1
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Abdelwahed AH, Heineman BD, Wu GY. Novel Approaches to Inhibition of HBsAg Expression from cccDNA and Chromosomal Integrants: A Review. J Clin Transl Hepatol 2023; 11:1485-1497. [PMID: 38161502 PMCID: PMC10752814 DOI: 10.14218/jcth.2023.00067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/19/2023] [Accepted: 08/16/2023] [Indexed: 01/03/2024] Open
Abstract
Hepatitis B virus (HBV) is a widely prevalent liver infection that can cause acute or chronic hepatitis. Although current treatment modalities are highly effective in the suppression of viral levels, they cannot eliminate the virus or achieve definitive cure. This is a consequence of the complex nature of HBV-host interactions. Major challenges to achieving sustained viral suppression include the presence of a high viral burden from the HBV DNA and hepatitis B surface antigen (HBsAg), the presence of reservoirs for HBV replication and antigen production, and the HBV-impaired innate and adaptive immune response of the host. Those therapeutic methods include cell entry inhibitors, HBsAg inhibitors, gene editing approaches, immune-targeting therapies and direct inhibitors of covalently closed circular DNA (cccDNA). Novel approaches that target these key mechanisms are now being studied in preclinical and clinical phases. In this review article, we provide a comprehensive review on mechanisms by which HBV escapes elimination from current treatments, and highlight new agents to achieve a definitive HBV cure.
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Affiliation(s)
- Ahmed H. Abdelwahed
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Health Center, Farmington, CT, USA
| | - Brent D. Heineman
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Health Center, Farmington, CT, USA
| | - George Y. Wu
- Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut Health Center, Farmington, CT, USA
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2
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Jacobs R, Dogbey MD, Mnyandu N, Neves K, Barth S, Arbuthnot P, Maepa MB. AAV Immunotoxicity: Implications in Anti-HBV Gene Therapy. Microorganisms 2023; 11:2985. [PMID: 38138129 PMCID: PMC10745739 DOI: 10.3390/microorganisms11122985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 11/30/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Hepatitis B virus (HBV) has afflicted humankind for decades and there is still no treatment that can clear the infection. The development of recombinant adeno-associated virus (rAAV)-based gene therapy for HBV infection has become important in recent years and research has made exciting leaps. Initial studies, mainly using mouse models, showed that rAAVs are non-toxic and induce minimal immune responses. However, several later studies demonstrated rAAV toxicity, which is inextricably associated with immunogenicity. This is a major setback for the progression of rAAV-based therapies toward clinical application. Research aimed at understanding the mechanisms behind rAAV immunity and toxicity has contributed significantly to the inception of approaches to overcoming these challenges. The target tissue, the features of the vector, and the vector dose are some of the determinants of AAV toxicity, with the latter being associated with the most severe adverse events. This review discusses our current understanding of rAAV immunogenicity, toxicity, and approaches to overcoming these hurdles. How this information and current knowledge about HBV biology and immunity can be harnessed in the efforts to design safe and effective anti-HBV rAAVs is discussed.
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Affiliation(s)
- Ridhwaanah Jacobs
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Infectious Diseases and Oncology Research Institute (IDORI), Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
| | - Makafui Dennis Dogbey
- Medical Biotechnology and Immunotherapy Research Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa; (M.D.D.)
| | - Njabulo Mnyandu
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Infectious Diseases and Oncology Research Institute (IDORI), Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
| | - Keila Neves
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Infectious Diseases and Oncology Research Institute (IDORI), Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
| | - Stefan Barth
- Medical Biotechnology and Immunotherapy Research Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa; (M.D.D.)
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Infectious Diseases and Oncology Research Institute (IDORI), Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
| | - Mohube Betty Maepa
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Infectious Diseases and Oncology Research Institute (IDORI), Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
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3
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Kasianchuk N, Dobrowolska K, Harkava S, Bretcan A, Zarębska-Michaluk D, Jaroszewicz J, Flisiak R, Rzymski P. Gene-Editing and RNA Interference in Treating Hepatitis B: A Review. Viruses 2023; 15:2395. [PMID: 38140636 PMCID: PMC10747710 DOI: 10.3390/v15122395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
The hepatitis B virus (HBV) continues to cause substantial health and economic burdens, and its target of elimination may not be reached in 2030 without further efforts in diagnostics, non-pharmaceutical prevention measures, vaccination, and treatment. Current therapeutic options in chronic HBV, based on interferons and/or nucleos(t)ide analogs, suppress the virus replication but do not eliminate the pathogen and suffer from several constraints. This paper reviews the progress on biotechnological approaches in functional and definitive HBV treatments, including gene-editing tools, i.e., zinc-finger proteins, transcription activator-like effector nucleases, and CRISPR/Cas9, as well as therapeutics based on RNA interference. The advantages and challenges of these approaches are also discussed. Although the safety and efficacy of gene-editing tools in HBV therapies are yet to be demonstrated, they show promise for the revitalization of a much-needed advance in the field and offer viral eradication. Particular hopes are related to CRISPR/Cas9; however, therapeutics employing this system are yet to enter the clinical testing phases. In contrast, a number of candidates based on RNA interference, intending to confer a functional cure, have already been introduced to human studies. However, larger and longer trials are required to assess their efficacy and safety. Considering that prevention is always superior to treatment, it is essential to pursue global efforts in HBV vaccination.
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Affiliation(s)
- Nadiia Kasianchuk
- Faculty of Biology, Adam Mickiewicz University in Poznań, 61-614 Poznań, Poland
| | | | - Sofiia Harkava
- Junior Academy of Sciences of Ukraine, Regional Branch in Dnipro, 49000 Dnipro, Ukraine;
| | - Andreea Bretcan
- National College “Ienăchiță Văcărescu”, 130016 Târgoviște, Romania;
| | - Dorota Zarębska-Michaluk
- Department of Infectious Diseases and Allergology, Jan Kochanowski University, 25-317 Kielce, Poland;
| | - Jerzy Jaroszewicz
- Department of Infectious Diseases and Hepatology, Medical University of Silesia in Katowice, 41-902 Bytom, Poland;
| | - Robert Flisiak
- Department of Infectious Diseases and Hepatology, Medical University of Białystok, 15-540 Białystok, Poland;
| | - Piotr Rzymski
- Department of Environmental Medicine, Poznan University of Medical Sciences, 60-806 Poznań, Poland
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4
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Zhang H, Tu T. Targeting Hepatitis B Virus DNA Using Designer Gene Editors. Clin Liver Dis 2023; 27:895-916. [PMID: 37778776 DOI: 10.1016/j.cld.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Chronic hepatitis B virus (HBV) infection is a serious disease that currently has no cure. Key forms of HBV include covalently closed circular DNA, which mediates chronic persistence, and integrated DNA, which contributes to immune evasion and carcinogenesis. These forms are not targeted by current therapies; however, gene editing technologies have emerged as promising tools for disrupting HBV DNA. Gene editor-induced double-stranded breaks at precise locations within the HBV genome can induce effects ranging from inactivation of target genes to complete degradation of the target genome. Although promising, several challenges remain in efficacy and safety that require solutions.
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Affiliation(s)
- Henrik Zhang
- Westmead Institute for Medical Research, University of Sydney School of Medicine and Health, 176 Hawkesbury Road, Westmead, NSW 2145, Australia
| | - Thomas Tu
- Westmead Institute for Medical Research, University of Sydney School of Medicine and Health, 176 Hawkesbury Road, Westmead, NSW 2145, Australia.
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5
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Olenginski LT, Attionu SK, Henninger EN, LeBlanc RM, Longhini AP, Dayie TK. Hepatitis B Virus Epsilon (ε) RNA Element: Dynamic Regulator of Viral Replication and Attractive Therapeutic Target. Viruses 2023; 15:1913. [PMID: 37766319 PMCID: PMC10534774 DOI: 10.3390/v15091913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Hepatitis B virus (HBV) chronically infects millions of people worldwide, which underscores the importance of discovering and designing novel anti-HBV therapeutics to complement current treatment strategies. An underexploited but attractive therapeutic target is ε, a cis-acting regulatory stem-loop RNA situated within the HBV pregenomic RNA (pgRNA). The binding of ε to the viral polymerase protein (P) is pivotal, as it triggers the packaging of pgRNA and P, as well as the reverse transcription of the viral genome. Consequently, small molecules capable of disrupting this interaction hold the potential to inhibit the early stages of HBV replication. The rational design of such ligands necessitates high-resolution structural information for the ε-P complex or its individual components. While these data are currently unavailable for P, our recent structural elucidation of ε through solution nuclear magnetic resonance spectroscopy marks a significant advancement in this area. In this review, we provide a brief overview of HBV replication and some of the therapeutic strategies to combat chronic HBV infection. These descriptions are intended to contextualize our recent experimental efforts to characterize ε and identify ε-targeting ligands, with the ultimate goal of developing novel anti-HBV therapeutics.
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Affiliation(s)
- Lukasz T. Olenginski
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Solomon K. Attionu
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Erica N. Henninger
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Regan M. LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Andrew P. Longhini
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Theodore K. Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
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6
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Colón-Thillet R, Stone D, Loprieno MA, Klouser L, Roychoudhury P, Santo TK, Xie H, Stensland L, Upham SL, Pepper G, Huang ML, Aubert M, Jerome KR. Liver-Humanized NSG-PiZ Mice Support the Study of Chronic Hepatitis B Virus Infection and Antiviral Therapies. Microbiol Spectr 2023; 11:e0517622. [PMID: 37199630 PMCID: PMC10269919 DOI: 10.1128/spectrum.05176-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/27/2023] [Indexed: 05/19/2023] Open
Abstract
Hepatitis B virus (HBV) is a pathogen of major public health importance that is largely incurable once a chronic infection is established. Only humans and great apes are fully permissive to HBV infection, and this species restriction has impacted HBV research by limiting the utility of small animal models. To combat HBV species restrictions and enable more in vivo studies, liver-humanized mouse models have been developed that are permissive to HBV infection and replication. Unfortunately, these models can be difficult to establish and are expensive commercially, which has limited their academic use. As an alternative mouse model to study HBV, we evaluated liver-humanized NSG-PiZ mice and showed that they are fully permissive to HBV. HBV selectively replicates in human hepatocytes within chimeric livers, and HBV-positive (HBV+) mice secrete infectious virions and hepatitis B surface antigen (HBsAg) into blood while also harboring covalently closed circular DNA (cccDNA). HBV+ mice develop chronic infections lasting at least 169 days, which should enable the study of new curative therapies targeting chronic HBV, and respond to entecavir therapy. Furthermore, HBV+ human hepatocytes in NSG-PiZ mice can be transduced by AAV3b and AAV.LK03 vectors, which should enable the study of gene therapies that target HBV. In summary, our data demonstrate that liver-humanized NSG-PiZ mice can be used as a robust and cost-effective alternative to existing chronic hepatitis B (CHB) models and may enable more academic research labs to study HBV disease pathogenesis and antiviral therapy. IMPORTANCE Liver-humanized mouse models have become the gold standard for the in vivo study of hepatitis B virus (HBV), yet their complexity and cost have prohibited widespread use of existing models in research. Here, we show that the NSG-PiZ liver-humanized mouse model, which is relatively inexpensive and simple to establish, can support chronic HBV infection. Infected mice are fully permissive to hepatitis B, supporting both active replication and spread, and can be used to study novel antiviral therapies. This model is a viable and cost-effective alternative to other liver-humanized mouse models that are used to study HBV.
