1
|
Romero S, Unchwaniwala N, Evans EL, Eliceiri KW, Loeb DD, Sherer NM. Live Cell Imaging Reveals HBV Capsid Translocation from the Nucleus To the Cytoplasm Enabled by Cell Division. mBio 2023; 14:e0330322. [PMID: 36809075 PMCID: PMC10127671 DOI: 10.1128/mbio.03303-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/17/2023] [Indexed: 02/23/2023] Open
Abstract
Hepatitis B virus (HBV) capsid assembly is traditionally thought to occur predominantly in the cytoplasm, where the virus gains access to the virion egress pathway. To better define sites of HBV capsid assembly, we carried out single cell imaging of HBV Core protein (Cp) subcellular trafficking over time under conditions supporting genome packaging and reverse transcription in Huh7 hepatocellular carcinoma cells. Time-course analyses including live cell imaging of fluorescently tagged Cp derivatives showed Cp to accumulate in the nucleus at early time points (~24 h), followed by a marked re-distribution to the cytoplasm at 48 to 72 h. Nucleus-associated Cp was confirmed to be capsid and/or high-order assemblages using a novel dual label immunofluorescence strategy. Nuclear-to-cytoplasmic re-localization of Cp occurred predominantly during nuclear envelope breakdown in conjunction with cell division, followed by strong cytoplasmic retention of Cp. Blocking cell division resulted in strong nuclear entrapment of high-order assemblages. A Cp mutant, Cp-V124W, predicted to exhibit enhanced assembly kinetics, also first trafficked to the nucleus to accumulate at nucleoli, consistent with the hypothesis that Cp's transit to the nucleus is a strong and constitutive process. Taken together, these results provide support for the nucleus as an early-stage site of HBV capsid assembly, and provide the first dynamic evidence of cytoplasmic retention after cell division as a mechanism underpinning capsid nucleus-to-cytoplasm relocalization. IMPORTANCE Hepatitis B virus (HBV) is an enveloped, reverse-transcribing DNA virus that is a major cause of liver disease and hepatocellular carcinoma. Subcellular trafficking events underpinning HBV capsid assembly and virion egress remain poorly characterized. Here, we developed a combination of fixed and long-term (>24 h) live cell imaging technologies to study the single cell trafficking dynamics of the HBV Core Protein (Cp). We demonstrate that Cp first accumulates in the nucleus, and forms high-order structures consistent with capsids, with the predominant route of nuclear egress being relocalization to the cytoplasm during cell division in conjunction with nuclear membrane breakdown. Single cell video microscopy demonstrated unequivocally that Cp's localization to the nucleus is constitutive. This study represents a pioneering application of live cell imaging to study HBV subcellular transport, and demonstrates links between HBV Cp and the cell cycle.
Collapse
Affiliation(s)
- Sofia Romero
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Nuruddin Unchwaniwala
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Edward L. Evans
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Kevin W. Eliceiri
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Daniel D. Loeb
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Nathan M. Sherer
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| |
Collapse
|
2
|
Radhakrishnan S, Martin CA, Rammohan A, Vij M, Chandrasekar M, Rela M. Significance of nucleologenesis, ribogenesis, and nucleolar proteome in the pathogenesis and recurrence of hepatocellular carcinoma. Expert Rev Gastroenterol Hepatol 2023; 17:363-378. [PMID: 36919496 DOI: 10.1080/17474124.2023.2191189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
INTRODUCTION Emerging evidence suggests that enhanced ribosome biogenesis, increased size, and quantitative distribution of nucleoli are associated with dysregulated transcription, which in turn drives a cell into aberrant cellular proliferation and malignancy. Nucleolar alterations have been considered a prognostic histological marker for aggressive tumors. More recently, advancements in the understanding of chromatin network (nucleoplasm viscosity) regulated liquid-liquid phase separation mechanism of nucleolus formation and their multifunctional role shed light on other regulatory processes, apart from ribosomal biogenesis of the nucleolus. AREAS COVERED Using hepatocellular carcinoma as a model to study the role of nucleoli in tumor progression, we review the potential of nucleolus coalescence in the onset and development of tumors through non-ribosomal biogenesis pathways, thereby providing new avenues for early diagnosis and cancer therapy. EXPERT OPINION Molecular-based classifications have failed to identify the nucleolar-based molecular targets that facilitate cell-cycle progression. However, the algorithm-based tumor risk identification with high-resolution medical images suggests prominent nucleoli, karyotheca, and increased nucleus/cytoplasm ratio as largely associated with tumor recurrence. Nonetheless, the role of the non-ribosomal functions of nucleoli in tumorigenesis remains elusive. This clearly indicates the lacunae in the study of the nucleolar proteins pertaining to cancer. [Figure: see text].
Collapse
Affiliation(s)
| | | | - Ashwin Rammohan
- The Institute of Liver Disease & Transplantation, Dr. Rela Institute & Medical Centre, Chennai, India
| | - Mukul Vij
- Department of Pathology, Dr. Rela Institute & Medical Centre, Chennai, India
| | - Mani Chandrasekar
- Department of Oncology, Dr. Rela Institute & Medical Centre, Chennai, India
| | - Mohamed Rela
- Cell Laboratory, National Foundation for Liver Research, Chennai, India
- The Institute of Liver Disease & Transplantation, Dr. Rela Institute & Medical Centre, Chennai, India
| |
Collapse
|
3
|
Su PY, Yen SCB, Yang CC, Chang CH, Lin WC, Shih C. Hepatitis B virus virion secretion is a CRM1-spike-mediated late event. J Biomed Sci 2022; 29:44. [PMID: 35729569 PMCID: PMC9210616 DOI: 10.1186/s12929-022-00827-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 06/16/2022] [Indexed: 11/10/2022] Open
Abstract
Background Hepatitis B virus (HBV) is a major human pathogen worldwide. To date, there is no curative treatment for chronic hepatitis B. The mechanism of virion secretion remains to be investigated. Previously, we found that nuclear export of HBc particles can be facilitated via two CRM1-specific nuclear export signals (NES) at the spike tip. Methods In this study, we used site-directed mutagenesis at the CRM1 NES, as well as treatment with CRM1 inhibitors at a low concentration, or CRM1-specific shRNA knockdown, in HBV-producing cell culture, and measured the secretion of various HBV viral and subviral particles via a native agarose gel electrophoresis assay. Separated HBV particles were characterized by Western blot analysis, and their genomic DNA contents were measured by Southern blot analysis. Secreted extracellular particles were compared with intracellular HBc capsids for DNA synthesis and capsid formation. Virion secretion and the in vivo interactions among HBc capsids, CRM1 and microtubules, were examined by proximity ligation assay, immunofluorescence microscopy, and nocodazole treatment. Results We report here that the tip of spike of HBV core (HBc) particles (capsids) contains a complex sensor for secretion of both HBV virions and naked capsids. HBV virion secretion is closely associated with HBc nuclear export in a CRM1-dependent manner. At the conformationally flexible spike tips of HBc particles, NES motifs overlap extensively with motifs important for secretion of HBV virions and naked capsids. Conclusions We provided experimental evidence that virions and naked capsids can egress via two distinct, yet overlapping, pathways. Unlike the secretion of naked capsids, HBV virion secretion is highly CRM1- and microtubule-dependent. CRM1 is well known for its involvement in nuclear transport in literature. To our knowledge, this is the first report that CRM1 is required for virion secretion. CRM1 inhibitors could be a promising therapeutic candidate for chronic HBV patients in clinical medicine. Supplementary Information The online version contains supplementary material available at 10.1186/s12929-022-00827-w.
Collapse
Affiliation(s)
- Pei-Yi Su
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, No.100, Shih-Chuan 1st Road, Sanmin, 80708, Kaohsiung, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Shin-Chwen Bruce Yen
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, No.100, Shih-Chuan 1st Road, Sanmin, 80708, Kaohsiung, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ching-Chun Yang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chih-Hsu Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wen-Chang Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chiaho Shih
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, No.100, Shih-Chuan 1st Road, Sanmin, 80708, Kaohsiung, Taiwan. .,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
| |
Collapse
|
4
|
Honda T, Yamada N, Murayama A, Shiina M, Aly HH, Kato A, Ito T, Ishizu Y, Kuzuya T, Ishigami M, Murakami Y, Tanaka T, Moriishi K, Nishitsuji H, Shimotohno K, Ishikawa T, Fujishiro M, Muramatsu M, Wakita T, Kato T. Amino Acid Polymorphism in Hepatitis B Virus Associated With Functional Cure. Cell Mol Gastroenterol Hepatol 2021; 12:1583-1598. [PMID: 34352407 PMCID: PMC8536788 DOI: 10.1016/j.jcmgh.2021.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS To provide an adequate treatment strategy for chronic hepatitis B, it is essential to know which patients are expected to have a good prognosis and which patients do not require therapeutic intervention. Previously, we identified the substitution of isoleucine to leucine at amino acid 97 (I97L) in the hepatitis B core region as a key predictor among patients with stable hepatitis. In this study, we attempted to identify the point at which I97L affects the hepatitis B virus (HBV) life cycle and to elucidate the underlying mechanisms governing the stabilization of hepatitis. METHODS To confirm the clinical features of I97L, we used a cohort of hepatitis B e antigen-negative patients with chronic hepatitis B infected with HBV-I97 wild-type (wt) or HBV-I97L. The effects of I97L on viral characteristics were evaluated by in vitro HBV production and infection systems with the HBV reporter virus and cell culture-generated HBV. RESULTS The ratios of reduction in hepatitis B surface antigen and HBV DNA were higher in patients with HBV-I97L than in those with HBV-I97wt. HBV-I97L exhibited lower infectivity than HBV-I97wt in both infection systems with reporter HBV and cell culture-generated HBV. HBV-I97L virions exhibiting low infectivity primarily contained a single-stranded HBV genome. The lower efficiency of cccDNA synthesis was demonstrated after infection of HBV-I97L or transfection of the molecular clone of HBV-I97L. CONCLUSIONS The I97L substitution reduces the level of cccDNA through the generation of immature virions with single-stranded genomes. This I97L-associated low efficiency of cccDNA synthesis may be involved in the stabilization of hepatitis.
