51
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Peters MG, Locarnini S. New Direct-Acting Antiviral Agents and Immunomodulators for Hepatitis B Virus Infection. Gastroenterol Hepatol (N Y) 2017; 13:348-356. [PMID: 28690451 PMCID: PMC5495044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chronic hepatitis B (CHB) affects over 350 million individuals worldwide and is the most common cause of liver cancer. In the United States, CHB affects at least 2 to 3 million individuals, and current therapies can control the disease but not cure it. There are over 30 new molecules being studied in CHB in preclinical to phase 2 studies, targeting specific parts of the hepatitis B virus (HBV) life cycle and the host immune response. When discussing new therapies for CHB, it is critical to understand both the various phases of CHB and the life cycle of HBV. This article will discuss both of these issues, as well as mechanisms of action of potential therapies and possible ways to combine such therapies in the various phases of CHB.
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Affiliation(s)
- Marion G Peters
- Dr Peters is a professor of medicine and chief of hepatology research in the Department of Medicine at the University of California in San Francisco, California. Dr Locarnini is a professor of microbiology and immunology at the University of Melbourne and is director of the WHO Regional Reference Laboratory for Hepatitis B within the Victorian Infectious Diseases Reference Laboratory at the Doherty Institute in Melbourne, Australia
| | - Stephen Locarnini
- Dr Peters is a professor of medicine and chief of hepatology research in the Department of Medicine at the University of California in San Francisco, California. Dr Locarnini is a professor of microbiology and immunology at the University of Melbourne and is director of the WHO Regional Reference Laboratory for Hepatitis B within the Victorian Infectious Diseases Reference Laboratory at the Doherty Institute in Melbourne, Australia
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52
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Zahur M, Tolö J, Bähr M, Kügler S. Long-Term Assessment of AAV-Mediated Zinc Finger Nuclease Expression in the Mouse Brain. Front Mol Neurosci 2017; 10:142. [PMID: 28588449 PMCID: PMC5440507 DOI: 10.3389/fnmol.2017.00142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/25/2017] [Indexed: 12/24/2022] Open
Abstract
Gene editing tools like TALENs, ZFNs and Crispr/Cas now offer unprecedented opportunities for targeted genetic manipulations in virtually all species. Most of the recent research in this area has concentrated on manipulation of the genome in isolated cells, which then give rise to transgenic animals or modified stem cell lines. Much less is known about applicability of genetic scissors in terminally differentiated, non-dividing cells like neurons of the adult brain. We addressed this question by expression of a pair of ZFNs targeting the murine cathepsin D gene in CNS neurons by means of an optimized AAV viral vector. We show that ZFN expression resulted in substantial depletion of cathepsin D from neuronal lysosomes, demonstrating a robust gene deletion. Importantly, long-term ZFN expression in CNS neurons did not impair essential neuronal functionality and did not cause inflammation or neurodegeneration, suggesting that potent genetic scissors can be expressed safely in the mouse brain. This finding opens up new venues to create novel research models for neurodegenerative disorders.
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Affiliation(s)
- Muzna Zahur
- Department of Neurology, University Medical Center GöttingenGöttingen, Germany
| | - Johan Tolö
- Department of Neurology, University Medical Center GöttingenGöttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain at Department of Neurology, University Medical Center GöttingenGöttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medical Center GöttingenGöttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain at Department of Neurology, University Medical Center GöttingenGöttingen, Germany
| | - Sebastian Kügler
- Department of Neurology, University Medical Center GöttingenGöttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain at Department of Neurology, University Medical Center GöttingenGöttingen, Germany
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53
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Hensel KO, Rendon JC, Navas MC, Rots MG, Postberg J. Virus-host interplay in hepatitis B virus infection and epigenetic treatment strategies. FEBS J 2017; 284:3550-3572. [PMID: 28457020 DOI: 10.1111/febs.14094] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/25/2017] [Accepted: 04/26/2017] [Indexed: 12/11/2022]
Abstract
Worldwide, chronic hepatitis B virus (HBV) infection is a major health problem and no cure exists. Importantly, hepatocyte intrusion by HBV particles results in a complex deregulation of both viral and host cellular genetic and epigenetic processes. Among the attempts to develop novel therapeutic approaches against HBV infection, several options targeting the epigenomic regulation of HBV replication are gaining attention. These include the experimental treatment with 'epidrugs'. Moreover, as a targeted approach, the principle of 'epigenetic editing' recently is being exploited to control viral replication. Silencing of HBV by specific rewriting of epigenetic marks might diminish viral replication, viremia, and infectivity, eventually controlling the disease and its complications. Additionally, epigenetic editing can be used as an experimental tool to increase our limited understanding regarding the role of epigenetic modifications in viral infections. Aiming for permanent epigenetic reprogramming of the viral genome without unspecific side effects, this breakthrough may pave the roads for an ambitious technological pursuit: to start designing a curative approach utilizing manipulative molecular therapies for viral infections in vivo.
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Affiliation(s)
- Kai O Hensel
- HELIOS Medical Centre Wuppertal, Paediatrics Centre, Centre for Clinical & Translational Research (CCTR), Faculty of Health, Centre for Biomedical Education & Research (ZBAF), Witten/Herdecke University, Germany
| | - Julio C Rendon
- Epigenetic Editing, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen (UMCG), The Netherlands.,Grupo de Gastrohepatologia, Facultad de Medicina, Universidad de Antioquia (UdeA), Medellin, Colombia
| | - Maria-Cristina Navas
- Grupo de Gastrohepatologia, Facultad de Medicina, Universidad de Antioquia (UdeA), Medellin, Colombia
| | - Marianne G Rots
- Epigenetic Editing, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen (UMCG), The Netherlands
| | - Jan Postberg
- HELIOS Medical Centre Wuppertal, Paediatrics Centre, Centre for Clinical & Translational Research (CCTR), Faculty of Health, Centre for Biomedical Education & Research (ZBAF), Witten/Herdecke University, Germany
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54
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In vivo dynamics of AAV-mediated gene delivery to sensory neurons of the trigeminal ganglia. Sci Rep 2017; 7:927. [PMID: 28424485 PMCID: PMC5430444 DOI: 10.1038/s41598-017-01004-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 03/24/2017] [Indexed: 01/22/2023] Open
Abstract
The ability to genetically manipulate trigeminal ganglion (TG) neurons would be useful in the study of the craniofacial nervous system and latent alphaherpesvirus infections. We investigated adeno-associated virus (AAV) vectors for gene delivery to the TG after intradermal whiskerpad delivery in mice. We demonstrated that AAV vectors of serotypes 1, 7, 8, and 9 trafficked from the whiskerpad into TG neurons and expressed transgenes within cell bodies and axons of sensory neurons in all three branches of the TG. Gene expression was highest with AAV1, and steadily increased over time up to day 28. Both constitutive and neuronal-specific promoters were able to drive transgene expression in TG neurons. Levels of vector genomes in the TG increased with input dose, and multiple transgenes could be co-delivered to TG neurons by separate AAV vectors. In conclusion, AAV1 vectors are suitable for gene delivery to TG sensory neurons following intradermal whiskerpad injection.