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Affiliation(s)
- Rossana Colón-Thillet
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Michelle A. Loprieno
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Lindsay Klouser
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Pavitra Roychoudhury
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Tracy K. Santo
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Hong Xie
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Laurence Stensland
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Sarah L. Upham
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Gregory Pepper
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Meei-Li Huang
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Martine Aubert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Keith R. Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
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7
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Pan Y, Xia H, He Y, Zeng S, Shen Z, Huang W. The progress of molecules and strategies for the treatment of HBV infection. Front Cell Infect Microbiol 2023; 13:1128807. [PMID: 37009498 PMCID: PMC10053227 DOI: 10.3389/fcimb.2023.1128807] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/03/2023] [Indexed: 03/17/2023] Open
Abstract
Hepatitis B virus infections have always been associated with high levels of mortality. In 2019, hepatitis B virus (HBV)-related diseases resulted in approximately 555,000 deaths globally. In view of its high lethality, the treatment of HBV infections has always presented a huge challenge. The World Health Organization (WHO) came up with ambitious targets for the elimination of hepatitis B as a major public health threat by 2030. To accomplish this goal, one of the WHO’s strategies is to develop curative treatments for HBV infections. Current treatments in a clinical setting included 1 year of pegylated interferon alpha (PEG-IFNα) and long-term nucleoside analogues (NAs). Although both treatments have demonstrated outstanding antiviral effects, it has been difficult to develop a cure for HBV. The reason for this is that covalently closed circular DNA (cccDNA), integrated HBV DNA, the high viral burden, and the impaired host immune responses all hinder the development of a cure for HBV. To overcome these problems, there are clinical trials on a number of antiviral molecules being carried out, all -showing promising results so far. In this review, we summarize the functions and mechanisms of action of various synthetic molecules, natural products, traditional Chinese herbal medicines, as clustered regularly interspaced short palindromic repeats and their associated proteins (CRISPR/Cas)-based systems, zinc finger nucleases (ZFNs), and transcription activator-like effector nucleases (TALENs), all of which could destroy the stability of the HBV life cycle. In addition, we discuss the functions of immune modulators, which can enhance or activate the host immune system, as well some representative natural products with anti-HBV effects.
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8
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Tripathi S, Khatri P, Fatima Z, Pandey RP, Hameed S. A Landscape of CRISPR/Cas Technique for Emerging Viral Disease Diagnostics and Therapeutics: Progress and Prospects. Pathogens 2022; 12:pathogens12010056. [PMID: 36678404 PMCID: PMC9863163 DOI: 10.3390/pathogens12010056] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/22/2022] [Accepted: 12/25/2022] [Indexed: 12/31/2022] Open
Abstract
Viral diseases have emerged as a serious threat to humanity and as a leading cause of morbidity worldwide. Many viral diagnostic methods and antiviral therapies have been developed over time, but we are still a long way from treating certain infections caused by viruses. Acquired immunodeficiency syndrome (AIDS) is one of the challenges where current medical science advancements fall short. As a result, new diagnostic and treatment options are desperately needed. The CRISPR/Cas9 system has recently been proposed as a potential therapeutic approach for viral disease treatment. CRISPR/Cas9 is a specialised, effective, and adaptive gene-editing technique that can be used to modify, delete, or correct specific DNA sequences. It has evolved into an advanced, configurable nuclease-based single or multiple gene-editing tool with a wide range of applications. It is widely preferred simply because its operational procedures are simple, inexpensive, and extremely efficient. Exploration of infectious virus genomes is required for a comprehensive study of infectious viruses. Herein, we have discussed the historical timeline-based advancement of CRISPR, CRISPR/Cas9 as a gene-editing technology, the structure of CRISPR, and CRISPR as a diagnostic tool for studying emerging viral infections. Additionally, utilizing CRISPR/Cas9 technology to fight viral infections in plants, CRISPR-based diagnostics of viruses, pros, and cons, and bioethical issues of CRISPR/Cas9-based genomic modification are discussed.
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Affiliation(s)
- Shyam Tripathi
- Centre for Drug Design Discovery and Development (C4D), SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat 131029, India
| | - Purnima Khatri
- Centre for Drug Design Discovery and Development (C4D), SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat 131029, India
- Department of Microbiology, SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat 131029, India
| | - Zeeshan Fatima
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, University of Bisha, Bisha 61922, Saudi Arabia
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India
| | - Ramendra Pati Pandey
- Centre for Drug Design Discovery and Development (C4D), SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat 131029, India
- Department of Microbiology, SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat 131029, India
- Correspondence: (R.P.P.); (S.H.)
| | - Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India
- Correspondence: (R.P.P.); (S.H.)
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9
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Watanabe T, Hayashi S, Tanaka Y. Drug Discovery Study Aimed at a Functional Cure for HBV. Viruses 2022; 14:v14071393. [PMID: 35891374 PMCID: PMC9321005 DOI: 10.3390/v14071393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/19/2022] [Accepted: 06/23/2022] [Indexed: 02/04/2023] Open
Abstract
Hepatitis B virus (HBV) causes acute and, most importantly, chronic hepatitis B worldwide. Antiviral treatments have been developed to reduce viral loads but few patients with chronic hepatitis B (CHB) achieve a functional cure. The development of new therapeutic agents is desirable. Recently, many novel agents have been developed, including drugs targeting HBV-DNA and HBV-RNA. This review provides an overview of the developmental status of these drugs, especially direct acting antiviral agents (DAAs). Serological biomarkers of HBV infection are essential for predicting the clinical course of CHB. It is also important to determine the amount and activity of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. Hepatitis B core-associated antigen (HBcrAg) is a new HBV marker that has an important role in reflecting cccDNA in CHB, because it is associated with hepatic cccDNA, as well as serum HBV DNA. The highly sensitive HBcrAg (iTACT-HBcrAg) assay could be a very sensitive HBV activation marker and an alternative to HBV DNA testing for monitoring reactivation. Many of the drugs currently in clinical trials have shown efficacy in reducing hepatitis B surface antigen (HBsAg) levels. Combination therapies with DAAs and boost immune response are also under development; finding the best combinations will be important for therapeutic development.
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Bianca C, Sidhartha E, Tiribelli C, El-Khobar KE, Sukowati CHC. Role of hepatitis B virus in development of hepatocellular carcinoma: Focus on covalently closed circular DNA. World J Hepatol 2022; 14:866-884. [PMID: 35721287 PMCID: PMC9157711 DOI: 10.4254/wjh.v14.i5.866] [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] [Received: 11/30/2021] [Revised: 01/31/2022] [Accepted: 04/25/2022] [Indexed: 02/06/2023] Open
Abstract
Chronic infection with hepatitis B virus (HBV) remains a major global health problem, especially in developing countries. It may lead to prolonged liver damage, fibrosis, cirrhosis, and hepatocellular carcinoma. Persistent chronic HBV infection is related to host immune response and the stability of the covalently closed circular DNA (cccDNA) in human hepatocytes. In addition to being essential for viral transcription and replication, cccDNA is also suspected to play a role in persistent HBV infections or hepatitis relapses since cccDNA is very stable in non-dividing human hepatocytes. Understanding the pathogenicity and oncogenicity of HBV components would be essential in the development of new diagnostic tools and treatment strategies. This review summarizes the role and molecular mechanisms of HBV cccDNA in hepatocyte transformation and hepatocarcinogenesis and current efforts to its detection and targeting.
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Affiliation(s)
- Claryssa Bianca
- Department of Biomedicine, Indonesia International Institute for Life Sciences, Jakarta 13210, Indonesia
| | - Elizabeth Sidhartha
- Department of Biomedicine, Indonesia International Institute for Life Sciences, Jakarta 13210, Indonesia
| | - Claudio Tiribelli
- Centro Studi Fegato, Fondazione Italiana Fegato ONLUS, Trieste 34149, Italy
| | - Korri Elvanita El-Khobar
- Eijkman Center for Molecular Biology, National Research and Innovation Agency (BRIN), Jakarta 10340, Indonesia
| | - Caecilia H C Sukowati
- Centro Studi Fegato, Fondazione Italiana Fegato ONLUS, Trieste 34149, Italy
- Eijkman Center for Molecular Biology, National Research and Innovation Agency (BRIN), Jakarta 10340, Indonesia
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11
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Jacobs R, Singh P, Smith T, Arbuthnot P, Maepa MB. Prospects of viral vector-mediated delivery of sequences encoding anti-HBV designer endonucleases. Gene Ther 2022:10.1038/s41434-022-00342-5. [PMID: 35606493 DOI: 10.1038/s41434-022-00342-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/09/2022]
Abstract
Available treatment for chronic hepatitis B virus (HBV) infection offers modest functional curative efficacy. The viral replicative intermediate comprising covalently closed circular DNA (cccDNA) is responsible for persistent chronic HBV infection. Hence, current efforts have focused on developing therapies that disable cccDNA. Employing gene editing tools has emerged as an attractive strategy, with the end goal of establishing permanently inactivated cccDNA. Although anti-HBV designer nucleases are effective in vivo, none has yet progressed to clinical trial. Lack of safe and efficient delivery systems remains the limiting factor. Several vectors may be used to deliver anti-HBV gene editor-encoding sequences, with viral vectors being at the forefront. Despite the challenges associated with packaging large gene editor-encoding sequences into viral vectors, advancement in the field is overcoming such limitations. Translation of viral vector-mediated gene editing against HBV to clinical application is within reach. This review discusses the prospects of delivering HBV targeted designer nucleases using viral vectors.
