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Zhang X, Wang X, Wu M, Ghildyal R, Yuan Z. Animal Models for the Study of Hepatitis B Virus Pathobiology and Immunity: Past, Present, and Future. Front Microbiol 2021; 12:715450. [PMID: 34335553 PMCID: PMC8322840 DOI: 10.3389/fmicb.2021.715450] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/18/2021] [Indexed: 12/11/2022] Open
Abstract
Hepatitis B virus (HBV) infection is a global public health problem that plagues approximately 240 million people. Chronic hepatitis B (CHB) often leads to liver inflammation and aberrant repair which results in diseases ranging from liver fibrosis, cirrhosis, to hepatocellular carcinoma. Despite its narrow species tropism, researchers have established various in vivo models for HBV or its related viruses which have provided a wealth of knowledge on viral lifecycle, pathogenesis, and immunity. Here we briefly revisit over five decades of endeavor in animal model development for HBV and summarize their advantages and limitations. We also suggest directions for further improvements that are crucial for elucidation of the viral immune-evasion strategies and for development of novel therapeutics for a functional cure.
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Affiliation(s)
- Xiaonan Zhang
- Centre for Research in Therapeutic Solutions, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia.,Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Xiaomeng Wang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Min Wu
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Reena Ghildyal
- Centre for Research in Therapeutic Solutions, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
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2
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Seitz S, Habjanič J, Schütz AK, Bartenschlager R. The Hepatitis B Virus Envelope Proteins: Molecular Gymnastics Throughout the Viral Life Cycle. Annu Rev Virol 2020; 7:263-288. [PMID: 32600157 DOI: 10.1146/annurev-virology-092818-015508] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
New hepatitis B virions released from infected hepatocytes are the result of an intricate maturation process that starts with the formation of the nucleocapsid providing a confined space where the viral DNA genome is synthesized via reverse transcription. Virion assembly is finalized by the enclosure of the icosahedral nucleocapsid within a heterogeneous envelope. The latter contains integral membrane proteins of three sizes, collectively known as hepatitis B surface antigen, and adopts multiple conformations in the course of the viral life cycle. The nucleocapsid conformation depends on the reverse transcription status of the genome, which in turn controls nucleocapsid interaction with the envelope proteins for virus exit. In addition, after secretion the virions undergo a distinct maturation step during which a topological switch of the large envelope protein confers infectivity. Here we review molecular determinants for envelopment and models that postulate molecular signals encoded in the capsid scaffold conducive or adverse to the recruitment of envelope proteins.
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Affiliation(s)
- Stefan Seitz
- Department of Infectious Diseases, University of Heidelberg, 69120 Heidelberg, Germany;
| | - Jelena Habjanič
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, 85748 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Anne K Schütz
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, 85748 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, University of Heidelberg, 69120 Heidelberg, Germany; .,Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
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3
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Abstract
Hepatitis B virus (HBV) affects more than 257 million people globally, resulting in progressively worsening liver disease, manifesting as fibrosis, cirrhosis, and hepatocellular carcinoma. The exceptionally narrow species tropism of HBV restricts its natural hosts to humans and non-human primates, including chimpanzees, gorillas, gibbons, and orangutans. The unavailability of completely immunocompetent small-animal models has contributed to the lack of curative therapeutic interventions. Even though surrogates allow the study of closely related viruses, their host genetic backgrounds, immune responses, and molecular virology differ from those of HBV. Various different models, based on either pure murine or xenotransplantation systems, have been introduced over the past years, often making the choice of the optimal model for any given question challenging. Here, we offer a concise review of in vivo model systems employed to study HBV infection and steps in the HBV life cycle or pathogenesis.
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Affiliation(s)
| | - Catherine Cherry
- Section of Virology, Department of Medicine, Imperial College London, W2 1PGLondon, U.K
| | - Harry Gunn
- Section of Virology, Department of Medicine, Imperial College London, W2 1PGLondon, U.K
| | - Marcus Dorner
- Section of Virology, Department of Medicine, Imperial College London, W2 1PGLondon, U.K
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4
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Singh AK, Kumar R, Pandey AK. Hepatocellular Carcinoma: Causes, Mechanism of Progression and Biomarkers. Curr Chem Genom Transl Med 2018; 12:9-26. [PMID: 30069430 PMCID: PMC6047212 DOI: 10.2174/2213988501812010009] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/15/2018] [Accepted: 05/20/2018] [Indexed: 01/18/2023] Open
Abstract
Hepatocellular Carcinoma (HCC) is one of the most common malignant tumours in the world. It is a heterogeneous group of a tumour that vary in risk factor and genetic and epigenetic alteration event. Mortality due to HCC in last fifteen years has increased. Multiple factors including viruses, chemicals, and inborn and acquired metabolic diseases are responsible for its development. HCC is closely associated with hepatitis B virus, and at least in some regions of the world with hepatitis C virus. Liver injury caused by viral factor affects many cellular processes such as cell signalling, apoptosis, transcription, DNA repair which in turn induce important effects on cell survival, growth, transformation and maintenance. Molecular mechanisms of hepatocellular carcinogenesis may vary depending on different factors and this is probably why a large set of mechanisms have been associated with these tumours. Various biomarkers including α-fetoprotein, des-γ-carboxyprothrombin, glypican-3, golgi protein-73, squamous cell carcinoma antigen, circulating miRNAs and altered DNA methylation pattern have shown diagnostic significance. This review article covers up key molecular pathway alterations, biomarkers for diagnosis of HCC, anti-HCC drugs and relevance of key molecule/pathway/receptor as a drug target.
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Affiliation(s)
| | | | - Abhay K. Pandey
- Department of Biochemistry, University of Allahabad, Allahabad 211002, India
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5
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Witt-Kehati D, Bitton Alaluf M, Shlomai A. Advances and Challenges in Studying Hepatitis B Virus In Vitro. Viruses 2016; 8:v8010021. [PMID: 26784218 PMCID: PMC4728581 DOI: 10.3390/v8010021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 11/30/2015] [Accepted: 01/06/2016] [Indexed: 12/17/2022] Open
Abstract
Hepatitis B virus (HBV) is a small DNA virus that infects the liver. Current anti-HBV drugs efficiently suppress viral replication but do not eradicate the virus due to the persistence of its episomal DNA. Efforts to develop reliable in vitro systems to model HBV infection, an imperative tool for studying HBV biology and its interactions with the host, have been hampered by major limitations at the level of the virus, the host and infection readouts. This review summarizes major milestones in the development of in vitro systems to study HBV. Recent advances in our understanding of HBV biology, such as the discovery of the bile-acid pump sodium-taurocholate cotransporting polypeptide (NTCP) as a receptor for HBV, enabled the establishment of NTCP expressing hepatoma cell lines permissive for HBV infection. Furthermore, advanced tissue engineering techniques facilitate now the establishment of HBV infection systems based on primary human hepatocytes that maintain their phenotype and permissiveness for infection over time. The ability to differentiate inducible pluripotent stem cells into hepatocyte-like cells opens the door for studying HBV in a more isogenic background, as well. Thus, the recent advances in in vitro models for HBV infection holds promise for a better understanding of virus-host interactions and for future development of more definitive anti-viral drugs.
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Affiliation(s)
- Dvora Witt-Kehati
- The Liver Institute, Rabin Medical Center Beilinson Hospital, Petah-Tikva, Israel.
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - Maya Bitton Alaluf
- Department of Medicine D, Rabin Medical Center Beilinson Hospital, Petah-Tikva, Israel.
| | - Amir Shlomai
- The Liver Institute, Rabin Medical Center Beilinson Hospital, Petah-Tikva, Israel.
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
- Department of Medicine D, Rabin Medical Center Beilinson Hospital, Petah-Tikva, Israel.
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6
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Li J, Tong S. From DCPD to NTCP: the long journey towards identifying a functional hepatitis B virus receptor. Clin Mol Hepatol 2015; 21:193-9. [PMID: 26523264 PMCID: PMC4612279 DOI: 10.3350/cmh.2015.21.3.193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/15/2015] [Indexed: 12/13/2022] Open
Abstract
Hepatitis B virus (HBV) is the prototype of hepatotropic DNA viruses (hepadnaviruses) infecting a wide range of human and non-human hosts. Previous studies with duck hepatitis B virus (DHBV) identified duck carboxypeptidase D (dCPD) as a host specific binding partner for full-length large envelope protein, and p120 as a binding partner for several truncated versions of the large envelope protein. p120 is the P protein of duck glycine decarboxylase (dGLDC) with restricted expression in DHBV infectible tissues. Several lines of evidence suggest the importance of dCPD, and especially p120, in productive DHBV infection, although neither dCPD nor p120 cDNA could confer susceptibility to DHBV infection in any cell line. Recently, sodium taurocholate cotransporting polypeptide (NTCP) has been identified as a binding partner for the N-terminus of HBV large envelope protein. Importantly, knock down and reconstitution experiments unequivocally demonstrated that NTCP is both necessary and sufficient for in vitro infection by HBV and hepatitis delta virus (HDV), an RNA virus using HBV envelope proteins for its transmission. What remains unclear is whether NTCP is the major HBV receptor in vivo. The fact that some HBV patients are homozygous with an NTCP mutation known to abolish its receptor function suggests the existence of NTCP-independent pathways of HBV entry. Also, NTCP very likely mediates just one step of the HBV entry process, with additional co-factors for productive HBV infection still to be discovered. NTCP offers a novel therapeutic target for the control of chronic HBV infection.
