scholarly journals The Genotype (A to H) Dependent N-terminal Sequence of HBV Large Surface Protein Affects Viral Replication, Secretion and Infectivity

2021 ◽  
Vol 12 ◽  
Author(s):  
Guomin Ou ◽  
Lingyuan He ◽  
Luwei Wang ◽  
Ji Song ◽  
Xinyuan Lai ◽  
...  
Keyword(s):  
Type Strain ◽  
Surface Protein ◽  
Dependent Manner ◽  
Terminal Sequence ◽  
Hbv Replication ◽  
B Virus ◽  
N Terminus ◽  
And Function ◽  
Full Length Genome ◽  
Type Strains

Genetic variability has significant impacts on biological characteristics and pathogenicity of hepatitis B virus (HBV), in which the N-terminal sequence of the presurface 1 (preS1) region of HBV large surface protein (LHBs) displays genotype (GT) dependent genetic heterogeneity. However, the influence of this heterogeneity on its biological roles is largely unknown. By analyzing 6560 full-length genome sequences of GTA-GTH downloaded from HBVdb database, the preS1 N-terminal sequences were divided into four representative types, namely C-type (representative of GTA, GTB, and GTC), H-type (GTF and GTH), E-type (GTE and GTG), and D-type (GTD), respectively. We artificially substituted the preS1 N-termini of GTC and GTD plasmids or viral strains with each sequence of the four representative types. The roles of preS1 N-terminus on HBV replication, secretion and infectivity were investigated using HepG2 or HepG2-NTCP cells. In the transfection experiments, the results showed that the extracellular HBsAg levels and HBsAg secretion coefficients in D- and E-type strains were significantly higher than those in C- and H-type strains. D-type strain produced more extracellular HBV DNA than C-type strain. We further observed that D-, H-, and E-type strains increased the levels of intracellular replicative HBV DNAs, comparing with C-type strain. In the infection experiments, the levels of extracellular HBeAg, intracellular HBV total RNA and pgRNA/preC mRNA in D- and E-type strains were markedly higher than C and H-type ones. Our data suggest that the preS1 N-termini affect HBV replication, secretion and infectivity in a genotype dependent manner. The C- and H-type strains prefer to attenuate HBsAg secretion, while the strains of D- and E-type promoted infectivity. The existence and function of the intergenotypic shift of preS1 in naturally occurring recombination requires further investigation, as the data we acquired are mostly related to recombinant preS1 region between N-terminus of preS1 from genotypes A-H and the remaining preS1 portion of GTC or GTD.

scholarly journals Hepatitis B Virus-Encoded MicroRNA Controls Viral Replication

2017 ◽  
Vol 91 (10) ◽  
Author(s):  
Xi Yang ◽  
Hongfeng Li ◽  
Huahui Sun ◽  
Hongxia Fan ◽  
Yaqi Hu ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Persistent Infection ◽  
Hepatoma Cell ◽  
Hbv Infection ◽  
Dependent Manner ◽  
Dna Virus ◽  
Hbv Replication ◽  
B Virus ◽  
Self Replication

