A novel cDNA-uPA/SCID/Rag2-/- /Jak3-/- mouse model for hepatitis virus infection and reconstruction of human immune system.

Although human hepatocyte-transplanted immunodeficient mice support infection with hepatitis viruses, these mice fail to develop viral hepatitis due to the lack of an adaptive immune system. In this study, we generated new immunodeficiency cDNA-urokinase-type plasminogen activator (uPA)/SCID/Rag2-/- /Jak3-/- mice and established a mouse model with both a humanized liver and immune system. Transplantation of human hepatocytes with human leukocyte antigen (HLA)-A24 resulted in establishment of a highly replaced liver in cDNA-uPA/SCID/Rag2-/- /Jak3-/- mice. These mice were successfully infected with hepatitis B virus (HBV) and hepatitis C virus (HCV) for a prolonged period and facilitate analysis of the effect of anti-HCV drugs. Administration of peripheral blood mononuclear cells (PBMCs) obtained from an HLA-A24 donor resulted in establishment of 22.6%-81.3% human CD45-positive mononuclear cell chimerism in liver-infiltrating cells without causing graft-versus-host disease in cDNA-uPA/SCID/Rag2-/- /Jak3-/- mice without human hepatocyte transplantation. When mice were transplanted with human hepatocytes and then administered HLA-A24-positive human PBMCs, an alloimmune response between transplanted human hepatocytes and PBMCs occurred, with production of transplanted hepatocyte-specific anti-HLA antibody. In conclusion, we succeeded in establishing a humanized liver/immune system characterized by an allo-reaction between transplanted human immune cells and human liver using a novel cDNA-uPA/SCID/Rag2-/- /Jak3-/- mouse. This mouse model can be used to generate a chronic hepatitis mouse model with a human immune system with application not only to hepatitis virus virology but also to investigation of the pathology of post-transplantation liver rejection.

The presence of vessels encapsulating tumor clusters is associated with an immunosuppressive tumor microenvironment in hepatocellular carcinoma.

Recently, a distinct vascular pattern in hepatocellular carcinoma (HCC) called vessels encapsulating tumor-forming clusters (VETC) has received attention because of its association with poor prognosis. However, little is known about the mechanism by which VETC promotes an aggressive phenotype at the molecular level. In our study, the association between differences in stepwise signal intensity in the HB phase and molecular subtypes and somatic mutations associated with the immune microenvironment were investigated using the International Cancer Genome Consortium (ICGC) cohort (66 patients). To our knowledge, this is the first study to analyze the molecular patterns of VETC using RNA-Seq data. The VETC+ HCC group showed significantly lower overall survival and higher cumulative incidence of extrahepatic metastasis after curative hepatic resection than the VETC- HCC group. The VETC+ group exhibited molecular features indicative of lower immune activation than the VETC- group, suggesting that tumor cells in the VETC+ group were more likely to escape from the immune response, which could lead to the shorter OS (Overall survival) and higher risk of metastasis. On the other hand, gene expression levels of fibroblast growth factor receptors were upregulated in VETC+ HCC, suggesting that VETC+ HCC might benefit from lenvatinib treatment. Our results demonstrate that VETC+ HCC was associated with the suppression of tumor immune responses at the molecular level.

Signal Activation of Hepatitis B Virus-Related Hepatocarcinogenesis by Up-regulation of SUV39h1.

BACKGROUND: Hepatitis B virus (HBV) X (HBx) protein is associated with hepatocellular carcinogenesis via the induction of malignant transformation and mitochondrial dysfunction. However, the association between HBx and histone methyltransferase in carcinogenesis has not been fully clarified. In the current study, we analyzed the association between HBx and the histone methyltransferase suppressor of variegation 3-9 homolog 1 (SUV39h1) using HBV replication models. METHODS: We constructed several HBx and SUV39h1 expression plasmids and analyzed the association between HBx and SUV39h1 with respect to HBV replication and hepatocarcinogenesis. RESULTS: SUV39h1 up-regulation was observed in HBV-infected humanized mouse livers and clinical HBV-related hepatocellular carcinoma tissues, indicating that SUV39h1 expression might be regulated by HBV infection. Through in vitro analysis, we determined that the coactivator domain of HBx interacts with the PSET (PostSET) and SET (Su(var)3-9, Enhancer-of-zeste, Trithorax) domains of SUV39h1. The expression levels of 4 genes, activating transcription factor 6, α-fetoprotein, growth arrest and DNA damage-inducible 45a, and dual-specificity phosphatase 1, known to induce carcinogenesis via HBx expression, were up-regulated by HBx and further up-regulated in the presence of both HBx and SUV39h1. Furthermore, histone methyltransferase activity, the main function of SUV39h1, was enhanced in the presence of HBx. CONCLUSIONS: We demonstrated that SUV39h1 and HBx enhance each other's activity, leading to HBx-mediated hepatocarcinogenesis. We propose that regulation of this interaction could help suppress development of hepatocellular carcinoma.