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Affiliation(s)
- Jisu Li
- Liver Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, USA
| | - Shuping Tong
- Liver Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, USA. ; Key lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
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7
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Tham HW, Balasubramaniam VRMT, Tejo BA, Ahmad H, Hassan SS. CPB1 of Aedes aegypti interacts with DENV2 E protein and regulates intracellular viral accumulation and release from midgut cells. Viruses 2014; 6:5028-46. [PMID: 25521592 PMCID: PMC4276941 DOI: 10.3390/v6125028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/24/2014] [Accepted: 12/11/2014] [Indexed: 11/21/2022] Open
Abstract
Aedes aegypti is a principal vector responsible for the transmission of dengue viruses (DENV). To date, vector control remains the key option for dengue disease management. To develop new vector control strategies, a more comprehensive understanding of the biological interactions between DENV and Ae. aegypti is required. In this study, a cDNA library derived from the midgut of female adult Ae. aegypti was used in yeast two-hybrid (Y2H) screenings against DENV2 envelope (E) protein. Among the many interacting proteins identified, carboxypeptidase B1 (CPB1) was selected, and its biological interaction with E protein in Ae. aegypti primary midgut cells was further validated. Our double immunofluorescent assay showed that CPB1-E interaction occurred in the endoplasmic reticulum (ER) of the Ae. aegypti primary midgut cells. Overexpression of CPB1 in mosquito cells resulted in intracellular DENV2 genomic RNA or virus particle accumulation, with a lower amount of virus release. Therefore, we postulated that in Ae. aegypti midgut cells, CPB1 binds to the E protein deposited on the ER intraluminal membranes and inhibits DENV2 RNA encapsulation, thus inhibiting budding from the ER, and may interfere with immature virus transportation to the trans-Golgi network.
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Affiliation(s)
- Hong-Wai Tham
- Virus-Host Interaction Research Group, Infectious Disease Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Vinod R M T Balasubramaniam
- Virus-Host Interaction Research Group, Infectious Disease Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Bimo Ario Tejo
- Department of Biotechnology and Neuroscience, Faculty of Life Science, Surya University, 15810 Tangerang, Banten, Indonesia.
| | - Hamdan Ahmad
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM, Pulau Pinang, Malaysia.
| | - Sharifah Syed Hassan
- Virus-Host Interaction Research Group, Infectious Disease Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
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8
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Gupta N, Goyal M, Wu CH, Wu GY. The Molecular and Structural Basis of HBV-resistance to Nucleos(t)ide Analogs. J Clin Transl Hepatol 2014; 2:202-11. [PMID: 26357626 PMCID: PMC4548360 DOI: 10.14218/jcth.2014.00021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 07/26/2014] [Accepted: 07/27/2014] [Indexed: 02/06/2023] Open
Abstract
Infection with hepatitis B virus (HBV) is a worldwide health problem. Chronic hepatitis B can lead to fibrosis, liver cirrhosis, and hepatocellular carcinoma (HCC). Management of the latter two conditions often requires liver transplantation. Treatment with conventional interferon or pegylated interferon alpha can clear the virus, but the rates are very low. The likelihood, however, of viral resistance to interferon is minimal. The main problems with this therapy are the frequency and severity of side effects. In contrast, nucleos(t)ide analogs (NAs) have significantly lower side effects, but require long term treatment as sustained virological response rates are extremely low. However, long term treatment with NAs increases the risk for the development of anti-viral drug resistance. Only by understanding the molecular basis of resistance and using agents with multiple sites of action can drugs be designed to optimally prevent the occurrence of HBV antiviral resistance.
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Affiliation(s)
- Nidhi Gupta
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Heath Center, Farmington, USA
| | - Milky Goyal
- Department of Microbiology, College of Basic Sciences and Humanities, Punjab Agriculture University, Ludhiana, Punjab, India
| | - Catherine H. Wu
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Heath Center, Farmington, USA
| | - George Y. Wu
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Heath Center, Farmington, USA
- Correspondence to: George Y. Wu, Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Health Center, Farmington, CT 06030, USA. Tel: +1-800-535-6232. E-mail:
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9
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Watashi K, Urban S, Li W, Wakita T. NTCP and beyond: opening the door to unveil hepatitis B virus entry. Int J Mol Sci 2014; 15:2892-905. [PMID: 24557582 PMCID: PMC3958888 DOI: 10.3390/ijms15022892] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 12/19/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection, affecting approximately 240 million people worldwide, is a major public health problem that elevates the risk of developing liver cirrhosis and hepatocellular carcinoma. Given that current anti-HBV drugs are limited to interferon-based regimens and nucleos(t)ide analogs, the development of new anti-HBV agents is urgently needed. The viral entry process is generally an attractive target implicated in antiviral strategies. Using primary cells from humans and Tupaia belangeri, as well as HepaRG cells, important determinants of viral entry have been achieved. Recently, sodium taurocholate cotransporting polypeptide (NTCP) was identified as an HBV entry receptor and enabled the establishment of a susceptible cell line that can efficiently support HBV infection. This finding will allow a deeper understanding of the requirements for efficient HBV infection, including the elucidation of the molecular entry mechanism. In addition, pharmacological studies suggest that NTCP is able to serve as a therapeutic target. This article summarizes our current knowledge on the mechanisms of HBV entry and the role of NTCP in this process.
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Affiliation(s)
- Koichi Watashi
- Department of Virology II, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, 162-8640 Tokyo, Japan.
| | - Stephan Urban
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany.
| | - Wenhui Li
- National Institute of Biological Sciences, No.7 Science Park Road, ZGC Life Science Park, Changping, 102206 Beijing, China.
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, 162-8640 Tokyo, Japan.
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10
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Sodium taurocholate cotransporting polypeptide mediates woolly monkey hepatitis B virus infection of Tupaia hepatocytes. J Virol 2013; 87:7176-84. [PMID: 23596296 DOI: 10.1128/jvi.03533-12] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Primary Tupaia hepatocytes (PTHs) are susceptible to woolly monkey hepatitis B virus (WMHBV) infection, but the identity of the cellular receptor(s) mediating WMHBV infection of PTHs remains unclear. Recently, sodium taurocholate cotransporting polypeptide (NTCP) was identified as a functional receptor for human hepatitis B virus (HBV) infection of primary human and Tupaia hepatocytes. In this study, a synthetic pre-S1 peptide from WMHBV was found to bind specifically to cells expressing Tupaia NTCP (tsNTCP) and it efficiently blocked WMHBV entry into PTHs; silencing of tsNTCP in PTHs significantly inhibited WMHBV infection. Ectopic expression of tsNTCP rendered HepG2 cells susceptible to WMHBV infection. These data demonstrate that tsNTCP is a functional receptor for WMHBV infection of PTHs. The result also indicates that NTCP's orthologs likely act as a common cellular receptor for all known primate hepadnaviruses.
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11
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Delgado CL, Núñez E, Yélamos B, Gómez-Gutiérrez J, Peterson DL, Gavilanes F. Spectroscopic Characterization and Fusogenic Properties of PreS Domains of Duck Hepatitis B Virus. Biochemistry 2012; 51:8444-54. [DOI: 10.1021/bi3008406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carmen L. Delgado
- Departamento de Bioquímica
y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, Madrid 28040, Spain
| | - Elena Núñez
- Departamento de Bioquímica
y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, Madrid 28040, Spain
| | - Belén Yélamos
- Departamento de Bioquímica
y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, Madrid 28040, Spain
| | - Julián Gómez-Gutiérrez
- Departamento de Bioquímica
y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, Madrid 28040, Spain
| | - Darrell L. Peterson
- Department of Biochemistry and
Molecular Biology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia 23298, United
States
| | - Francisco Gavilanes
- Departamento de Bioquímica
y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, Madrid 28040, Spain
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12
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Xie Y, Zhai J, Deng Q, Tiollais P, Wang Y, Zhao M. Entry of hepatitis B virus: mechanism and new therapeutic target. ACTA ACUST UNITED AC 2010; 58:301-7. [PMID: 20570056 DOI: 10.1016/j.patbio.2010.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 04/12/2010] [Indexed: 12/21/2022]
Abstract
Entry of hepatitis B virus (HBV) into human hepatocytes constitutes the initial step in viral infection. The study of HBV entry had long been hampered by the lack of efficient cell culture systems and small animal models. The situation was greatly improved in the last decade with the development of HBV-infectible HepaRG cell line and primary Tupaia hepatocyte culture. Armed with these new tools, marked progresses have been achieved in the elucidation of the mechanism of HBV entry. Plenty of evidences indicate that the viral large surface protein (LHBs) is essential for HBV entry. Several regions in the PreS1 domain of LHBs have been verified to contribute directly to the viral attachment. In addition, a myristate moiety linked to the N-terminal glycine of PreS1 appears critical for HBV infectivity. Recently, the cysteine-rich antigenic loop of the S domain was identified as another crucial determinant for HBV infectivity. On the other hand, several cellular proteins were implicated in HBV attachment to hepatic cells, though definitive proofs are required in support to their functional involvement in HBV infection. Aiming to blocking viral entry, a couple of approaches based on acylated PreS1-derived peptides and short PreS1-binding peptides are currently under investigation, which have the potential to become novel antiviral therapeutics.
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Affiliation(s)
- Y Xie
- Key Laboratory of Medical Molecular Virology, Shanghai Medical College, Fudan University, Shanghai, China.
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13
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Initiation of duck hepatitis B virus infection requires cleavage by a furin-like protease. J Virol 2010; 84:4569-78. [PMID: 20181690 DOI: 10.1128/jvi.02281-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The entry mechanism of hepatitis B virus (HBV) has not been defined, and this impedes development of antiviral therapies aimed at an early step in the viral life cycle. HBV infection has both host and tissue specificities. For the related duck hepatitis B virus (DHBV), duck carboxypeptidase D (DCPD) has been proposed as the species-specific docking receptor, while glycine decarboxylase (DGD) may serve as a tissue-specific cofactor or secondary receptor. DGD binds to several truncated versions of the viral large envelope protein but not to the full-length protein, suggesting a need for proteolytic cleavage of the envelope protein by a furin-like proprotein convertase. In the present study, we found that transfected DCPD could confer DHBV binding to non-duck cell lines but that this was followed by rapid virus release from cells. Coexpression of furin led to DCPD cleavage and increased virus retention. Treatment of DHBV particles with endosome prepared from duck liver led to cleavage of the large envelope protein, and such viral preparation could generate a small amount of covalently closed circular DNA in LMH cells, a chicken hepatoma cell line resistant to DHBV infection. A furin inhibitor composed of decanoyl-RVKR-chloromethylketone blocked endosomal cleavage of the large envelope protein in vitro and suppressed DHBV infection of primary duck hepatocytes in vivo. These findings suggest that furin or a furin-like proprotein convertase facilitates DHBV infection by cleaving both the docking receptor and the viral large envelope protein.