Collapse
Affiliation(s)
- Takashi Honda
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Norie Yamada
- Department of Virology II, National Institute of Infectious Diseases, Tokyo
| | - Asako Murayama
- Department of Virology II, National Institute of Infectious Diseases, Tokyo
| | - Masaaki Shiina
- Department of Virology II, National Institute of Infectious Diseases, Tokyo
| | - Hussein Hassan Aly
- Department of Virology II, National Institute of Infectious Diseases, Tokyo
| | - Asuka Kato
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Takanori Ito
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Yoji Ishizu
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Teiji Kuzuya
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Masatoshi Ishigami
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Yoshiki Murakami
- Department of Molecular Pathology, Tokyo Medical University, Tokyo
| | - Tomohisa Tanaka
- Department of Microbiology, Graduate School of Medicine, University of Yamanashi, Yamanashi
| | - Kohji Moriishi
- Department of Microbiology, Graduate School of Medicine, University of Yamanashi, Yamanashi
| | - Hironori Nishitsuji
- Genome Medical Sciences Project, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Kunitada Shimotohno
- Genome Medical Sciences Project, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Tetsuya Ishikawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | - Mitsuhiro Fujishiro
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya
| | | | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Tokyo
| | - Takanobu Kato
- Department of Virology II, National Institute of Infectious Diseases, Tokyo,Correspondence Address correspondence to: Takanobu Kato, MD, PhD, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan. fax: +81-3-5285-1161.
| |
Collapse
|
5
|
Chen J, Liu B, Tang X, Zheng X, Lu J, Zhang L, Wang W, Candotti D, Fu Y, Allain JP, Li C, Li L, Li T. Role of core protein mutations in the development of occult HBV infection. J Hepatol 2021; 74:1303-1314. [PMID: 33453326 DOI: 10.1016/j.jhep.2020.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/04/2020] [Accepted: 12/14/2020] [Indexed: 02/05/2023]
Abstract
BACKGROUND & AIMS Occult HBV infection (OBI) is associated with transfusion-transmitted HBV infection and hepatocellular carcinoma. Studies on OBI genesis have concentrated on mutations in the S region and the regulatory elements. Herein, we aimed to determine the role of mutations in the core region on OBIs. METHODS An OBI strain (SZA) carrying 9 amino acid (aa) substitutions in the core protein/capsid (Cp) was selected by sequence alignment and Western blot analysis from 26 genotype B OBI samples to extensively explore the impact of Cp mutations on viral antigen production in vitro and in vivo. RESULTS A large panel of 30 Cp replicons were generated by a replication-competent pHBV1.3 carrying SZA or wild-type (WT) Cp in a 1.3-fold over-length of HBV genome, in which the various Cp mutants were individually introduced by repairing site mutations of SZA-Cp or creating site mutations of WT-Cp by site-directed mutagenesis. The expression of HBcAg, HBeAg, and HBsAg and viral RNA was quantified from individual SZA and WT Cp mutant replicons in transfected Huh7 cells or infected mice, respectively. An analysis of the effect of Cp mutants on intracellular or extracellular viral protein production indicated that the W62R mutation in Cp had a critical impact on the reduction of HBcAg and HBeAg production during HBV replication, whereas P50H and/or S74G mutations played a limited role in influencing viral protein production invivo. CONCLUSIONS W62R and its combination mutations in HBV Cp might massively affect HBcAg and HBeAg production during viral replication, which, in turn, might contribute to the occurrence of OBI. LAY SUMMARY Occult hepatitis B virus infections (OBIs) have been found to be associated with amino acid mutations in the S region of the HBV, but the role of mutations in the core protein (Cp) remains unclear. In this study, an OBI strain (SZA) carrying 9 amino acid substitutions in Cp has been examined comprehensively in vitro and in vivo. The W62R mutation in Cp majorly reduces HBcAg and HBeAg production during HBV replication, potentially contributing to the occurrence of OBI.
Collapse
Affiliation(s)
- Jingna Chen
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China; Department of Laboratory Medicine, General Hospital of Southern Theatre Command of PLA, Guangzhou, China; Department of Clinical Laboratory, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Bochao Liu
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Xi Tang
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China; Department of Infectious Diseases, The First Foshan People's Hospital, Foshan, China
| | - Xin Zheng
- Shenzhen Blood Center, Shenzhen, China
| | - Jinhui Lu
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Ling Zhang
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Wenjing Wang
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Daniel Candotti
- Department of Blood Transmitted Agents, National Institute of Blood Transfusion, Paris, France
| | - Yongshui Fu
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China; Guangzhou Blood Center, Guangzhou, China
| | - Jean-Pierre Allain
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China; Department of Haematology, University of Cambridge, Cambridge, UK
| | - Chengyao Li
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China.
| | - Linhai Li
- Department of Laboratory Medicine, General Hospital of Southern Theatre Command of PLA, Guangzhou, China.
| | - Tingting Li
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China.
| |
Collapse
|
6
|
Abstract
Viral hepatitis causes more deaths than tuberculosis and HIV-1 infection. Most cases are due to chronic infection with hepatitis B virus (HBV), which afflicts >250 million people. Current therapies are rarely curative, and new approaches are needed. Here, we report the discovery (by nuclear magnetic resonance) of a small molecule binder in the hydrophobic pocket in the HBV capsid. This structural element is, in an unknown manner, central in capsid envelopment. Binding of the pocket factor induces a distinct, stable conformation in the capsid, as expected for a signaling switch. This brings not only a new molecular view on the mechanism underlying capsid envelopment, but it also opens a rationale for its inhibition. Viral hepatitis is growing into an epidemic illness, and it is urgent to neutralize the main culprit, hepatitis B virus (HBV), a small-enveloped retrotranscribing DNA virus. An intriguing observation in HB virion morphogenesis is that capsids with immature genomes are rarely enveloped and secreted. This prompted, in 1982, the postulate that a regulated conformation switch in the capsid triggers envelopment. Using solid-state NMR, we identified a stable alternative conformation of the capsid. The structural variations focus on the hydrophobic pocket of the core protein, a hot spot in capsid–envelope interactions. This structural switch is triggered by specific, high-affinity binding of a pocket factor. The conformational change induced by the binding is reminiscent of a maturation signal. This leads us to formulate the “synergistic double interaction” hypothesis, which explains the regulation of capsid envelopment and indicates a concept for therapeutic interference with HBV envelopment.
Collapse
|
7
|
Abstract
Hepatitis B virus (HBV) core protein (Cp) can be found in the nucleus and cytoplasm of infected hepatocytes; however, it preferentially segregates to a specific compartment correlating with disease status. Regulation of this intracellular partitioning of Cp remains obscure. In this paper, we report that cellular compartments are filled and vacated by Cp in a time- and concentration-dependent manner in both transfections and infections. At early times after transfection, Cp, in a dimeric state, preferentially localizes to the nucleolus. Later, the nucleolar compartment is emptied and Cp progresses to being predominantly nuclear, with a large fraction of the protein in an assembled state. Nuclear localization is followed by cell-wide distribution, and then Cp becomes exclusively cytoplasmic. The same trend in Cp movement is seen during an infection. Putative nucleolar retention signals have been identified and appear to be structure dependent. Export of Cp from the nucleus involves the CRM1 exportin. Time-dependent flux can be recapitulated by modifying Cp concentration, suggesting transitions are regulated by reaching a threshold concentration.
Collapse
|
8
|
Shih C, Wu SY, Chou SF, Yuan TTT. Virion Secretion of Hepatitis B Virus Naturally Occurring Core Antigen Variants. Cells 2020; 10:cells10010043. [PMID: 33396864 PMCID: PMC7823318 DOI: 10.3390/cells10010043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 02/07/2023] Open
Abstract
In natural infection, hepatitis B virus (HBV) core protein (HBc) accumulates frequent mutations. The most frequent HBc variant in chronic hepatitis B patients is mutant 97L, changing from an isoleucine or phenylalanine to a leucine (L) at HBc amino acid 97. One dogma in the HBV research field is that wild type HBV secretes predominantly virions containing mature double-stranded DNA genomes. Immature genomes, containing single-stranded RNA or DNA, do not get efficiently secreted until reaching genome maturity. Interestingly, HBc variant 97L does not follow this dogma in virion secretion. Instead, it exhibits an immature secretion phenotype, which preferentially secretes virions containing immature genomes. Other aberrant behaviors in virion secretion were also observed in different naturally occurring HBc variants. A hydrophobic pocket around amino acid 97 was identified by bioinformatics, genetic analysis, and cryo-EM. We postulated that this hydrophobic pocket could mediate the transduction of the genome maturation signal for envelopment from the capsid interior to its surface. Virion morphogenesis must involve interactions between HBc, envelope proteins (HBsAg) and host factors, such as components of ESCRT (endosomal sorting complex required for transport). Immature secretion can be offset by compensatory mutations, occurring at other positions in HBc or HBsAg. Recently, we demonstrated in mice that the persistence of intrahepatic HBV DNA is related to virion secretion regulated by HBV genome maturity. HBV virion secretion could be an antiviral drug target.
Collapse
Affiliation(s)
- Chiaho Shih
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
- Correspondence: (C.S.); (T.-T.T.Y.)
| | - Szu-Yao Wu
- Chimera Bioscience Inc., No. 18 Siyuan St., Zhongzheng Dist., Taipei 10087, Taiwan;
| | - Shu-Fan Chou
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA;
| | - Ta-Tung Thomas Yuan
- TFBS Bioscience, Inc. 3F, No. 103, Ln 169, Kangning St., Xizhi Dist., New Taipei City 221, Taiwan
- Correspondence: (C.S.); (T.-T.T.Y.)
| |
Collapse
|
9
|
Lazarevic I, Banko A, Miljanovic D, Cupic M. Biological features of hepatitis B virus strains associated with fulminant hepatitis. Future Virol 2020. [DOI: 10.2217/fvl-2020-0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accumulating evidence suggests that hepatitis B virus (HBV) biological features may influence the course and clinical manifestations of infection and possibly the development of fulminant hepatitis (FH). Since HBV is not a cytocidal virus, virus-induced liver damage results from an interplay between the virus replication and the host's defense. Therefore, viral factors contributing to enhanced replication, induction of a stronger immune attack or apoptosis of hepatocytes could be crucial in development of FH. Numerous mutations in basal core promoter, pre-C, C and S regions of the HBV genome contribute to development of FH by different mechanisms, including enhanced viral replication, the loss of a decoy for immune response, unbalanced expression of viral proteins and retention of unprocessed cytotoxic proteins in hepatocytes.