Efficacy of glecaprevir and pibrentasvir treatment for genotype 1b hepatitis C virus drug resistance-associated variants in humanized mice.

Combination therapy with glecaprevir (GLE) and pibrentasvir (PIB) has high efficacy for pan-genotypic hepatitis C virus (HCV)-infected patients. However, the efficacy for patients who acquired potent NS5A inhibitor resistance-associated variants (RAVs) as a result of failure to respond to previous direct-acting antiviral (DAA) therapies is unclear. We investigated the efficacy of GLE/PIB treatment for genotype 1b HCV strains containing RAVs using subgenomic replicon systems and human hepatocyte transplanted mice. Mice were injected with serum samples obtained from a DAA-naïve patient or daclatasvir plus asunaprevir (DCV/ASV) treatment failures including NS5A-L31M/Y93H, -P58S/A92K or -P32 deletion (P32del) RAVs, then treated with GLE/PIB. HCV was eliminated by GLE/PIB treatment in mice with wild-type and NS5A-L31M/Y93H but relapsed in mice with NS5A-P58S/A92K, followed by emergence of additional NS5A mutations after cessation of the treatment. In NS5A-P32del-infected mice, serum HCV RNA remained positive during the GLE/PIB treatment. NS5A-P58S/A92K showed 1.5-fold resistance to PIB relative to wild-type based on analysis using HCV subgenomic replicon systems. When mice were administered various proportions of HCV wild-type and P32del strains and treated with GLE/PIB, serum HCV RNA remained positive in mice with high frequencies of P32del. In these mice, the P32del was undetectable by deep sequencing before GLE/PIB treatment, but P32del strains relapsed after cessation of the GLE/PIB treatment. GLE/PIB is effective for wild-type and NS5A-L31M/Y93H HCV strains, but the effect seems to be low for P58S/A92K and NS5A-P32del RAVs. Although NS5A-P32del was not detected, the mutation may be present at low frequency in DCV/ASV treatment failures.

Limitations of daclatasvir/asunaprevir plus beclabuvir treatment in cases of NS5A inhibitor treatment failure.

Combined daclatasvir (DCV)/asunaprevir (ASV) plus beclabuvir (BCV) treatment shows a high virological response for genotype 1b chronic hepatitis C patients. However, its efficacy for patients for whom previous direct-acting antiviral (DAA) therapy failed is not known. We analysed the efficacy of DCV/ASV/BCV treatment for HCV-infected mice and chronic hepatitis patients. Human hepatocyte chimaeric mice were injected with serum samples obtained from either a DAA-naïve patient or a DCV/ASV treatment failure and were then treated with DCV/ASV alone or in combination with BCV for 4 weeks. DCV/ASV treatment successfully eliminated the virus in DAA-naïve-patient HCV-infected mice. DCV/ASV treatment failure HCV-infected mice developed viral breakthrough during DCV/ASV treatment, with the emergence of NS5A-L31V/Y93H HCV resistance-associated variants (RAVs) being observed by direct sequencing. DCV/ASV/BCV treatment inhibited viral breakthrough in NS5A-L31V/Y93H-mutated HCV-infected mice, but HCV relapsed with the emergence of NS5B-P495S variants after the cessation of the treatment. The efficacy of the triple therapy was also analysed in HCV-infected patients; one DAA-naïve patient and four prior DAA treatment failures were treated with 12 weeks of DCV/ASV/BCV therapy. Sustained virological response was achieved in a DAA-naïve patient and one of the DCV/ASV treatment failures through DCV/ASV/BCV therapy; however, HCV relapse occurred in the other patients with prior DCV/ASV and/or sofosbuvir/ledipasvir treatment failures. DCV/ASV/BCV therapy seems to have limited efficacy for patients with NS5A RAVs for whom prior DAA treatment has failed.