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Affiliation(s)
- Ridhwaanah Jacobs
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Prashika Singh
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tiffany Smith
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mohube Betty Maepa
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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12
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Leowattana W, Leowattana T. Chronic hepatitis B: New potential therapeutic drugs target. World J Virol 2022; 11:57-72. [PMID: 35117971 PMCID: PMC8788212 DOI: 10.5501/wjv.v11.i1.57] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/13/2021] [Accepted: 01/05/2022] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis B (CHB) infection remains the most causative agent of liver-related morbidity and mortality worldwide. It impacts nearly 300 million people. The current treatment for chronic infection with the hepatitis B virus (HBV) is complex and lacks a durable treatment response, especially hepatitis B surface antigen (HBsAg) loss, necessitating indefinite treatment in most CHB patients due to the persistence of HBV covalently closed circular DNA (cccDNA). New drugs that target distinct steps of the HBV life cycle have been investigated, which comprise inhibiting the entry of HBV into hepatocytes, disrupting or silencing HBV cccDNA, modulating nucleocapsid assembly, interfering HBV transcription, and inhibiting HBsAg release. The achievement of a functional cure or sustained HBsAg loss in CHB patients represents the following approach towards HBV eradication. This review will explore the up-to-date advances in the development of new direct-acting anti-HBV drugs. Hopefully, with the combination of the current antiviral drugs and the newly developed direct-acting antiviral drugs targeting the different steps of the HBV life cycle, the ultimate eradication of CHB infection will soon be achieved.
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Affiliation(s)
- Wattana Leowattana
- Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Tawithep Leowattana
- Department of Medicine, Faculty of Medicine, Srinakharinwirot University, Bangkok 10110, Thailand
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Li G, Li X, Zhuang S, Wang L, Zhu Y, Chen Y, Sun W, Wu Z, Zhou Z, Chen J, Huang X, Wang J, Li D, Li W, Wang H, Wei W. Gene editing and its applications in biomedicine. SCIENCE CHINA. LIFE SCIENCES 2022; 65:660-700. [PMID: 35235150 PMCID: PMC8889061 DOI: 10.1007/s11427-021-2057-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/06/2021] [Indexed: 02/06/2023]
Abstract
The steady progress in genome editing, especially genome editing based on the use of clustered regularly interspaced short palindromic repeats (CRISPR) and programmable nucleases to make precise modifications to genetic material, has provided enormous opportunities to advance biomedical research and promote human health. The application of these technologies in basic biomedical research has yielded significant advances in identifying and studying key molecular targets relevant to human diseases and their treatment. The clinical translation of genome editing techniques offers unprecedented biomedical engineering capabilities in the diagnosis, prevention, and treatment of disease or disability. Here, we provide a general summary of emerging biomedical applications of genome editing, including open challenges. We also summarize the tools of genome editing and the insights derived from their applications, hoping to accelerate new discoveries and therapies in biomedicine.
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Affiliation(s)
- Guanglei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Xiangyang Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Songkuan Zhuang
- Department of Clinical Laboratory, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, 518035, China
| | - Liren Wang
- Shanghai Frontiers Science Research Base of Genome Editing and Cell Therapy, Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Yifan Zhu
- Shanghai Frontiers Science Research Base of Genome Editing and Cell Therapy, Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Yangcan Chen
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wen Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zeguang Wu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Zhuo Zhou
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Jia Chen
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Jin Wang
- Department of Clinical Laboratory, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, 518035, China.
| | - Dali Li
- Shanghai Frontiers Science Research Base of Genome Editing and Cell Therapy, Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China.
| | - Wei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China.
- Bejing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
- HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China.
| | - Haoyi Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Wensheng Wei
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China.
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Mnyandu N, Limani SW, Arbuthnot P, Maepa MB. Advances in designing Adeno-associated viral vectors for development of anti-HBV gene therapeutics. Virol J 2021; 18:247. [PMID: 34903258 PMCID: PMC8670254 DOI: 10.1186/s12985-021-01715-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/26/2021] [Indexed: 12/25/2022] Open
Abstract
Despite the five decades having passed since discovery of the hepatitis B virus (HBV), together with development of an effective anti-HBV vaccine, infection with the virus remains a serious public health problem and results in nearly 900,000 annual deaths worldwide. Current therapies do not eliminate the virus and viral replication typically reactivates after treatment withdrawal. Hence, current endeavours are aimed at developing novel therapies to achieve a functional cure. Nucleic acid-based therapeutic approaches are promising, with several candidates showing excellent potencies in preclinical and early stages of clinical development. However, this class of therapeutics is yet to become part of standard anti-HBV treatment regimens. Obstacles delaying development of gene-based therapies include lack of clinically relevant delivery methods and a paucity of good animal models for preclinical characterisation. Recent studies have demonstrated safety and efficiency of Adeno-associated viral vectors (AAVs) in gene therapy. However, AAVs do have flaws and this has prompted research aimed at improving design of novel and artificially synthesised AAVs. Main goals are to improve liver transduction efficiencies and avoiding immune clearance. Application of AAVs to model HBV replication in vivo is also useful for characterising anti-HBV gene therapeutics. This review summarises recent advances in AAV engineering and their contributions to progress with anti-HBV gene therapy development.
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Affiliation(s)
- Njabulo Mnyandu
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Shonisani Wendy Limani
- 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
| | - Mohube Betty Maepa
- 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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Lin H, Li G, Peng X, Deng A, Ye L, Shi L, Wang T, He J. The Use of CRISPR/Cas9 as a Tool to Study Human Infectious Viruses. Front Cell Infect Microbiol 2021; 11:590989. [PMID: 34513721 PMCID: PMC8430244 DOI: 10.3389/fcimb.2021.590989] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/04/2021] [Indexed: 12/12/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) systems are a set of versatile gene-editing toolkit that perform diverse revolutionary functions in various fields of application such as agricultural practices, food industry, biotechnology, biomedicine, and clinical research. Specially, as a novel antiviral method of choice, CRISPR/Cas9 system has been extensively and effectively exploited to fight against human infectious viruses. Infectious diseases including human immunodeficiency virus (HIV), hepatitis B virus (HBV), human papillomavirus (HPV), and other viruses are still global threats with persistent potential to probably cause pandemics. To facilitate virus removals, the CRISPR/Cas9 system has already been customized to confer new antiviral capabilities into host animals either by modifying host genome or by directly targeting viral inherent factors in the form of DNA. Although several limitations and difficulties still need to be conquered, this technology holds great promises in the treatment of human viral infectious diseases. In this review, we will first present a brief biological feature of CRISPR/Cas9 systems, which includes a description of CRISPR/Cas9 structure and composition; thereafter, we will focus on the investigations and applications that employ CRISPR/Cas9 system to combat several human infectious viruses and discuss challenges and future perspectives of using this new platform in the preclinical and clinical settings as an antiviral strategy.
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Affiliation(s)
- Huafeng Lin
- Changsha Hospital for Maternal and Child Health Care of Hunan Normal University, Changsha, China.,Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Gang Li
- Institute of Biomedicine and Department of Cell Biology, Jinan University, Guangzhou, China
| | - Xiangwen Peng
- Changsha Hospital for Maternal and Child Health Care of Hunan Normal University, Changsha, China
| | - Aimin Deng
- Changsha Hospital for Maternal and Child Health Care of Hunan Normal University, Changsha, China
| | - Lei Ye
- Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Lei Shi
- Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
| | - Tuanmei Wang
- Changsha Hospital for Maternal and Child Health Care of Hunan Normal University, Changsha, China
| | - Jun He
- Changsha Hospital for Maternal and Child Health Care of Hunan Normal University, Changsha, China
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16
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Recent developments with advancing gene therapy to treat chronic infection with hepatitis B virus. Curr Opin HIV AIDS 2021; 15:200-207. [PMID: 32141890 DOI: 10.1097/coh.0000000000000623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW The available vaccine and therapies against hepatitis B virus (HBV) rarely eliminate chronic infection with the virus. High mortality resulting from complicating cirrhosis and hepatocellular carcinoma makes improving anti-HBV therapy an important priority. Recent advances with using gene therapy to counter HBV have potential and are the focus of this review. RECENT FINDINGS The stable replication-competent HBV intermediate comprising covalently closed circular DNA (cccDNA) is the template for expression of all viral genes. Inactivating cccDNA has thus been a focus of research aimed at achieving cure for HBV infection. Many studies have reported profound inhibition of replication of the virus using silencing and editing techniques. Therapeutic gene silencing with synthetic short interfering RNA is now in clinical trials. Ability to mutate and permanently inactivate cccDNA with engineered gene editors, such as those derived from CRISPR/Cas or TALENs, is particularly appealing but has not yet reached clinical evaluation. SUMMARY Gene silencing and gene editing potentially provide the means to cure HBV infection. However, achieving efficient delivery of therapeutic sequences, ensuring their specificity of action and progress with other antiviral strategies are likely to determine utility of gene therapy for chronic HBV infection.
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Ligat G, Verrier ER, Nassal M, Baumert TF. Hepatitis B virus-host interactions and novel targets for viral cure. Curr Opin Virol 2021; 49:41-51. [PMID: 34029994 PMCID: PMC7613419 DOI: 10.1016/j.coviro.2021.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023]
Abstract
Chronic infection with HBV is a major cause of advanced liver disease and hepatocellular carcinoma. Nucleos(t)ide analogues effectively control HBV replication but viral cure is rare. Hence treatment has often to be administered for an indefinite duration, increasing the risk for selection of drug resistant virus variants. PEG-interferon-α-based therapies can sometimes cure infection but suffer from a low response rate and severe side-effects. CHB is characterized by the persistence of a nuclear covalently closed circular DNA (cccDNA), which is not targeted by approved drugs. Targeting host factors which contribute to the viral life cycle provides new opportunities for the development of innovative therapeutic strategies aiming at HBV cure. An improved understanding of the host immune system has resulted in new potentially curative candidate approaches. Here, we review the recent advances in understanding HBV–host interactions and highlight how this knowledge contributes to exploiting host-targeting strategies for a viral cure.