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55
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Combining Engineered Nucleases with Adeno-associated Viral Vectors for Therapeutic Gene Editing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1016:29-42. [PMID: 29130152 DOI: 10.1007/978-3-319-63904-8_2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With the recent advent of several generations of targeted DNA nucleases, most recently CRISPR/Cas9, genome editing has become broadly accessible across the biomedical community. Importantly, the capacity of these nucleases to modify specific genomic loci associated with human disease could render new classes of genetic disease, including autosomal dominant or even idiopathic disease, accessible to gene therapy. In parallel, the emergence of adeno-associated virus (AAV) as a clinically important vector raises the possibility of integrating these two technologies towards the development of gene editing therapies. Though clear challenges exist, numerous proof-of-concept studies in preclinical models offer exciting promise for the future of gene therapy.
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56
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Boucle S, Bassit L, Ehteshami M, Schinazi RF. Toward Elimination of Hepatitis B Virus Using Novel Drugs, Approaches, and Combined Modalities. Clin Liver Dis 2016; 20:737-749. [PMID: 27742011 PMCID: PMC5119551 DOI: 10.1016/j.cld.2016.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hepatitis B virus (HBV) causes significant morbidity and mortality worldwide. The majority of chronically infected individuals do not achieve a functional and complete cure. Treated persons who achieve a long-term sustained virologic response (undetectable HBV DNA), are still at high risk of developing morbidity and mortality from liver complications. This review focuses on novel, mechanistically diverse anti-HBV therapeutic strategies currently in development or in clinical evaluation, and highlights new combination strategies that may contribute to full elimination of HBV DNA and covalently closed circular DNA from the infected liver, leading to a complete cure of chronic hepatitis B.
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Affiliation(s)
- Sebastien Boucle
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Center for AIDS Research, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA 30322, USA
| | - Leda Bassit
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Center for AIDS Research, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA 30322, USA
| | - Maryam Ehteshami
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Center for AIDS Research, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA 30322, USA
| | - Raymond F Schinazi
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Center for AIDS Research, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA 30322, USA.
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57
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Buchholz F, Hauber J. Antiviral therapy of persistent viral infection using genome editing. Curr Opin Virol 2016; 20:85-91. [PMID: 27723558 DOI: 10.1016/j.coviro.2016.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/23/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023]
Abstract
Chronic viral infections are often incurable because current antiviral strategies do not target chromosomally integrated or non-replicating episomal viral genomes. The rapid development of technologies for genome editing may possibly soon allow for therapeutic targeting of viral genomes and, hence, for development of curative strategies for persistent viral infection. However, detailed investigation of different antiviral genome editing approaches recently revealed various undesired effects. In particular, the problem of frequent and swift development of resistant viruses has to be thoroughly analysed before genome editing approaches become an established option for antiviral treatment.
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Affiliation(s)
- Frank Buchholz
- Medical Systems Biology, UCC, Medical Faculty Carl Gustav Carus, TU Dresden, Am Tatzberg 47/49, D-01307 Dresden, Germany
| | - Joachim Hauber
- Heinrich Pette Institute - Leibniz Institute for Experimental Virology, Martinistrasse 52, D-20251 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg, Germany.
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58
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Abstract
Chronic hepatitis B virus (HBV) infection continues to be a major health burden worldwide. Currently available antiviral treatment options for chronic hepatitis B include pegylated interferon alpha2a (PegIFN) or nucleos(t)ide analogues (NAs). The major advantages of NAs are good tolerance and potent antiviral activity associated with high rates of sustained on-treatment response to therapy. The advantages of PegIFN include a finite course of treatment, the absence of drug resistance, and an opportunity to obtain a durable post-treatment response to therapy. Furthermore, PegIFN is the only approved agent known to be active against hepatitis D virus (HDV). The use of these two antiviral agents with different mechanisms of action in combination against hepatitis B is theoretically an attractive approach for treatment. Although several studies have confirmed certain virological advantages of combination therapies, data supporting a long-term clinical benefit for patients are lacking and monotherapy with PegIFN or NAs remains the therapy of choice. Moreover, with the current treatment approaches, only a limited number of patients achieve hepatitis B surface antigen (HBsAg) loss. HBsAg loss is considered a "functional cure", but does not mean viral eradication. There is a need for novel therapeutic approaches that enable not only suppression of viral replication, but resolution of HBV infection. A key challenge is to target covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. The recent development and availability of innovative in vitro and in vivo systems and sensitive molecular techniques has opened new possibilities to study the complex network of interactions that HBV establishes with the host in the course of infection and to define new targets for antiviral strategies. Several new antiviral or immunomodulatory compounds have reached preclinical or clinical testing with the aim of silencing or eradicating cccDNA to achieve functional cure. Many of these strategies may also be effective for the treatment of HDV, which is dependent on HBsAg for its life cycle. This Clinical Trial Watch summarizes the most recent therapeutic strategies designed to directly target the viruses B and D or to improve immune responses during chronic HBV infection.
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59
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Aubert M, Madden EA, Loprieno M, DeSilva Feelixge HS, Stensland L, Huang ML, Greninger AL, Roychoudhury P, Niyonzima N, Nguyen T, Magaret A, Galleto R, Stone D, Jerome KR. In vivo disruption of latent HSV by designer endonuclease therapy. JCI Insight 2016; 1. [PMID: 27642635 DOI: 10.1172/jci.insight.88468] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A large portion of the global population carries latent herpes simplex virus (HSV), which can periodically reactivate, resulting in asymptomatic shedding or formation of ulcerative lesions. Current anti-HSV drugs do not eliminate latent virus from sensory neurons where HSV resides, and therefore do not eliminate the risk of transmission or recurrent disease. Here, we report the ability of HSV-specific endonucleases to induce mutations of essential HSV genes both in cultured neurons and in latently infected mice. In neurons, viral genomes are susceptible to endonuclease-mediated mutagenesis, regardless of the time of treatment after HSV infection, suggesting that both HSV lytic and latent forms can be targeted. Mutagenesis frequency after endonuclease exposure can be increased nearly 2-fold by treatment with a histone deacetylase (HDAC) inhibitor. Using a mouse model of latent HSV infection, we demonstrate that a targeted endonuclease can be delivered to viral latency sites via an adeno-associated virus (AAV) vector, where it is able to induce mutation of latent HSV genomes. These data provide the first proof-of-principle to our knowledge for the use of a targeted endonuclease as an antiviral agent to treat an established latent viral infection in vivo.