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14
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Stein LL, Loomba R. Drug targets in hepatitis B virus infection. Infect Disord Drug Targets 2009; 9:105-16. [PMID: 19275699 DOI: 10.2174/187152609787847677] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatitis B virus infection (HBV) is a significant global health problem. Despite the success of universal hepatitis B vaccination in many countries, more than 350 million individuals worldwide are chronically infected and 15- 40% of those will develop cirrhosis and/or hepatocellular carcinoma if left untreated. Available therapies for chronic hepatitis B (CHB) infection are effective at decreasing viremia and improving measured clinical outcomes, however, no single therapy is optimal. As such, alternative drug therapies and the investigation of their role in the management of CHB are warranted. Significant improvements in the understanding of the HBV life cycle, viral genomics, and virus-host interactions continue to lead to the development of novel viral targets and immune modulators. Currently, two major classes of agents are utilized in CHB: the interferons and the nucleos(t)ide analogues. Each agent has individual advantages and drawbacks. The development of specific antiviral therapy has led to the emergence of HBV drug-resistant strains that has limited the long-term therapeutic potential of available agents. This necessitates the development of new agents that target both wild-type and drug-resistant strains. Further understanding of the basic mechanisms and clinical nuances of drug therapy is warranted. As most novel therapies are in the earliest stages of clinical development and testing, in the near future, treatment will continue to be long-term and likely involve the use of combination therapies to prevent viral resistance. In this review, we will highlight the HBV life cycle and genome, focusing in on current and potential novel antiviral drug targets as well as the benefits and clinical challenges with these therapies.
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Affiliation(s)
- Lance L Stein
- Division of Gastroenterology, Department of Medicine, University of California - San Diego, CA, USA
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15
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Abstract
Hepatitis B virus (HBV) infects more than 300 million people worldwide and is a common cause of liver disease and liver cancer. HBV, a member of the Hepadnaviridae family, is a small DNA virus with unusual features similar to retroviruses. HBV replicates through an RNA intermediate and can integrate into the host genome. The unique features of the HBV replication cycle confer a distinct ability of the virus to persist in infected cells. Virological and serological assays have been developed for diagnosis of various forms of HBV-associated disease and for treatment of chronic hepatitis B infection. HBV infection leads to a wide spectrum of liver disease ranging from acute (including fulminant hepatic failure) to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Acute HBV infection can be either asymptomatic or present with symptomatic acute hepatitis. Most adults infected with the virus recover, but 5%-10% are unable to clear the virus and become chronically infected. Many chronically infected persons have mild liver disease with little or no long-term morbidity or mortality. Other individuals with chronic HBV infection develop active disease, which can progress to cirrhosis and liver cancer. These patients require careful monitoring and warrant therapeutic intervention. Extrahepatic manifestations of HBV infection are rare but can be difficult to diagnose and manage. The challenges in the area of HBV-associated disease are the lack of knowledge in predicting outcome and progression of HBV infection and an unmet need to understand the molecular, cellular, immunological, and genetic basis of various disease manifestations associated with HBV infection.
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Affiliation(s)
- T. Jake Liang
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, MD
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16
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Maenz C, Loscher C, Iwanski A, Bruns M. Inhibition of duck hepatitis B virus infection of liver cells by combined treatment with viral e antigen and carbohydrates. J Gen Virol 2009; 89:3016-3026. [PMID: 19008388 DOI: 10.1099/vir.0.2008/003541-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The e antigen (eAg) of duck hepatitis B virus (DHBV) is a glycosylated secretory protein with a currently unknown function. We concentrated this antigen from the supernatants of persistently infected primary duck liver cell cultures by ammonium sulphate precipitation, adsorption chromatography over concanavalin A Sepharose, preparative isoelectric focusing and molecular sieve chromatography. The combined treatment of duck liver cells with DHBV eAg (DHBe) concentrate and alpha-methyl-d-mannopyranoside strongly inhibited DHBV replication at de novo infection. When DHBe was added to non-infected primary duck liver cells, it was found to be associated with liver sinusoidal endothelial cells. This binding could be inhibited by the addition of alpha-methyl-d-mannopyranoside and other sugar molecules. The inhibitory effect of DHBe on infection could play a role in maintaining viral persistence.
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Affiliation(s)
- Claudia Maenz
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, 20251 Hamburg, Germany
| | - Christine Loscher
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, 20251 Hamburg, Germany
| | - Alicja Iwanski
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, 20251 Hamburg, Germany
| | - Michael Bruns
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, 20251 Hamburg, Germany
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17
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Abstract
Hepatitis B viruses are small enveloped DNA viruses referred to as Hepadnaviridae that cause transient or persistent (chronic) infections of the liver. This family is divided into two genera, orthohepadnavirus and avihepadnavirus, which infect mammals or birds as natural hosts, respectively. They possess a narrow host range determined by the initial steps of viral attachment and entry. Hepatitis B virus is the focus of biomedical research owing to its medical significance. Approximately 2 billion people have serological evidence of hepatitis B, and of these approximately 350 million people have chronic infections (World Health Organisation, Fact Sheet WHO/204, October 2000). Depending on viral and host factors, the outcomes of infection with hepatitis B virus vary between acute hepatitis, mild or severe chronic hepatitis or cirrhosis. Chronic infections are associated with an increased risk for the development of hepatocellular carcinoma.
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Affiliation(s)
- Hans-Jürgen Netter
- Monash University, Department of Microbiology, Clayton Campus, Victoria 3800, Australia
| | - Shau-Feng Chang
- Industrial Technology Research Institute, Biomedical Engineering Laboratories, 300 Hsinchu, Taiwan
| | - Michael Bruns
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, 20251 Hamburg, Germany
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18
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Abstract
Chronic hepatitis B continues to be a major cause of end-stage liver disease and hepatocellular carcinoma worldwide. Nucleos(t)ide analogues have proven to be effective in controlling the disease and perhaps decreasing the incidence of hepatocellular carcinoma. However, development of drug resistance is a major limitation to their long-term effectiveness. Understanding the mechanisms of drug resistance are important for designing new agents and devising strategies to manage and prevent the development of antiviral drug resistance. The development of resistance is determined by an interplay of viral, host, and drug characteristics Homology of the HBV polymerase to the human immunodeficiency virus-1 reverse transcriptase has allowed predictions to be made on the effect mutations have on HBV polymerase structure. In vitro functional studies provide complementary information. Several broad principles on the mechanism of resistance have emerged from these studies. First, most of the primary mutations cluster in the vicinity of the incoming nucleotide and act by directly affecting the position or stability of the bound substrate, template, or primer. In contrast, secondary mutations tend to occur away from the nucleotide-binding pocket. Finally, the structural and functional consequences of mutations are quite variable among the different agents. This paper reviews the key mutations and mechanisms associated with resistance to the nucleos(t)ide analogues approved for clinical use and discuss new targets for drug development.
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Affiliation(s)
- Marc Ghany
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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19
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Maenz C, Chang SF, Iwanski A, Bruns M. Entry of duck hepatitis B virus into primary duck liver and kidney cells after discovery of a fusogenic region within the large surface protein. J Virol 2007; 81:5014-23. [PMID: 17360753 PMCID: PMC1900202 DOI: 10.1128/jvi.02290-06] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hepatitis B viruses exhibit a narrow host range specificity that is believed to be mediated by a domain of the large surface protein, designated L. For duck hepatitis B virus, it has been shown that the pre-S domain of L binds to carboxypeptidase D, a cellular receptor present in many species on a wide variety of cell types. Nonetheless, only hepatocytes become infected. It has remained vague which viral features determine host range specificity and organotropicity. By using chymotrypsin to treat duck hepatitis B virus, we addressed the question of whether a putative fusogenic region within the amino-terminal end of the small surface protein may participate in viral entry and possibly constitute one of the determinants of the host range of the virus. Addition of the enzyme to virions resulted in increased infectivity. Remarkably, even remnants of enzyme-treated subviral particles proved to be inhibitory to infection. A noninfectious deletion mutant devoid of the binding region for carboxypeptidase D could be rendered infectious for primary duck hepatocytes by treatment with chymotrypsin. Although because of the protease treatment mutant and wild-type viruses may have become infectious in an unspecific and receptor-independent manner, their host range specificity was not affected, as shown by the inability of the virus to replicate in different hepatoma cell lines, as well as primary chicken hepatocytes. Instead, the organotropicity of the virus could be reduced, which was demonstrated by infection of primary duck kidney cells.
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Affiliation(s)
- Claudia Maenz
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Martinistrasse 52, D-20251 Hamburg, Germany
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20
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Funk A, Mhamdi M, Will H, Sirma H. Avian hepatitis B viruses: Molecular and cellular biology, phylogenesis, and host tropism. World J Gastroenterol 2007; 13:91-103. [PMID: 17206758 PMCID: PMC4065881 DOI: 10.3748/wjg.v13.i1.91] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The human hepatitis B virus (HBV) and the duck hepatitis B virus (DHBV) share several fundamental features. Both viruses have a partially double-stranded DNA genome that is replicated via a RNA intermediate and the coding open reading frames (ORFs) overlap extensively. In addition, the genomic and structural organization, as well as replication and biological characteristics, are very similar in both viruses. Most of the key features of hepadnaviral infection were first discovered in the DHBV model system and subsequently confirmed for HBV. There are, however, several differences between human HBV and DHBV. This review will focus on the molecular and cellular biology, evolution, and host adaptation of the avian hepatitis B viruses with particular emphasis on DHBV as a model system.