ABSTRACT MicroRNAs (miRNAs) are a class of small, single-stranded, noncoding, functional RNAs. Hepatitis B virus (HBV) is an enveloped DNA virus with virions and subviral forms of particles that lack a core. It was not known whether HBV encodes miRNAs. Here, we identified an HBV-encoded miRNA (called HBV-miR-3) by deep sequencing and Northern blotting. HBV-miR-3 is located at nucleotides (nt) 373 to 393 of the HBV genome and was generated from 3.5-kb, 2.4-kb, and 2.1-kb HBV in a classic miRNA biogenesis (Drosha-Dicer-dependent) manner. HBV-miR-3 was highly expressed in hepatoma cell lines with an integrated HBV genome and HBV+ hepatoma tumors. In patients with HBV infection, HBV-miR-3 was released into the circulation by exosomes and HBV virions, and HBV-miR-3 expression had a positive correlation with HBV titers in the sera of patients in the acute phase of HBV infection. More interestingly, we found that HBV-miR-3 represses HBsAg, HBeAg, and replication of HBV. HBV-miR-3 targets the unique site of the HBV 3.5-kb transcript to specifically reduce HBc protein expression, levels of pregenomic RNA (pgRNA), and HBV replication intermediate (HBV-RI) generation but does not affect the HBV DNA polymerase level, thus suppressing HBV virion production (replication). This may explain the low levels of HBV virion generation with abundant subviral particles lacking core during HBV replication, which may contribute to the development of persistent infection in patients. Taken together, our findings shed light on novel mechanisms by which HBV-encoded miRNA controls the process of self-replication by regulating HBV transcript during infection. IMPORTANCE Hepatitis B is a liver infection caused by the hepatitis B virus (HBV) that can become a long-term, chronic infection and lead to cirrhosis or liver cancer. HBV is a small DNA virus that belongs to the hepadnavirus family, with virions and subviral forms of particles that lack a core. MicroRNA (miRNA), a small (∼22-nt) noncoding RNA, was recently found to be an important regulator of gene expression. We found that HBV encodes miRNA (HBV-miR-3). More importantly, we revealed that HBV-miR-3 targets its transcripts to attenuate HBV replication. This may contribute to explaining how HBV infection leads to mild damage in liver cells and the subsequent establishment/maintenance of persistent infection. Our findings highlight a mechanism by which HBV-encoded miRNA controls the process of self-replication by regulating the virus itself during infection and might provide new biomarkers for diagnosis and treatment of hepatitis B.

scholarly journals Hepatitis B Virus X Protein Induces Perinuclear Mitochondrial Clustering in Microtubule- and Dynein-Dependent Manners

2006 ◽  
Vol 81 (4) ◽  
pp. 1714-1726 ◽  
Author(s):  
Sujeong Kim ◽  
Hye-Young Kim ◽  
Seungmin Lee ◽  
Sung Woo Kim ◽  
Seonghyang Sohn ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Nuclear Periphery ◽  
Mitogen Activated Protein Kinase ◽  
Transport Systems ◽  
Dependent Manner ◽  
Atpase Inhibitor ◽  
X Protein ◽  
Hbv Replication ◽  
B Virus

ABSTRACT The hepatitis B virus (HBV) X protein (HBx) is thought to play a key role in HBV replication and the development of liver cancer. It became apparent that HBx induces mitochondrial clustering at the nuclear periphery, but the molecular basis for mitochondrial clustering is not understood. Since mitochondria move along the cytoskeleton as a cargo of motor proteins, we hypothesized that mitochondrial clustering induced by HBx occurs by an altered intracellular motility. Here, we demonstrated that the treatment of HBx-expressing cells with a microtubule-disrupting drug (nocodazole) abrogated mitochondrial clustering, while the removal of nocodazole restored clustering within 30 to 60 min, indicating that mitochondrial transport is occurring in a microtubule-dependent manner. The addition of a cytochalasin D-disrupting actin filament, however, did not measurably affect mitochondrial clustering. Mitochondrial clustering was further studied by observations of HBV-related hepatoma cells and HBV-replicating cells. Importantly, the abrogation of the dynein activity in HBx-expressing cells by microinjection of a neutralizing anti-dynein intermediate-chain antibody, dynamitin overexpression, or the addition of a dynein ATPase inhibitor significantly suppressed the mitochondrial clustering. In addition, HBx induced the activation of the p38 mitogen-activated protein kinase (MAPK) and inhibition of the p38 kinase activity by SB203580-attenuated HBx-induced mitochondrial clustering. Taken together, HBx activation of the p38 MAPK contributed to the increase in the microtubule-dependent dynein activity. The data suggest that HBx plays a novel regulatory role in subcellular transport systems, perhaps facilitating the process of maturation and/or assembly of progeny particles during HBV replication. Furthermore, mitochondrion aggregation induced by HBx may represent a cellular process that underlies disease progression during chronic viral infection.