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Affiliation(s)
- Martine Aubert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Emily A Madden
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Michelle Loprieno
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | | | - Laurence Stensland
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Alexander L Greninger
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Pavitra Roychoudhury
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Nixon Niyonzima
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Thuy Nguyen
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Amalia Magaret
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA; Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | | | - Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Keith R Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA; Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
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60
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Stone D, Niyonzima N, Jerome KR. Genome editing and the next generation of antiviral therapy. Hum Genet 2016; 135:1071-82. [PMID: 27272125 PMCID: PMC5002242 DOI: 10.1007/s00439-016-1686-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 05/15/2016] [Indexed: 12/18/2022]
Abstract
Engineered endonucleases such as homing endonucleases (HEs), zinc finger nucleases (ZFNs), Tal-effector nucleases (TALENS) and the RNA-guided engineered nucleases (RGENs or CRISPR/Cas9) can target specific DNA sequences for cleavage, and are proving to be valuable tools for gene editing. Recently engineered endonucleases have shown great promise as therapeutics for the treatment of genetic disease and infectious pathogens. In this review, we discuss recent efforts to use the HE, ZFN, TALEN and CRISPR/Cas9 gene-editing platforms as antiviral therapeutics. We also discuss the obstacles facing gene-editing antiviral therapeutics as they are tested in animal models of disease and transition towards human application.
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Affiliation(s)
- Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Nixon Niyonzima
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA, USA
| | - Keith R. Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
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61
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Kim DH, Kang HS, Kim KH. Roles of hepatocyte nuclear factors in hepatitis B virus infection. World J Gastroenterol 2016; 22:7017-7029. [PMID: 27610013 PMCID: PMC4988315 DOI: 10.3748/wjg.v22.i31.7017] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/02/2016] [Accepted: 06/29/2016] [Indexed: 02/07/2023] Open
Abstract
Approximately 350 million people are estimated to be persistently infected with hepatitis B virus (HBV) worldwide. HBV maintains persistent infection by employing covalently closed circular DNA (cccDNA), a template for all HBV RNAs. Chronic hepatitis B (CHB) patients are currently treated with nucleos(t)ide analogs such as lamivudine, adefovir, entecavir, and tenofovir. However, these treatments rarely cure CHB because they are unable to inhibit cccDNA transcription and inhibit only a late stage in the HBV life cycle (the reverse transcription step in the nucleocapsid). Therefore, an understanding of the factors regulating cccDNA transcription is required to stop this process. Among numerous factors, hepatocyte nuclear factors (HNFs) play the most important roles in cccDNA transcription, especially in the generation of viral genomic RNA, a template for HBV replication. Therefore, proper control of HNF function could lead to the inhibition of HBV replication. In this review, we summarize and discuss the current understanding of the roles of HNFs in the HBV life cycle and the upstream factors that regulate HNFs. This knowledge will enable the identification of new therapeutic targets to cure CHB.
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62
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Lin CL, Kao JH. Review article: novel therapies for hepatitis B virus cure - advances and perspectives. Aliment Pharmacol Ther 2016; 44:213-22. [PMID: 27302653 DOI: 10.1111/apt.13694] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 03/26/2016] [Accepted: 05/21/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Current anti-viral therapies, interferon and nucleos(t)ide analogues, have been proven to reduce the progression of chronic hepatitis B (CHB). However, covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) persists, resulting in viral relapse after the discontinuation of treatment. AIM To discuss and review novel therapies for chronic hepatitis B infection. METHODS Recent published studies which searched from PubMed were comprehensive reviewed. The key words include chronic hepatitis B, hepatitis B virus cure, covalently closed circular DNA, direct acting anti-virals and host targeting agents. RESULTS Several novel agents through viral and host targets approaches are under investigations towards functional cure of HBV. On the one hand, direct acting anti-virals targeting virus itself, such as HBV new polymerase inhibitor, entry inhibitor, engineered site-specific nucleases and RNA interference, could inhibit amplification of cccDNA as well as intrahepatic HBV infection and eliminate or silence cccDNA transcription. Inhibitors of HBV nucleocapsid assembly suppress capsid formation and prevent synthesis of HBV DNA. On the other hand, host targeting agents (HTA) include lymphotoxin-β receptor agonist, toll-like receptor agonist, immune checkpoint inhibitors and adenovirus-based therapeutic vaccine. Through enhancing innate and adaptive immune responses, these agents could induce noncytolytic destruction of cccDNA or attack HBV-infected hepatocytes. CONCLUSION With these promising approaches, we hope to reach global hepatitis B virus control in the middle of this century.
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Affiliation(s)
- C-L Lin
- Department of Gastroenterology, Renai branch, Taipei City Hospital, Taipei, Taiwan.,Department of Psychology, National Chengchi University, Taipei, Taiwan
| | - J-H Kao
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.,Hepatitis Research Center, National Taiwan University, National Taiwan University Hospital, Taipei, Taiwan.,Department of Medical Research, National Taiwan University, National Taiwan University Hospital, Taipei, Taiwan
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63
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Morikawa K, Suda G, Sakamoto N. Viral life cycle of hepatitis B virus: Host factors and druggable targets. Hepatol Res 2016; 46:871-7. [PMID: 26776362 DOI: 10.1111/hepr.12650] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 01/09/2016] [Accepted: 01/12/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Kenichi Morikawa
- Division of Gastroenterology and Hepatology, Hokkaido University Hospital, Sapporo, Japan.,Division of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Goki Suda
- Division of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Naoya Sakamoto
- Division of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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64
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Quantification of designer nuclease induced mutation rates: a direct comparison of different methods. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2016; 3:16047. [PMID: 27419195 PMCID: PMC4934480 DOI: 10.1038/mtm.2016.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 05/21/2016] [Accepted: 05/23/2016] [Indexed: 02/08/2023]
Abstract
Designer nucleases are broadly applied to induce site-specific DNA double-strand breaks (DSB) in genomic DNA. These are repaired by nonhomologous end joining leading to insertions or deletions (in/dels) at the respective DNA-locus. To detect in/del mutations, the heteroduplex based T7-endonuclease I -assay is widely used. However, it only provides semi-quantitative evidence regarding the number of mutated alleles. Here we compared T7-endonuclease I- and heteroduplex mobility assays, with a quantitative polymerase chain reaction mutation detection method. A zinc finger nuclease pair specific for the human adeno-associated virus integration site 1 (AAVS1), a transcription activator-like effector nuclease pair specific for the human DMD gene, and a zinc finger nuclease- and a transcription activator-like effector nuclease pair specific for the human CCR5 gene were explored. We found that the heteroduplex mobility assays and T7-endonuclease I - assays detected mutations but the relative number of mutated cells/alleles can only be estimated. In contrast, the quantitative polymerase chain reaction based method provided quantitative results which allow calculating mutation and homologous recombination rates in different eukaryotic cell types including human peripheral blood mononuclear cells. In conclusion, our quantitative polymerase chain reaction based mutation detection method expands the array of methods for in/del mutation detection and facilitates quantification of introduced in/del mutations for a genomic locus containing a mixture of mutated and unmutated DNA.
