P = 0.01). CONCLUSIONS: HBV genotype D predominated both in patients with overt and occult HBV infection. Different profiles of amino acid substitutions in the major hydrophilic region were seen in these two groups in Egypt.

4'-modified nucleoside analogs: potent inhibitors active against entecavir-resistant hepatitis B virus.

UNLABELLED: Certain nucleoside/nucleotide reverse transcriptase (RT) inhibitors (NRTIs) are effective against human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV). However, both viruses often acquire NRTI resistance, making it crucial to develop more-potent agents that offer profound viral suppression. Here, we report that 4'-C-cyano-2-amino-2'-deoxyadenosine (CAdA) is a novel, highly potent inhibitor of both HBV (half maximal inhibitory concentration [IC50 ] = 0.4 nM) and HIV-1 (IC50 = 0.4 nM). In contrast, the approved anti-HBV NRTI, entecavir (ETV), potently inhibits HBV (IC50 = 0.7 nM), but is much less active against HIV-1 (IC50 = 1,000 nM). Similarly, the highly potent HIV-1 inhibitor, 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA; IC50 = 0.3 nM) is less active against HBV (IC50 = 160 nM). Southern analysis using Huh-7 cells transfected with HBV-containing plasmids demonstrated that CAdA was potent against both wild-type (IC50 = 7.2 nM) and ETV-resistant HBV (IC50 = 69.6 nM for HBVETV-RL180M/S202G/M204V), whereas ETV failed to reduce HBVETV-RL180M/S202G/M204V DNA even at 1 µM. Once-daily peroral administration of CAdA reduced HBVETV-RL180M/S202G/M204V viremia (P = 0.0005) in human-liver-chimeric/ HBVETV-RL180M/S202G/M204V-infected mice, whereas ETV completely failed to reduce HBVETV-RL180M/S202G/M204V viremia. None of the mice had significant drug-related body-weight or serum human-albumin concentration changes. Molecular modeling suggests that a shallower HBV-RT hydrophobic pocket at the polymerase active site can better accommodate the slightly shorter 4'-cyano of CAdA-triphosphate (TP), but not the longer 4'-ethynyl of EFdA-TP. In contrast, the deeper HIV-1-RT pocket can efficiently accommodate the 4'-substitutions of both NRTIs. The ETV-TP's cyclopentyl ring can bind more efficiently at the shallow HBV-RT binding pocket. CONCLUSION: These data provide insights on the structural and functional associations of HBV- and HIV-1-RTs and show that CAdA may offer new therapeutic options for HBV patients.

Characterization of novel entecavir resistance mutations.

BACKGROUND & AIMS: Entecavir (ETV) is approved for the treatment of chronic hepatitis B virus (HBV) infections, but the virus can acquire resistance to the drug. This requires lamivudine resistance mutations (LAMr) and at least one additional mutation. Here, we characterized two novel mutations, rtI163V and rtA186T, associated with viral breakthrough (VBT) in an ETV-refractory patient. METHODS: HBV from an ETV-refractory patient was sequenced, and newly identified mutations were inserted into a replication-competent clone by mutagenesis. Clones were analyzed for replication efficacy and susceptibility to ETV in vitro. Chimeric mice with human hepatocytes were inoculated with the patient's serum at VBT, and monitored for viral mutation pattern using a next-generation sequencing approach. RESULTS: RtI163V and rtA186T mutations were detected together with LAMr (rtL180M and rtM204V) at VBT. RtA186T plus LAMr reduced susceptibility to ETV more than 111.1-fold compared with the wild-type clone, while rtI163V plus LAMr resulted in a 20.4-fold reduction. RtA186T significantly reduced viral replication efficacy, while the rtI163V mutation rescued it. Interestingly, the viral mutation pattern in the chimeric mice indicated dominant (or selective) proliferation of a clone containing rtI163V and rtA186T mutations plus LAMr under ETV treatment. Three-dimensional docking simulation indicated that rtA186T reduced the binding affinity of the HBV polymerase to ETV. CONCLUSIONS: VBT in this ETV-refractory patient is attributable to the novel ETV resistance mutations rtI163V and rtA186T. RtA186T was apparently responsible for ETV resistance but the selection of a clone with the double mutation plus LAMr suggests that rtI163V is required to sustain viral fitness.

Fatal reactivation of hepatitis B virus infection in a patient with adult T-cell leukemia-lymphoma receiving the anti-CC chemokine receptor 4 antibody mogamulizumab.

We report an adult T-cell leukemia-lymphoma (ATL) patient suffering from fatal reactivation of hepatitis B virus (HBV) infection after treatment with the anti-CC chemokine receptor 4 (CCR4) monoclonal antibody, mogamulizumab. HBV reactivation occurred without liver damage in this hepatitis B surface antigen (HBsAg) negative patient, who was seropositive for antibodies against the viral core and surface antigens at baseline, after two cycles of CHOP regimen (cyclophosphamide, doxorubicin, vincristine and prednisolone) followed by six cycles of THP-COP regimen (cyclophosphamide, pirarubicin, vincristine and prednisolone). Unexpectedly, mogamulizumab monotherapy for relapsed CCR4 positive ATL induced sudden and fatal liver failure due to HBV reactivation, despite antiviral prophylaxis with entecavir. This clinical course may not only offer important suggestions to prevent critical HBV reactivation in HBsAg positive cancer patients who receive immune-enhancing drugs such as anti-CCR4 antibody, but also provide a clue to understanding the pathogenesis of HBV reactivation following systemic chemotherapy.