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Affiliation(s)
- Gaëtan Ligat
- Université de Strasbourg, F-67000 Strasbourg, France; Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMRS 1110, F-67000 Strasbourg, France.
| | - Eloi R Verrier
- Université de Strasbourg, F-67000 Strasbourg, France; Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMRS 1110, F-67000 Strasbourg, France.
| | - Michael Nassal
- University Hospital Freiburg, Dept. of Internal Medicine 2/Molecular Biology, D79106 Freiburg, Germany.
| | - Thomas F Baumert
- Université de Strasbourg, F-67000 Strasbourg, France; Inserm, Institut de Recherche sur les Maladies Virales et Hépatiques UMRS 1110, F-67000 Strasbourg, France; Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Nouvel Hôpital Civil, 67000 Strasbourg, France.
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18
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Maepa MB, Bloom K, Ely A, Arbuthnot P. Hepatitis B virus: promising drug targets and therapeutic implications. Expert Opin Ther Targets 2021; 25:451-466. [PMID: 33843412 DOI: 10.1080/14728222.2021.1915990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Current therapy for infection with hepatitis B virus (HBV) rarely clears the virus, and viremia commonly resurges following treatment withdrawal. To prevent serious complications of the infection, research has been aimed at identifying new viral and host targets that can be exploited to inactivate HBV replication.Areas covered: This paper reviews the use of these new molecular targets to advance anti-HBV therapy. Emphasis is on appraising data from pre-clinical and early clinical studies described in journal articles published during the past 10 years and available from PubMed.Expert opinion: The wide range of viral and host factors that can be targeted to disable HBV is impressive and improved insight into HBV molecular biology continues to provide the basis for new drug design. In addition to candidate therapies that have direct or indirect actions on HBV covalently closed circular DNA (cccDNA), compounds that inhibit HBsAg secretion, viral entry, destabilize viral RNA and effect enhanced immune responses to HBV show promise. Preclinical and clinical evaluation of drug candidates, as well as investigating use of treatment combinations, are encouraging. The field is poised at an interesting stage and indications are that reliably achieving functional cure from HBV infection is a tangible goal.
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Affiliation(s)
- Mohube Betty Maepa
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Kristie Bloom
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Abdullah Ely
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick Arbuthnot
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
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19
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Ely A, Singh P, Smith TS, Arbuthnot P. In vitro transcribed mRNA for expression of designer nucleases: Advantages as a novel therapeutic for the management of chronic HBV infection. Adv Drug Deliv Rev 2021; 168:134-146. [PMID: 32485207 DOI: 10.1016/j.addr.2020.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 05/14/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023]
Abstract
Chronic infection with the hepatitis B virus (HBV) remains a significant worldwide medical problem. While diseases caused by HIV infection, tuberculosis and malaria are on the decline, new cases of chronic hepatitis B are on the rise. Because often fatal complications of cirrhosis and hepatocellular carcinoma are associated with chronic hepatitis B, the need for a cure is as urgent as ever. Currently licensed therapeutics fail to eradicate the virus and this is attributable to persistence of the viral replication intermediate comprising covalently closed circular DNA (cccDNA). Elimination or inactivation of the viral cccDNA is thus a goal of research aimed at hepatitis B cure. The ability to engineer nucleases that are capable of specific cleavage of a DNA sequence now provides the means to disable cccDNA permanently. The scientific literature is replete with many examples of using designer zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and RNA-guided endonucleases (RGENs) to inactivate HBV. However, important concerns about safety, dose control and efficient delivery need to be addressed before the technology is employed in a clinical setting. Use of in vitro transcribed mRNA to express therapeutic gene editors goes some way to overcoming these concerns. The labile nature of RNA limits off-target effects and enables dose control. Compatibility with hepatotropic non-viral vectors is convenient for the large scale preparation that will be required for advancing gene editing as a mode of curing chronic hepatitis B.
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20
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Suzuki Y, Onuma H, Sato R, Sato Y, Hashiba A, Maeki M, Tokeshi M, Kayesh MEH, Kohara M, Tsukiyama-Kohara K, Harashima H. Lipid nanoparticles loaded with ribonucleoprotein-oligonucleotide complexes synthesized using a microfluidic device exhibit robust genome editing and hepatitis B virus inhibition. J Control Release 2020; 330:61-71. [PMID: 33333121 DOI: 10.1016/j.jconrel.2020.12.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/02/2020] [Accepted: 12/10/2020] [Indexed: 12/25/2022]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system has considerable therapeutic potential for use in treating a wide range of intractable genetic and infectious diseases including hepatitis B virus (HBV) infections. While non-viral delivery technologies for the CRISPR/Cas system are expected to have clinical applications, difficulties associated with the clinically relevant synthesis of formulations and the poor efficiency of delivery severely hinder therapeutic genome editing. We report herein on the production of a lipid nanoparticle (LNP)-based CRISPR/Cas ribonucleoprotein (RNP) delivery nanoplatform synthesized using a clinically relevant mixer-equipped microfluidic device. DNA cleavage activity and the aggregation of Cas enzymes was completely avoided under the optimized synthetic conditions. The optimized formulation, which was identified through 2 steps of design of experiments, exhibited excellent gene disruption (up to 97%) and base substitution (up to 23%) without any apparent cytotoxicity. The addition of negative charges to the RNPs by complexing single-stranded oligonucleotide (ssON) significantly enhanced the delivery of both Cas9 and Cpf1 RNPs. The optimized formulation significantly suppressed both HBV DNA and covalently closed circular DNA (cccDNA) in HBV-infected human liver cells compared to adeno-associated virus type 2 (AAV2). These findings represent a significant contribution to the development of CRISPR/Cas RNP delivery technology and its practical applications in genome editing therapy.
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Affiliation(s)
- Yuichi Suzuki
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan
| | - Haruno Onuma
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan
| | - Risa Sato
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan
| | - Yusuke Sato
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan.
| | - Akari Hashiba
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan
| | - Masatoshi Maeki
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Hokkaido, Japan; JST PRESTO, Saitama, Japan
| | - Manabu Tokeshi
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Hokkaido, Japan; Innovative Research Center for Preventive Medical Engineering, Nagoya University, Nagoya, Japan; Institute of Nano-Life Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, Japan
| | - Mohammad Enamul Hoque Kayesh
- Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan; Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan; Department of Microbiology and Public Health, Patuakhali Science and Technology University, Patuakhali, Bangladesh
| | - Michinori Kohara
- Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kyoko Tsukiyama-Kohara
- Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan; Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Hideyoshi Harashima
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan.
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CRISPR-Cas9 gene editing of hepatitis B virus in chronically infected humanized mice. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 20:258-275. [PMID: 33473359 PMCID: PMC7803634 DOI: 10.1016/j.omtm.2020.11.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/18/2020] [Indexed: 02/07/2023]
Abstract
Chronic hepatitis B virus (HBV) infection is a major public health problem. New treatment approaches are needed because current treatments do not target covalently closed circular DNA (cccDNA), the template for HBV replication, and rarely clear the virus. We harnessed adeno-associated virus (AAV) vectors and CRISPR-Staphylococcus aureus (Sa)Cas9 to edit the HBV genome in liver-humanized FRG mice chronically infected with HBV and receiving entecavir. Gene editing was detected in livers of five of eight HBV-specific AAV-SaCas9-treated mice, but not control mice, and mice with detectable HBV gene editing showed higher levels of SaCas9 delivery to HBV+ human hepatocytes than those without gene editing. HBV-specific AAV-SaCas9 therapy significantly improved survival of human hepatocytes, showed a trend toward decreasing total liver HBV DNA and cccDNA, and was well tolerated. This work provides evidence for the feasibility and safety of in vivo gene editing for chronic HBV infections, and it suggests that with further optimization, this approach may offer a plausible way to treat or even cure chronic HBV infections.
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22
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Younis MA, Khalil IA, Harashima H. Gene Therapy for Hepatocellular Carcinoma: Highlighting the Journey from Theory to Clinical Applications. ADVANCED THERAPEUTICS 2020. [DOI: 10.1002/adtp.202000087] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Mahmoud A. Younis
- Laboratory of Innovative Nanomedicine, Faculty of Pharmaceutical Sciences Hokkaido University Kita‐12, Nishi‐6, Kita‐ku Sapporo 060‐0812 Japan
- Faculty of Pharmacy Assiut University Assiut 71526 Egypt
| | - Ikramy A. Khalil
- Laboratory of Innovative Nanomedicine, Faculty of Pharmaceutical Sciences Hokkaido University Kita‐12, Nishi‐6, Kita‐ku Sapporo 060‐0812 Japan
- Faculty of Pharmacy Assiut University Assiut 71526 Egypt
| | - Hideyoshi Harashima
- Laboratory of Innovative Nanomedicine, Faculty of Pharmaceutical Sciences Hokkaido University Kita‐12, Nishi‐6, Kita‐ku Sapporo 060‐0812 Japan
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23
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Xia Y, Guo H. Hepatitis B virus cccDNA: Formation, regulation and therapeutic potential. Antiviral Res 2020; 180:104824. [PMID: 32450266 PMCID: PMC7387223 DOI: 10.1016/j.antiviral.2020.104824] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/03/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
Abstract
Hepatitis B virus (HBV) infection remains a major public health concern worldwide with about 257 million individuals chronically infected. Current therapies can effectively control HBV replication and slow down disease progress, but cannot cure HBV infection. Upon infection, HBV establishes a pool of covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. The cccDNA exists as a minichromosome and resists to antivirals, thus a therapeutic eradication of cccDNA from the infected cells remains unattainable. In this review, we summarize the state of knowledge on the mechanisms underlying cccDNA formation and regulation, and discuss the possible strategies that may contribute to the eradication of HBV through targeting cccDNA.
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Affiliation(s)
- Yuchen Xia
- State Key Laboratory of Virology and Hubei Province Key Laboratory of Allergy and Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
| | - Haitao Guo
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA.