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65
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Li BS, Sun DX. Role of covalently closed circular DNA in treatment of chronic hepatitis B. Shijie Huaren Xiaohua Zazhi 2016; 24:1824-1831. [DOI: 10.11569/wcjd.v24.i12.1824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
During hepatitis B virus (HBV) infection, covalently closed circular DNA (cccDNA) acts as the template for the synthesis of viral RNA and new virions. Current therapies rarely achieve an elimination of cccDNA. Biosynthesis of relaxed circular (RC) DNA by reverse transcription of the viral pregenomic RNA is now understood quite well, yet conversion of RC-DNA to cccDNA is still obscure. Conceptual and recent experimental data link cccDNA formation to cellular DNA repair, which is increasingly appreciated as a critical interface between cells and viruses. This review aims to summarize current knowledge on cccDNA molecular biology, to highlight the experimental restrictions that have hitherto hampered faster progress and to discuss cccDNA as a target for potentially curative therapies for chronic hepatitis B.
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66
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Roychoudhury P, De Silva Feelixge HS, Pietz HL, Stone D, Jerome KR, Schiffer JT. Pharmacodynamics of anti-HIV gene therapy using viral vectors and targeted endonucleases. J Antimicrob Chemother 2016; 71:2089-99. [PMID: 27090632 DOI: 10.1093/jac/dkw104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/29/2016] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES A promising curative approach for HIV is to use designer endonucleases that bind and cleave specific target sequences within latent genomes, resulting in mutations that render the virus replication incompetent. We developed a mathematical model to describe the expression and activity of endonucleases delivered to HIV-infected cells using engineered viral vectors in order to guide dose selection and predict therapeutic outcomes. METHODS We developed a mechanistic model that predicts the number of transgene copies expressed at a given dose in individual target cells from fluorescence of a reporter gene. We fitted the model to flow cytometry datasets to determine the optimal vector serotype, promoter and dose required to achieve maximum expression. RESULTS We showed that our model provides a more accurate measure of transduction efficiency compared with gating-based methods, which underestimate the percentage of cells expressing reporter genes. We identified that gene expression follows a sigmoid dose-response relationship and that the level of gene expression saturation depends on vector serotype and promoter. We also demonstrated that significant bottlenecks exist at the level of viral uptake and gene expression: only ∼1 in 220 added vectors enter a cell and, of these, depending on the dose and promoter used, between 1 in 15 and 1 in 1500 express transgene. CONCLUSIONS Our model provides a quantitative method of dose selection and optimization that can be readily applied to a wide range of other gene therapy applications. Reducing bottlenecks in delivery will be key to reducing the number of doses required for a functional cure.
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Affiliation(s)
- Pavitra Roychoudhury
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Harlan L Pietz
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA Department of Microbiology, University of Washington, Seattle, WA, USA Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Keith R Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA Department of Microbiology, University of Washington, Seattle, WA, USA Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Joshua T Schiffer
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA Department of Medicine, University of Washington, Seattle, WA, USA
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67
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Ely A, Moyo B, Arbuthnot P. Progress With Developing Use of Gene Editing To Cure Chronic Infection With Hepatitis B Virus. Mol Ther 2016; 24:671-7. [PMID: 26916283 DOI: 10.1038/mt.2016.43] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/16/2016] [Indexed: 02/07/2023] Open
Abstract
Chronic infection with hepatitis B virus (HBV) occurs in approximately 6% of the world's population. Carriers of the virus are at risk for life-threatening complications, and developing curative treatment remains a priority. The main shortcoming of licensed therapies is that they do not affect viral covalently closed circular DNA (cccDNA), a stable intermediate of replication. Harnessing gene editing to mutate cccDNA provides the means to inactivate HBV gene expression permanently. Reports have described use of engineered zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR) with CRISPR-associated (Cas) nucleases. Although inhibition of viral replication has been demonstrated, reliably detecting mutations in cccDNA has been difficult. Also, the dearth of murine models that mimic cccDNA formation has hampered analysis in vivo. To reach a stage of clinical use, efficient delivery of the editors to HBV-infected hepatocytes and limiting unintended off-target effects will be important. Investigating therapeutic efficacy in combination with other treatment strategies, such as immunotherapies, may be useful to augment antiviral effects. Advancing gene editing as a mode of treating HBV infection is now at an interesting stage and significant progress is likely to be made in the immediate future.
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Affiliation(s)
- Abdullah Ely
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Buhle Moyo
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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68
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Digital detection of endonuclease mediated gene disruption in the HIV provirus. Sci Rep 2016; 6:20064. [PMID: 26829887 PMCID: PMC4735761 DOI: 10.1038/srep20064] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/18/2015] [Indexed: 12/11/2022] Open
Abstract
Genome editing by designer nucleases is a rapidly evolving technology utilized in a highly diverse set of research fields. Among all fields, the T7 endonuclease mismatch cleavage assay, or Surveyor assay, is the most commonly used tool to assess genomic editing by designer nucleases. This assay, while relatively easy to perform, provides only a semi-quantitative measure of mutation efficiency that lacks sensitivity and accuracy. We demonstrate a simple droplet digital PCR assay that quickly quantitates a range of indel mutations with detection as low as 0.02% mutant in a wild type background and precision (≤6%CV) and accuracy superior to either mismatch cleavage assay or clonal sequencing when compared to next-generation sequencing. The precision and simplicity of this assay will facilitate comparison of gene editing approaches and their optimization, accelerating progress in this rapidly-moving field.
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69
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Maeder ML, Gersbach CA. Genome-editing Technologies for Gene and Cell Therapy. Mol Ther 2016; 24:430-46. [PMID: 26755333 PMCID: PMC4786923 DOI: 10.1038/mt.2016.10] [Citation(s) in RCA: 410] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 01/07/2016] [Indexed: 12/11/2022] Open
Abstract
Gene therapy has historically been defined as the addition of new genes to human cells. However, the recent advent of genome-editing technologies has enabled a new paradigm in which the sequence of the human genome can be precisely manipulated to achieve a therapeutic effect. This includes the correction of mutations that cause disease, the addition of therapeutic genes to specific sites in the genome, and the removal of deleterious genes or genome sequences. This review presents the mechanisms of different genome-editing strategies and describes each of the common nuclease-based platforms, including zinc finger nucleases, transcription activator-like effector nucleases (TALENs), meganucleases, and the CRISPR/Cas9 system. We then summarize the progress made in applying genome editing to various areas of gene and cell therapy, including antiviral strategies, immunotherapies, and the treatment of monogenic hereditary disorders. The current challenges and future prospects for genome editing as a transformative technology for gene and cell therapy are also discussed.