Prevalence of NS5A resistance associated variants in NS5A inhibitor treatment failures and an effective treatment for NS5A-P32 deleted hepatitis C virus in humanized mice.

Patients with chronic hepatitis C virus (HCV) infection who have failed to respond to direct-acting antiviral (DAA) treatment often acquire drug resistance-associated variants (RAVs). The NS5A-P32 deletion (P32del) RAV confers potent resistance to NS5A inhibitors; therefore, patients who acquire this deletion are likely to fail to respond to DAA re-treatment. We investigated the prevalence of N55A-P32del in patients who failed to respond to prior NS5A inhibitor treatment using direct sequencing and analyzed the efficacy of DAA combination treatment in the presence of NS5A-P32del RAVs using human hepatocyte transplanted mice. NS5A-P32del was detected in one of 23 (4.3%) patients who had failed to respond to prior NS5A inhibitor treatment. Although four weeks of NS3/4A protease inhibitor glecaprevir plus NS5A inhibitor pibrentasvir treatment effectively suppressed HCV replication in wild-type HCV-infected mice, serum HCV RNA never became negative in P32del HCV-infected mice. When P32del HCV-infected mice were treated with four weeks of glecaprevir plus pibrentasvir combined with the NS5B polymerase inhibitor sofosbuvir, serum HCV RNA became negative, and the virus was eliminated from the liver in three out of four mice. We conclude that the combination of sofosbuvir and glecaprevir plus pibrentasvir may be an effective new treatment option for patients with NS5A-P32del.

CTL-associated and NK cell-associated immune responses induce different HBV DNA reduction patterns in chronic hepatitis B patients.

The activation of hepatitis B virus (HBV)-related hepatitis is associated with both natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). We analyzed the association between the immune response and changes in the proportion of Pre-S deletion variants. We quantified Pre-S deleted HBV (HBV-del) and wild-type HBV (HBV-wt) DNA levels in sera obtained from HBV-infected mice and chronic hepatitis B patients. In chronic hepatitis B patients, the HBV-del proportion usually increased during or after ALT elevation but did not occur during all ALT elevations. To clarify this difference in the immunological responses, we performed in vivo analyses using HBV-infected human hepatocyte chimeric mice. Although HBV-del proportions did not change in mice with NK cell-associated hepatitis or in mice treated with entecavir, the proportions sharply increased in mice with CTL-associated hepatitis. Furthermore, the number of patients in which HBV-del proportions were greater than 5% was significantly higher in chronic hepatitis B patients than in asymptomatic carriers (P = 0.023). We identified associations between virological response in chronic hepatitis B patients and two different immune responses. The proportion of HBV-del variants could be a useful biomarker for distinguishing between chronic hepatitis and asymptomatic carriers.

Persistent Loss of Hepatitis B Virus Markers in Serum without Cellular Immunity by Combination of Peginterferon and Entecavir Therapy in Humanized Mice.

Nucleot(s)ide analogues and peginterferon (PEG-IFN) treatment are the only approved therapies for chronic hepatitis B virus (HBV) infection. However, complete eradication of the virus, as indicated by persistent loss of hepatitis B surface antigen (HBsAg), is rare among treated patients. This is due to long-term persistence of the HBV genome in infected hepatocytes in the form of covalently closed circular DNA (cccDNA). In this study, we investigated whether administration of a large dose of a nucleoside analogue in combination with PEG-IFN can achieve long-term loss of HBsAg in human hepatocyte chimeric mice. Mice were treated with a high dose of entecavir and/or PEG-IFN for 6 weeks. High-dose combination therapy with both drugs resulted in persistently negative HBV DNA in serum. Although small amounts of HBV DNA and cccDNA (0.1 and 0.01 copy/cell, respectively) remained in the mouse livers, some of the mice remained persistently negative for serum HBV DNA at 13 weeks after cessation of the therapy. Serum HBsAg and hepatitis B core-related antigen (HBcrAg) continued to decrease and eventually became negative at 12 weeks after cessation of the therapy. Analysis of the HBV genome in treated mice showed accumulation of G-to-A hypermutation and CpG III island methylation. Persistent loss of serum HBV DNA and loss of HBV markers by high-dose entecavir and PEG-IFN combination treatment in chimeric mice suggests that control of HBV can be achieved even in the absence of a cellular immune response.