Collapse
Affiliation(s)
- Ivana Lazarevic
- Institute of Microbiology & Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| | - Ana Banko
- Institute of Microbiology & Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| | - Danijela Miljanovic
- Institute of Microbiology & Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| | - Maja Cupic
- Institute of Microbiology & Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| |
Collapse
|
10
|
Persistence of Hepatitis B Virus DNA and the Tempos between Virion Secretion and Genome Maturation in a Mouse Model. J Virol 2019; 93:JVI.01001-19. [PMID: 31462567 PMCID: PMC6819939 DOI: 10.1128/jvi.01001-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/23/2019] [Indexed: 12/19/2022] Open
Abstract
Chronic infection with human hepatitis B virus (HBV) could lead to cirrhosis and hepatoma. At present, there is no effective treatment to eradicate the virus from patients. HBV in chronic carriers does not exist as a single homogeneous population. The most frequent naturally occurring mutation in HBV core protein occurs at amino acid 97, changing an isoleucine to leucine (I97L). One dogma in the field is that only virions containing a mature genome are preferentially secreted into the medium. Here, we demonstrated that mutant I97L can secrete immature genome in mice. Although viral DNA of mutant I97L with immature genome is less persistent than wild-type HBV in time course experiments, viral DNA of mutant P130T with genome hypermaturation, surprisingly, is more persistent. Therefore, virion secretion regulated by genome maturity could influence viral persistence. It remains an open issue whether virion secretion could be a drug target for HBV therapy. Hepatitis B virus (HBV) core protein (HBc) accumulates frequent mutations in natural infection. Wild-type HBV is known to secrete predominantly virions containing mature DNA genome. However, a frequent naturally occurring HBc variant, I97L, changing from an isoleucine to a leucine at amino acid 97, exhibited an immature secretion phenotype in culture, which preferentially secretes virions containing immature genomes. In contrast, mutant P130T, changing from a proline to a threonine at amino acid 130, exhibited a hypermaturation phenotype by accumulating an excessive amount of intracellular fully mature DNA genome. Using a hydrodynamic delivery mouse model, we studied the in vivo behaviors of these two mutants, I97L and P130T. We detected no naked core particles in all hydrodynamically injected mice. Mutant I97L in mice exhibited pleiotropic phenotypes: (i) excessive numbers of serum HBV virions containing immature genomes, (ii) significantly reduced numbers of intracellular relaxed-circle and single-stranded DNAs, and (iii) less persistent intrahepatic and secreted HBV DNAs than wild-type HBV. These pleiotropic phenotypes were observed in both immunocompetent and immunodeficient mice. Although mutant P130T also displayed a hypermaturation phenotype in vivo, it cannot efficiently rescue the immature virion secretion of mutant I97L. Unexpectedly, the single mutant P130T exhibited in vivo a novel phenotype in prolonging the persistence of HBV genome in hepatocytes. Taken together, our studies provide a plausible rationale for HBV to regulate envelopment morphogenesis and virion secretion via genome maturity, which is likely to play an important role in the persistence of viral DNA in this mouse model. IMPORTANCE Chronic infection with human hepatitis B virus (HBV) could lead to cirrhosis and hepatoma. At present, there is no effective treatment to eradicate the virus from patients. HBV in chronic carriers does not exist as a single homogeneous population. The most frequent naturally occurring mutation in HBV core protein occurs at amino acid 97, changing an isoleucine to leucine (I97L). One dogma in the field is that only virions containing a mature genome are preferentially secreted into the medium. Here, we demonstrated that mutant I97L can secrete immature genome in mice. Although viral DNA of mutant I97L with immature genome is less persistent than wild-type HBV in time course experiments, viral DNA of mutant P130T with genome hypermaturation, surprisingly, is more persistent. Therefore, virion secretion regulated by genome maturity could influence viral persistence. It remains an open issue whether virion secretion could be a drug target for HBV therapy.
Collapse
|
11
|
Lazarevic I, Banko A, Miljanovic D, Cupic M. Immune-Escape Hepatitis B Virus Mutations Associated with Viral Reactivation upon Immunosuppression. Viruses 2019; 11:v11090778. [PMID: 31450544 PMCID: PMC6784188 DOI: 10.3390/v11090778] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 02/07/2023] Open
Abstract
Hepatitis B virus (HBV) reactivation occurs as a major complication of immunosuppressive therapy among persons who have recovered from acute hepatitis and those who have controlled chronic infection. Recent literature data emphasize the presence of a high degree of S gene variability in HBV isolates from patients who developed reactivation. In reactivated HBV, the most frequently detected mutations belong to the second loop of “a” determinant in HBsAg. These mutations were identified to be immune escape and responsible for vaccine- and diagnostic-escape phenomena. Their emergence clearly provides survival in the presence of a developed humoral immune response and is often associated with impaired serological diagnosis of HBV reactivation. The knowledge of their existence and roles can elucidate the process of reactivation and strongly highlights the importance of HBV DNA detection in monitoring all patients with a history of HBV infection who are undergoing immunosuppression. This review discusses the possible influence of the most frequently found immune-escape mutations on HBV reactivation.
Collapse
Affiliation(s)
- Ivana Lazarevic
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia.
| | - Ana Banko
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| | - Danijela Miljanovic
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| | - Maja Cupic
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr Subotica 1, 11000 Belgrade, Serbia
| |
Collapse
|
12
|
Arizala JAC, Takahashi M, Burnett JC, Ouellet DL, Li H, Rossi JJ. Nucleolar Localization of HIV-1 Rev Is Required, Yet Insufficient for Production of Infectious Viral Particles. AIDS Res Hum Retroviruses 2018; 34:961-981. [PMID: 29804468 PMCID: PMC6238656 DOI: 10.1089/aid.2017.0306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Combination antiretroviral therapy fails in complete suppression of HIV-1 due to drug resistance and persistent latency. Novel therapeutic intervention requires knowledge of intracellular pathways responsible for viral replication, specifically those untargeted by antiretroviral drugs. An understudied phenomenon is the nucleolar localization of Rev phosphoprotein, which completes nucleocytoplasmic transport of unspliced/partially spliced HIV mRNA through multimerization with intronic cis-acting targets-the Rev-response element (RRE). Rev contains a nucleolar localization signal (NoLS) comprising the COOH terminus of the arginine-rich motif for accumulation within nucleoli-speculated as the interaction ground for Rev with cellular proteins mediating mRNA-independent nuclear export and splicing. Functionality of Rev nucleolar access during HIV-1 production and infection was investigated in the context of deletion and single-point mutations within Rev-NoLS. Mutations induced upon Rev-NoLS are hypothesized to inactivate the HIV-1 infectious cycle. HIV-1HXB2 replication ceased with Rev mutations lacking nucleolar access due to loss or replacement of multiple arginine residues. Rev mutations missing single arginine residues remained strictly nucleolar in pattern and participated in proviral production, however, with reduced efficiency. Viral RNA packaging also decreased in efficiency after expression of nucleolar-localizing mutations. These results were observed during propagation of variant HIV-1NL4-3 containing nucleolar-localizing mutations within the viral backbone (M4, M5, and M6). Lentiviral particles produced with Rev single-point mutations were transducible at extremely low frequency. Similarly, HIV-1NL4-3 Rev-NoLS variants lost infectivity, unlike virulent WT (wild type) HIV-1NL4-3. HIV-1NL4-3 variants were capable of CD4+ host entry and reverse transcription as WT HIV-1NL4-3, but lacked ability to complete a full infectious cycle. We currently reveal that viral integration is deregulated in the presence of Rev-NoLS mutations.
Collapse
Affiliation(s)
- Jerlisa Ann C. Arizala
- Department of Molecular and Cellular Biology, Beckman Research Institute at the City of Hope, Duarte, California
- Irell & Manella Graduate School of Biological Sciences, Duarte, California
| | - Mayumi Takahashi
- Department of Molecular and Cellular Biology, Beckman Research Institute at the City of Hope, Duarte, California
- Irell & Manella Graduate School of Biological Sciences, Duarte, California
| | - John C. Burnett
- Department of Molecular and Cellular Biology, Beckman Research Institute at the City of Hope, Duarte, California
| | - Dominique L. Ouellet
- Department of Molecular and Cellular Biology, Beckman Research Institute at the City of Hope, Duarte, California
| | - Haitang Li
- Department of Molecular and Cellular Biology, Beckman Research Institute at the City of Hope, Duarte, California
| | - John J. Rossi
- Department of Molecular and Cellular Biology, Beckman Research Institute at the City of Hope, Duarte, California
- Irell & Manella Graduate School of Biological Sciences, Duarte, California
| |
Collapse
|
13
|
Fernández-Ponce C, Durán-Ruiz MC, Narbona-Sánchez I, Muñoz-Miranda JP, Arbulo-Echevarria MM, Serna-Sanz A, Baumann C, Litrán R, Aguado E, Bloch W, García-Cozar F. Ultrastructural Localization and Molecular Associations of HCV Capsid Protein in Jurkat T Cells. Front Microbiol 2018; 8:2595. [PMID: 29354102 PMCID: PMC5758585 DOI: 10.3389/fmicb.2017.02595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 12/12/2017] [Indexed: 12/24/2022] Open
Abstract
Hepatitis C virus core protein is a highly basic viral protein that multimerizes with itself to form the viral capsid. When expressed in CD4+ T lymphocytes, it can induce modifications in several essential cellular and biological networks. To shed light on the mechanisms underlying the alterations caused by the viral protein, we have analyzed HCV-core subcellular localization and its associations with host proteins in Jurkat T cells. In order to investigate the intracellular localization of Hepatitis C virus core protein, we have used a lentiviral system to transduce Jurkat T cells and subsequently localize the protein using immunoelectron microscopy techniques. We found that in Jurkat T cells, Hepatitis C virus core protein mostly localizes in the nucleus and specifically in the nucleolus. In addition, we performed pull-down assays combined with Mass Spectrometry Analysis, to identify proteins that associate with Hepatitis C virus core in Jurkat T cells. We found proteins such as NOLC1, PP1γ, ILF3, and C1QBP implicated in localization and/or traffic to the nucleolus. HCV-core associated proteins are implicated in RNA processing and RNA virus infection as well as in functions previously shown to be altered in Hepatitis C virus core expressing CD4+ T cells, such as cell cycle delay, decreased proliferation, and induction of a regulatory phenotype. Thus, in the current work, we show the ultrastructural localization of Hepatitis C virus core and the first profile of HCV core associated proteins in T cells, and we discuss the functions and interconnections of these proteins in molecular networks where relevant biological modifications have been described upon the expression of Hepatitis C virus core protein. Thereby, the current work constitutes a necessary step toward understanding the mechanisms underlying HCV core mediated alterations that had been described in relevant biological processes in CD4+ T cells.