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Affiliation(s)
| | - Charles A Gersbach
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.,Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, USA.,Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina, USA
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70
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Detection of treatment-resistant infectious HIV after genome-directed antiviral endonuclease therapy. Antiviral Res 2015; 126:90-8. [PMID: 26718067 DOI: 10.1016/j.antiviral.2015.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/11/2015] [Accepted: 12/18/2015] [Indexed: 02/08/2023]
Abstract
Incurable chronic viral infections are a major cause of morbidity and mortality worldwide. One potential approach to cure persistent viral infections is via the use of targeted endonucleases. Nevertheless, a potential concern for endonuclease-based antiviral therapies is the emergence of treatment resistance. Here we detect for the first time an endonuclease-resistant infectious virus that is found with high frequency after antiviral endonuclease therapy. While testing the activity of HIV pol-specific zinc finger nucleases (ZFNs) alone or in combination with three prime repair exonuclease 2 (Trex2), we identified a treatment-resistant and infectious mutant virus that was derived from a ZFN-mediated disruption of reverse transcriptase (RT). Although gene disruption of HIV protease, RT and integrase could inhibit viral replication, a chance single amino acid insertion within the thumb domain of RT produced a virus that could actively replicate. The endonuclease-resistant virus could replicate in primary CD4(+) T cells, but remained susceptible to treatment with antiretroviral RT inhibitors. When secondary ZFN-derived mutations were introduced into the mutant virus's RT or integrase domains, replication could be abolished. Our observations suggest that caution should be exercised during endonuclease-based antiviral therapies; however, combination endonuclease therapies may prevent the emergence of resistance.
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71
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Liang TJ, Block TM, McMahon BJ, Ghany MG, Urban S, Guo JT, Locarnini S, Zoulim F, Chang KM, Lok AS. Present and future therapies of hepatitis B: From discovery to cure. Hepatology 2015; 62:1893-908. [PMID: 26239691 PMCID: PMC4681668 DOI: 10.1002/hep.28025] [Citation(s) in RCA: 239] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 07/31/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Hepatitis B virus (HBV) is a significant global pathogen, infecting more than 240 million people worldwide. While treatment for HBV has improved, HBV patients often require lifelong therapies and cure is still a challenging goal. Recent advances in technologies and pharmaceutical sciences have heralded a new horizon of innovative therapeutic approaches that are bringing us closer to the possibility of a functional cure of chronic HBV infection. In this article, we review the current state of science in HBV therapy and highlight new and exciting therapeutic strategies spurred by recent scientific advances. Some of these therapies have already entered into clinical phase, and we will likely see more of them moving along the development pipeline. CONCLUSION With growing interest in developing and efforts to develop more effective therapies for HBV, the challenging goal of a cure may be well within reach in the near future.
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Affiliation(s)
- T. Jake Liang
- Liver Diseases Branch, NIDDK, NIH, Bethesda, MD. USA
| | | | - Brian J. McMahon
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, AK. USA
| | - Marc G. Ghany
- Liver Diseases Branch, NIDDK, NIH, Bethesda, MD. USA
| | - Stephan Urban
- Dept of Infectious Diseases, Molecular Virology and German Center for Infection Diseases (DZIF), Univ Hospital Heidelberg, Heidelberg, Germany
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, Doylestown, PA. USA
| | | | - Fabien Zoulim
- Victorian Infectious Diseases Reference Laboratory, Doherty Institute, Melbourne, VIC, Australia
| | - Kyong-Mi Chang
- Dept of Medicine, Philadelphia VAMC & University of Pennsylvania, Philadelphia, PA. USA
| | - Anna S. Lok
- Div of Gastroenterology and Hepatology, Univ of Michigan, Ann Arbor, MI. USA
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72
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Genome Engineering Using Adeno-associated Virus: Basic and Clinical Research Applications. Mol Ther 2015; 24:458-64. [PMID: 26373345 DOI: 10.1038/mt.2015.151] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 07/21/2015] [Indexed: 12/18/2022] Open
Abstract
In addition to their broad potential for therapeutic gene delivery, adeno-associated virus (AAV) vectors possess the innate ability to stimulate homologous recombination in mammalian cells at high efficiencies. This process--referred to as AAV-mediated gene targeting--has enabled the introduction of a diverse array of genomic modifications both in vitro and in vivo. With the recent emergence of targeted nucleases, AAV-mediated genome engineering is poised for clinical translation. Here, we review key properties of AAV vectors that underscore its unique utility in genome editing. We highlight the broad range of genome engineering applications facilitated by this technology and discuss the strong potential for unifying AAV with targeted nucleases for next-generation gene therapy.
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73
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Yang N, Bertoletti A. Advances in therapeutics for chronic hepatitis B. Hepatol Int 2015; 10:277-85. [PMID: 26363922 DOI: 10.1007/s12072-015-9661-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/07/2015] [Indexed: 02/06/2023]
Abstract
Chronic hepatitis B infection remains a major disease burden globally, and leads to high risk of hepatocellular carcinoma development. Current therapies of nucleot(s)ide analogues and interferon alpha treatment remain limited in their efficacy. Several key findings in the hepatitis B virus (HBV) life cycle have led to the development of novel antiviral drugs to inhibit viral replication and persistence. In addition, recent studies on HBV-specific innate and adaptive immune responses have advanced development of immunotherapy to restore immune mediated virus control in chronic hepatitis B patients. In this review, we discuss potential new therapeutic strategies targeting HBV or the host immune system that might lead to a sustained cure for chronic hepatitis B.
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Affiliation(s)
- Ninghan Yang
- Viral Hepatitis Laboratory, Singapore Institute of Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
| | - Antonio Bertoletti
- Viral Hepatitis Laboratory, Singapore Institute of Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore. .,Emerging Infectious Disease (EID) Program, Duke-NUS Graduate Medical School, Singapore, Singapore.
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74
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CRISPR/Cas9 nickase-mediated disruption of hepatitis B virus open reading frame S and X. Sci Rep 2015; 5:13734. [PMID: 26334116 PMCID: PMC4558539 DOI: 10.1038/srep13734] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 08/04/2015] [Indexed: 02/07/2023] Open
Abstract
Current antiviral therapies cannot cure hepatitis B virus (HBV) infection; successful HBV eradication would require inactivation of the viral genome, which primarily persists in host cells as episomal covalently closed circular DNA (cccDNA) and, to a lesser extent, as chromosomally integrated sequences. However, novel designer enzymes, such as the CRISPR/Cas9 RNA-guided nuclease system, provide technologies for developing advanced therapy strategies that could directly attack the HBV genome. For therapeutic application in humans, such designer nucleases should recognize various HBV genotypes and cause minimal off-target effects. Here, we identified cross-genotype conserved HBV sequences in the S and X region of the HBV genome that were targeted for specific and effective cleavage by a Cas9 nickase. This approach disrupted not only episomal cccDNA and chromosomally integrated HBV target sites in reporter cell lines, but also HBV replication in chronically and de novo infected hepatoma cell lines. Our data demonstrate the feasibility of using the CRISPR/Cas9 nickase system for novel therapy strategies aiming to cure HBV infection.