Dual effects of interleukin-18: inhibiting hepatitis B virus replication in HepG2.2.15 cells and promoting hepatoma cells metastasis

2011 ◽  
Vol 301 (3) ◽  
pp. G565-G573 ◽  
Author(s):  
Yijuan Zhang ◽  
Yunbo Li ◽  
Yifan Ma ◽  
Shuhui Liu ◽  
Yinglong She ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hepatoma Cells ◽  
Human Hepatocytes ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Interleukin 18 ◽  
Hbv Replication ◽  
B Virus ◽  
And Migration

Interleukin-18 (IL-18) has been reported to inhibit hepatitis B virus (HBV) replication in the liver of HBV transgenic mice; however, the molecular mechanism of its antiviral effect has not been fully understood. In the present study, it was shown that IL-18 and its receptors (IL-18R) were constitutively expressed in hepatoma cell lines HepG2 and HepG2.2.15 as well as normal liver cell line HL-7702. We demonstrated that IL-18 directly inhibited HBV replication in HepG2.2.15 cells via downregulating the activities of HBV core and X gene promoters. The suppressed HBV replication by IL-18 could be rescued by the administration of BAY11-7082, an inhibitor of transcription factor NF-κB. On the other hand, it was of interest that IL-18 promoted HepG2 cell metastasis and migration dose dependently in both wound-healing assays and Transwell assays. The underlying mechanism could be partially attributable to the increased activities of extracellular matrix metalloproteinase (MMP)-9, MMP-3, and MMP-2 by IL-18, which upregulated the mRNA levels of MMP-3 and MMP-9 in a NF-κB-dependent manner. Furthermore, it was confirmed that expression of IL-18/IL-18R and most MMPs were remarkably upregulated in hepatocellular carcinoma (HCC) liver cancer tissue specimens, suggesting that IL-18/IL-18R-triggered signaling pathway was closely related to HCC metastasis in vivo. Therefore, we revealed the dual effects of IL-18 in human hepatocytes: it not only inhibited HBV replication but also promoted hepatoma cells metastasis and migration. NF-κB played a critical role in both effects. Our work contributed to a deeper understanding of the biological function of IL-18 in human hepatocytes.

scholarly journals Toll-Like Receptor Signaling Inhibits Hepatitis B Virus Replication In Vivo

2005 ◽  
Vol 79 (11) ◽  
pp. 7269-7272 ◽  
Author(s):  
Masanori Isogawa ◽  
Michael D. Robek ◽  
Yoshihiro Furuichi ◽  
Francis V. Chisari
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Therapeutic Strategy ◽  
Dependent Manner ◽  
Toll Like Receptor ◽  
Chronic Hbv Infection ◽  
Hbv Replication ◽  
B Virus ◽  
Chronic Hbv

ABSTRACT Toll-like receptors (TLR) play a key role in innate immunity. To examine the ability of diverse TLRs to modulate hepatitis B virus (HBV) replication, HBV transgenic mice received a single intravenous injection of ligands specific for TLR2, TLR3, TLR4, TLR5, TLR7, and TLR9. All of the ligands except for TLR2 inhibited HBV replication in the liver noncytopathically within 24 h in a α/β interferon-dependent manner. The ability of these TLR ligands to induce antiviral cytokines at the site of HBV replication suggests that TLR activation could represent a powerful and novel therapeutic strategy for the treatment of chronic HBV infection.

scholarly journals The N-Terminus Makes the Difference: Impact of Genotype-Specific Disparities in the N-Terminal Part of The Hepatitis B Virus Large Surface Protein on Morphogenesis of Viral and Subviral Particles

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1898
Author(s):  
Bingfu Jiang ◽  
Xingjian Wen ◽  
Qingyan Wu ◽  
Daniela Bender ◽  
Gert Carra ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Subcellular Distribution ◽  
Regulatory Element ◽  
Surface Protein ◽  
Terminal Part ◽  
Amino Terminal ◽  
B Virus ◽  
N Terminus ◽  
The Difference