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24
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Zhao K, Liu A, Xia Y. Insights into Hepatitis B Virus DNA Integration-55 Years after Virus Discovery. Innovation (N Y) 2020; 1:100034. [PMID: 34557710 PMCID: PMC8454683 DOI: 10.1016/j.xinn.2020.100034] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatitis B virus (HBV), which was discovered in 1965, is a threat to global public health. HBV infects human hepatocytes and leads to acute and chronic liver diseases, and there is no cure. In cells infected by HBV, viral DNA can be integrated into the cellular genome. HBV DNA integration is a complicated process during the HBV life cycle. Although HBV integration normally results in replication-incompetent transcripts, it can still act as a template for viral protein expression. Of note, it is a primary driver of hepatocellular carcinoma (HCC). Recently, with the development of detection methods and research models, the molecular biology and the pathogenicity of HBV DNA integration have been better revealed. Here, we review the advances in the research of HBV DNA integration, including molecular mechanisms, detection methods, research models, the effects on host and viral gene expression, the role of HBV integrations in the pathogenesis of HCC, and potential treatment strategies. Finally, we discuss possible future research prospects of HBV DNA integration. HBV DNA integration is associated with hepatocarcinogenesis via multiple mechanisms HBV double-stranded linear DNA (dslDNA) is the dominant substrate for integration into the host genome The insertion sites of HBV DNA integration occur throughout the whole host genome using the NHEJ or MMEJ DNA repair pathway HBV DNA integration should be used as a clinical indicator for disease monitoring and treatment of patients with HBV infection
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25
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Screening and Evaluation of Novel Compounds against Hepatitis B Virus Polymerase Using Highly Purified Reverse Transcriptase Domain. Viruses 2020; 12:v12080840. [PMID: 32752057 PMCID: PMC7472185 DOI: 10.3390/v12080840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/28/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022] Open
Abstract
Hepatitis B virus (HBV) polymerase seems to be very hard to express and purify sufficiently, which has long hampered the generation of anti-HBV drugs based on the nature of the polymerase. To date, there has been no useful system developed for drug screening against HBV polymerase. In this study, we successfully obtained a highly purified reverse transcriptase (RT) domain of the polymerase, which has a template/primer and substrate binding activity, and established a novel high-throughput screening (HTS) system using purified RT protein for finding novel polymerase inhibitors. To examine whether the assay system provides reliable results, we tested the small scale screening using pharmacologically active compounds. As a result, the pilot screening identified already-known anti-viral polymerase agents. Then, we screened 20,000 chemical compounds and newly identified four hits. Several of these compounds inhibited not only the HBV RT substrate and/ template/primer binding activity, but also Moloney murine leukemia virus RT activity, which has an elongation activity. Finally, these candidates did show to be effective even in the cell-based assay. Our screening system provides a useful tool for searching candidate inhibitors against HBV.
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Wu X, Ma W, Mei C, Chen X, Yao Y, Liu Y, Qin X, Yuan Y. Description of CRISPR/Cas9 development and its prospect in hepatocellular carcinoma treatment. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2020; 39:97. [PMID: 32487115 PMCID: PMC7268395 DOI: 10.1186/s13046-020-01603-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/25/2020] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most common malignancies today. Patients suffer from HCC since its high malignancy and limited treatment means. With the development of genetic research, new therapeutic strategy comes up in the way of gene editing. Clustered regularly interspaced short palindromic repeat/CRISPR-associated nuclease 9 (CRISPR/Cas9) was discovered as an immune sequence in bacteria and archaea. After artificial transformation and follow-up research, it is widely used as a gene editing tool. In this review, the development of CRISPR/Cas9 is summarized in retrospect. Through the evaluation of novel research in HCC, it is concluded that CRISPR/Cas9 would promote cancer research and provide a new tool for genetic treatment in prospect.
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Affiliation(s)
- Xiaoling Wu
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Weijie Ma
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Chengjie Mei
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Xi Chen
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Ye Yao
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Yingyi Liu
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Xian Qin
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China
| | - Yufeng Yuan
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, Hubei Province, China.
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Abstract
Chronic hepatitis B (CHB) is a widespread global infection and a leading cause of hepatocellular carcinoma and liver failure. Current approaches to treat CHB involve the suppression of viral replication with either interferon or nucleos(t)ide analog therapy, but neither of these approaches can reliably induce viral eradication, immunologic control or long-lived viral suppression in the absence of continued therapy. In this update, we explore the major obstacles of CHB cure and review new therapeutic strategies and drug candidates.
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Affiliation(s)
- Lydia Tang
- Division of Clinical Care & Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Oncology, University of Maryland Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
| | - Shyam Kottilil
- Division of Clinical Care & Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Oncology, University of Maryland Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
| | - Eleanor Wilson
- Division of Clinical Care & Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Oncology, University of Maryland Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
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Targets and future direct-acting antiviral approaches to achieve hepatitis B virus cure. Lancet Gastroenterol Hepatol 2019; 4:883-892. [DOI: 10.1016/s2468-1253(19)30190-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/06/2019] [Accepted: 05/14/2019] [Indexed: 12/13/2022]
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Liu S, Xin Y. HBV cccDNA: The Stumbling Block for Treatment of HBV Infection. J Clin Transl Hepatol 2019; 7:195-196. [PMID: 31608210 PMCID: PMC6783674 DOI: 10.14218/jcth.2019.00047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 09/20/2019] [Accepted: 09/20/2019] [Indexed: 12/17/2022] Open
Affiliation(s)
- Shousheng Liu
- Central Laboratories, Qingdao Municipal Hospital, Qingdao, China
| | - Yongning Xin
- Department of Infectious Disease, Qingdao Municipal Hospital, Qingdao, China
- Correspondence to: Yongning Xin, Department of Infectious Disease, Qingdao Municipal Hospital, 1 Jiaozhou Road, Qingdao, Shandong 266011, China. Tel: +86-532-82789463, Fax: +86-532-85968434, E-mail:
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Zhu A, Liao X, Li S, Zhao H, Chen L, Xu M, Duan X. HBV cccDNA and Its Potential as a Therapeutic Target. J Clin Transl Hepatol 2019; 7:258-262. [PMID: 31608218 PMCID: PMC6783673 DOI: 10.14218/jcth.2018.00054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 04/02/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022] Open
Abstract
Chronic hepatitis B virus infection continues to be a major health burden worldwide. It can cause various degrees of liver damage and is strongly associated with the development of liver cirrhosis and hepatocellular carcinoma. Covalently closed circular DNA in the nucleus of infected cells cannot be disabled by present therapies which may lead to HBV persistence and relapse. In this review, we summarized the current knowledge on hepatitis B virus covalently closed circular DNA and its potential role as a therapeutic target.
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Affiliation(s)
- Anjing Zhu
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
| | - Xinzhong Liao
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
| | - Shuang Li
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
| | - Hang Zhao
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
| | - Limin Chen
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
| | - Min Xu
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
| | - Xiaoqiong Duan
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences and Peking Union Medical College, Chengdu, China
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Abstract
Chronic hepatitis B remains a significant cause of morbidity and mortality worldwide. Most hepatitis B virus (HBV)-infected individuals are neither diagnosed nor treated. In those treated, nucleos(t)ide polymerase inhibitors persistently suppress viremia to the limits of quantitation; however, few achieve a "functional cure," defined as sustained off-treatment loss of detectable serum HBV DNA with or without loss of hepatitis B surface antigen. The low cure rate has been attributed to an inability to eliminate the viral reservoir of covalently closed circular DNA from hepatocytes. This review focuses on the diverse therapeutic approaches currently under development that may contribute to the goal of HBV cure.
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Kostyusheva AP, Kostyushev DS, Brezgin SA, Zarifyan DN, Volchkova EV, Chulanov VP. Small Molecular Inhibitors of DNA Double Strand Break Repair Pathways Increase the ANTI-HBV Activity of CRISPR/Cas9. Mol Biol 2019. [DOI: 10.1134/s0026893319010072] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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33
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He X, Xie H, Liu X, Gu F. Basic and Clinical Application of Adeno-Associated Virus-Mediated Genome Editing. Hum Gene Ther 2019; 30:673-681. [PMID: 30588843 DOI: 10.1089/hum.2018.190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Traditional gene therapy (gene replacement) has made a breakthrough in treating inherited diseases. Adeno-associated virus (AAV) has emerged as a highly promising vector with innate ability, boosting the development of gene replacement and gene targeting. With the recent advance of engineered nucleases that work efficiently in human cells, AAV mediated-genome editing with nucleases has raised hopes for in situ gene therapy of inherited and non-inherited diseases. Here, the applications of AAV-mediated genome editing are highlighted, and the prospect of AAV and nucleases that will render extension of such success in clinical gene therapy is discussed.