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Affiliation(s)
- Anneke Funk
- Department of General Virology, Heinrich-Pette-Institut fur experimentelle Virologie und Immunologie an der Universitat Hamburg, PO Box 201652, Hamburg 20206, Germany
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21
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Abstract
Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds. All members of this family can cause acute and chronic hepatic infection, which in the case of human hepatitis B virus (HBV) constitutes a major global health problem. Although our knowledge about the molecular biology of these highly liver-specific viruses has profoundly increased in the last two decades, the mechanisms of attachment and productive entrance into the differentiated host hepatocytes are still enigmatic. The difficulties in studying hepadnaviral entry were primarily caused by the lack of easily accessible in vitro infection systems. Thus, for more than twenty years, differentiated primary hepatocytes from the respective species were the only in vitro models for both orthohepadnaviruses (e.g. HBV) and avihepadnaviruses (e.g. duck hepatitis B virus [DHBV]). Two important discoveries have been made recently regarding HBV: (1) primary hepatocytes from tree-shrews; i.e., Tupaia belangeri, can be substituted for primary human hepatocytes, and (2) a human hepatoma cell line (HepaRG) was established that gains susceptibility for HBV infection upon induction of differentiation in vitro. A number of potential HBV receptor candidates have been described in the past, but none of them have been confirmed to function as a receptor. For DHBV and probably all other avian hepadnaviruses, carboxypeptidase D (CPD) has been shown to be indispensable for infection, although the exact role of this molecule is still under debate. While still restricted to the use of primary duck hepatocytes (PDH), investigations performed with DHBV provided important general concepts on the first steps of hepadnaviral infection. However, with emerging data obtained from the new HBV infection systems, the hope that DHBV utilizes the same mechanism as HBV only partially held true. Nevertheless, both HBV and DHBV in vitro infection systems will help to: (1) functionally dissect the hepadnaviral entry pathways, (2) perform reverse genetics (e.g. test the fitness of escape mutants), (3) titrate and map neutralizing antibodies, (4) improve current vaccines to combat acute and chronic infections of hepatitis B, and (5) develop entry inhibitors for future clinical applications.
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Affiliation(s)
- Dieter Glebe
- Institute of Medical Virology, Justus-Liebig University of Giessen, Frankfurter Strasse 107, D-35392 Giessen, Germany.
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22
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Franke C, Matschl U, Bruns M. Enzymatic treatment of duck hepatitis B virus: topology of the surface proteins for virions and noninfectious subviral particles. Virology 2006; 359:126-36. [PMID: 17045625 DOI: 10.1016/j.virol.2006.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 08/14/2006] [Accepted: 09/02/2006] [Indexed: 12/29/2022]
Abstract
The large surface antigen L of duck hepatitis B virus exhibits a mixed topology with the preS domains of the protein alternatively exposed to the particles' interior or exterior. After separating virions from subviral particles (SVPs), we compared their L topologies and showed that both particle types exhibit the same amount of L with the following differences: 1--preS of intact virions was enzymatically digested with chymotrypsin, whereas in SVPs only half of preS was accessible, 2--phosphorylation of L at S118 was completely removed by phosphatase treatment only in virions, 3--iodine-125 labeling disclosed a higher ratio of exposed preS to S domains in virions compared to SVPs. These data point towards different surface architectures of virions and SVPs. Because the preS domain acts in binding to a cellular receptor of hepatocytes, our findings implicate the exclusion of SVPs as competitors for the receptor binding and entry of virions.
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Affiliation(s)
- Claudia Franke
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Martinistrasse 52, D-20251 Hamburg, Germany
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23
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Dandri M, Volz T, Lutgehetmann M, Petersen J. Modeling infection with hepatitis B viruses in vivo. Future Virol 2006. [DOI: 10.2217/17460794.1.4.461] [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
Hepatitis B virus (HBV) is a human-specific liver pathogen whose viral cycle and mechanisms of pathogenesis are not yet fully understood. Along with invaluable infection studies in chimpanzees, avian and mammalian HBV-related viruses continue to offer ample opportunities for studies in their natural hosts. Yet, none of these hosts are commonly used laboratory animals; the lack of reliable in vitro infection systems and convenient animal models has severely hampered progress in HBV research. The need to perform studies in HBV-permissive hepatocytes has led researchers to create new, challenging human–mouse chimera infection models. The types of animal models currently available to perform infection studies with HBV are presented and discussed in this review.
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Affiliation(s)
- Maura Dandri
- University Hospital Hamburg, Department of Medicine, University of Hamburg, Eppendorf, Martinistr 52, D-20246 Hamburg, Germany
| | - Tassilo Volz
- University Hospital Hamburg, Department of Medicine, University of Hamburg, Eppendorf, Martinistr 52, D-20246 Hamburg, Germany
| | - Marc Lutgehetmann
- University Hospital Hamburg, Department of Medicine, University of Hamburg, Eppendorf, Martinistr 52, D-20246 Hamburg, Germany
| | - Jorg Petersen
- University Hospital Hamburg, Department of Medicine, University of Hamburg, Eppendorf, Martinistr 52, D-20246 Hamburg, Germany
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24
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Stoeckl L, Funk A, Kopitzki A, Brandenburg B, Oess S, Will H, Sirma H, Hildt E. Identification of a structural motif crucial for infectivity of hepatitis B viruses. Proc Natl Acad Sci U S A 2006; 103:6730-4. [PMID: 16618937 PMCID: PMC1458949 DOI: 10.1073/pnas.0509765103] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Infectious entry of hepatitis B viruses (HBV) has nonconventional facets. Here we analyzed whether a cell-permeable peptide [translocation motif (TLM)] identified within the surface protein of human HBV is a general feature of all hepadnaviruses and plays a role in the viral life cycle. Surface proteins of all hepadnaviruses contain conserved functional TLMs. Genetic inactivation of the duck HBV TLMs does not interfere with viral morphogenesis; however, these mutants are noninfectious. TLM mutant viruses bind to cells and are taken up into the endosomal compartment, but they cannot escape from endosomes. Processing of surface protein by endosomal proteases induces their exposure on the virus surface. This unmasking of TLMs mediates translocation of viral particles across the endosomal membrane into the cytosol, a prerequisite for productive infection. The ability of unmasked TLMs to translocate processed HBV particles across cellular membranes was shown by confocal immunofluorescence microscopy and by infection of nonpermissive cell lines with HBV processed in vitro with endosomal lysate. Based on these data, we propose an infectious entry mechanism unique for hepadnaviruses that involves virus internalization by receptor-mediated endocytosis followed by processing of surface protein in endosomes. This processing activates the function of TLMs that are essential for viral particle translocation through the endosomal membrane into the cytosol and productive infection.
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Affiliation(s)
- Lars Stoeckl
- *Department of Molecular Virology, Robert Koch Institute, D-13353 Berlin, Germany; and
| | - Anneke Funk
- Department of General Virology, Heinrich Pette Institute, D-20251 Hamburg, Germany
| | - Ariane Kopitzki
- *Department of Molecular Virology, Robert Koch Institute, D-13353 Berlin, Germany; and
| | - Boerries Brandenburg
- *Department of Molecular Virology, Robert Koch Institute, D-13353 Berlin, Germany; and
| | - Stefanie Oess
- Institute of Biochemistry, Zentrum der Biologischen Chemie, D-60590 Frankfurt, Germany
| | - Hans Will
- Department of General Virology, Heinrich Pette Institute, D-20251 Hamburg, Germany
| | - Hüseyin Sirma
- Department of General Virology, Heinrich Pette Institute, D-20251 Hamburg, Germany
| | - Eberhard Hildt
- Department of Internal Medicine II, University of Freiburg, Hugstetterstrasse 55, D-79106 Freiburg, Germany
- *Department of Molecular Virology, Robert Koch Institute, D-13353 Berlin, Germany; and
- Institute of Virology, Humboldt University (Charite), D-13353 Berlin, Germany
- **To whom correspondence should be addressed. E-mail:
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25
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Chojnacki J, Anderson DA, Grgacic EVL. A hydrophobic domain in the large envelope protein is essential for fusion of duck hepatitis B virus at the late endosome. J Virol 2006; 79:14945-55. [PMID: 16282493 PMCID: PMC1287569 DOI: 10.1128/jvi.79.23.14945-14955.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The duck hepatitis B virus (DHBV) envelope is comprised of two transmembrane (TM) proteins, the large (L) and the small (S), that assemble into virions and subviral particles. Secondary-structure predictions indicate that L and S have three alpha-helical, membrane-spanning domains, with TM1 predicted to act as the fusion peptide following endocytosis of DHBV into the hepatocyte. We used bafilomycin A1 during infection of primary duck hepatocytes to show that DHBV must be trafficked from the early to the late endosome for fusion to occur. Alanine substitution mutations in TM1 of L and S, which lowered TM1 hydrophobicity, were used to examine the role of TM1 in infectivity. The high hydrophobicity of the TM1 domain of L, but not of S, was shown to be essential for virus infection at a step downstream of receptor binding and virus internalization. Using wild-type and mutant synthetic peptides, we demonstrate that the hydrophobicity of this domain is required for the aggregation and the lipid mixing of phospholipid vesicles, supporting the role of TM1 as the fusion peptide. While lipid mixing occurred at pH 7, the kinetics of insertion of the fusion peptide was increased at pH 5, consistent with the location of DHBV in the late-endosome compartment and previous studies of the nonessential role of low pH for infectivity. Exchange of the TM1 of DHBV with that of hepatitis B virus yielded functional, infectious DHBV particles, suggesting that TM1 of all of the hepadnaviruses act similarly in the fusion mechanism.