Development of a Novel Site-Specific Pegylated Interferon Beta for Antiviral Therapy of Chronic Hepatitis B Virus.

Although nucleot(s)ide analogues and pegylated interferon alpha 2a (PEG-IFN-α2a) can suppress hepatitis B virus (HBV) replication, it is difficult to achieve complete HBV elimination from hepatocytes. A novel site-specific pegylated recombinant human IFN-ß (TRK-560) was recently developed. In the present study, we evaluated the antiviral effects of TRK-560 on HBV replication in vitro and in vivo. In vitro and in vivo HBV replication models were treated with antivirals including TRK-560, and changes in HBV markers were evaluated. To analyze antiviral mechanisms, cDNA microarray analysis and an enzyme-linked immunoassay (ELISA) were performed. TRK-560 significantly suppressed the production of intracellular HBV replication intermediates and extracellular HBV surface antigen (HBsAg) (P < 0.001 and P < 0.001, respectively), and the antiviral effects of TRK-560 were enhanced in combination with nucleot(s)ide analogues, such as entecavir and tenofovir disoproxil fumarate. The reduction in HBV DNA levels by TRK-560 treatment was significantly higher than that by PEG-IFN-α2a treatment both in vitro and in vivo (P = 0.004 and P = 0.046, respectively), and intracellular HBV covalently closed circular DNA (cccDNA) reduction by TRK-560 treatment was also significantly higher than that by PEG-IFN-α2a treatment in vivo (P = 0.0495). cDNA microarrays and ELISA for CXCL10 production revealed significant differences between TRK-560 and PEG-IFN-α2a in the induction potency of interferon-stimulated genes. TRK-560 shows a stronger antiviral potency via higher induction of interferon-stimulated genes and stronger stimulation of immune cell chemotaxis than PEG-IFN-α2a. As HBsAg loss and HBV cccDNA eradication are important clinical goals, these results suggest a potential role for TRK-560 in the development of more effective treatment for chronic hepatitis B infection.

Usefulness of humanized cDNA-uPA/SCID mice for the study of hepatitis B virus and hepatitis C virus virology.

Urokinase-type plasminogen activator/severe combined immunodeficiency (uPA/SCID) mice transplanted with human hepatocytes are permissive for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. However, one of the problems affecting uPA transgenic mice is the expansion of mouse hepatocyte colonies due to homologous recombination of the uPA gene. In this study, we attempted to infect HBV and HCV in humanized cDNA-uPA/SCID mice, a novel uPA transgenic mouse model designed to overcome this disadvantage. Three hundred and eighty-six uPA/SCID and 493 cDNA-uPA/SCID mice were transplanted with human hepatocytes and then injected with either HBV- or HCV-positive human serum samples or HBV-transfected cell culture medium. Twelve weeks after human hepatocyte transplantation, the mouse serum concentration of human albumin, which is correlated with the degree of repopulation by human hepatocytes, was significantly higher in cDNA-uPA/SCID mice compared with uPA/SCID mice. HBV-infected cDNA-uPA/SCID mice showed significantly greater and more persistent viraemia, and similar virological effects by entecavir treatment were achieved in both systems. HCV-infected cDNA-uPA/SCID mice developed more frequent and significantly higher viraemia compared with uPA/SCID mice. The present study using a large number of mice showed that cDNA-uPA/SCID mice transplanted with human hepatocytes developed high and long-term persistent viraemia following HBV and HCV infection, and a higher survival rate was observed in cDNA-uPA/SCID compared with uPA/SCID mice. These mice may be a useful animal model for the study of HBV and HCV virology and the analysis of the effect of antiviral drugs.

Real-world efficacy and safety of daclatasvir and asunaprevir therapy for hepatitis C virus-infected cirrhosis patients.