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75
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Guo JT, Guo H. Metabolism and function of hepatitis B virus cccDNA: Implications for the development of cccDNA-targeting antiviral therapeutics. Antiviral Res 2015; 122:91-100. [PMID: 26272257 DOI: 10.1016/j.antiviral.2015.08.005] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/07/2015] [Indexed: 02/07/2023]
Abstract
Persistent hepatitis B virus (HBV) infection relies on the stable maintenance and proper functioning of a nuclear episomal form of the viral genome called covalently closed circular (ccc) DNA. One of the major reasons for the failure of currently available antiviral therapeutics to achieve a cure of chronic HBV infection is their inability to eradicate or inactivate cccDNA. In this review article, we summarize our current understanding of cccDNA metabolism in hepatocytes and the modulation of cccDNA by host pathophysiological and immunological cues. Perspectives on the future investigation of cccDNA biology, as well as strategies and progress in therapeutic elimination and/or transcriptional silencing of cccDNA through rational design and phenotypic screenings, are also discussed. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."
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Affiliation(s)
- Ju-Tao Guo
- Baruch S. Blumberg Institute, Hepatitis B Foundation, Doylestown, PA 18902, USA.
| | - Haitao Guo
- Department of Microbiology and Immunology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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76
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Qian F, Li M, Zhu CW. Impact of antiviral agents on levels of hepatitis B virus covalently closed circular DNA. Shijie Huaren Xiaohua Zazhi 2015; 23:3495-3504. [DOI: 10.11569/wcjd.v23.i22.3495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis caused by hepatitis B virus (HBV) infection remains an incurable disease at present, which is mainly because the approved antiviral agents, such as interferon-alpha and nucleos(t)ide analogues, cannot effectively eradicate intrahepatic hepatitis B virus covalently closed circular DNA (cccDNA). And thus a suboptimal efficacy of antiviral agents and relapse after therapy occur very commonly. Therefore, novel drugs and treatment strategies remain to be developed on the basis of further theoretical and clinical research of HBV infection to achieve the ultimate goal of eradication of HBV cccDNA in the future. In this paper, we discuss multiple agents and therapeutic regimens influencing cccDNA levels, in order to help clinicians comprehensively understand the present situation in the research of the clearance of HBV cccDNA.
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77
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Zeisel MB, Lucifora J, Mason WS, Sureau C, Beck J, Levrero M, Kann M, Knolle PA, Benkirane M, Durantel D, Michel ML, Autran B, Cosset FL, Strick-Marchand H, Trépo C, Kao JH, Carrat F, Lacombe K, Schinazi RF, Barré-Sinoussi F, Delfraissy JF, Zoulim F. Towards an HBV cure: state-of-the-art and unresolved questions--report of the ANRS workshop on HBV cure. Gut 2015; 64:1314-26. [PMID: 25670809 DOI: 10.1136/gutjnl-2014-308943] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/10/2015] [Indexed: 12/11/2022]
Abstract
HBV infection is a major cause of liver cirrhosis and hepatocellular carcinoma. Although HBV infection can be efficiently prevented by vaccination, and treatments are available, to date there is no reliable cure for the >240 million individuals that are chronically infected worldwide. Current treatments can only achieve viral suppression, and lifelong therapy is needed in the majority of infected persons. In the framework of the French National Agency for Research on AIDS and Viral Hepatitis 'HBV Cure' programme, a scientific workshop was held in Paris in June 2014 to define the state-of-the-art and unanswered questions regarding HBV pathobiology, and to develop a concerted strategy towards an HBV cure. This review summarises our current understanding of HBV host-interactions leading to viral persistence, as well as the roadblocks to be overcome to ultimately address unmet medical needs in the treatment of chronic HBV infection.
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Affiliation(s)
- Mirjam B Zeisel
- Inserm, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France Université de Strasbourg, Strasbourg, France
| | - Julie Lucifora
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France
| | | | - Camille Sureau
- INTS, Laboratoire de Virologie Moléculaire, Paris, France
| | - Jürgen Beck
- Department of Internal Medicine 2/Molecular Biology, University Hospital Freiburg, Freiburg, Germany
| | - Massimo Levrero
- Center for Life Nanosciences (CNLS)-IIT/Sapienza, Rome, Italy Laboratory of Gene Expression, Department of Internal Medicine (DMISM), Sapienza University of Rome, Italy
| | - Michael Kann
- Université de Bordeaux, Microbiologie fondamentale et Pathogénicité, UMR 5234, Bordeaux, France CNRS, Microbiologie fondamentale et Pathogénicité, UMR 5234, Bordeaux, France CHU de Bordeaux, Bordeaux, France
| | - Percy A Knolle
- Technische Universität München, Institut für Molekulare Immunologie, München, Germany
| | - Monsef Benkirane
- Institut de Génétique Humaine, Laboratoire de Virologie Moléculaire, CNRS UPR1142, Montpellier, France
| | - David Durantel
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France
| | - Marie-Louise Michel
- Laboratoire de Pathogenèse des Virus de l'Hépatite B, Département de Virologie, Institut Pasteur, Paris, France
| | - Brigitte Autran
- Laboratory of Immunity and Infection, Inserm U945, Paris, France Laboratory of Immunity and Infection, UPMC University Paris 06, Unité mixte de recherche-S945, Paris, France Inserm, IFR 113, Immunité-Cancer-Infection, Paris, France
| | - François-Loïc Cosset
- CIRI-International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France. Inserm, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France. CNRS, UMR5308, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| | | | - Christian Trépo
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France Department of Hepatology, Croix-Rousse Hospital, Hospices Civils de Lyon, Lyon, France
| | - Jia-Horng Kao
- Department of Internal Medicine, Department of Medical Research, Graduate Institute of Clinical Medicine, and Hepatitis Research Center, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Fabrice Carrat
- Inserm, UMR_S 1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France Sorbonne Universités, UPMC Univ Paris 06, Paris, France Assistance Publique Hôpitaux de Paris, Hôpital Saint Antoine, Paris, France
| | - Karine Lacombe
- Inserm, UMR_S 1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France Sorbonne Universités, UPMC Univ Paris 06, Paris, France Assistance Publique Hôpitaux de Paris, Hôpital Saint Antoine, Paris, France
| | - Raymond F Schinazi
- Center for AIDS Research, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, Georgia, USA
| | - Françoise Barré-Sinoussi
- Inserm and Unit of Regulation of Retroviral Infections, Department of Virology, Institut Pasteur, Paris, France
| | | | - Fabien Zoulim
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France Department of Hepatology, Croix-Rousse Hospital, Hospices Civils de Lyon, Lyon, France
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78
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Progress and Prospects of Anti-HBV Gene Therapy Development. Int J Mol Sci 2015; 16:17589-610. [PMID: 26263978 PMCID: PMC4581210 DOI: 10.3390/ijms160817589] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/20/2015] [Accepted: 07/22/2015] [Indexed: 12/11/2022] Open
Abstract
Despite the availability of an effective vaccine against hepatitis B virus (HBV), chronic infection with the virus remains a major global health concern. Current drugs against HBV infection are limited by emergence of resistance and rarely achieve complete viral clearance. This has prompted vigorous research on developing better drugs against chronic HBV infection. Advances in understanding the life cycle of HBV and improvements in gene-disabling technologies have been impressive. This has led to development of better HBV infection models and discovery of new drug candidates. Ideally, a regimen against chronic HBV infection should completely eliminate all viral replicative intermediates, especially covalently closed circular DNA (cccDNA). For the past few decades, nucleic acid-based therapy has emerged as an attractive alternative that may result in complete clearance of HBV in infected patients. Several genetic anti-HBV strategies have been developed. The most studied approaches include the use of antisense oligonucleotides, ribozymes, RNA interference effectors and gene editing tools. This review will summarize recent developments and progress made in the use of gene therapy against HBV.