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Affiliation(s)
- Xiubin He
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, P.R. China
| | - Haihua Xie
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, P.R. China
| | - Xiexie Liu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, P.R. China
| | - Feng Gu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, P.R. China
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Shankar S, Sreekumar A, Prasad D, Das AV, Pillai MR. Genome editing of oncogenes with ZFNs and TALENs: caveats in nuclease design. Cancer Cell Int 2018; 18:169. [PMID: 30386178 PMCID: PMC6198504 DOI: 10.1186/s12935-018-0666-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/17/2018] [Indexed: 01/18/2023] Open
Abstract
Background Gene knockout technologies involving programmable nucleases have been used to create knockouts in several applications. Gene editing using Zinc-finger nucleases (ZFNs), Transcription activator like effectors (TALEs) and CRISPR/Cas systems has been used to create changes in the genome in order to make it non-functional. In the present study, we have looked into the possibility of using six fingered CompoZr ZFN pair to target the E6 gene of HPV 16 genome. Methods HPV 16+ve cell lines; SiHa and CaSki were used for experiments. CompoZr ZFNs targeting E6 gene were designed and constructed by Sigma-Aldrich. TALENs targeting E6 and E7 genes were made using TALEN assembly kit. Gene editing was monitored by T7E1 mismatch nuclease and Nuclease resistance assays. Levels of E6 and E7 were further analyzed by RT-PCR, western blot as well as immunoflourescence analyses. To check if there is any interference due to methylation, cell lines were treated with sodium butyrate, and Nocodazole. Results Although ZFN editing activity in yeast based MEL-I assay was high, it yielded very low activity in tumor cell lines; only 6% editing in CaSki and negligible activity in SiHa cell lines. Though editing efficiency was better in CaSki, no significant reduction in E6 protein levels was observed in immunocytochemical analysis. Further, in silico analysis of DNA binding prediction revealed that some of the ZFN modules bound to sequence that did not match the target sequence. Hence, alternate ZFN pairs for E6 and E7 were not synthesized since no further active sites could be identified by in silico analyses. Then we designed TALENs to target E6 and E7 gene. TALENs designed to target E7 gene led to reduction of E7 levels in CaSki and SiHa cervical cancer cell lines. However, TALEN designed to target E6 gene did not yield any editing activity. Conclusions Our study highlights that designed nucleases intended to obtain bulk effect should have a reasonable editing activity which reflects phenotypically as well. Nucleases with low editing efficiency, intended for generation of knockout cell lines nucleases could be obtained by single cell cloning. This could serve as a criterion for designing ZFNs and TALENs. Electronic supplementary material The online version of this article (10.1186/s12935-018-0666-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sumitra Shankar
- Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Ahalya Sreekumar
- Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Deepti Prasad
- Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Ani V Das
- Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
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35
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De Silva Feelixge HS, Stone D, Roychoudhury P, Aubert M, Jerome KR. CRISPR/Cas9 and Genome Editing for Viral Disease-Is Resistance Futile? ACS Infect Dis 2018; 4:871-880. [PMID: 29522311 PMCID: PMC5993632 DOI: 10.1021/acsinfecdis.7b00273] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chronic viral infections remain a major public health issue affecting millions of people worldwide. Highly active antiviral treatments have significantly improved prognosis and infection-related morbidity and mortality but have failed to eliminate persistent viral forms. Therefore, new strategies to either eradicate or control these viral reservoirs are paramount to allow patients to stop antiretroviral therapy and realize a cure. Viral genome disruption based on gene editing by programmable endonucleases is one promising curative gene therapy approach. Recent findings on RNA-guided human immunodeficiency virus 1 (HIV-1) genome cleavage by Cas9 and other gene-editing enzymes in latently infected cells have shown high levels of site-specific genome disruption and potent inhibition of virus replication. However, HIV-1 can readily develop resistance to genome editing at a single antiviral target site. Current data suggest that cellular repair associated with DNA double-strand breaks can accelerate the emergence of resistance. On the other hand, a combination antiviral target strategy can exploit the same repair mechanism to functionally cure HIV-1 infection in vitro while avoiding the development of resistance. This perspective summarizes recent findings on the biology of resistance to genome editing and discusses the significance of viral genetic diversity on the application of gene editing strategies toward cure.
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Affiliation(s)
- Harshana S De Silva Feelixge
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle 98109, WA, USA
| | - Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle 98109, WA, USA
| | - Pavitra Roychoudhury
- Department of Laboratory Medicine, University of Washington, 1959 NE Pacific St, Seattle 98195, WA, USA
| | - Martine Aubert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle 98109, WA, USA
| | - Keith R Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle 98109, WA, USA
- Department of Laboratory Medicine, University of Washington, 1959 NE Pacific St, Seattle 98195, WA, USA
- Department of Microbiology, University of Washington, 1959 NE Pacific St, Seattle 98195, WA, USA
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36
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Abstract
With high morbidity and mortality worldwide, there is great interest in effective therapies for chronic hepatitis B (CHB) virus. There are currently several dozen investigational agents being developed for treatment of CHB. They can be broadly divided into two categories: (1) direct-acting antivirals (DAAs) that interfere with a specific step in viral replication; and (2) host-targeting agents that inhibit viral replication by modifying host cell function, with the latter group further divided into the subcategories of immune modulators and agents that target other host functions. Included among the DAAs being developed are RNA interference therapies, covalently closed circular DNA (cccDNA) formation and transcription inhibitors, core/capsid inhibitors, reverse transcriptase inhibitors, hepatitis B surface antigen (HBsAg) release inhibitors, antisense oligonucleotides, and helioxanthin analogues. Included among the host-targeting agents are entry inhibitors, cyclophilin inhibitors, and multiple immunomodulatory agents, including Toll-like receptor agonists, immune checkpoint inhibitors, therapeutic vaccines, engineered T cells, and several cytokine agents, including recombinant human interleukin-7 (CYT107) and SB 9200, a novel therapy that is believed to both have direct antiviral properties and to induce endogenous interferon. In this review we discuss agents that are currently in the clinical stage of development for CHB treatment as well as strategies and agents currently at the evaluation and discovery phase and potential future targets. Effective approaches to CHB may require suppression of viral replication combined with one or more host-targeting agents. Some of the recent research advances have led to the hope that with such a combined approach we may have a functional cure for CHB in the not distant future.
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Affiliation(s)
- Altaf Dawood
- Department of Internal Medicine, Section of Gastroenterology, University of Nevada School of Medicine, Las Vegas, NV, USA
| | - Syed Abdul Basit
- Department of Internal Medicine, Section of Gastroenterology, University of Nevada School of Medicine, Las Vegas, NV, USA
| | - Mahendran Jayaraj
- Department of Internal Medicine, Section of Gastroenterology, University of Nevada School of Medicine, Las Vegas, NV, USA
| | - Robert G Gish
- Department of Internal Medicine, Section of Gastroenterology, University of Nevada School of Medicine, Las Vegas, NV, USA.
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University Medical Center, Stanford, CA, USA.
- Hepatitis B Foundation, Doylestown, PA, USA.
- Asian Pacific Health Foundation, San Diego, CA, USA.
- National Viral Hepatitis Roundtable, Washington, DC, USA.
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González C, Tabernero D, Cortese MF, Gregori J, Casillas R, Riveiro-Barciela M, Godoy C, Sopena S, Rando A, Yll M, Lopez-Martinez R, Quer J, Esteban R, Buti M, Rodríguez-Frías F. Detection of hyper-conserved regions in hepatitis B virus X gene potentially useful for gene therapy. World J Gastroenterol 2018; 24:2095-2107. [PMID: 29785078 PMCID: PMC5960815 DOI: 10.3748/wjg.v24.i19.2095] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 03/26/2018] [Accepted: 05/06/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To detect hyper-conserved regions in the hepatitis B virus (HBV) X gene (HBX) 5’ region that could be candidates for gene therapy.
METHODS The study included 27 chronic hepatitis B treatment-naive patients in various clinical stages (from chronic infection to cirrhosis and hepatocellular carcinoma, both HBeAg-negative and HBeAg-positive), and infected with HBV genotypes A-F and H. In a serum sample from each patient with viremia > 3.5 log IU/mL, the HBX 5’ end region [nucleotide (nt) 1255-1611] was PCR-amplified and submitted to next-generation sequencing (NGS). We assessed genotype variants by phylogenetic analysis, and evaluated conservation of this region by calculating the information content of each nucleotide position in a multiple alignment of all unique sequences (haplotypes) obtained by NGS. Conservation at the HBx protein amino acid (aa) level was also analyzed.
RESULTS NGS yielded 1333069 sequences from the 27 samples, with a median of 4578 sequences/sample (2487-9279, IQR 2817). In 14/27 patients (51.8%), phylogenetic analysis of viral nucleotide haplotypes showed a complex mixture of genotypic variants. Analysis of the information content in the haplotype multiple alignments detected 2 hyper-conserved nucleotide regions, one in the HBX upstream non-coding region (nt 1255-1286) and the other in the 5’ end coding region (nt 1519-1603). This last region coded for a conserved amino acid region (aa 63-76) that partially overlaps a Kunitz-like domain.
CONCLUSION Two hyper-conserved regions detected in the HBX 5’ end may be of value for targeted gene therapy, regardless of the patients’ clinical stage or HBV genotype.
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Affiliation(s)
- Carolina González
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - David Tabernero
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Maria Francesca Cortese
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Marçall Yll, Josep Quer, Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Vall d’Hebron Institut Recerca-Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Josep Gregori
- Marçall Yll, Josep Quer, Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Vall d’Hebron Institut Recerca-Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
- Roche Diagnostics SL, Sant Cugat del Vallès 08174, Spain
| | - Rosario Casillas
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Marçall Yll, Josep Quer, Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Vall d’Hebron Institut Recerca-Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Mar Riveiro-Barciela
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
- Rafael Esteban and Maria Buti, Liver Unit, Department of Internal Medicine, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Cristina Godoy
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Marçall Yll, Josep Quer, Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Vall d’Hebron Institut Recerca-Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Sara Sopena
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Ariadna Rando
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Marçal Yll
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Rosa Lopez-Martinez
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Josep Quer
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Rafael Esteban
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Maria Buti
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Francisco Rodríguez-Frías
- Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid 28029, Spain
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Bloom K, Maepa MB, Ely A, Arbuthnot P. Gene Therapy for Chronic HBV-Can We Eliminate cccDNA? Genes (Basel) 2018; 9:E207. [PMID: 29649127 PMCID: PMC5924549 DOI: 10.3390/genes9040207] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 02/06/2023] Open
Abstract
Chronic infection with the hepatitis B virus (HBV) is a global health concern and accounts for approximately 1 million deaths annually. Amongst other limitations of current anti-HBV treatment, failure to eliminate the viral covalently closed circular DNA (cccDNA) and emergence of resistance remain the most worrisome. Viral rebound from latent episomal cccDNA reservoirs occurs following cessation of therapy, patient non-compliance, or the development of escape mutants. Simultaneous viral co-infections, such as by HIV-1, further complicate therapeutic interventions. These challenges have prompted development of novel targeted hepatitis B therapies. Given the ease with which highly specific and potent nucleic acid therapeutics can be rationally designed, gene therapy has generated interest for antiviral application. Gene therapy strategies developed for HBV include gene silencing by harnessing RNA interference, transcriptional inhibition through epigenetic modification of target DNA, genome editing by designer nucleases, and immune modulation with cytokines. DNA-binding domains and effectors based on the zinc finger (ZF), transcription activator-like effector (TALE), and clustered regularly interspaced short palindromic repeat (CRISPR) systems are remarkably well suited to targeting episomal cccDNA. This review discusses recent developments and challenges facing the field of anti-HBV gene therapy, its potential curative significance and the progress towards clinical application.