The N-terminus of the hepatitis B virus (HBV) large surface protein (LHB) differs with respect to genotypes. Compared to the amino terminus of genotype (Gt)D, in GtA, GtB and GtC, an additional identical 11 amino acids (aa) are found, while GtE and GtG share another similar 10 aa. Variants of GtB and GtC affecting this N-terminal part are associated with hepatoma formation. Deletion of these amino-terminal 11 aa in GtA reduces the amount of LHBs and changes subcellular accumulation (GtA-like pattern) to a dispersed distribution (GtD-like pattern). Vice versa, the fusion of the GtA-derived N-terminal 11 aa to GtD causes a GtA-like phenotype. However, insertion of the corresponding GtE-derived 10 aa to GtD has no effect. Deletion of these 11aa decreases filament size while neither the number of released viral genomes nor virion size and infectivity are affected. A negative regulatory element (aa 2–8) and a dominant positive regulatory element (aa 9–11) affecting the amount of LHBs were identified. The fusion of this motif to eGFP revealed that the effect on protein amount and subcellular distribution is not restricted to LHBs. These data identify a novel region in the N-terminus of LHBs affecting the amount and subcellular distribution of LHBs and identify release-promoting and -inhibiting aa residues within this motive.

RNA Helicase DDX17 inhibits Hepatitis B Virus Replication by Blocking Viral Pregenomic RNA Encapsidation

2021 ◽  
Author(s):  
Richeng Mao ◽  
Minhui Dong ◽  
Zhongliang Shen ◽  
Hu Zhang ◽  
Yuanjie Liu ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Rna Degradation ◽  
Viral Rna ◽  
Health Concern ◽  
Dependent Manner ◽  
Stem Loop ◽  
Hbv Replication ◽  
Dead Box ◽  
B Virus

DDX17 is a member of the DEAD-Box helicase family proteins involved in cellular RNA folding, splicing, and translation. It has been reported that DDX17 serves as a co-factor of host zinc finger antiviral protein (ZAP)-mediated retroviral RNA degradation and exerts direct antiviral function against Raft Valley Fever Virus though binding to specific stem-loop structures of viral RNA. Intriguingly, we have previously shown that ZAP inhibits Hepatitis B virus (HBV) replication through promoting viral RNA decay, and the ZAP-responsive element (ZRE) of HBV pregenomic RNA (pgRNA) contains a stem-loop structure, specifically epsilon, which serves as the packaging signal for pgRNA encapsidation. In this study, we demonstrated that the endogenous DDX17 is constitutively expressed in human hepatocyte-derived cells but dispensable for ZAP-mediated HBV RNA degradation. However, DDX17 was found to inhibit HBV replication primarily by reducing the level of cytoplasmic encapsidated pgRNA in a helicase-dependent manner. Immunofluorescence assay revealed that DDX17 could gain access to cytoplasm from nucleus in the presence of HBV RNA. In addition, RNA immunoprecipitation and electrophoretic mobility shift assays demonstrated that the enzymatically active DDX17 competes with HBV polymerase to bind to pgRNA at the 5’ epsilon motif. In summary, our study suggests that DDX17 serves as an intrinsic host restriction factor against HBV through interfering with pgRNA encapsidation. IMPORTANCE Hepatitis B virus (HBV) chronic infection, a long-studied but yet incurable disease, remains a major public health concern worldwide. Given that HBV replication cycle highly depends on host factors, deepening our understanding of the host-virus interaction is thus of great significance in the journey of finding a cure. In eukaryotic cells, RNA helicases of DEAD-box family are highly conserved enzymes involved in diverse processes of cellular RNA metabolism. Emerging data have shown that DDX17, a typical member of DEAD box family, functions as an antiviral factor through interacting with viral RNA. In this study, we, for the first time, demonstrate that DDX17 inhibits HBV through blocking the formation of viral replication complex, which not only broadens the antiviral spectrum of DDX17, but also provides new insight into the molecular mechanism of DDX17-mediated virus-host interaction.

scholarly journals Interferons Accelerate Decay of Replication-Competent Nucleocapsids of Hepatitis B Virus

2010 ◽  
Vol 84 (18) ◽  
pp. 9332-9340 ◽  
Author(s):  
Chunxiao Xu ◽  
Haitao Guo ◽  
Xiao-Ben Pan ◽  
Richeng Mao ◽  
Wenquan Yu ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dependent Manner ◽  
Hbv Replication ◽  
B Virus ◽  
Cellular Antiviral Response ◽  
Ifn Γ ◽  
Antiviral Mechanism ◽  
Murine Hepatocyte