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Affiliation(s)
- J Chojnacki
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Australia
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26
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Abstract
Hepatitis B is one of the most prevalent viral diseases in the world. It leads to chronic liver disease in 10% of infected individuals, putting them at an increased risk for liver-related morbidity and mortality from complications of cirrhosis and hepatocellular carcinoma. Despite the success of universal hepatitis B vaccination in many countries, this disease remains a major public health problem, resulting in more than 500,000 deaths per year. Although the current therapy for chronic hepatitis B (CHB) is effective, it is not optimal; novel approaches to the management of CHB are needed. An improved understanding of virus-host interactions, advances in gene therapy, the development of molecular therapies targeted at different stages of the hepatitis B virus life cycle, and new insights into various approaches of immune modulation will lead to the development of better therapeutic agents for the management of CHB. These advances herald a new era of combination therapy. In this review, we will discuss emerging therapies and potential mechanisms, and highlight the promises and pitfalls of these new treatment strategies.
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Affiliation(s)
- Rohit Loomba
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - T Jake Liang
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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27
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Barrera A, Guerra B, Notvall L, Lanford RE. Mapping of the hepatitis B virus pre-S1 domain involved in receptor recognition. J Virol 2005; 79:9786-98. [PMID: 16014940 PMCID: PMC1181564 DOI: 10.1128/jvi.79.15.9786-9798.2005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hepatitis B virus (HBV) and woolly monkey hepatitis B virus (WMHBV) are primate hepadnaviruses that display restricted tissue and host tropisms. Hepatitis D virus (HDV) particles pseudotyped with HBV and WMHBV envelopes (HBV-HDV and WM-HDV) preferentially infect human and spider monkey hepatocytes, respectively, thereby confirming host range bias in vitro. The analysis of chimeric HBV and WMHBV large (L) envelope proteins suggests that the pre-S1 domain may comprise two regions that affect infectivity: one within the amino-terminal 40 amino acids of pre-S1 and one downstream of this region. In the present study, we further characterized the role of the amino terminus of pre-S1 in infectivity by examining the ability of synthetic peptides to competitively block HDV infection of primary human and spider monkey hepatocytes. A synthetic peptide representing the first 45 residues of the pre-S1 domain of the HBV L protein blocked infectivity of HBV-HDV and WM-HDV, with a requirement for myristylation of the amino terminal residue. Competition studies with truncated peptides suggested that pre-S1 residues 5 to 20 represent the minimal domain for inhibition of HDV infection and, thus, presumably represent the residues involved in virus-host receptor interaction. Recombinant pre-S1 proteins expressed in insect cells blocked infection with HBV-HDV and WM-HDV at a concentration of 1 nanomolar. The ability of short pre-S1 peptides to efficiently inhibit HDV infection suggests that they represent suitable ligands for identification of the HBV receptor and that a pre-S1 mimetic may represent a rational therapy for the treatment of HBV infection.
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Affiliation(s)
- Azeneth Barrera
- Department of Virology and Immunology, Southwest National Primate Research Center, Southwest Foundation for Biomedical Research, TX 78227, USA
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28
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Guo H, Mason WS, Aldrich CE, Saputelli JR, Miller DS, Jilbert AR, Newbold JE. Identification and characterization of avihepadnaviruses isolated from exotic anseriformes maintained in captivity. J Virol 2005; 79:2729-42. [PMID: 15708992 PMCID: PMC548436 DOI: 10.1128/jvi.79.5.2729-2742.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Five new hepadnaviruses were cloned from exotic ducks and geese, including the Chiloe wigeon, mandarin duck, puna teal, Orinoco sheldgoose, and ashy-headed sheldgoose. Sequence comparisons revealed that all but the mandarin duck viruses were closely related to existing isolates of duck hepatitis B virus (DHBV), while mandarin duck virus clones were closely related to Ross goose hepatitis B virus. Nonetheless, the S protein, core protein, and functional domains of the Pol protein were highly conserved in all of the new isolates. The Chiloe wigeon and puna teal hepatitis B viruses, the two new isolates most closely related to DHBV, also lacked an AUG start codon at the beginning of their X open reading frame (ORF). But as previously reported for the heron, Ross goose, and stork hepatitis B viruses, an AUG codon was found near the beginning of the X ORF of the mandarin duck, Orinoco, and ashy-headed sheldgoose viruses. In all of the new isolates, the X ORF ended with a stop codon at the same position. All of the cloned viruses replicated when transfected into the LMH line of chicken hepatoma cells. Significant differences between the new isolates and between these and previously reported isolates were detected in the pre-S domain of the viral envelope protein, which is believed to determine viral host range. Despite this, all of the new isolates were infectious for primary cultures of Pekin duck hepatocytes, and infectivity in young Pekin ducks was demonstrated for all but the ashy-headed sheldgoose isolate.
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Affiliation(s)
- Haitao Guo
- Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19111, USA
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29
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Lambert C, Thomé N, Kluck CJ, Prange R. Functional incorporation of green fluorescent protein into hepatitis B virus envelope particles. Virology 2005; 330:158-67. [PMID: 15527842 PMCID: PMC7111749 DOI: 10.1016/j.virol.2004.09.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 08/13/2004] [Accepted: 09/20/2004] [Indexed: 12/22/2022]
Abstract
The envelope of hepatitis B virus (HBV), containing the L, M, and S proteins, is essential for virus entry and maturation. For direct visualization of HBV, we determined whether envelope assembly could accommodate the green fluorescent protein (GFP). While the C-terminal addition of GFP to S trans-dominant negatively inhibited empty envelope particle secretion, the N-terminal GFP fusion to S (GFP.S) was co-integrated into the envelope, giving rise to fluorescent particles. Microscopy and topogenesis analyses demonstrated that the proper intracellular distribution and folding of GFP.S, required for particle export were rescued by interprotein interactions with wild-type S. Thereby, a dual location of GFP, inside and outside the envelope, was observed. GFP.S was also efficiently packaged into the viral envelope, and these GFP-tagged virions retained the capacity for attachment to HBV receptor-positive cells in vitro. Together, GFP-tagged virions should be suitable to monitor HBV uptake and egress in live hepatocytes.
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Affiliation(s)
- Carsten Lambert
- Department of Medical Microbiology and Hygiene, University of Mainz, D-55101 Mainz, Germany
| | - Nicole Thomé
- Department of Medical Microbiology and Hygiene, University of Mainz, D-55101 Mainz, Germany
| | - Christoph J. Kluck
- Biochemistry Center, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Reinhild Prange
- Department of Medical Microbiology and Hygiene, University of Mainz, D-55101 Mainz, Germany
- Corresponding author. Mailing address: Institute for Medical Microbiology and Hygiene, University of Mainz, Augustusplatz, D-55101 Mainz, Germany. Fax: +49 6131 3932359.
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30
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Schultz U, Grgacic E, Nassal M. Duck hepatitis B virus: an invaluable model system for HBV infection. Adv Virus Res 2005; 63:1-70. [PMID: 15530560 DOI: 10.1016/s0065-3527(04)63001-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ursula Schultz
- Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, D-79106 Freiburg, Germany
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31
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Funk A, Mhamdi M, Lin L, Will H, Sirma H. Itinerary of hepatitis B viruses: delineation of restriction points critical for infectious entry. J Virol 2004; 78:8289-300. [PMID: 15254201 PMCID: PMC446123 DOI: 10.1128/jvi.78.15.8289-8300.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Little is known about cellular determinants essential for human hepatitis B virus infection. Using the duck hepatitis B virus as a model, we first established a sensitive binding assay for both virions and subviral particles and subsequently elucidated the characteristics of the early viral entry steps. The infection itinerary was found to initiate with the attachment of viral particles to a low number of binding sites on hepatocytes (about 10(4) per cell). Virus internalization was fully accomplished in less than 3 h but was then followed by a period of unprecedented length, about 14 h, until completion of nuclear import of the viral genome. Steps subsequent to virus entry depended on both intact microtubules and their dynamic turnover but not on actin cytoskeleton. Notably, cytoplasmic trafficking of viral particles and emergence of nuclear covalently closed circular DNA requires microtubules during entry only at and for specific time periods. Taken together, these data disclose for the first time a series of steps and their kinetics that are essential for the entry of hepatitis B viruses into hepatocytes and are different from those of any other virus reported so far.
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Affiliation(s)
- Anneke Funk
- Department of General Virology, Heinrich-Pette-Institut, Hamburg, Germany
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32
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Walters KA, Joyce MA, Addison WR, Fischer KP, Tyrrell DLJ. Superinfection exclusion in duck hepatitis B virus infection is mediated by the large surface antigen. J Virol 2004; 78:7925-37. [PMID: 15254165 PMCID: PMC446106 DOI: 10.1128/jvi.78.15.7925-7937.2004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 03/19/2004] [Indexed: 12/17/2022] Open
Abstract
Superinfection exclusion is the phenomenon whereby a virus prevents the subsequent infection of an already infected host cell. The Pekin duck hepatitis B virus (DHBV) model was used to investigate superinfection exclusion in hepadnavirus infections. Superinfection exclusion was shown to occur both in vivo and in vitro with a genetically marked DHBV, DHBV-ClaI, which was unable to establish an infection in either DHBV-infected ducklings or DHBV-infected primary duck hepatocytes (PDHs). In addition, exclusion occurred in vivo even when the second virus had a replicative advantage. Superinfection exclusion appears to be restricted to DHBV, as adenovirus, herpes simplex virus type 1, and vesicular stomatitis virus were all capable of efficiently infecting DHBV-infected PDHs. Exclusion was dependent on gene expression by the original infecting virus, since UV-irradiated DHBV was unable to mediate the exclusion of DHBV-ClaI. Using recombinant adenoviruses expressing DHBV proteins, we determined that the large surface antigen mediated exclusion. The large surface antigen is known to cause down-regulation of a DHBV receptor, carboxypeptidase D (CPD). Receptor down-regulation is a mechanism of superinfection exclusion seen in other viral infections, and so it was investigated as a possible mechanism of DHBV-mediated exclusion. However, a mutant large surface antigen which did not down-regulate CPD was still capable of inhibiting DHBV infection of PDHs. In addition, exclusion of DHBV-ClaI did not correlate with a decrease in CPD levels. Finally, virus binding assays and confocal microscopy analysis of infected PDHs indicated that the block in infection occurs after internalization of the second virus. We suggest that superinfection exclusion may result from the role of the L surface antigen as a regulator of intracellular trafficking.