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Affiliation(s)
- Kristie Bloom
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS 2050, South Africa.
| | - Mohube Betty Maepa
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS 2050, South Africa.
| | - Abdullah Ely
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS 2050, South Africa.
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS 2050, South Africa.
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Liu Y, Zhao M, Gong M, Xu Y, Xie C, Deng H, Li X, Wu H, Wang Z. Inhibition of hepatitis B virus replication via HBV DNA cleavage by Cas9 from Staphylococcus aureus. Antiviral Res 2018; 152:58-67. [PMID: 29458131 DOI: 10.1016/j.antiviral.2018.02.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/23/2018] [Accepted: 02/12/2018] [Indexed: 12/27/2022]
Abstract
Chronic hepatitis B virus (HBV) infection is difficult to cure due to the presence of covalently closed circular DNA (cccDNA). Accumulating evidence indicates that the CRISPR/Cas9 system effectively disrupts HBV genome, including cccDNA, in vitro and in vivo. However, efficient delivery of CRISPR/Cas9 system to the liver or hepatocytes using an adeno-associated virus (AAV) vector remains challenging due to the large size of Cas9 from Streptococcus pyogenes (Sp). The recently identified Cas9 protein from Staphylococcus aureus (Sa) is smaller than SpCas9 and thus is able to be packaged into the AAV vector. To examine the efficacy of SaCas9 system on HBV genome destruction, we designed 5 guide RNAs (gRNAs) that targeted different HBV genotypes, 3 of which were shown to be effective. The SaCas9 system significantly reduced HBV antigen expression, as well as pgRNA and cccDNA levels, in Huh7, HepG2.2.15 and HepAD38 cells. The dual expression of gRNAs/SaCas9 in these cell lines resulted in more efficient HBV genome cleavage. In the mouse model, hydrodynamic injection of gRNA/SaCas9 plasmids resulted in significantly lower levels of HBV protein expression. We also delivered the SaCas9 system into mice with persistent HBV replication using an AAV vector. Both the AAV vector and the mRNA of Cas9 could be detected in the C3H mouse liver cells. Decreased hepatitis B surface antigen (HBsAg), HBV DNA and pgRNA levels were observed when a higher titer of AAV was injected, although this decrease was not significantly different from the control. In summary, the SaCas9 system accurately and efficiently targeted the HBV genome and inhibited HBV replication both in vitro and in vivo. The system was delivered by an AAV vector and maybe used as a novel therapeutic strategy against chronic HBV infection.
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Affiliation(s)
- Yu Liu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Miaoxian Zhao
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Mingxing Gong
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ying Xu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Cantao Xie
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Haohui Deng
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xueying Li
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hongkai Wu
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Zhanhui Wang
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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Schinazi RF, Ehteshami M, Bassit L, Asselah T. Towards HBV curative therapies. Liver Int 2018; 38 Suppl 1:102-114. [PMID: 29427479 PMCID: PMC6481632 DOI: 10.1111/liv.13656] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022]
Abstract
Tremendous progress has been made over the last 2 decades to discover and develop approaches to control hepatitis B virus (HBV) infections and to prevent the development of hepatocellular carcinoma using various interferons and small molecules as antiviral agents. However, none of these agents have significant impact on eliminating HBV from infected cells. Currently the emphasis is on silencing or eliminating cccDNA, which could lead to a cure for HBV. Various approaches are being developed including the development of capsid effectors, CRISPR/Cas9, TALENS, siRNA, entry and secretion inhibitors, as well as immunological approaches. It is very likely that a combination of these modalities will need to be employed to successfully eliminate HBV or prevent virus rebound on discontinuation of therapy. In the next 5 years clinical data will emerge which will provide insight on the safety and feasibility of these approaches and if they can be applied to eradicate HBV infections globally. In this review, we summarize current treatments and we highlight and examine recent therapeutic strategies that are currently being evaluated at the preclinical and clinical stage.
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Affiliation(s)
- Raymond F. Schinazi
- Center for AIDS Research, Emory University School of Medicine, Atlanta, GA, USA
| | - Maryam Ehteshami
- Center for AIDS Research, Emory University School of Medicine, Atlanta, GA, USA
| | - Leda Bassit
- Center for AIDS Research, Emory University School of Medicine, Atlanta, GA, USA
| | - Tarik Asselah
- Department of Hepatology, Centre de Recherche sur l’Inflammation, Viral Hepatitis INSERM UMR 1149, AP-HP Hôpital Beaujon, Université Paris Diderot, Clichy, France
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41
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Moyo B, Bloom K, Scott T, Ely A, Arbuthnot P. Advances with using CRISPR/Cas-mediated gene editing to treat infections with hepatitis B virus and hepatitis C virus. Virus Res 2018; 244:311-320. [PMID: 28087399 DOI: 10.1016/j.virusres.2017.01.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/21/2022]
Abstract
Chronic infections with hepatitis B and hepatitis C viruses (HBV and HCV) account for the majority of cases of cirrhosis and hepatocellular carcinoma. Current therapies for the infections have limitations and improved efficacy is necessary to prevent complications in carriers of the viruses. In the case of HBV persistence, the replication intermediate comprising covalently closed circular DNA (cccDNA) is particularly problematic. Licensed therapies have little effect on cccDNA and HBV replication relapses following treatment withdrawal. Disabling cccDNA is thus key to curing HBV infections and application of gene editing technology, such as harnessing the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system, has curative potential. Several studies have reported good efficacy when employing CRISPR/Cas technologies to disable HBV replication in cultured cells and in hydrodynamically injected mice. Recent advances with HCV drug development have revolutionized treatment of the infection. Nevertheless, individuals may be refractory to treatment. Targeting RNA from HCV with CRISPR/Cas isolated from Francisella novicida may have therapeutic utility. Although preclinical work shows that CRISPR/Cas technology has potential to overcome infection with HBV and HCV, significant challenges need to be met. Ensuring specificity for viral targets and efficient delivery of the gene editing sequences to virus-infected cells are particularly important. The field is at an interesting stage and the future of curative antiviral drug regimens, particularly for treatment of chronic HBV infection, may well entail use of combinations that include derivatives of CRISPR/Cas.
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MESH Headings
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- CRISPR-Associated Protein 9
- CRISPR-Cas Systems
- Clustered Regularly Interspaced Short Palindromic Repeats
- DNA Cleavage
- DNA, Circular/genetics
- DNA, Circular/metabolism
- DNA, Viral/genetics
- DNA, Viral/metabolism
- Endonucleases/genetics
- Endonucleases/metabolism
- Hepacivirus/genetics
- Hepacivirus/growth & development
- Hepacivirus/metabolism
- Hepatitis B virus/genetics
- Hepatitis B virus/growth & development
- Hepatitis B virus/metabolism
- Hepatitis B, Chronic/therapy
- Hepatitis B, Chronic/virology
- Hepatitis C, Chronic/therapy
- Hepatitis C, Chronic/virology
- Humans
- Molecular Targeted Therapy/methods
- Patient Safety
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
- Virus Replication
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Affiliation(s)
- Buhle Moyo
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Kristie Bloom
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Tristan Scott
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa; Center for Gene Therapy, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Abdullah Ely
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa.
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Abstract
Use of digital polymerase chain reaction (dPCR) technology is rapidly growing and diversifying into a range of areas in life science. The release of dPCR commercial systems has facilitated access, leading to recognition of the potential advantages compared to previous quantitative PCR technologies, and the scope for novel applications. The capability of dPCR to deliver unprecedented levels of precision, accuracy, and resolution in quantification of nucleic acids has triggered a strong interest by academia and the life sciences industry in use of this technology as a molecular diagnostic tool. However, the performance of dPCR, as for a "classical" PCR assay, essentially still relies on enzyme-based amplification of nucleic acid using specific reagents and instrumentation. This chapter describes basic concepts, key properties, and important factors to consider for the verification and validation of dPCR measurements.
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Affiliation(s)
| | - Kerry R Emslie
- National Measurement Institute, Lindfield, NSW, Australia
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43
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Abstract
Persistent hepatitis B virus (HBV) infection of hepatocytes is associated with a covalently closed circular DNA (cccDNA) episome. Although serologic hepatitis B surface antigen tests are negative, the presence of cccDNA is obviously increased in HBeAg-positive patients compared with that in HBeAg-negative patients, inactive carriers and patients. Moreover, trace cccDNA levels can also be found in the liver cells of patients with resolved hepatitis B infections. Therefore, clearance of cccDNA in hepatocytes could be an effective cure for HBV. In this review, we summarize the strategies that have been employed to eliminate cccDNA in recent years and discuss the future development of treatments for chronic hepatitis B.
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44
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Alonso S, Guerra AR, Carreira L, Ferrer JÁ, Gutiérrez ML, Fernandez-Rodriguez CM. Upcoming pharmacological developments in chronic hepatitis B: can we glimpse a cure on the horizon? BMC Gastroenterol 2017; 17:168. [PMID: 29268704 PMCID: PMC5740721 DOI: 10.1186/s12876-017-0726-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 12/12/2017] [Indexed: 02/08/2023] Open
Abstract
Background Hepatitis B virus (HBV) chronic infection affects up to 240 million people in the world and it is a common cause of cirrhosis and hepatocellular carcinoma (HCC). HBV covalently closed circular DNA (cccDNA) plays an essential role in HBV persistence and replication. Current pharmacological treatment with nucleos(t)ide analogues (NA) may suppress HBV replication with little or no impact on cccDNA, hence lifelong treatment is required in the vast majority of patients. Clearances of intrahepatic cccDNA and/or HBsAg are critical endpoints for future antiviral therapy in chronic HBV. Recent promising developments targeting different molecular HBV life cycle steps are being pre-clinically tested or have moved forward in early clinical trials. Methods We review the current state of the art of these pharmacological developments, mainly focusing on efficacy and safety results, which are expected to lay the ground for future HBV eradication. An inclusive literature search on new treatments of HBV using the following electronic databases: Pubmed/MEDLINE, AMED, CINAHL and the Cochrane Central Register of Controlled Trials. Full-text manuscripts and abstracts published over the last 12 years, from 2005 to March 2011 were reviewed for relevance and reference lists were crosschecked for additional applicable studies regarding new HBV antiviral treatment. Results HBV entry inhibitors, HBV core inhibitors, HBV cccDNA transcripts RNA interference, HBV cell apoptosis inducers, HBV RNA, viral proteins and DNA knock down agents, HBV release inhibitors, anti-sense nucleosides, exogenous interferon stimulation, interferon response stimulation and HBV therapeutic vaccines were reviewed. Conclusion This review will provide readers with an updated vision of current and foreseeable therapeutic developments in chronic hepatitis B.