ABSTRACT Alpha interferon (IFN-α) is an approved medication for chronic hepatitis B. Gamma interferon (IFN-γ) is a key mediator of host antiviral immunity against hepatitis B virus (HBV) infection in vivo. However, the molecular mechanism by which these antiviral cytokines suppress HBV replication remains elusive. Using an immortalized murine hepatocyte (AML12)-derived cell line supporting tetracycline-inducible HBV replication, we show in this report that both IFN-α and IFN-γ efficiently reduce the amount of intracellular HBV nucleocapsids. Furthermore, we provide evidence suggesting that the IFN-induced cellular antiviral response is able to distinguish and selectively accelerate the decay of HBV replication-competent nucleocapsids but not empty capsids in a proteasome-dependent manner. Our findings thus reveal a novel antiviral mechanism of IFNs and provide a basis for a better understanding of HBV pathobiology.

scholarly journals Development of a novel anti-hepatitis B virus agent via Sp1

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michiyo Hayakawa ◽  
Hideaki Umeyama ◽  
Mitsuo Iwadate ◽  
Y.-H. Taguchi ◽  
Yoshihiko Yano ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Dependent Manner ◽  
Hbv Replication ◽  
B Virus ◽  
Multiple Regions ◽  
Viral Relapse ◽  
Dose Dependent ◽  
Molecular Compounds ◽  
Alpha Glucosidase ◽  
Effect Gene

AbstractNucleos(t)ide analog (NA) therapy has proven effective in treating chronic hepatitis B. However, NAs frequently result in viral relapse after the cessation of therapy. This is because NAs cannot fully eliminate the viral episomal covalently closed circular DNA (cccDNA) in the nucleus. In this study, we identified small molecular compounds that control host factors related to viral replication using in silico screening with simulated annealing based on bioinformatics for protein-ligand flexible docking. Twelve chemical compound candidates for alpha-glucosidase (AG) inhibitors were identified from a library of chemical compounds and used to treat fresh human hepatocytes infected with HBV. They were then monitored for their anti-viral effects. HBV replication was inhibited by one candidate (1-[3-(4-tert-butylcyclohexyl)oxy-2-hydroxypropyl]-2,2,6,6-tetramethylpiperidin-4-ol) in a dose-dependent manner. This compound significantly reduced ccc DNA production, compared to Entecavir (p < 0.05), and had a lower anti-AG effect. Gene expression analysis and structural analysis of this compound showed that its inhibitive effect on HBV was via interaction with Sp1. The nuclear transcription factor Sp1 acts on multiple regions of HBV to suppress HBV replication. Identifying candidates that control nuclear transcription factors facilitate the development of novel therapies. Drugs with a mechanism different from NA are promising for the elimination of HBV.

scholarly journals Hide and seek: interplay between influenza viruses and B cells

2020 ◽  
Vol 32 (9) ◽  
pp. 605-611 ◽  
Author(s):  
Masayuki Kuraoka ◽  
Yu Adachi ◽  
Yoshimasa Takahashi
Keyword(s):  
B Cells ◽  
B Cell ◽  
Surface Protein ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
Native Structure ◽  
Humoral Immune ◽  
Protective Antibodies ◽  
Major Surface ◽  
And Function

Abstract Influenza virus constantly acquires genetic mutations/reassortment in the major surface protein, hemagglutinin (HA), resulting in the generation of strains with antigenic variations. There are, however, HA epitopes that are conserved across influenza viruses and are targeted by broadly protective antibodies. A goal for the next-generation influenza vaccines is to stimulate B-cell responses against such conserved epitopes in order to provide broad protection against divergent influenza viruses. Broadly protective B cells, however, are not easily activated by HA antigens with native structure, because the virus has multiple strategies to escape from the humoral immune responses directed to the conserved epitopes. One such strategy is to hide the conserved epitopes from the B-cell surveillance by steric hindrance. Technical advancement in the analysis of the human B-cell antigen receptor (BCR) repertoire has dissected the BCRs to HA epitopes that are hidden in the native structure but are targeted by broadly protective antibodies. We describe here the characterization and function of broadly protective antibodies and strategies that enable B cells to seek these hidden epitopes, with potential implications for the development of universal influenza vaccines.

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