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Affiliation(s)
- Kathie-Anne Walters
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
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33
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Barrera A, Guerra B, Lee H, Lanford RE. Analysis of host range phenotypes of primate hepadnaviruses by in vitro infections of hepatitis D virus pseudotypes. J Virol 2004; 78:5233-43. [PMID: 15113905 PMCID: PMC400381 DOI: 10.1128/jvi.78.10.5233-5243.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Hepatitis B virus (HBV) and woolly monkey hepatitis B virus (WMHBV) have natural host ranges that are limited to closely related species. The barrier for infection of primates seems to be at the adsorption and/or entry steps of the viral replication cycle, since a human hepatoma cell line is permissive for HBV and WMHBV replication following transfection of cloned DNA. We hypothesized that the HBV and WMHBV envelope proteins contain the principal viral determinants of host range. As previously shown by using the hepatitis D virus (HDV) system, recombinant HBV-HDV particles were infectious in chimpanzee as well as human hepatocytes. We extended the HDV system to include HDV particles pseudotyped with the WMHBV envelope. In agreement with the natural host ranges of HBV and WMHBV, in vitro infections demonstrated that HBV-HDV and WM-HDV particles preferentially infected human and spider monkey cells, respectively. Previous studies have implicated the pre-S1 region of the large (L) envelope protein in receptor binding and host range; therefore, recombinant HDV particles were pseudotyped with the hepadnaviral envelopes containing chimeric L proteins with the first 40 amino acids from the pre-S1 domain exchanged between HBV and WMHBV. Surprisingly, addition of the human amino terminus to the WMHBV L protein increased infectivity on spider monkey hepatocytes but did not increase infectivity for human hepatocytes. Based upon these data, we discuss the possibility that the L protein may be comprised of two domains that affect infectivity and that sequences downstream of residue 40 may influence host range and receptor binding or entry.
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Affiliation(s)
- Azeneth Barrera
- Department of Virology and Immunology, Southwest National Primate Research Center, Southwest Foundation for Biomedical Research, 7620 NW Loop 410, San Antonio, TX 78227, USA
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34
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Li J, Tong S, Lee HB, Perdigoto AL, Spangenberg HC, Wands JR. Glycine decarboxylase mediates a postbinding step in duck hepatitis B virus infection. J Virol 2004; 78:1873-81. [PMID: 14747552 PMCID: PMC369508 DOI: 10.1128/jvi.78.4.1873-1881.2004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Envelope protein precursors of many viruses are processed by a basic endopeptidase to generate two molecules, one for receptor binding and the other for membrane fusion. Such a cleavage event has not been demonstrated for the hepatitis B virus family. Two binding partners for duck hepatitis B virus (DHBV) pre-S envelope protein have been identified. Duck carboxypeptidase D (DCPD) interacts with the full-length pre-S protein and is the DHBV docking receptor, while duck glycine decarboxylase (DGD) has the potential to bind several deletion constructs of the pre-S protein in vitro. Interestingly, DGD but not DCPD expression was diminished following prolonged culture of primary duck hepatocytes (PDH), which impaired productive DHBV infection. Introduction of exogenous DGD promoted formation of protein-free viral genome, suggesting restoration of several early events in viral life cycle. Conversely, blocking DGD expression in fresh PDH by antisense RNA abolished DHBV infection. Moreover, addition of DGD antibodies soon after virus binding reduced endogenous DGD protein levels and impaired production of covalently closed circular DNA, the template for DHBV gene expression and genome replication. Our findings implicate this second pre-S binding protein as a critical cellular factor for productive DHBV infection. We hypothesize that DCPD, a molecule cycling between the cell surface and the trans-Golgi network, targets DHBV particles to the secretary pathway for proteolytic cleavage of viral envelope protein. DGD represents the functional equivalent of other virus receptors in its interaction with processed viral particles.
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Affiliation(s)
- Jisu Li
- The Liver Research Center, Rhode Island Hospital and Brown Medical School, Providence, Rhode Island 02903, USA.
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35
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Baranowski E, Ruiz-Jarabo CM, Pariente N, Verdaguer N, Domingo E. Evolution of cell recognition by viruses: a source of biological novelty with medical implications. Adv Virus Res 2004; 62:19-111. [PMID: 14719364 PMCID: PMC7119103 DOI: 10.1016/s0065-3527(03)62002-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The picture beginning to form from genome analyses of viruses, unicellular organisms, and multicellular organisms is that viruses have shared functional modules with cells. A process of coevolution has probably involved exchanges of genetic information between cells and viruses for long evolutionary periods. From this point of view present-day viruses show flexibility in receptor usage and a capacity to alter through mutation their receptor recognition specificity. It is possible that for the complex DNA viruses, due to a likely limited tolerance to generalized high mutation rates, modifications in receptor specificity will be less frequent than for RNA viruses, albeit with similar biological consequences once they occur. It is found that different receptors, or allelic forms of one receptor, may be used with different efficiency and receptor affinities are probably modified by mutation and selection. Receptor abundance and its affinity for a virus may modulate not only the efficiency of infection, but also the capacity of the virus to diffuse toward other sites of the organism. The chapter concludes that receptors may be shared by different, unrelated viruses and that one virus may use several receptors and may expand its receptor specificity in ways that, at present, are largely unpredictable.
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Affiliation(s)
- Eric Baranowski
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain
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36
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Cooper A, Paran N, Shaul Y. The earliest steps in hepatitis B virus infection. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1614:89-96. [PMID: 12873769 DOI: 10.1016/s0005-2736(03)00166-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The early steps in hepatitis B virus (HBV) infection, a human hepadnavirus, initiates from cell attachment followed by entry and delivery of the genetic information to the nucleus. Despite the fact that these steps determine the virus-related pathogenesis, their molecular basis is poorly understood. Cumulative data suggest that this process can be divided to cell attachment, endocytosis, membrane fusion and post-fusion consecutive steps. These steps are likely to be regulated by the viral envelope proteins and by the cellular membrane, receptors and extracellular matrix. In the absence of animal model for HBV, the duck hepadnavirus DHBV turned out to be a fruitful animal model. Therefore data concerning the early, post-attachment steps in hepadnaviral entry are largely based on studies performed with DHBV in primary duck liver hepatocytes. These studies are now starting to illuminate the mechanisms of hepadnavirus route of cell entry and to provide some new insights on the molecular basis of the strict species specificity of hepadnavirus infection.
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Affiliation(s)
- Arik Cooper
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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37
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Bilello JP, Cable EE, Myers RL, Isom HC. Role of paracellular junction complexes in baculovirus-mediated gene transfer to nondividing rat hepatocytes. Gene Ther 2003; 10:733-49. [PMID: 12704412 DOI: 10.1038/sj.gt.3301937] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gene delivery to differentiated hepatocytes is notoriously difficult. Hepatocytes plated on collagen-coated dishes and maintained in dimethyl sulfoxide (DMSO)-supplemented medium acquire paracellular junctions, arrange themselves in multicellular islands and are an excellent in vitro model for studying liver function. Baculovirus-mediated gene delivery to hepatocytes in this culture system is restricted to peripheral cells of the islands. However, this limitation can be overcome by transient calcium depletion of the cells prior to and during baculovirus infection. Examination of the mechanism underlying this process revealed that calcium depletion was accompanied by a transient loss of intercellular contacts and paracellular junction complex integrity, increased distance between adjoining cells, and internalization of the tight junction protein, zona occludens ZO-1. Internalization of ZO-1 was accompanied by baculovirus infection of internal cells of hepatocyte islands. When calcium levels were restored, paracellular junction complex integrity returned to normal by 12 h. No permanent alterations in hepatocyte ultrastructure and albumin mRNA, and protein expression were caused by this gene transfer method. Loss in paracellular junction complex integrity exposes the basolateral (sinusoidal) surface of hepatocytes resulting in homogeneous baculovirus-mediated gene delivery to approximately 75% of the cells in long-term DMSO culture. We conclude that the use of recombinant baculovirus as a vector in combination with transient calcium depletion is a highly efficient method for delivering exogenous genes to hepatocytes without loss of hepatic differentiation.
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Affiliation(s)
- J P Bilello
- Department of Microbiology and Immunology, Milton S. Hersey Medical Center, The Penn State College of Medicine, Hershey, PA 17033, USA
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38
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Abstract
Virus infection is initiated by recognition and attachment of the virus to the cell surface. Despite the fact that this interaction determines the virus-related pathogenesis, its molecular basis remained obscure for HBV. This process is mediated primarily by the viral envelope and the cellular receptors. HBV infection is not exceptional in this regard but its putative receptors have not been identified yet. The recent development of protocols to establish HBV susceptible cell lines and unique tools to measure HBV-cell attachment at a single cell resolution set the stage for the study of HBV-host cell interaction. These studies revealed that the QLDPAF epitope of the HBV surface antigen large protein (LHBsAg) plays a major role in this process. Quantitative measurements suggested the presence of a second player in this process and both act synergistically to improve cell attachment. As the step of virus-cell attachment is potentially susceptible to specific inhibitors, understanding the molecular basis of virus-cell attachment can be expected to have therapeutic impacts.