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Affiliation(s)
- Sonia Alonso
- Unit of Gastroenterology, Hospital Universitario Fundación Alcorcón, Av. Budapest-1, 28922, Alcorcon, Madrid, Spain
| | - Adriana-René Guerra
- Unit of Gastroenterology, Hospital Universitario Fundación Alcorcón, Av. Budapest-1, 28922, Alcorcon, Madrid, Spain
| | - Lourdes Carreira
- Unit of Gastroenterology, Hospital Universitario Fundación Alcorcón, Av. Budapest-1, 28922, Alcorcon, Madrid, Spain
| | - Juan-Ángel Ferrer
- Unit of Gastroenterology, Hospital Universitario Fundación Alcorcón, Av. Budapest-1, 28922, Alcorcon, Madrid, Spain
| | - María-Luisa Gutiérrez
- Unit of Gastroenterology, Hospital Universitario Fundación Alcorcón, Av. Budapest-1, 28922, Alcorcon, Madrid, Spain
| | - Conrado M Fernandez-Rodriguez
- Unit of Gastroenterology, Hospital Universitario Fundación Alcorcón, Av. Budapest-1, 28922, Alcorcon, Madrid, Spain.
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45
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Bachtarzi H. Ex vivo and in vivo genome editing: a regulatory scientific framework from early development to clinical implementation. Regen Med 2017; 12:1015-1030. [PMID: 29243558 DOI: 10.2217/rme-2017-0095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Recent advances in human genome science have paved the way to a new class of human gene therapies based on gene editing, with the potential to provide a long-lasting curative strategy for many debilitating and complex disorders, for which there is an unmet medical need. Therapeutic genome editing encompasses both ex vivo and in vivo gene correction modalities, for which similar and also application-specific considerations apply, which dictate the overall strategy to be followed from a scientific, clinical and regulatory perspective. Here, the major regulatory barriers to successful clinical implementation are discussed, together with the key issues to be considered for generating safe (minimizing risks of tumorigenesis and off-target effects) and effective gene editing-based medicines for application in regenerative medicine.
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46
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Trevisan M, Palù G, Barzon L. Genome editing technologies to fight infectious diseases. Expert Rev Anti Infect Ther 2017; 15:1001-1013. [PMID: 29090592 DOI: 10.1080/14787210.2017.1400379] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Genome editing by programmable nucleases represents a promising tool that could be exploited to develop new therapeutic strategies to fight infectious diseases. These nucleases, such as zinc-finger nucleases, transcription activator-like effector nucleases, clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 9 (Cas9) and homing endonucleases, are molecular scissors that can be targeted at predetermined loci in order to modify the genome sequence of an organism. Areas covered: By perturbing genomic DNA at predetermined loci, programmable nucleases can be used as antiviral and antimicrobial treatment. This approach includes targeting of essential viral genes or viral sequences able, once mutated, to inhibit viral replication; repurposing of CRISPR-Cas9 system for lethal self-targeting of bacteria; targeting antibiotic-resistance and virulence genes in bacteria, fungi, and parasites; engineering arthropod vectors to prevent vector-borne infections. Expert commentary: While progress has been done in demonstrating the feasibility of using genome editing as antimicrobial strategy, there are still many hurdles to overcome, such as the risk of off-target mutations, the raising of escape mutants, and the inefficiency of delivery methods, before translating results from preclinical studies into clinical applications.
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Affiliation(s)
- Marta Trevisan
- a Department of Molecular Medicine , University of Padova , Padova , Italy
| | - Giorgio Palù
- a Department of Molecular Medicine , University of Padova , Padova , Italy
| | - Luisa Barzon
- a Department of Molecular Medicine , University of Padova , Padova , Italy
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Wilson EMP, Tang L, Kottilil S. Eradication Strategies for Chronic Hepatitis B Infection. Clin Infect Dis 2017; 62 Suppl 4:S318-25. [PMID: 27190322 DOI: 10.1093/cid/ciw044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Chronic hepatitis B infection affects >300 million people worldwide and is a leading cause of liver failure and cancer. Current approaches to treatment for chronic hepatitis B involve suppression of hepatitis B virus (HBV) DNA with the use of nucleoside analogues. Chronic suppressive therapy rarely results in a "functional cure" or absence of detectable HBV DNA in plasma and loss of detectable hepatitis B surface antigen after cessation of therapy. The major obstacles to achieving a functional cure are the presence of covalently closed circular DNA and ineffective/exhaustive immune system. This review focuses on novel approaches to target viral life cycle and host immunity to achieve a functional cure.
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Affiliation(s)
- Eleanor M P Wilson
- Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore
| | - Lydia Tang
- Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore
| | - Shyam Kottilil
- Division of Clinical Care and Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore
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48
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Ruiz de Galarreta M, Lujambio A. Therapeutic editing of hepatocyte genome in vivo. J Hepatol 2017; 67:818-828. [PMID: 28527665 DOI: 10.1016/j.jhep.2017.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/21/2017] [Accepted: 05/08/2017] [Indexed: 02/07/2023]
Abstract
The recent development of gene editing platforms enables making precise changes in the genome of eukaryotic cells. Programmable nucleases, such as meganucleases, zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeat (CRISPR)-associated nucleases have revolutionized the way research is conducted as they facilitate the rapid production of mutant or knockout cellular and animal models. These same genetic tools can potentially be applied to cure or alleviate a variety of diseases, including genetic diseases that lack an efficient therapy. Thus, gene editing platforms could be used for correcting mutations that cause a disease, restoration of the expression of genes that are missing, or be used for the removal of deleterious genes or viral genomes. In the context of liver diseases, genome editing could be developed to treat not only hereditary monogenic liver diseases but also hepatitis B infection and diseases that have both genetic and non-genetic components. While the prospect of translating these therapeutic strategies to a clinical setting is highly appealing, there are numerous challenges that need to be addressed first. Safety, efficiency, specificity, and delivery are some of the obstacles that will need to be addressed before each specific gene treatment is safely used in patients. Here, we discuss the most used gene editing platforms, their mechanisms of action, their potential for liver disease treatment, the most pressing challenges, and future prospects.
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Affiliation(s)
- Marina Ruiz de Galarreta
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA; Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Amaia Lujambio
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, USA; Liver Cancer Program, Division of Liver Diseases, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, USA; Graduate School of Biomedical Sciences at Icahn School of Medicine at Mount Sinai, New York, USA.
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49
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The state of gene therapy research in Africa, its significance and implications for the future. Gene Ther 2017; 24:581-589. [PMID: 28692018 PMCID: PMC7094717 DOI: 10.1038/gt.2017.57] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 12/12/2022]
Abstract
Gene therapy has made impressive recent progress and has potential for treating a wide range of diseases, many of which are important to Africa. However, as a result of lack of direct public funding and skilled personnel, direct research on gene therapy in Africa is currently limited and resources to support the endeavor are modest. A strength of the technology is that it is based on principles of rational design, and the tools of gene therapy are now highly versatile. For example gene silencing and gene editing may be used to disable viral genes for therapeutic purposes. Gene therapy may thus lead to cure from infections with HIV-1, hepatitis B virus and Ebola virus, which are of significant public health importance in Africa. Although enthusiasm for gene therapy is justified, significant challenges to implementing the technology remain. These include ensuring efficient delivery of therapeutic nucleic acids to target cells, limiting unintended effects, cost and complexity of treatment regimens. In addition, implementation of effective legislation that will govern gene therapy research will be a challenge. Nevertheless, it is an exciting prospect that gene therapy should soon reach the mainstream of medical management. Participation of African researchers in the exciting developments is currently limited, but their involvement is important to address health problems, develop capacity and enhance economic progress of the continent.
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50
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Niyonzima N, Lambert AR, Werther R, De Silva Feelixge H, Roychoudhury P, Greninger AL, Stone D, Stoddard BL, Jerome KR. Tuning DNA binding affinity and cleavage specificity of an engineered gene-targeting nuclease via surface display, flow cytometry and cellular analyses. Protein Eng Des Sel 2017; 30:503-522. [PMID: 28873986 PMCID: PMC5914421 DOI: 10.1093/protein/gzx037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/19/2017] [Accepted: 07/06/2017] [Indexed: 11/14/2022] Open
Abstract
The combination of yeast surface display and flow cytometric analyses and selections is being used with increasing frequency to alter specificity of macromolecular recognition, including both protein-protein and protein-nucleic acid interactions. Here we describe the use of yeast surface display and cleavage-dependent flow cytometric assays to increase the specificity of an engineered meganuclease. The re-engineered meganuclease displays a significantly tightened specificity profile, while binding its cognate target site with a slightly lower, but still sub-nanomolar affinity. When incorporated into otherwise identical megaTAL protein scaffolds, these two nucleases display significantly different activity and toxicity profiles in cellulo. The structural basis for reprogrammed DNA cleavage specificity was further examined via high-resolution X-ray crystal structures of both enzymes. This analysis illustrated the altered protein-DNA contacts produced by mutagenesis and selection, that resulted both in altered readout of those based and a necessary reduction in DNA binding affinity that were necessary to improve specificity across the target site. The results of this study provide an illustrative example of the potential (and the challenges) associated with the use of surface display and flow cytometry for the retargeting and optimization of enzymes that act on nucleic acid substrates in a sequence-specific manner.
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Affiliation(s)
- Nixon Niyonzima
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Abigail R. Lambert
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Rachel Werther
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Harshana De Silva Feelixge
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Pavitra Roychoudhury
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Alexander L. Greninger
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
- Virology Division, Department of Laboratory Medicine, University of Washington, 1616 Eastlake Ave. E, Seattle WA 98102, USA
| | - Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Barry L. Stoddard
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | - Keith R. Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
- Virology Division, Department of Laboratory Medicine, University of Washington, 1616 Eastlake Ave. E, Seattle WA 98102, USA
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