BACKGROUND AND AIMS: Daclatasvir and asunaprevir combination therapy has shown a high virological response for chronic genotype 1 hepatitis C virus (HCV) infected-patients. However, the real-world efficacy and safety of the therapy for patients with cirrhosis are unknown. METHODS: A total of 252 patients with genotype 1 HCV infection (158 with chronic hepatitis and 94 with compensated liver cirrhosis) were treated with 24 weeks of daclatasvir and asunaprevir combination therapy. Plasma concentrations of daclatasvir and asunaprevir at day 5 of treatment, end-of-treatment response, sustained virological response (SVR), and the frequencies of adverse events were analyzed. RESULT: Plasma asunaprevir concentration was significantly higher, and daclatasvir concentration tended to be higher, in cirrhosis patients compared with chronic hepatitis patients. End-of-treatment response was achieved in 95.6% and 94.7% of chronic hepatitis and cirrhosis patients, respectively, and SVR was achieved in 94.3% and 92.6%. Although pre-treatment NS5A drug resistant-associated variants were detected, a high SVR rate was achieved when the population frequency of the variant was low. The frequencies of treatment-related adverse events in cirrhosis patients were similar to those in chronic hepatitis patients. Treatment discontinuation due to adverse events occurred in three and two patients in chronic hepatitis and cirrhosis groups, respectively; however, four out of five patients with treatment discontinuation nonetheless achieved SVR. CONCLUSION: Patients with compensated liver cirrhosis have similar virological response and tolerance for daclatasvir plus asunaprevir therapy to patients with chronic hepatitis. This combination therapy might offer a safe and effective treatment for chronic HCV infected-patients with compensated cirrhosis.

Protease Inhibitor Resistance Remains Even After Mutant Strains Become Undetectable by Deep Sequencing.

BACKGROUND: Although treatment-emergent NS3/4A protease inhibitor (PI)-resistant variants typically decrease in frequency after cessation of PI therapy in patients with chronic hepatitis C virus (HCV) infection, HCV susceptibility to PIs in patients who have not responded to previous PI therapy has not been addressed. METHODS: Patients with chronic HCV genotype 1 infection were treated either with simeprevir plus interferon or with daclatasvir plus asunaprevir. Frequencies of drug-resistant mutations among patients with treatment failure were analyzed by deep sequencing. Human hepatocyte chimeric mice were injected with serum samples obtained from either treatment-naive patients or nonresponders to treatment with daclatasvir plus asunaprevir and then were treated with simeprevir and sofosbuvir. RESULTS: Virological response to daclatasvir plus asunaprevir treatment was significantly lower in patients with simeprevir treatment failure as compared to those without previous treatment. Deep-sequencing analysis showed that the frequency of PI treatment-emergent NS3-D168 mutations gradually decreased and were completely replaced by wild-type genes after cessation of therapy. However, mice injected with serum obtained from a patient with PI treatment failure rapidly developed NS3-D168 mutations at significantly higher frequencies following either simeprevir or sofosbuvir treatment. CONCLUSIONS: The virological response to daclatasvir plus asunaprevir treatment was low in patients with simeprevir treatment failure. PI resistance remains even after disappearance of mutant strains by deep sequencing.

Early events in hepatitis B virus infection: From the cell surface to the nucleus.

While most adults are able to clear acute hepatitis B virus (HBV) infection, chronic HBV infection is recalcitrant to current therapy because of the persistence of covalently closed circular DNA in the nucleus. Complete clearance of the virus in these patients is rare, and long-term therapy with interferon and/or nucleoside analogues may be required in an attempt to suppress viral replication and prevent progressive liver damage. The difficulty of establishing HBV infection in cell culture and experimental organisms has hindered efforts to elucidate details of the HBV life cycle, but it has also revealed the importance of the cellular microenvironment required for HBV binding and entry. Recent studies have demonstrated an essential role of sodium-taurocholate cotransporting polypeptide as a functional receptor in HBV infection, which has facilitated the development of novel infection systems and opened the way for more detailed understanding of the early steps of HBV infection as well as a potential new therapeutic target. However, many gaps remain in understanding of how HBV recognizes and attaches to hepatocytes prior to binding to sodium-taurocholate cotransporting polypeptide, as well as events that are triggered after binding, including entry into the cell, intracellular transport, and passage through the nuclear pore complex. This review summarizes current knowledge of the initial stages of HBV infection leading to the establishment of covalently closed circular DNA in the nucleus.

HTLV-1 Tax oncoprotein stimulates ROS production and apoptosis in T cells by interacting with USP10.