Collapse
Affiliation(s)
- Cecilia Fernández-Ponce
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| | - Maria C Durán-Ruiz
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| | - Isaac Narbona-Sánchez
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| | - Juan P Muñoz-Miranda
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| | - Mikel M Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| | | | | | - Rocío Litrán
- Department of Condensed Matter Physics, University of Cádiz, Puerto Real, Spain
| | - Enrique Aguado
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Francisco García-Cozar
- Department of Biomedicine, Biotechnology and Public Health, University of Cadiz and Institute of Biomedical Research Cádiz (INIBICA), Cadiz, Spain
| |
Collapse
|
14
|
Honda T, Ishigami M, Ishizu Y, Kuzuya T, Hayashi K, Ishikawa T, Murakami Y, Iwadate M, Umeyama H, Toyoda H, Kumada T, Katano Y, Goto H, Hirooka Y. Core I97L mutation in conjunction with P79Q is associated with persistent low HBV DNA and HBs antigen clearance in patients with chronic hepatitis B. Clin Microbiol Infect 2016; 23:407.e1-407.e7. [PMID: 27998820 DOI: 10.1016/j.cmi.2016.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/21/2016] [Accepted: 12/12/2016] [Indexed: 01/04/2023]
Abstract
OBJECTIVES When considering treatment for chronic hepatitis B (CHB), it is important to discriminate between patients with persistent low HBV DNA and patients with active hepatitis, who may proceed to cirrhosis. In this study, we sought to identify mutations in patients expected to have persistent low HBV DNA and ultimately exhibit clearance of hepatitis B surface antigen (HBsAg). METHODS Serum samples were obtained from 33 CHB genotype C patients, divided based on HBV DNA and alanine aminotransferase (ALT) levels following observation for >2 years: Group A (n=10), transient HBV DNA ≥5.0 log copies/mL and ALT ≥120 IU/L; Group B (n=11), persistent HBV DNA <5.0 and ALT <60; and Group C (n=12), persistent HBV DNA <4.0 and ALT <30. Full-length HBV sequences were compared among groups. Subsequently, 82 patients with CHB were evaluated for the I97L mutation and the additional mutation P79Q. We compared cumulative incidences of persistent low HBV DNA and HBsAg clearance in patients with or without I97L and P79Q by the Kaplan-Meier method. RESULTS Incidence of Core mutation I97L differed significantly among groups: A, 30% (3/10); B, 36.4% (4/11); C, 83.3% (10/12) (p = 0.021). Cumulative incidences of persistent low HBV DNA and HBsAg clearance were significantly higher in patients with I97L than in those with wild-type I97 (p = 0.003 and p = 0.016, respectively), and even higher in those with P79Q. CONCLUSIONS In patients with CHB, measurement of I97L and additional mutation P79Q would be useful for predicting persistent low HBV DNA, normal ALT, and HBsAg clearance.
Collapse
Affiliation(s)
- T Honda
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - M Ishigami
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Y Ishizu
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - T Kuzuya
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - K Hayashi
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - T Ishikawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Y Murakami
- Department of Hepatology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - M Iwadate
- Department of Biological Science, Chuo University, Tokyo, Japan
| | - H Umeyama
- Department of Biological Science, Chuo University, Tokyo, Japan
| | - H Toyoda
- Department of Gastroenterology, Ogaki Municipal Hospital, Ogaki, Gifu, Japan
| | - T Kumada
- Department of Gastroenterology, Ogaki Municipal Hospital, Ogaki, Gifu, Japan
| | - Y Katano
- Department of Gastroenterology, Banbuntane Hotokukai Hospital, Fujita Health University, School of Medicine, Nagoya, Japan
| | - H Goto
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Y Hirooka
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
15
|
HBV maintains electrostatic homeostasis by modulating negative charges from phosphoserine and encapsidated nucleic acids. Sci Rep 2016; 6:38959. [PMID: 27958343 PMCID: PMC5154190 DOI: 10.1038/srep38959] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/14/2016] [Indexed: 12/22/2022] Open
Abstract
Capsid assembly and stability of hepatitis B virus (HBV) core protein (HBc) particles depend on balanced electrostatic interactions between encapsidated nucleic acids and an arginine-rich domain (ARD) of HBc in the capsid interior. Arginine-deficient ARD mutants preferentially encapsidated spliced viral RNA and shorter DNA, which can be fully or partially rescued by reducing the negative charges from acidic residues or serine phosphorylation of HBc, dose-dependently. Similarly, empty capsids without RNA encapsidation can be generated by ARD hyper-phosphorylation in insect, bacteria, and human hepatocytes. De-phosphorylation of empty capsids by phosphatase induced capsid disassembly. Empty capsids can convert into RNA-containing capsids by increasing HBc serine de-phosphorylation. In an HBV replicon system, we observed a reciprocal relationship between viral and non-viral RNA encapsidation, suggesting both non-viral RNA and serine-phosphorylation could serve as a charge balance buffer in maintaining electrostatic homeostasis. In addition, by comparing the biochemistry assay results between a replicon and a non-replicon system, we observed a correlation between HBc de-phosphorylation and viral replication. Balanced electrostatic interactions may be important to other icosahedral particles in nature.
Collapse
|
16
|
MicroRNA miR-204 and miR-1236 inhibit hepatitis B virus replication via two different mechanisms. Sci Rep 2016; 6:34740. [PMID: 27734898 PMCID: PMC5062086 DOI: 10.1038/srep34740] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/19/2016] [Indexed: 12/30/2022] Open
Abstract
Hepatitis B virus (HBV) is a major human pathogen. In this study, we found that miR-204 and miR-1236 were down-regulated in HBV-producing cells, and each could suppress HBV replication. Using a bioinformatic approach and a reporter assay, we identified miR-1236, which can reduce HBV replication and protein production by directly targeting at HBV specific mRNA. In contrast, miR-204 was identified by a microarray approach, and had no effect on HBV RNA and protein production. Surprisingly, miR-204 could inhibit HBV pregenomic RNA encapsidation and capsid assembly. We further demonstrated that HBV suppressed miR-204 expression via activating a host transcription factor STAT3. We established a positive feed-forward loop between HBV, miR-204 and STAT3. Interestingly, miR-204 has been considered as a tumor suppressor in some literature. Since the risk for hepatocellular carcinoma (HCC) is significantly increased in chronic HBV patients, it is possible that chronic suppression of miR-204 by HBV contributes to HCC incidence. Both miR-204 and miR-1236 might be useful for developing new therapeutics against HBV.
Collapse
|
17
|
Chen C, Wang JCY, Pierson EE, Keifer DZ, Delaleau M, Gallucci L, Cazenave C, Kann M, Jarrold MF, Zlotnick A. Importin β Can Bind Hepatitis B Virus Core Protein and Empty Core-Like Particles and Induce Structural Changes. PLoS Pathog 2016; 12:e1005802. [PMID: 27518410 PMCID: PMC4982637 DOI: 10.1371/journal.ppat.1005802] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 07/11/2016] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) capsids are found in many forms: immature single-stranded RNA-filled cores, single-stranded DNA-filled replication intermediates, mature cores with relaxed circular double-stranded DNA, and empty capsids. A capsid, the protein shell of the core, is a complex of 240 copies of core protein. Mature cores are transported to the nucleus by a complex that includes both importin α and importin β (Impα and Impβ), which bind to the core protein's C-terminal domains (CTDs). Here we have investigated the interactions of HBV core protein with importins in vitro. Strikingly, empty capsids and free core protein can bind Impβ without Impα. Cryo-EM image reconstructions show that the CTDs, which are located inside the capsid, can extrude through the capsid to be bound by Impβ. Impβ density localized on the capsid exterior near the quasi-sixfold vertices, suggested a maximum of 30 Impβ per capsid. However, examination of complexes using single molecule charge-detection mass spectrometry indicate that some complexes include over 90 Impβ molecules. Cryo-EM of capsids incubated with excess Impβ shows a population of damaged particles and a population of "dark" particles with internal density, suggesting that Impβ is effectively swallowed by the capsids, which implies that the capsids transiently open and close and can be destabilized by Impβ. Though the in vitro complexes with great excess of Impβ are not biological, these results have implications for trafficking of empty capsids and free core protein; activities that affect the basis of chronic HBV infection.
Collapse
Affiliation(s)
- Chao Chen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Joseph Che-Yen Wang
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Elizabeth E. Pierson
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - David Z. Keifer
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Mildred Delaleau
- Universite de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Lara Gallucci
- Universite de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Christian Cazenave
- Universite de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Michael Kann
- Universite de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CHU de Bordeaux, Bordeaux, France
| | - Martin F. Jarrold
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Adam Zlotnick
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, United States of America
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| |
Collapse
|
18
|
Kim H, Lee SA, Do SY, Kim BJ. Precore/core region mutations of hepatitis B virus related to clinical severity. World J Gastroenterol 2016; 22:4287-4296. [PMID: 27158197 PMCID: PMC4853686 DOI: 10.3748/wjg.v22.i17.4287] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/10/2016] [Accepted: 04/07/2016] [Indexed: 02/06/2023] Open
Abstract
Despite the availability of an effective vaccine, hepatitis B virus (HBV) infection remains a major health problem, with more than 350 million chronically infected people worldwide and over 1 million annual deaths due to cirrhosis and liver cancer. HBV mutations are primarily generated due both to a lack of proofreading capacity by HBV polymerase and to host immune pressure, which is a very important factor for predicting disease progression and therapeutic outcomes. Several types of HBV precore/core (preC/C) mutations have been described to date. The host immune response against T cells drives mutation in the preC/C region. Specifically, preC/C mutations in the MHC class II restricted region are more common than in other regions and are significantly related to hepatocellular carcinoma. Certain mutations, including preC G1896A, are also significantly related to HBeAg-negative chronic infection. This review article mainly focuses on the HBV preC/C mutations that are related to disease severity and on the HBeAg serostatus of chronically infected patients.