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79
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Gish RG, Given BD, Lai CL, Locarnini SA, Lau JYN, Lewis DL, Schluep T. Chronic hepatitis B: Virology, natural history, current management and a glimpse at future opportunities. Antiviral Res 2015; 121:47-58. [PMID: 26092643 DOI: 10.1016/j.antiviral.2015.06.008] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/16/2015] [Indexed: 02/08/2023]
Abstract
The host immune system plays an important role in chronic hepatitis B (CHB), both in viral clearance and hepatocellular damage. Advances in our understanding of the natural history of the disease have led to redefining the major phases of infection, with the "high replicative, low inflammatory" phase now replacing what was formerly termed the "immune tolerant" phase, and the "nonreplicative phase" replacing what was formerly termed the "inactive carrier" phase. As opposed to the earlier view that HBV establishes chronic infection by exploiting the immaturity of the neonate's immune system, new findings on trained immunity show that the host is already somewhat "matured" following birth, and is actually very capable of responding immunologically, potentially altering future hepatitis B treatment strategies. While existing therapies are effective in reducing viral load and necroinflammation, often restoring the patient to near-normal health, they do not lead to a cure except in very rare cases and, in many patients, viremia rebounds after cessation of treatment. Researchers are now challenged to devise therapies that will eliminate infection, with a particular focus on eliminating the persistence of viral cccDNA in the nuclei of hepatocytes. In the context of chronic hepatitis B, new definitions of 'cure' are emerging, such as 'functional' and 'virological' cure, defined by stable off-therapy suppression of viremia and antigenemia, and the normalization of serum ALT and other liver-related laboratory tests. Continued advances in the understanding of the complex biology of chronic hepatitis B have resulted in the development of new, experimental therapies targeting viral and host factors and pathways previously not accessible to therapy, approaches which may lead to virological cures in the near term and functional cures upon long term follow-up. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."
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Affiliation(s)
- Robert G Gish
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University Medical Center, Stanford, CA, USA.
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80
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Ramanan V, Shlomai A, Cox DB, Schwartz RE, Michailidis E, Bhatta A, Scott DA, Zhang F, Rice CM, Bhatia SN. CRISPR/Cas9 cleavage of viral DNA efficiently suppresses hepatitis B virus. Sci Rep 2015; 5:10833. [PMID: 26035283 PMCID: PMC4649911 DOI: 10.1038/srep10833] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 04/29/2015] [Indexed: 02/07/2023] Open
Abstract
Chronic hepatitis B virus (HBV) infection is prevalent, deadly, and seldom cured due to the persistence of viral episomal DNA (cccDNA) in infected cells. Newly developed genome engineering tools may offer the ability to directly cleave viral DNA, thereby promoting viral clearance. Here, we show that the CRISPR/Cas9 system can specifically target and cleave conserved regions in the HBV genome, resulting in robust suppression of viral gene expression and replication. Upon sustained expression of Cas9 and appropriately chosen guide RNAs, we demonstrate cleavage of cccDNA by Cas9 and a dramatic reduction in both cccDNA and other parameters of viral gene expression and replication. Thus, we show that directly targeting viral episomal DNA is a novel therapeutic approach to control the virus and possibly cure patients.
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Affiliation(s)
- Vyas Ramanan
- Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Amir Shlomai
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - David B.T. Cox
- Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute, Cambridge, MA 02139, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Robert E. Schwartz
- Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Division of Gastroenterology and Hepatology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Eleftherios Michailidis
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Ankit Bhatta
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - David A. Scott
- Broad Institute, Cambridge, MA 02139, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Feng Zhang
- Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute, Cambridge, MA 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Charles M. Rice
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Sangeeta N. Bhatia
- Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Broad Institute, Cambridge, MA 02139, USA
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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81
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Liu X, Hao R, Chen S, Guo D, Chen Y. Inhibition of hepatitis B virus by the CRISPR/Cas9 system via targeting the conserved regions of the viral genome. J Gen Virol 2015; 96:2252-2261. [PMID: 25904148 DOI: 10.1099/vir.0.000159] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) remains a global health threat as chronic HBV infection may lead to liver cirrhosis or cancer. Current antiviral therapies with nucleoside analogues can inhibit the replication of HBV, but do not disrupt the already existing HBV covalently closed circular DNA. The newly developed CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated 9) system is a powerful tool to target cellular genome DNA for gene editing. In order to investigate the possibility of using the CRISPR/Cas9 system to disrupt the HBV DNA templates, we designed eight guide RNAs (gRNAs) that targeted the conserved regions of different HBV genotypes, which could significantly inhibit HBV replication both in vitro and in vivo. Moreover, the HBV-specific gRNA/Cas9 system could inhibit the replication of HBV of different genotypes in cells, and the viral DNA was significantly reduced by a single gRNA/Cas9 system and cleared by a combination of different gRNA/Cas9 systems.
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Affiliation(s)
- Xing Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Ruidong Hao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Shuliang Chen
- School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Deyin Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China.,School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China
| | - Yu Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, 430072, PR China
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Abstract
Recent advances in the development of genome editing technologies based on programmable nucleases have substantially improved our ability to make precise changes in the genomes of eukaryotic cells. Genome editing is already broadening our ability to elucidate the contribution of genetics to disease by facilitating the creation of more accurate cellular and animal models of pathological processes. A particularly tantalizing application of programmable nucleases is the potential to directly correct genetic mutations in affected tissues and cells to treat diseases that are refractory to traditional therapies. Here we discuss current progress toward developing programmable nuclease-based therapies as well as future prospects and challenges.