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Affiliation(s)
- Nir Paran
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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39
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Prassolov A, Hohenberg H, Kalinina T, Schneider C, Cova L, Krone O, Frölich K, Will H, Sirma H. New hepatitis B virus of cranes that has an unexpected broad host range. J Virol 2003; 77:1964-76. [PMID: 12525630 PMCID: PMC140978 DOI: 10.1128/jvi.77.3.1964-1976.2003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
All hepadnaviruses known so far have a very limited host range, restricted to their natural hosts and a few closely related species. This is thought to be due mainly to sequence divergence in the large envelope protein and species-specific differences in host components essential for virus propagation. Here we report an infection of cranes with a novel hepadnavirus, designated CHBV, that has an unexpectedly broad host range and is only distantly evolutionarily related to avihepadnaviruses of related hosts. Direct DNA sequencing of amplified CHBV DNA as well a sequencing of cloned viral genomes revealed that CHBV is most closely related to, although distinct from, Ross' goose hepatitis B virus (RGHBV) and slightly less closely related to duck hepatitis B virus (DHBV). Phylogenetically, cranes are very distant from geese and ducks and are most closely related to herons and storks. Naturally occurring hepadnaviruses in the last two species are highly divergent in sequence from RGHBV and DHBV and do not infect ducks or do so only marginally. In contrast, CHBV from crane sera and recombinant CHBV produced from LMH cells infected primary duck hepatocytes almost as efficiently as DHBV did. This is the first report of a rather broad host range of an avihepadnavirus. Our data imply either usage of similar or identical entry pathways and receptors by DHBV and CHBV, unusual host and virus adaptation mechanisms, or divergent evolution of the host genomes and cellular components required for virus propagation.
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Affiliation(s)
- Alexej Prassolov
- Heinrich Pette Institute of Experimental Virology and Immunology, Hamburg. Institute of Zoo and Wildlife Research, Berlin, Germany
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40
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Urban S, Gripon P. Inhibition of duck hepatitis B virus infection by a myristoylated pre-S peptide of the large viral surface protein. J Virol 2002; 76:1986-90. [PMID: 11799193 PMCID: PMC135925 DOI: 10.1128/jvi.76.4.1986-1990.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We have used the duck hepatitis B virus (DHBV) model to study the interference with infection by a myristoylated peptide representing an N-terminal pre-S subdomain of the large viral envelope protein. Although lacking the essential part of the carboxypeptidase D (formerly called gp180) receptor binding site, the peptide binds hepatocytes and subsequently blocks DHBV infection. Since its activity requires an amino acid sequence involved in host discrimination between DHBV and the related heron HBV (T. Ishikawa and D. Ganem, Proc. Natl. Acad. Sci. USA 92:6259-6263, 1995), we suggest that it is related to the postulated host-discriminating cofactor of infection.
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Affiliation(s)
- Stephan Urban
- Zentrum für Molekulare Biologie, Universität Heidelberg (ZMBH), 69120 Heidelberg, Germany.
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41
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Spangenberg HC, Lee HB, Li J, Tan F, Skidgel R, Wands JR, Tong S. A short sequence within domain C of duck carboxypeptidase D is critical for duck hepatitis B virus binding and determines host specificity. J Virol 2001; 75:10630-42. [PMID: 11602705 PMCID: PMC114645 DOI: 10.1128/jvi.75.22.10630-10642.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Virus-cell surface receptor interactions are of major interest. Hepadnaviruses are a family of partially double-stranded DNA viruses with liver tropism and a narrow host range of susceptibility to infection. At least in the case of duck hepatitis B virus (DHBV), host specificity seems controlled partly at the receptor level. The middle portion in the pre-S region of the viral large envelope protein binds specifically to duck carboxypeptidase D (DCPD) but not to its human or chicken homologue. Although domain C of DCPD is implicated in ligand binding, the exact pre-S contact site remains to be determined. We prepared and tested a panel of chimeric constructs consisting of DCPD and human carboxypeptidase D (HCPD). Our results indicate that a short region at the N terminus of domain C (residues 920 to 949) is critical to DHBV binding and is a major determinant for the host specificity of DHBV infection. Replacing this region of the DCPD molecule with its human homologue abolished the DHBV interaction, whereas introducing this DCPD sequence into HCPD conferred efficient DHBV binding. Extensive analysis of site-directed mutants revealed that both conserved and nonconserved residues were important for the pre-S interaction. There were primary sequence variations and secondary structural differences that contributed to the inability of HCPD to bind the DHBV pre-S domain.
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Affiliation(s)
- H C Spangenberg
- Liver Research Center, Rhode Island Hospital and Brown University School of Medicine, Providence, Rhode Island 02903, USA
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42
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Bilello JP, Delaney WE, Boyce FM, Isom HC. Transient disruption of intercellular junctions enables baculovirus entry into nondividing hepatocytes. J Virol 2001; 75:9857-71. [PMID: 11559819 PMCID: PMC114558 DOI: 10.1128/jvi.75.20.9857-9871.2001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2001] [Accepted: 07/09/2001] [Indexed: 01/17/2023] Open
Abstract
Baculovirus infection has extended the capabilities for transfection of exogenous genes into a variety of mammalian cell types. Because rat hepatocytes plated on collagen-coated dishes and maintained in dimethyl sulfoxide (DMSO)-supplemented chemically defined medium are an excellent model system for studying liver function in vitro, we investigated the ability of baculoviruses to infect and deliver exogenous genes to cells in this culture system. Efficient delivery to hepatocytes in short-term culture becomes restricted to peripheral cells, or "edge" cells, as the hepatocytes acquire intercellular junctions and form islands with time in culture. This barrier to baculovirus entry can be overcome, and the percentage of internal cells within the hepatocyte islands that are infected with the baculovirus can be increased more than 100-fold, when cells are subjected to transient calcium depletion before and during infection. These findings suggest that at least in some cell types, such as hepatocytes, baculovirus entry may require contact with the basolateral surface. We conclude from this study that recombinant baculovirus infection following transient depletion of extracellular calcium results in delivery of exogenous genes to at least 75% of hepatocytes in long-term DMSO culture, thereby making it possible for the first time to carry out gain-of-function and loss-of-function studies in this cell system.
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Affiliation(s)
- J P Bilello
- Department of Microbiology and Immunology, Milton S. Hershey Medical Center, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033, USA
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43
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De Falco S, Ruvoletto MG, Verdoliva A, Ruvo M, Raucci A, Marino M, Senatore S, Cassani G, Alberti A, Pontisso P, Fassina G. Cloning and expression of a novel hepatitis B virus-binding protein from HepG2 cells. J Biol Chem 2001; 276:36613-23. [PMID: 11389143 DOI: 10.1074/jbc.m102377200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A direct involvement of the hepatitis B virus (HBV) preS1-(21-47) sequence in virus attachment to cell membrane receptor(s) and the presence on the plasma membranes of HepG2 cells of protein(s) with receptor activity for HBV have been suggested by many previous experiments. In this study, by using a tetravalent derivative of the preS1-(21-47) sequence, we have isolated by affinity chromatography from detergent-solubilized HepG2 plasma membranes a 44-kDa protein (HBV-binding protein; HBV-BP), which was found to closely correspond to the human squamous cell carcinoma antigen 1 (SCCA1), a member of the ovalbumin family of serine protease inhibitors. Comparison of SCCA1 sequence with the sequence of the corresponding HBV-BP cDNA, cloned by polymerase chain reaction starting from RNA poly(A)(+) fractions extracted from HepG2 cells, indicated the presence of only four nucleotide substitutions in the coding region, leading to three amino acid changes. Intact recombinant HBV-BP lacked inhibitory activity for serine proteases such as alpha-chymotrypsin and trypsin but inhibited with high potency cysteine proteases such as papain and cathepsin L. Direct binding experiments confirmed the interaction of recombinant HBV-BP with the HBV preS1 domain. HepG2 cells overexpressing HBV-BP after transfection of corresponding cDNA showed a virus binding capacity increased by 2 orders of magnitude compared with untransfected cells, while Chinese hamster ovary cells, which normally do not bind to HBV, acquired susceptibility to HBV binding after transfection. Native HBV particle entry was enhanced in transfected cells. Both recombinant HBV-BP and antibodies to recombinant HBV-BP blocked virus binding and internalization in transfected cells as well as in primary human hepatocytes in a dose-dependent manner. Our findings suggest that this protein plays a major role in HBV infection.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Neoplasm/chemistry
- Base Sequence
- Binding, Competitive
- CHO Cells
- Cathepsin L
- Cathepsins/antagonists & inhibitors
- Cell Line
- Cell Membrane/chemistry
- Cells, Cultured
- Chromatography
- Chymotrypsin/metabolism
- Cloning, Molecular
- Cricetinae
- Cysteine Endopeptidases
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Hepatitis B virus/metabolism
- Hepatocytes/metabolism
- Humans
- Kinetics
- Molecular Sequence Data
- Papain/antagonists & inhibitors
- Poly A/metabolism
- Protease Inhibitors
- Protein Binding
- Protein Structure, Tertiary
- Rats
- Receptors, Virus/biosynthesis
- Receptors, Virus/chemistry
- Receptors, Virus/metabolism
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Serpins
- Time Factors
- Transfection
- Trypsin/metabolism
- Tumor Cells, Cultured
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Affiliation(s)
- S De Falco
- TECNOGEN S.C.p.A., Parco Scientifico, 81015 Piana di Monte Verna (CE), Caserta 81015, Italy
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44
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Paran N, Geiger B, Shaul Y. HBV infection of cell culture: evidence for multivalent and cooperative attachment. EMBO J 2001; 20:4443-53. [PMID: 11500372 PMCID: PMC125578 DOI: 10.1093/emboj/20.16.4443] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hepadnaviruses do not infect cultured cells, therefore our knowledge of the mechanism of the early stages of virus-cell interaction is rather poor. In this study, we show that dimethylsulfoxide (DMSO)-treated HepG2 hepatoblastoma cells are infected efficiently by serum-derived hepatitis B virus (HBV) as monitored by viral gene expression and replication markers. To measure virus attachment, a variety of HBV surface proteins (HBsAgs) were conjugated to polystyrene beads and their capacity to attach cells was visualized and quantified by light microscopy at a single-cell resolution. Remarkably, DMSO increases the attachment efficiency by >200-fold. We further identify the QLDPAF sequence within preS1 as the receptor-binding viral domain epitope. Interestingly, a similar sequence is shared by several cellular, bacterial and viral proteins involved in cell adhesion, attachment and fusion. We also found that the small HBsAg contains a secondary attachment site that recognizes a distinct receptor on the cell membrane. Furthermore, we provide evidence in support of multivalent HBV attachment with synergistic interplay. Our data depict a mechanistic view of virus attachment and ingestion.