Collapse
|
19
|
Biophysical Characterization of Nucleophosmin Interactions with Human Immunodeficiency Virus Rev and Herpes Simplex Virus US11. PLoS One 2015; 10:e0143634. [PMID: 26624888 PMCID: PMC4704560 DOI: 10.1371/journal.pone.0143634] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/06/2015] [Indexed: 02/07/2023] Open
Abstract
Nucleophosmin (NPM1, also known as B23, numatrin or NO38) is a pentameric RNA-binding protein with RNA and protein chaperon functions. NPM1 has increasingly emerged as a potential cellular factor that directly associates with viral proteins; however, the significance of these interactions in each case is still not clear. In this study, we have investigated the physical interaction of NPM1 with both human immunodeficiency virus type 1 (HIV-1) Rev and Herpes Simplex virus type 1 (HSV-1) US11, two functionally homologous proteins. Both viral proteins show, in mechanistically different modes, high affinity for a binding site on the N-terminal oligomerization domain of NPM1. Rev, additionally, exhibits low-affinity for the central histone-binding domain of NPM1. We also showed that the proapoptotic cyclic peptide CIGB-300 specifically binds to NPM1 oligomerization domain and blocks its association with Rev and US11. Moreover, HIV-1 virus production was significantly reduced in the cells treated with CIGB-300. Results of this study suggest that targeting NPM1 may represent a useful approach for antiviral intervention.
Collapse
|
20
|
The Dual Role of an ESCRT-0 Component HGS in HBV Transcription and Naked Capsid Secretion. PLoS Pathog 2015; 11:e1005123. [PMID: 26431433 PMCID: PMC4592276 DOI: 10.1371/journal.ppat.1005123] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 08/03/2015] [Indexed: 12/15/2022] Open
Abstract
The Endosomal Sorting Complex Required for Transport (ESCRT) is an important cellular machinery for the sorting and trafficking of ubiquitinated cargos. It is also known that ESCRT is required for the egress of a number of viruses. To investigate the relationship between ESCRT and hepatitis B virus (HBV), we conducted an siRNA screening of ESCRT components for their potential effect on HBV replication and virion release. We identified a number of ESCRT factors required for HBV replication, and focused our study here on HGS (HRS, hepatocyte growth factor-regulated tyrosine kinase substrate) in the ESCRT-0 complex. Aberrant levels of HGS suppressed HBV transcription, replication and virion secretion. Hydrodynamic delivery of HGS in a mouse model significantly suppressed viral replication in the liver and virion secretion in the serum. Surprisingly, overexpression of HGS stimulated the release of HBV naked capsids, irrespective of their viral RNA, DNA, or empty contents. Mutant core protein (HBc 1-147) containing no arginine-rich domain (ARD) failed to secrete empty virions with or without HGS. In contrast, empty naked capsids of HBc 1-147 could still be promoted for secretion by HGS. HGS exerted a strong positive effect on the secretion of naked capsids, at the expense of a reduced level of virions. The association between HGS and HBc appears to be ubiquitin-independent. Furthermore, HBc is preferentially co-localized with HGS near the cell periphery, instead of near the punctate endosomes in the cytoplasm. In summary, our work demonstrated the importance of an optimum level of HGS in HBV propagation. In addition to an effect on HBV transcription, HGS can diminish the pool size of intracellular nucleocapsids with ongoing genome maturation, probably in part by promoting the secretion of naked capsids. The secretion routes of HBV virions and naked capsids can be clearly distinguished based on the pleiotropic effect of HGS involved in the ESCRT-0 complex.
Collapse
|
21
|
Nuclear export of human hepatitis B virus core protein and pregenomic RNA depends on the cellular NXF1-p15 machinery. PLoS One 2014; 9:e106683. [PMID: 25360769 PMCID: PMC4215830 DOI: 10.1371/journal.pone.0106683] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/31/2014] [Indexed: 12/17/2022] Open
Abstract
Hepatitis B virus (HBV) core protein (HBc) can shuttle between nucleus and cytoplasm. Cytoplasm-predominant HBc is clinically associated with severe liver inflammation. Previously, we found that HBc arginine-rich domain (ARD) can associate with a host factor NXF1 (TAP) by coimmunoprecipitation. It is well known that NXF1-p15 heterodimer can serve as a major export receptor of nuclear mRNA as a ribonucleoprotein complex (RNP). In the NXF1-p15 pathway, TREX (transcription/export) complex plays an important role in coupling nuclear pre-mRNA processing with mRNA export in mammalian cells. Here, we tested the hypothesis whether HBc and HBV specific RNA can be exported via the TREX and NXF1-p15 mediated pathway. We demonstrated here that HBc can physically and specifically associate with TREX components, and the NXF1-p15 export receptor by coimmunoprecipitation. Accumulation of HBc protein in the nucleus can be induced by the interference with TREX and NXF1-p15 mediated RNA export machinery. HBV transcripts encodes a non-spliced 3.5 kb pregenomic RNA (pgRNA) which can serve as a template for reverse transcription. Cytoplasmic HBV pgRNA appeared to be reduced by siRNA treatment specific for the NXF1-p15 complex by quantitative RT-qPCR and Northern blot analyses. This result suggests that the pgRNA was also exported via the NXF1-p15 machinery. We entertain the hypothesis that HBc protein can be exported as an RNP cargo via the mRNA export pathway by hijacking the TREX and NXF1-p15 complex. In our current and previous studies, HBc is not required for pgRNA accumulation in the cytoplasm. Furthermore, HBc ARD can mediate nuclear export of a chimeric protein containing HBc ARD in a pgRNA-independent manner. Taken together, it suggests that while both pgRNA and HBc protein exports are dependent on NXF1-p15, they are using the same export machinery in a manner independent of each other.
Collapse
|
22
|
Gai X, Zhao P, Pan Y, Shan H, Yue X, Du J, Zhang Z, Liu P, Ma H, Guo M, Yang X, Sun W, Gao L, Ma C, Liang X. Hepatitis B virus core protein enhances human telomerase reverse transcriptase expression and hepatocellular carcinoma cell proliferation in a c-Ets2-dependent manner. Int J Biochem Cell Biol 2013; 45:1174-85. [DOI: 10.1016/j.biocel.2013.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 03/10/2013] [Accepted: 03/18/2013] [Indexed: 02/07/2023]
|
23
|
Naturally occurring precore/core region mutations of hepatitis B virus genotype C related to hepatocellular carcinoma. PLoS One 2012; 7:e47372. [PMID: 23071796 PMCID: PMC3468518 DOI: 10.1371/journal.pone.0047372] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 09/12/2012] [Indexed: 12/12/2022] Open
Abstract
Previous studies have proved the presence of several distinct types of mutations in hepatitis B virus (HBV) infections, which are related to the progression of liver disease. However, few reports have detailed the mutation frequencies and mutation patterns in the precore/core (preC/C) region, which are based on the clinical status and HBeAg serostatus. Our aim in this study is to investigate the relationships between the preC/C mutations and clinical severity or HBeAg serostatus from patients chronically infected with HBV genotype C. A total of 70 Korean chronic patients, including 35 with hepatocellular carcinoma (HCC), participated in this study. HBV genotyping and precore/core mutations were analyzed by direct sequencing. All patients were confirmed to have genotype C infections. Mutations in the C region were distributed in a non-random manner. In particular, mutations in the MHC class II restricted region were found to be significantly related to HCC. Six (preC-W28*, C-P5H/L/T, C-E83D, C-I97F/L, C-L100I and C-Q182K/*) and seven types (preC-W28*, preC-G29D, C-D32N/H, C-E43K, C-P50A/H/Y, C-A131G/N/P and C-S181H/P) of mutations in the preC/C region were found to be related to HCC and to affect the HBeAg serostatus, respectively. In conclusion, our data indicated that HBV variants in the C region, particularly in the MHC class II restricted region, may contribute to the progress of HCC in chronic patients infected with genotype C. In addition, we found several distinct preC/C mutations in the Korean chronic cohort, which affect the clinical status of HCC and HBeAg serostatus of patients infected with genotype C.
Collapse
|
24
|
Affiliation(s)
- Mark O. J. Olson
- Dept. Biochemistry, University of Mississippi Medical Center, North State St. 2500, Jackson, 39216 Mississippi USA
| |
Collapse
|
25
|
Wu JF, Ni YH, Lin YT, Lee TJ, Hsu SHJ, Chen HL, Tsuei DJ, Hsu HY, Chang MH. Human interleukin-10 genotypes are associated with different precore/core gene mutation patterns in children with chronic hepatitis B virus infection. J Pediatr 2011; 158:808-13. [PMID: 21168854 DOI: 10.1016/j.jpeds.2010.11.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 10/08/2010] [Accepted: 11/02/2010] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To elucidate the association between human interleukin-10 (IL-10) genotypes and hepatitis B virus (HBV) precore/core gene mutation in children with chronic HBV infection. STUDY DESIGN The study group comprised of 21 children with chronic HBV infection with spontaneous hepatitis B e antigen (HBeAg) seroconversion who were followed for more than 10 years. Another nine children without HBeAg seroconversion served as the control subjects. Sera at the immune tolerance and inflammatory phase (alanine aminotransferase, >80 IU/L) were subjected to HBV precore/core sequence analysis. IL-10 -1082 polymorphism was also determined. RESULTS HBV precore/core gene mutation increased significantly more in the inflammatory phase than in the tolerance phase (G1896A, 76.2% versus 4.8%; C1913A, 33.3% versus 0%; C2189A, 28.6% versus 4.8%; G2304A, 52.4% versus 14.3%) in study group (n = 21) but not the control group (n = 9). Subjects with the G/G genotype at the IL-10-1082 polymorphism site had higher C2189A mutation rate than the A allele carriers (P = .02). C2189A mutation carriers are associated with more viral load decrement from tolerance to inflammatory phase (P = .01) and earlier spontaneous HBeAg seroconversion (P = .01). CONCLUSIONS The G/G genotype at the IL-10 -1082 polymorphism is associated with higher C2189A mutations, lower HBV viral load at immune inflammatory phase, and earlier spontaneous HBeAg seroconversion than A allele carriers.
Collapse
Affiliation(s)
- Jia-Feng Wu
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
The Multifunctional Nucleolar Protein Nucleophosmin/NPM/B23 and the Nucleoplasmin Family of Proteins. THE NUCLEOLUS 2011. [PMCID: PMC7121557 DOI: 10.1007/978-1-4614-0514-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nucleophosmin (NPM)/nucleoplasmin family of nuclear chaperones has three members: NPM1, NPM2, and NPM3. Nuclear chaperones serve to ensure proper assembly of nucleosomes and proper formation of higher order structures of chromatin. In fact, this family of proteins has such diverse functions in cellular processes such as chromatin remodeling, ribosome biogenesis, genome stability, centrosome replication, cell cycle, transcriptional regulation, apoptosis, and tumor suppression. Of the members of this family, NPM1 is the most studied and is the main focus of this review. NPM2 and NPM3 are less well characterized, and are also discussed wherever appropriate. The structure–function relationship of NPM proteins has largely been worked out. Other than the many processes in which NPM1 takes part, the major interest comes from its involvement in human cancers, particularly acute myeloid leukemia (AML). Its significance stems from the fact that AML with mutated NPM1 accounts for ∼30% of all AML cases and usually has good prognosis. Its clinical importance also comes from its involvement in virus replication, particularly in the era of outbreaks of infectious diseases.