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia (ATL), and the viral oncoprotein Tax plays key roles in the immortalization of human T cells, lifelong persistent infection, and leukemogenesis. We herein identify the ubiquitin-specific protease 10 (USP10) as a Tax-interactor in HTLV-1-infected T cells. USP10 is an antistress factor against various environmental stresses, including viral infections and oxidative stress. On exposure to arsenic, an oxidative stress inducer, USP10 is recruited into stress granules (SGs), and USP10-containing SGs reduce reactive oxygen species (ROS) production and inhibit ROS-dependent apoptosis. We found that interaction of Tax with USP10 inhibits arsenic-induced SG formation, stimulates ROS production, and augments ROS-dependent apoptosis in HTLV-1-infected T cells. These findings suggest that USP10 is a host factor that inhibits stress-induced ROS production and apoptosis in HTLV-1-infected T cells; however, its activities are attenuated by Tax. A clinical study showed that combination therapy containing arsenic is effective against some forms of ATL. Therefore, these findings may be relevant to chemotherapy against ATL.

Human T-cell leukemia virus type 1 Tax protein interacts with and mislocalizes the PDZ domain protein MAGI-1.

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia (ATL). HTLV-1 encodes the oncoprotein Tax1, which is essential for immortalization of human T-cells and persistent HTLV-1 infection in vivo. Tax1 has a PDZ binding motif (PBM) at its C-terminus. This motif is crucial for the transforming activity of Tax1 to a T-cell line and persistent HTLV-1 infection. Tax1 through the PBM interacts with PDZ domain proteins such as Dlg1 and Scribble, but it has not been determined yet, which cellular PDZ proteins mediate the functions of Tax1 PBM. Here we demonstrate that Tax1 interacts with the PDZ domain protein MAGI-1 in a PBM-dependent manner, and the interaction mislocalizes MAGI-1 from the detergent-soluble to the detergent-insoluble cellular fraction in 293T cells and in HTLV-1-infected T-cells. In addition, Tax1-transformation of a T-cell line from interleukin (IL)-2-dependent to IL-2-independent growth selects cells with irreversibly reduced expression of MAGI-1 at mRNA level. These findings imply that Tax1, like other viral oncoproteins, targets MAGI-1 as a mechanism to suppress its anti-tumor functions in HTLV-1-infected cells to contribute to the transforming activity of T-cells and persistent HTLV-1 infection.

The burden of Hepatitis B virus infection in Kenya: A systematic review and meta-analysis.

Background: Chronic Hepatitis B virus (HBV) infection causes liver cirrhosis and cancer and is a major public health concern in Kenya. However, so far no systematic review and meta-analysis has been conducted to estimate the burden of disease in the country. A better understanding of HBV infection prevalence will help the government implement efficient strategies at eliminating the disease. This systematic review and meta-analysis was therefore conducted to summarize and update the available information on the burden of HBV in Kenya. Method: We systematically searched PubMed, Science Direct, Web of Science, Scopus, African Journals OnLine, and Google Scholar databases to retrieve primary studies conducted between January 1990 and June 2021 that assessed the prevalence of HBV infection in Kenya based on measurement of the Hepatitis B Surface Antigen (HBsAg). Meta-analysis was performed using the random effects model where HBsAg prevalence was estimated at a 95% confidence interval (CI) after simple pooling analysis. Potential sources of heterogeneity were also investigated. Results: Fifty studies were included in the meta-analysis with a sample size of 108448. The overall pooled prevalence estimate of HBV in Kenya was 7.8% (95% CI: 5.8-10.1). Subgroup analysis revealed the highest prevalence among patients presenting with jaundice at 41.7% (95% CI: 13.5-73.3) whereas blood donors had the lowest prevalence at 4.1% (95% CI: 2.4-6.3). Prevalence in Human Immunodeficiency Virus (HIV)-infected individuals was 8.2% (95% CI: 5.8-11.0). An estimate of the total variation between studies revealed substantial heterogeneity (I2 = 99%) which could be explained by the study type, the risk status of individuals, and the region of study. Conclusion: We present the first systematic review and meta-analysis of the prevalence of HBV in Kenya. Our results show that the burden of HBV in Kenya is still enormous. This calls for an urgent need to implement public health intervention measures and strategic policies that will bring the disease under control and lead to final elimination. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=264859, identifier: CRD42021264859.

Deficiency of SCAP inhibits HBV pathogenesis via activation of the interferon signaling pathway.