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Affiliation(s)
- David Benjamin Turitz Cox
- 1] Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [2] Department of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [3] Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [4] McGovern Institute for Brain Research at MIT, Cambridge, Massachusetts, USA
| | - Randall Jeffrey Platt
- 1] Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [2] McGovern Institute for Brain Research at MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [4] Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Feng Zhang
- 1] Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA. [2] McGovern Institute for Brain Research at MIT, Cambridge, Massachusetts, USA. [3] Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [4] Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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83
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Kennedy EM, Cullen BR. Bacterial CRISPR/Cas DNA endonucleases: A revolutionary technology that could dramatically impact viral research and treatment. Virology 2015; 479-480:213-20. [PMID: 25759096 DOI: 10.1016/j.virol.2015.02.024] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/25/2015] [Accepted: 02/06/2015] [Indexed: 02/06/2023]
Abstract
CRISPR/Cas systems mediate bacterial adaptive immune responses that evolved to protect bacteria from bacteriophage and other horizontally transmitted genetic elements. Several CRISPR/Cas systems exist but the simplest variant, referred to as Type II, has a single effector DNA endonuclease, called Cas9, which is guided to its viral DNA target by two small RNAs, the crRNA and the tracrRNA. Initial efforts to adapt the CRISPR/Cas system for DNA editing in mammalian cells, which focused on the Cas9 protein from Streptococcus pyogenes (Spy), demonstrated that Spy Cas9 can be directed to DNA targets in mammalian cells by tracrRNA:crRNA fusion transcripts called single guide RNAs (sgRNA). Upon binding, Cas9 induces DNA cleavage leading to mutagenesis as a result of error prone non-homologous end joining (NHEJ). Recently, the Spy Cas9 system has been adapted for high throughput screening of genes in human cells for their relevance to a particular phenotype and, more generally, for the targeted inactivation of specific genes, in cell lines and in vivo in a number of model organisms. The latter aim seems likely to be greatly enhanced by the recent development of Cas9 proteins from bacterial species such as Neisseria meningitidis and Staphyloccus aureus that are small enough to be expressed using adeno-associated (AAV)-based vectors that can be readily prepared at very high titers. The evolving Cas9-based DNA editing systems therefore appear likely to not only impact virology by allowing researchers to screen for human genes that affect the replication of pathogenic human viruses of all types but also to derive clonal human cell lines that lack individual gene products that either facilitate or restrict viral replication. Moreover, high titer AAV-based vectors offer the possibility of directly targeting DNA viruses that infect discrete sites in the human body, such as herpes simplex virus and hepatitis B virus, with the hope that the entire population of viral DNA genomes might be destroyed. In conclusion, we believe that the continued rapid evolution of CRISPR/Cas technology will soon have a major, possibly revolutionary, impact on the field of virology.
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Affiliation(s)
- Edward M Kennedy
- Department of Molecular Genetics and Microbiology and Center for Virology, Duke University Medical Center, Durham, NC, USA
| | - Bryan R Cullen
- Department of Molecular Genetics and Microbiology and Center for Virology, Duke University Medical Center, Durham, NC, USA.
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84
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Gebbing M, Bergmann T, Schulz E, Ehrhardt A. Gene therapeutic approaches to inhibit hepatitis B virus replication. World J Hepatol 2015; 7:150-164. [PMID: 25729471 PMCID: PMC4342598 DOI: 10.4254/wjh.v7.i2.150] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/23/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023] Open
Abstract
Acute and chronic hepatitis B virus (HBV) infections remain to present a major global health problem. The infection can be associated with acute symptomatic or asymptomatic hepatitis which can cause chronic inflammation of the liver and over years this can lead to cirrhosis and the development of hepatocellular carcinomas. Currently available therapeutics for chronically infected individuals aim at reducing viral replication and to slow down or stop the progression of the disease. Therefore, novel treatment options are needed to efficiently combat and eradicate this disease. Here we provide a state of the art overview of gene therapeutic approaches to inhibit HBV replication. We discuss non-viral and viral approaches which were explored to deliver therapeutic nucleic acids aiming at reducing HBV replication. Types of delivered therapeutic nucleic acids which were studied since many years include antisense oligodeoxynucleotides and antisense RNA, ribozymes and DNAzymes, RNA interference, and external guide sequences. More recently designer nucleases gained increased attention and were exploited to destroy the HBV genome. In addition we mention other strategies to reduce HBV replication based on delivery of DNA encoding dominant negative mutants and DNA vaccination. In combination with available cell culture and animal models for HBV infection, in vitro and in vivo studies can be performed to test efficacy of gene therapeutic approaches. Recent progress but also challenges will be specified and future perspectives will be discussed. This is an exciting time to explore such approaches because recent successes of gene therapeutic strategies in the clinic to treat genetic diseases raise hope to find alternative treatment options for patients chronically infected with HBV.
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Bloom K, Mussolino C, Arbuthnot P. Transcription Activator-Like Effector (TALE) Nucleases and Repressor TALEs for Antiviral Gene Therapy. CURRENT STEM CELL REPORTS 2015. [DOI: 10.1007/s40778-014-0008-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Seeger C, Sohn JA. Targeting Hepatitis B Virus With CRISPR/Cas9. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e216. [PMID: 25514649 PMCID: PMC4272409 DOI: 10.1038/mtna.2014.68] [Citation(s) in RCA: 220] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/03/2014] [Indexed: 02/07/2023]
Abstract
Hepatitis B virus persistence in infected hepatocytes is due to the presence of covalently closed circular DNA (cccDNA), the template for the transcription of viral RNAs. Antiviral therapies with nucleoside analogues inhibit replication of HBV DNA in capsids present in the cytoplasm of infected cells, but do not reduce or destroy nuclear cccDNA. To investigate whether cccDNA derived from infectious HBV could be directly targeted for destruction, we used the CRISPR/Cas9 system in HepG2 cells expressing the HBV receptor sodium taurocholate cotransporting polypeptide (NTCP). We tested different HBV-specific guide RNAs and demonstrated that they could inhibit HBV infections up to eightfold. Inhibition was due to mutations and deletions in cccDNA similar to those observed with chromosomal DNA cleaved by Cas9 and repaired by nonhomologous end joining (NHEJ). Interferon alpha (IFN-α) did not have a measurable effect on the antiviral activity of the CRISPR/Cas9 system, suggesting that Cas9 and NHEJ activities are not affected by induction of an innate immune response with the cytokine. Taken together, our results demonstrated that Cas9 can be recruited to cccDNA, opening the possibility for the development of future antiviral strategies aimed at targeting cccDNA for endonucleolytic cleavage with small molecules.
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Affiliation(s)
- Christoph Seeger
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Ji A Sohn
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
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