Collapse
|
27
|
Pan XB, Wei L, Han JC, Ma H, Deng K, Cong X. Artificial recombinant cell-penetrating peptides interfere with envelopment of hepatitis B virus nucleocapsid and viral production. Antiviral Res 2010; 89:109-14. [PMID: 21144865 DOI: 10.1016/j.antiviral.2010.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 11/19/2010] [Accepted: 12/01/2010] [Indexed: 11/29/2022]
Abstract
Hepatitis B virus (HBV) is a major human infectious pathogen, with over 300 million chronically infected patients worldwide. Current therapeutics for chronic HBV infection have shown only limited success. The plasma membrane represents an impermeable barrier for development of most macromolecular antiviral agents. To develop new anti-HBV macromolecules that can cross the membrane barrier, we designed a series of artificial recombinant peptides including cell penetrating sequence oligoarginine R7 and several nucleocapsid binding subunits (NBS). The anti-HBV function of these peptides was evaluated in a HBV DNA replicative cell line HepG2.2.15. Our results showed that the synthetic recombinant cell penetrating peptides retained the activity of cell penetrating in the living cells. HBV DNA in culture medium markedly decreased in cells treated with cell penetrating peptides bearing NBS for three days. Intracellular HBcAg and HBV DNA replicative intermediates increased by 2-3 fold. In conclusion, the synthetic recombinant cell penetrating peptides bearing NBS can efficiently enter into the cells; block nucleocapsid assembly and inhibit HBV release. Cell penetrating subunit presents a high efficiency tool to deliver synthetic antiviral peptides into cells.
Collapse
Affiliation(s)
- Xiao-Ben Pan
- Peking University People's Hospital, Peking University Hepatology Institute, 11# Xizhimeng South Street, Xicheng District, Beijing 100044, PR China.
| | | | | | | | | | | |
Collapse
|
28
|
Nuclear export and import of human hepatitis B virus capsid protein and particles. PLoS Pathog 2010; 6:e1001162. [PMID: 21060813 PMCID: PMC2965763 DOI: 10.1371/journal.ppat.1001162] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 09/24/2010] [Indexed: 12/21/2022] Open
Abstract
It remains unclear what determines the subcellular localization of hepatitis B virus (HBV) core protein (HBc) and particles. To address this fundamental issue, we have identified four distinct HBc localization signals in the arginine rich domain (ARD) of HBc, using immunofluorescence confocal microscopy and fractionation/Western blot analysis. ARD consists of four tight clustering arginine-rich subdomains. ARD-I and ARD-III are associated with two co-dependent nuclear localization signals (NLS), while ARD-II and ARD-IV behave like two independent nuclear export signals (NES). This conclusion is based on five independent lines of experimental evidence: i) Using an HBV replication system in hepatoma cells, we demonstrated in a double-blind manner that only the HBc of mutant ARD-II+IV, among a total of 15 ARD mutants, can predominantly localize to the nucleus. ii) These results were confirmed using a chimera reporter system by placing mutant or wild type HBc trafficking signals in the heterologous context of SV40 large T antigen (LT). iii) By a heterokaryon or homokaryon analysis, the fusion protein of SV40 LT-HBc ARD appeared to transport from nuclei of transfected donor cells to nuclei of recipient cells, suggesting the existence of an NES in HBc ARD. This putative NES is leptomycin B resistant. iv) We demonstrated by co-immunoprecipitation that HBc ARD can physically interact with a cellular factor TAP/NXF1 (Tip-associated protein/nuclear export factor-1), which is known to be important for nuclear export of mRNA and proteins. Treatment with a TAP-specific siRNA strikingly shifted cytoplasmic HBc to nucleus, and led to a near 7-fold reduction of viral replication, and a near 10-fold reduction in HBsAg secretion. v) HBc of mutant ARD-II+IV was accumulated predominantly in the nucleus in a mouse model by hydrodynamic delivery. In addition to the revised map of NLS, our results suggest that HBc could shuttle rapidly between nucleus and cytoplasm via a novel TAP-dependent NES.
Collapse
|
29
|
APOBEC3G directly binds Hepatitis B virus core protein in cell and cell free systems. Virus Res 2010; 151:213-9. [PMID: 20510315 PMCID: PMC7173111 DOI: 10.1016/j.virusres.2010.05.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 05/13/2010] [Accepted: 05/18/2010] [Indexed: 02/08/2023]
Abstract
APOBEC3G (A3G) is an intrinsic antiretroviral factor which can inhibit Hepatitis B virus (HBV) replication. This antiviral activity mainly depends on A3G incorporation into viral particles. However, the mechanisms of A3G packaging into HBV particles have not been well characterized. In this paper, we demonstrated that A3G interacted with the HBV core protein (HBc) directly in co-transfected HepG2 cells using the fluorescence resonance energy transfer (FRET) approach. In addition, we further found that this interaction did not require other factors in vitro using surface plasmon resonance (SPR) technology on BIAcore 3000. While cellular RNA or viral RNA was added to A3G protein solution before flow through the BIAcore chip, the interaction was not affected. In conclusion, these results suggest the possibility that A3G is incorporated into HBV viral particles via direct binding with HBc protein.
Collapse
|
30
|
Testing the balanced electrostatic interaction hypothesis of hepatitis B virus DNA synthesis by using an in vivo charge rebalance approach. J Virol 2009; 84:2340-51. [PMID: 20015989 DOI: 10.1128/jvi.01666-09] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Previously, a charge balance hypothesis was proposed to explain hepatitis B virus (HBV) capsid stability, assembly, RNA encapsidation, and DNA replication. This hypothesis emphasized the importance of a balanced electrostatic interaction between the positive charge from the arginine-rich domain (ARD) of the core protein (HBc) and the negative charge from the encapsidated nucleic acid. It remains unclear if any of the negative charge involved in this electrostatic interaction could come from the HBc protein per se, in addition to the encapsidated nucleic acid. HBc ARD IV mutant 173GG and ARD II mutant 173RR/R157A/R158A are arginine deficient and replication defective. Not surprisingly, the replication defect of ARD IV mutant 173GG can be rescued by restoring positively charged amino acids at the adjacent positions 174 and 175. However, most interestingly, it can be at least partially rescued by reducing negatively charged residues in the assembly domain, such as by glutamic acid-to-alanine (E-to-A) substitutions at position 46 or 117 and to a much lesser extent at position 113. Similar results were obtained for ARD II mutant 173RR/R157A/R158A. These amino acids are located on the inner surfaces of HBc icosahedral particles, and their acidic side chains point toward the capsid interior. For HBV DNA synthesis, the relative amount of positive versus negative charge in the electrostatic interactions is more important than the absolute amount of positive or negative charge. These results support the concept that balanced electrostatic interaction is important during the viral life cycle.
Collapse
|
31
|
Inoue J, Ueno Y, Nagasaki F, Wakui Y, Kondo Y, Fukushima K, Niitsuma H, Shimosegawa T. Enhanced intracellular retention of a hepatitis B virus strain associated with fulminant hepatitis. Virology 2009; 395:202-9. [PMID: 19850315 DOI: 10.1016/j.virol.2009.09.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 06/22/2009] [Accepted: 09/23/2009] [Indexed: 12/17/2022]
Abstract
A plasmid carrying 1.3-fold HBV genome was constructed from a HBV strain that caused five consecutive cases of fulminant hepatitis (pBFH2), and HepG2 cells were transfected with pBFH2 or its variants. The pBFH2 construct with A1762T/G1764A, G1862T, and G1896A showed the largest amount of core particle-associated intracellular HBV DNA, but no significant increase of extracellular HBV DNA in comparison with the wild construct, suggesting that these mutations might work together for retention of the replicative intermediates in the cells. The retention might relate to the localization of hepatitis B core antigen (HBcAg) in the nucleus of HepG2, which was observed by confocal fluorescence microscopy. HBcAg immunohistochemical examination of liver tissue samples obtained from the consecutive fulminant hepatitis patients showed stronger staining in the nucleus than acute hepatitis patients. In conclusion, the fulminant HBV strain caused retention of the core particles and the core particle-associated HBV DNA in the cells.
Collapse
Affiliation(s)
- Jun Inoue
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo, Aoba, Sendai 980-8574, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Abstract
Viruses are intracellular pathogens that have to usurp some of the cellular machineries to provide an optimal environment for their own replication. An increasing number of reports reveal that many viruses induce modifications of nuclear substructures including nucleoli, whether they replicate or not in the nucleus of infected cells. Indeed, during infection of cells with various types of human viruses, nucleoli undergo important morphological modifications. A large number of viral components traffic to and from the nucleolus where they interact with different cellular and/or viral factors, numerous host nucleolar proteins are redistributed in other cell compartments or are modified and some cellular proteins are delocalised in the nucleolus of infected cells. Well‐documented studies have established that several of these nucleolar modifications play a role in some steps of the viral cycle, and also in fundamental cellular pathways. The nucleolus itself is the place where several essential steps of the viral cycle take place. In other cases, viruses divert host nucleolar proteins from their known functions in order to exert new unexpected role(s). Copyright © 2009 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Anna Greco
- Université de Lyon, Lyon F-69003, France.
| |
Collapse
|
33
|
Eyre NS, Phillips RJ, Bowden S, Yip E, Dewar B, Locarnini SA, Beard MR. Hepatitis B virus and hepatitis C virus interaction in Huh-7 cells. J Hepatol 2009; 51:446-57. [PMID: 19596477 DOI: 10.1016/j.jhep.2009.04.025] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 03/26/2009] [Accepted: 04/11/2009] [Indexed: 12/15/2022]
Abstract
BACKGROUND/AIMS Co-infection with hepatitis B virus (HBV) and hepatitis C virus (HCV) increases the risk of development and the severity of chronic liver disease. Although dominant and suppressive effects of each virus over the other have been reported in vivo, in vitro studies of HBV/HCV co-infection have been limited to analysis of the effects of over-expression of HCV proteins on HBV replication. METHODS We have re-examined HBV/HCV interactions in Huh-7 cells following co-infection with cell culture-propagated HCV (HCVcc; genotype 2a) and a recombinant adenovirus vector capable of delivering a replication-competent HBV genome (AdHBV; genotype A). RESULTS While intracellular HCV RNA levels were significantly increased when cells were pre-infected with AdHBV, HCV replication and virion secretion were not altered by simultaneous infection with AdHBV or AdHBV superinfection of HCV-infected cells. Likewise intracellular and secreted HBV DNA levels and HBV promoter activities were either unchanged or modestly increased by HCVcc infection. Despite this, HCV E2 and HBsAg proteins colocalized extensively in co-infected cells suggesting shared stages in viral egress. CONCLUSIONS These studies indicate that there is little direct interaction of HBV and HCV in co-infected hepatocytes and imply that indirect effects of host-viral interactions dictate viral dominance in HBV/HCV co-infected individuals.