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Affiliation(s)
- Nir Paran
- Departments of
Molecular Genetics and Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel Corresponding author e-mail:
| | - Benjamin Geiger
- Departments of
Molecular Genetics and Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel Corresponding author e-mail:
| | - Yosef Shaul
- Departments of
Molecular Genetics and Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel Corresponding author e-mail:
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45
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Doo E, Liang TJ. Molecular anatomy and pathophysiologic implications of drug resistance in hepatitis B virus infection. Gastroenterology 2001; 120:1000-8. [PMID: 11231955 DOI: 10.1053/gast.2001.22454] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Synthesis of the hepatitis B virus (HBV) DNA genome occurs within the viral nucleocapsid in a mechanistically ordered fashion. The nucleocapsid contains small pores that permit influx of nucleotide triphosphates and metabolites of nucleoside analogues such as lamivudine for DNA synthesis. Lamivudine is a potent inhibitor of HBV and human immunodeficiency virus (HIV) reverse transcriptases, but substitutions of isoleucine or valine for methionine within the tyrosine-methionine-aspartate-aspartate (YMDD) motif are associated with virologic and clinical resistance to lamivudine therapy. Under lamivudine selection pressure, the high viral production rate and the low fidelity viral polymerase contribute to frequent development of the YMDD mutants. However, the pattern and dynamics of emergence of the mutant viruses over the wild-type virus are determined by multiple factors including replication efficiency, host immune response, and availability of replication space. Structural modeling of HIV reverse transcriptase has permitted key insights into the molecular basis of lamivudine resistance of HBV based on evolutionary relatedness of HIV and HBV. The side groups of isoleucine and valine of the YMDD mutants sterically prevent lamivudine from appropriately configuring into the nucleotide binding site of the reverse transcriptase. Aminotransferase flares are associated with lamivudine therapy and may signify clinical resistance with emergence of YMDD mutants. They may also herald the recovery phase with seroconversion and viral clearance. Reconstitution of the endogenous anti-HBV immune response may be equally important in the control of viral replication by lamivudine and other nucleoside analogues.
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Affiliation(s)
- E Doo
- Liver Diseases Section, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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46
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Ren S, Nassal M. Hepatitis B virus (HBV) virion and covalently closed circular DNA formation in primary tupaia hepatocytes and human hepatoma cell lines upon HBV genome transduction with replication-defective adenovirus vectors. J Virol 2001; 75:1104-16. [PMID: 11152483 PMCID: PMC114016 DOI: 10.1128/jvi.75.3.1104-1116.2001] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV), the causative agent of B-type hepatitis in humans, is a hepatotropic DNA-containing virus that replicates via reverse transcription. Because of its narrow host range, there is as yet no practical small-animal system for HBV infection. The hosts of the few related animal viruses, including woodchuck hepatitis B virus and duck hepatitis B virus, are either difficult to keep or only distantly related to humans. Some evidence suggests that tree shrews (tupaias) may be susceptible to infection with human HBV, albeit with low efficiency. Infection efficiency depends on interactions of the virus with factors on the surface and inside the host cell. To bypass restrictions during the initial entry phase, we used recombinant replication-defective adenovirus vectors, either with or without a green fluorescent protein marker gene, to deliver complete HBV genomes into primary tupaia hepatocytes. Here we show that these cells, like the human hepatoma cell lines HepG2 and Huh7, are efficiently transduced by the vectors and produce all HBV gene products required to generate the secretory antigens HBsAg and HBeAg, replication-competent nucleocapsids, and enveloped virions. We further demonstrate that covalently closed circular HBV DNA is formed. Therefore, primary tupaia hepatocytes support all steps of HBV replication following deposition of the genome in the nucleus, including the intracellular amplification cycle. These data provide a rational basis for in vivo experiments aimed at developing tupaias into a useful experimental animal system for HBV infection.
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Affiliation(s)
- S Ren
- Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, D-79106 Freiburg, Germany
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47
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Núñez E, Wei X, Delgado C, Rodríguez-Crespo I, Yélamos B, Gómez-Gutiérrez J, Peterson DL, Gavilanes F. Cloning, expression, and purification of histidine-tagged preS domains of hepatitis B virus. Protein Expr Purif 2001; 21:183-91. [PMID: 11162405 DOI: 10.1006/prep.2000.1368] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The preS domains of the hepatitis B virus are hydrophilic polypeptides that have been implicated, among other functions, in the binding of the virus to hepatocytes and in the induction of virus-neutralizing antibodies. A method of overproducing the preS domains of two different subtypes, adw and ayw, has been developed by adding a 6x His tag at the carboxy-terminal end of the polypeptides. Codons for the 6x His were added in reverse primers used to amplify the corresponding cDNAs. The polymerase chain reaction products were cloned into the expression vectors pET-3d (subtype ayw) and pT7-7 (subtype adw), under the control of the inducible bacteriophage T7 RNA polymerase promoter. Upon induction with isopropyl-beta-d-thiogalactopyranoside, proteins were overexpressed and purified by affinity chromatography on a Ni-nitrilotriacetic acid agarose column. This method yielded 20-40 mg of highly pure and very stable proteins per liter of cell culture. Circular dichroism and fluorescence spectroscopy of isolated preS-his-ayw and preS-his-adw, as well as their ability to bind polymerized human serum albumin, indicate that the 6x His tag does not modify the native-like conformation and, therefore, they may be considered as useful tools to study the function of these viral polypeptide regions.
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Affiliation(s)
- E Núñez
- Departamento de Bioquímica y Biología Molecular, Universidad Complutense, 28040 Madrid, Spain
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48
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Breiner KM, Urban S, Glass B, Schaller H. Envelope protein-mediated down-regulation of hepatitis B virus receptor in infected hepatocytes. J Virol 2001; 75:143-50. [PMID: 11119583 PMCID: PMC113907 DOI: 10.1128/jvi.75.1.143-150.2001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Entry of duck hepatitis B virus (DHBV) is initiated by specific interaction of its large envelope protein (L) with a cellular entry receptor, recently identified as carboxypeptidase D (CPD; historically gp180). In this report, we present evidence demonstrating that this receptor is down-regulated as a result of DHBV infection: (i) receptor levels determined by Western blot were much reduced in DHBV-infected duck livers and undetectable by immunostaining in infected cultured hepatocytes; (ii) results from metabolic labeling experiments indicate enhanced receptor protein turnover; (iii) the kinetics of receptor loss from newly infected cells correlated with the accumulation of newly synthesized viral protein; (iv) expression of DHBV L protein, transduced from a recombinant adenovirus, was sufficient to eliminate gp180/CPD from the Golgi compartment, its normal predominant location; (v) gp180/CPD remained absent from the Golgi compartment in infected hepatocytes, even after overexpression from a recombinant adenovirus, while residual amounts subsequently became detectable in a perinuclear compartment, containing DHBV L protein; (vi) expression of DHBV L protein in a HepG2 cell line, stably expressing gp180/CPD, leads to incomplete receptor maturation and induces its degradation. Taken together, these data are consistent with a model in which the virus receptor interacts early in the biosynthetic pathway with the viral L protein, leading to its retention in a pre-Golgi compartment and to subsequent degradation, thus preventing receptor interference with the export of DHBV via the secretory pathway which it shares with its receptor. Accordingly, and analogously with receptor down-regulation in retroviral systems, DHBV receptor down-modulation may account for the much-reduced efficiency of DHBV superinfection of preinfected hepatocytes.
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Affiliation(s)
- K M Breiner
- Mikrobiologie and Zentrum für Molekulare Biologie, Universität Heidelberg, 69120 Heidelberg, Germany
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Grgacic EV, Schaller H. A metastable form of the large envelope protein of duck hepatitis B virus: low-pH release results in a transition to a hydrophobic, potentially fusogenic conformation. J Virol 2000; 74:5116-22. [PMID: 10799586 PMCID: PMC110864 DOI: 10.1128/jvi.74.11.5116-5122.2000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have examined the structure and fusion potential of the duck hepatitis B virus (DHBV) envelope proteins by treating subviral particles with deforming agents known to release envelope proteins of viruses from a metastable to a fusion-active state. Exposure of DHBV particles to low pH triggered a major structural change in the large envelope protein (L), resulting in exposure of trypsin sites within its S domain but without affecting the same region in the small surface protein (S) subunits. This conformational change was associated with increased hydrophobicity of the particle surface, most likely arising from surface exposure of the hydrophobic first transmembrane domain (TM1). In the hydrophobic conformation, DHBV particles were able to bind to liposomes and intact cells, while in their absence these particles aggregated, resulting in viral inactivation. These results suggests that some L molecules are in a spring-loaded metastable state which, when released, exposes a previously hidden hydrophobic domain, a transition potentially representing the fusion-active state of the envelope.
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Affiliation(s)
- E V Grgacic
- Macfarlane Burnet Centre for Medical Research and Australian Centre for Hepatitis Virology, Fairfield 3078, Victoria, Australia.
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Affiliation(s)
- J Schneider-Schaulies
- Institut für Virologie und Immunbiologie, Universität Würzburg, Verbacher Str. 7, 97078 Würzburg, Germany.
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