Hepatitis B virus (HBV) infects the liver and is a major risk factor for liver cirrhosis and hepatocellular carcinoma. Approaches for an effective cure are thwarted by limited knowledge of virus-host interactions. Herein, we identified SCAP as a novel host factor that regulates HBV gene expression. SCAP, sterol regulatory element-binding protein (SREBP) cleavage-activating protein, is an integral membrane protein located in the endoplasmic reticulum. The protein plays a central role in controlling lipid synthesis and uptake by cells. We found that gene silencing of SCAP significantly inhibited HBV replication; furthermore, knockdown of SREBP2 but not SREBP1, the downstream effectors of SCAP, reduced HBs antigen production from HBV infected primary hepatocytes. We also demonstrated that knockdown of SCAP resulted in activation of interferons (IFNs) and IFN stimulated genes (ISGs). Conversely, ectopic expression of SREBP2 in SCAP-deficient cells restored expression of IFNs and ISGs. Importantly, expression of SREBP2 restored HBV production in SCAP knockdown cells, suggesting that SCAP participates in HBV replication through an effect on IFN production via its downstream effector SREBP2. This observation was further confirmed by blocking IFN signaling by an anti-IFN antibody, which restored HBV infection in SCAP-deficient cells. This led to the conclusion that SCAP regulates the IFN pathway through SREBP, thereby affecting the HBV lifecycle. This is the first study to reveal the involvement of SCAP in regulation of HBV infection. These results may facilitate development of new antiviral strategies against HBV.

Construction of an anti-hepatitis B virus preS1 antibody and usefulness of preS1 measurement for chronic hepatitis B patients: Anti-HBV PreS1 antibody.

OBJECTIVES: The preS1 region plays an essential role in hepatitis B virus (HBV) infection. We construct an antibody that binds to preS1 and a measurement system for serum preS1 in chronic HBV-infected patients. METHODS: Hybridoma clones that produce anti-preS1 antibodies were obtained by the iliac lymph node method. Epitope mapping was conducted, and an enzyme-linked immunosorbent assay (ELISA)-based method was developed. Using this ELISA system, serum preS1 levels were measured in 200 chronic HBV-infected patients. RESULTS: Eight types of hybridomas were obtained, of which antibody 3-55 using amino acids 38-47 as the epitope showed high binding affinity to preS1. Serum preS1 levels measured by ELISA using 3-55 antibody were correlated with HBsAg, HBcrAg and HBV DNA levels. Among HBeAg-negative patients without antiviral therapeutic objective (HBV DNA <3.3 log IU/mL or alanine aminotransferase ≤30 U/L), preS1 was significantly higher in subjects who had progressed to the point of requiring antiviral therapy compared to subjects who had maintained their status for the preceding three years (p<0.01). CONCLUSIONS: We constructed an antibody against preS1 and an ELISA system capable of measuring serum preS1 levels. PreS1 may serve as a novel tool to predict the need for antiviral therapy in HBeAg-negative HBV-infected patients.

In vitro analysis of hepatic stellate cell activation influenced by transmembrane 6 superfamily 2 polymorphism.

Non­alcoholic steatohepatitis (NASH) may progress via liver fibrosis along with hepatic stellate cell (HSC) activation. A single nucleotide polymorphism (SNP; rs58542926) located in transmembrane 6 superfamily 2 (TM6SF2) has been reported to be significantly associated with fibrosis in patients with NASH, but the precise mechanism is still unknown. The present study aimed to explore the role of TM6SF2 in HSC activation in vitro. Plasmids producing TM6SF2 wild-type (WT) and mutant type (MT) containing E167K amino acid substitution were constructed, and the activation of LX­2 cells was analyzed by overexpressing or knocking down TM6SF2 under transforming growth factor ß1 (TGFß) treatment. Intracellular α­smooth muscle actin (αSMA) expression in LX­2 cells was significantly repressed by TM6SF2­WT overexpression and increased by TM6SF2 knockdown. Following treatment with TGFß, αSMA expression was restored in TM6SF2­WT overexpressed LX­2 cells and was enhanced in TM6SF2 knocked­down LX­2 cells. Comparing αSMA expression under TM6SF2­WT or ­MT overexpression, expression of αSMA in TM6SF2­MT overexpressed cells was higher than that in TM6SF2­WT cells and was further enhanced by TGFß treatment. The present study demonstrated that intracellular αSMA expression in HCS was negatively regulated by TM6SF2 while the E167K substitution released this negative regulation and led to enhanced HSC activation by TGFß. These results suggest that the SNP in TM6SF2 may relate to sensitivity of HSC activation.

Publisher Correction: Regulation of the Hepatitis B virus replication and gene expression by the multi-functional protein TARDBP.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.