Collapse
Affiliation(s)
- Nicholas S Eyre
- Infectious Diseases Laboratories, Institute of Medical and Veterinary Sciences, Adelaide, SA, Australia
| | | | | | | | | | | | | |
Collapse
|
34
|
Hepatitis B virus replication and release are independent of core lysine ubiquitination. J Virol 2009; 83:4923-33. [PMID: 19244316 DOI: 10.1128/jvi.02644-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Ubiquitin conjugation to lysine residues regulates a variety of protein functions, including endosomal trafficking and degradation. While ubiquitin plays an important role in the release of many viruses, the requirement for direct ubiquitin conjugation to viral structural proteins is less well understood. Some viral structural proteins require ubiquitin ligase activity, but not ubiquitin conjugation, for efficient release. Recent evidence has shown that, like other viruses, hepatitis B virus (HBV) requires a ubiquitin ligase for release from the infected cell. The HBV core protein contains two lysine residues (K7 and K96), and K96 has been suggested to function as a potential ubiquitin acceptor site based on the fact that previous studies have shown that mutation of this amino acid to alanine blocks HBV release. We therefore reexamined the potential connection between core lysine ubiquitination and HBV replication, protein trafficking, and virion release. In contrast to alanine substitution, we found that mutation of K96 to arginine, which compared to alanine is more conserved but also cannot mediate ubiquitin conjugation, does not affect either virus replication or virion release. We also found that the core lysine mutants display wild-type sensitivity to the antiviral activity of interferon, which demonstrates that ubiquitination of core lysines does not mediate the interferon-induced disruption of HBV capsids. However, mutation of K96 to arginine alters the nuclear-cytoplasmic distribution of core, leading to an accumulation in the nucleolus. In summary, these studies demonstrate that although ubiquitin may regulate the HBV replication cycle, these mechanisms function independently of direct lysine ubiquitination of core protein.
Collapse
|
35
|
Shi KD, Hwang SG, Choi JH, Hwang IJ, Yoon JH, Kim KI, Kwon CI, Hong SP, Park PW, Rim KS. [Hepatitis B core antigen expression pattern predicts response to lamivudine therapy in patients with chronic hepatitis B]. THE KOREAN JOURNAL OF HEPATOLOGY 2008; 14:197-205. [PMID: 18617767 DOI: 10.3350/kjhep.2008.14.2.197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUNDS/AIMS Negative hepatitis B core antigen (HBcAg) staining in hepatocytes is indicative of viral replication by an active immune response. HBcAg is expressed mainly in the cytoplasm in patients with active hepatitis and hepatocyte regeneration, and mainly in the nuclei of hepatocytes in patients with minimal liver injury in the absence of hepatocyte regeneration. The aim of this study was to elucidate whether the existence and expression pattern of HBcAg predicts the response to antiviral treatment. METHODS The study involved 58 patients with biopsy-proven chronic hepatitis B who were treated with lamivudine. Hepatitis B e antigen (HBeAg), antibody to HBeAg, hepatitis B virus DNA, and alanine aminotransferase in serum were recorded every 3 months. The inflammation grade and the fibrosis stage of chronic hepatitis were scored from 0 to 4 according to lobular inflammation, portal inflammation, periportal inflammation, and fibrosis. RESULTS The 58 patients included 49(84%) HBcAg-positive patients, with HBcAg staining confined to the cytoplasm in 15(31%) and in both cytoplasm and nuclei in 34(69%). The grade of lobular inflammation and the total histology score were significantly higher in patients with cytoplasmic expression of HBcAg than in HBcAg-negative patients (lobular inflammation: 2.9 vs 2.1, P=0.02; total histology score: 12.2 vs 10.3, P=0.04). The virologic responses at 3, 6, 9, and 12 months differed significantly between the cytoplasmic and mixed expression groups (P<0.01). CONCLUSIONS The expression pattern of HBcAg (including its possible absence) before initial therapy appears to predict the response to antiviral treatment.
Collapse
Affiliation(s)
- Kyeh Dong Shi
- Department of Gastroenterology and Hepatology, Bundang CHA Hospital, College of Medicine, Pochon CHA University, Seongnam, Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
You JH, Howell G, Pattnaik AK, Osorio FA, Hiscox JA. A model for the dynamic nuclear/nucleolar/cytoplasmic trafficking of the porcine reproductive and respiratory syndrome virus (PRRSV) nucleocapsid protein based on live cell imaging. Virology 2008; 378:34-47. [PMID: 18550142 PMCID: PMC7103367 DOI: 10.1016/j.virol.2008.04.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 03/07/2008] [Accepted: 04/19/2008] [Indexed: 01/09/2023]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV), an arterivirus, in common with many other positive strand RNA viruses, encodes a nucleocapsid (N) protein which can localise not only to the cytoplasm but also to the nucleolus in virus-infected cells and cells over-expressing N protein. The dynamic trafficking of positive strand RNA virus nucleocapsid proteins and PRRSV N protein in particular between the cytoplasm and nucleolus is unknown. In this study live imaging of permissive and non-permissive cell lines, in conjunction with photo-bleaching (FRAP and FLIP), was used to investigate the trafficking of fluorescent labeled (EGFP) PRRSV-N protein. The data indicated that EGFP-PRRSV-N protein was not permanently sequestered to the nucleolus and had equivalent mobility to cellular nucleolar proteins. Further the nuclear import of N protein appeared to occur faster than nuclear export, which may account for the observed relative distribution of N protein between the cytoplasm and the nucleolus.
Collapse
Affiliation(s)
- Jae-Hwan You
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | | | | | | | | |
Collapse
|
37
|
Crowther RA. The Leeuwenhoek lecture 2006. Microscopy goes cold: frozen viruses reveal their structural secrets. Philos Trans R Soc Lond B Biol Sci 2008; 363:2441-51. [PMID: 17690055 PMCID: PMC2606804 DOI: 10.1098/rstb.2007.2150] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The electron microscope provides a powerful tool for investigating the structure of biological complexes such as viruses. A modern instrument is fully capable of atomic resolution on suitable non-biological specimens, but biological materials are difficult to preserve, owing to their fragility, and to image, owing to their radiation, sensitivity. The act of imaging the specimen severely damages it. Originally, samples were prepared by staining with a heavy metal salt, which provides a stable specimen but limits the amount of details that can be retrieved. Now particulate specimens, such as viruses, are prepared by rapid freezing of unstained material and observed in a frozen state with low doses of electrons. The resulting images require extensive computer processing to extract fully detailed three-dimensional information about the specimen. The whole process is referred to as single-particle electron cryomicroscopy. Using this approach, the structure of the human hepatitis B virus core was solved at the level of the protein fold. By comparing maps of RNA- and DNA-containing cores, it was possible to propose a model for the maturation and control of the envelopment of the virus during assembly. These examples show that cryomicroscopy offers great potential for understanding the structure and function of complex biological assemblies.
Collapse
Affiliation(s)
- R A Crowther
- Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
| |
Collapse
|
38
|
Nucleolin – Characteristics of Protein and its Role in Biology of Cancers and Viral Infections. ACTA ACUST UNITED AC 2008. [DOI: 10.2478/v10052-008-0003-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
39
|
Sirri V, Urcuqui-Inchima S, Roussel P, Hernandez-Verdun D. Nucleolus: the fascinating nuclear body. Histochem Cell Biol 2007; 129:13-31. [PMID: 18046571 PMCID: PMC2137947 DOI: 10.1007/s00418-007-0359-6] [Citation(s) in RCA: 295] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2007] [Indexed: 11/30/2022]
Abstract
Nucleoli are the prominent contrasted structures of the cell nucleus. In the nucleolus, ribosomal RNAs are synthesized, processed and assembled with ribosomal proteins. RNA polymerase I synthesizes the ribosomal RNAs and this activity is cell cycle regulated. The nucleolus reveals the functional organization of the nucleus in which the compartmentation of the different steps of ribosome biogenesis is observed whereas the nucleolar machineries are in permanent exchange with the nucleoplasm and other nuclear bodies. After mitosis, nucleolar assembly is a time and space regulated process controlled by the cell cycle. In addition, by generating a large volume in the nucleus with apparently no RNA polymerase II activity, the nucleolus creates a domain of retention/sequestration of molecules normally active outside the nucleolus. Viruses interact with the nucleolus and recruit nucleolar proteins to facilitate virus replication. The nucleolus is also a sensor of stress due to the redistribution of the ribosomal proteins in the nucleoplasm by nucleolus disruption. The nucleolus plays several crucial functions in the nucleus: in addition to its function as ribosome factory of the cells it is a multifunctional nuclear domain, and nucleolar activity is linked with several pathologies. Perspectives on the evolution of this research area are proposed.
Collapse
Affiliation(s)
- Valentina Sirri
- Nuclei and Cell Cycle, CNRS, Université Paris VI, Université Paris VII, Institut Jacques Monod, 2 place Jussieu, 75251 Paris Cedex 05, France
| | - Silvio Urcuqui-Inchima
- Nuclei and Cell Cycle, CNRS, Université Paris VI, Université Paris VII, Institut Jacques Monod, 2 place Jussieu, 75251 Paris Cedex 05, France
- Grupo de Inmunovirología, Biogénesis, Universidad de Antioquia, Calle 62 No. 52-59, Medellin, Colombia
| | - Pascal Roussel
- Nuclei and Cell Cycle, CNRS, Université Paris VI, Université Paris VII, Institut Jacques Monod, 2 place Jussieu, 75251 Paris Cedex 05, France
| | - Danièle Hernandez-Verdun
- Nuclei and Cell Cycle, CNRS, Université Paris VI, Université Paris VII, Institut Jacques Monod, 2 place Jussieu, 75251 Paris Cedex 05, France
| |
Collapse
|
40
|
Yang MR, Lee SR, Oh W, Lee EW, Yeh JY, Nah JJ, Joo YS, Shin J, Lee HW, Pyo S, Song J. West Nile virus capsid protein induces p53-mediated apoptosis via the sequestration of HDM2 to the nucleolus. Cell Microbiol 2007; 10:165-76. [PMID: 17697133 PMCID: PMC7162166 DOI: 10.1111/j.1462-5822.2007.01027.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The capsid protein of the West Nile virus (WNV) functions as an apoptotic agonist via the induction of mitochondrial dysfunction and the activation of caspases-9 and -3. Here, we have determined that the WNV capsid (WNVCp) is capable of binding to and sequestering HDM2 into the nucleolus. WNVCp was shown to interfere with the formation of the HDM2 and p53 complex, thereby causing the stabilization of p53 and the subsequent induction of its target apoptotic protein, Bax. Whereas WNVCp was capable of inducing the p53-dependent apoptotic process in wild-type mouse embryonic fibroblasts (MEF) or SH-SY5Y cells, it exerted no significant effects on p53-null MEF or on p53-knockdown SH-SY5Y cells. This suggests that WNVCp-mediated apoptosis requires p53. Furthermore, when WNV was transfected into cells, endogenous Hdm2 and WNVCp were able to interact physically. WNVCp expressed in wild-type MEF proved able to induce the translocation of the endogenous Hdm2 into the nucleolus. Consistently, WNV was highly pathogenic in the presence of p53, and was less so in the absence of p53. The results of these studies suggest that the apoptotic mechanism mediated by WNV might occur in accordance in a fashion similar to that of the tumour-suppressing mechanism mediated by ARF.
Collapse
Affiliation(s)
- Mi-Ran Yang
- Department of Food Science and Biotechnology, Sungkyunkwan University, Suwon 440-746, Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Oh W, Yang MR, Lee EW, Park KM, Pyo S, Yang JS, Lee HW, Song J. Jab1 mediates cytoplasmic localization and degradation of West Nile virus capsid protein. J Biol Chem 2006; 281:30166-74. [PMID: 16882664 DOI: 10.1074/jbc.m602651200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The clinical manifestations of West Nile virus (WNV), a member of the Flavivirus family, include febrile illness, sporadic encephalitis, and paralysis. The capsid (Cp) of WNV is thought to participate in these processes by inducing apoptosis through mitochondrial dysfunction and activation of caspase-9 and caspase-3. To further identify the molecular mechanism of the WNV capsid protein (WNVCp), yeast two-hybrid assays were employed using WNV-Cp as bait. Jab1, the fifth subunit of the COP9 signalosome, was subsequently identified as a molecule that interacts with WNVCp. Immunoprecipitation and glutathione S-transferase pulldown assays confirmed that direct interaction could occur between WNVCp and Jab1. Immunofluorescence microscopy demonstrated that the overexpressed WNVCp, which localized to the nucleolus, was translocated to the cytoplasm upon its co-expression with Jab1. When treated with leptomycin B, Jab1-facilitated nuclear exclusion of WNVCp was prevented, which indicated that the CRM1 complex is required for Jab1-facilitated nuclear export of WNVCp. Moreover, Jab1 promoted the degradation of WNVCp in a proteasome-dependent way. Consistent with this, WNVCp-mediated cell cycle arrest at the G(2) phase in H1299 was prevented by exogenous Jab1. Finally, an analysis of WNVCp deletion mutants indicated that the first 15 amino acids were required for interaction with Jab1. Furthermore, the double-point mutant of the WNVCp, P5A/P8A, was incapable of binding to Jab1. These results indicate that Jab1 has a potential protective effect against pathogenic WNVCp and might provide a novel target site for the treatment of disease caused by WNV.
Collapse
Affiliation(s)
- Wonkyung Oh
- Department of Food Science and Biotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Oh WK, Song J. Hsp70 functions as a negative regulator of West Nile virus capsid protein through direct interaction. Biochem Biophys Res Commun 2006; 347:994-1000. [PMID: 16854374 PMCID: PMC7117540 DOI: 10.1016/j.bbrc.2006.06.190] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 06/29/2006] [Indexed: 12/15/2022]
Abstract
West Nile virus (WNV) is a member of the Flavivirus family and induces febrile illness, sporadic encephalitis, and paralysis. The capsid (Cp) of WNV is thought to play a role in inducing these symptoms through caspase-3- and caspase-9-dependent apoptosis. Using WNVCp as bait for a yeast two-hybrid assay, we identified that Hsp70 interacted with WNVCp. The interaction between Hsp70 and WNVCp was further substantiated using purified proteins. Deletion analysis of Hsp70 indicated that WNVCp could bind to the substrate binding domain of Hsp70. The presence of WNVCp in the Hsp70-dependent folding system inhibited the refolding of β-galactosidase (β-gal), which showed that WNVCp might function as a negative regulator of Hsp70. Finally, the cytotoxic effect of WNVCp in 293T cells was prevented by ectopic Hsp70, suggesting a negative regulatory role of Hsp70 on WNVCp. Our findings suggest a possible negative regulatory role of Hps70 in the pathway of WNV infection.
Collapse
Affiliation(s)
- Won-kyung Oh
- Department of Food Science and Biotechnology, Faculty of Life Science and Technology Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Republic of Korea
| | | |
Collapse
|
43
|
Billaud JN, Peterson D, Barr M, Chen A, Sallberg M, Garduno F, Goldstein P, McDowell W, Hughes J, Jones J, Milich D. Combinatorial approach to hepadnavirus-like particle vaccine design. J Virol 2005; 79:13656-66. [PMID: 16227285 PMCID: PMC1262598 DOI: 10.1128/jvi.79.21.13656-13666.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The particulate hepatitis core protein (HBcAg) represents an efficient carrier platform with many of the characteristics uniquely required for the delivery of weak immunogens to the immune system. Although the HBcAg is highly immunogenic, the existing HBcAg-based platform technology has a number of theoretical and practical limitations, most notably the "preexisting immunity" and "assembly" problems. To address the assembly problem, we have developed the core protein from the woodchuck hepadnavirus (WHcAg) as a new particulate carrier platform system. WHcAg appears to tolerate insertions of foreign epitopes at a greater number of positions than HBcAg. For example, both within the external loop region and outside the loop region a total of 17 insertion sites were identified on WHcAg. Importantly, the identification of an expanded number of insertion sites was dependent on additional modifications to the C terminus that appear to stabilize the various internal insertions. Indeed, 21 separate C-terminal modifications have been generated that can be used in combination with the 17 insertion sites to ensure efficient hybrid WHcAg particle assembly. This combinatorial technology is also dependent on the sequence of the heterologous insert. Therefore, the three variables of insert position, C terminus, and epitope sequence are relevant in the design of hybrid WHcAg particles for vaccine purposes.
Collapse
Affiliation(s)
- Jean-Noel Billaud
- Vaccine Research Institute of San Diego, 3030 Bunker Hill Street, Suite 300, San Diego, CA 92109, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Roseman AM, Berriman JA, Wynne SA, Butler PJG, Crowther RA. A structural model for maturation of the hepatitis B virus core. Proc Natl Acad Sci U S A 2005; 102:15821-6. [PMID: 16247012 PMCID: PMC1276056 DOI: 10.1073/pnas.0504874102] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hepatitis B virus, a widespread and serious human pathogen, replicates by reverse transcription of an RNA intermediate. The virus consists of an inner nucleocapsid or core, surrounded by a lipid envelope containing virally encoded surface proteins. Using electron cryomicroscopy, we compare the structures of the bacterially expressed RNA-containing core particle and the mature DNA-containing core particle extracted from virions. We show that the mature core contains 240 subunits in a T = 4 arrangement similar to that in expressed core (T is the triangulation number and the icosahedral shell contains 60 T subunits). During the infective cycle, the core assembles in an immature state around a complex of viral pregenomic RNA and polymerase. After reverse transcription with concomitant degradation of the RNA, the now mature core buds through a cellular membrane containing the surface proteins to become enveloped. Envelopment must not happen before reverse transcription is completed, so it has been hypothesized that a change in capsid structure may signal maturation. Our results show significant differences in structure between the RNA- and DNA-containing cores. One such difference is in a hydrophobic pocket, formed largely from residues that, on mutation, lead to abnormal secretion. We suggest that the changes we see are related to maturation and control of envelopment, and we propose a mechanism based on DNA synthesis for their triggering.
Collapse
Affiliation(s)
- Alan M Roseman
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom
| | | | | | | | | |
Collapse
|
45
|
Cooper A, Tal G, Lider O, Shaul Y. Cytokine Induction by the Hepatitis B Virus Capsid in Macrophages Is Facilitated by Membrane Heparan Sulfate and Involves TLR2. THE JOURNAL OF IMMUNOLOGY 2005; 175:3165-76. [PMID: 16116207 DOI: 10.4049/jimmunol.175.5.3165] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hepatitis B virus (HBV) core Ag (HBcAg) serves as the structural subunit of the highly immunogenic capsid shell. HBcAg harbors a unique arginine-rich C terminus that was implicated in immune responses induced by the capsid. In this study, we examined the capacity of the HBV capsid to induce proinflammatory and regulatory cytokines in human THP-1 macrophages and the possible underlying mechanism. Full-length HBc capsids, but not HBc-144 capsids lacking the arginine-rich domain of HBcAg, efficiently bound differentiated THP-1 macrophages and strongly induced TNF-alpha, IL-6, and IL-12p40. Capsid binding to macrophages and cytokine induction were independent of the RNA associated with the arginine-rich domain. Soluble heparin and heparan sulfate but not chondroitin sulfates greatly diminished cytokine induction through inhibition of capsid binding to THP-1 macrophages. Furthermore, serine phosphorylation in the arginine-rich domain modulates capsid binding to macrophages and the cytokine response. Induction of cytokines by the capsid involved activation of NF-kappaB, ERK-1/2, and p38 MAPK and did not require endosomal acidification. Finally, NF-kappaB activation by the capsid in HEK 293 cells specifically required expression of TLR2 and was compromised by soluble heparin. Thus, cytokine induction by the HBV capsid in macrophages is facilitated by interaction of its arginine-rich domain with membrane heparan sulfate and involves signaling through TLR2.
Collapse
Affiliation(s)
- Arik Cooper
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | |
Collapse
|