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Su Y, Bu F, Zhu Y, Yang L, Wu Q, Zheng Y, Zhao J, Yu L, Jiang N, Wang Y, Wu J, Xie Y, Zhang X, Gao Y, Lan K, Deng Q. Hepatitis B virus core protein as a Rab-GAP suppressor driving liver disease progression. Sci Bull (Beijing) 2024:S2095-9273(24)00248-2. [PMID: 38670853 DOI: 10.1016/j.scib.2024.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/28/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024]
Abstract
Chronic hepatitis B virus (HBV) infection can lead to advanced liver pathology. Here, we establish a transgenic murine model expressing a basic core promoter (BCP)-mutated HBV genome. Unlike previous studies on the wild-type virus, the BCP-mutated HBV transgenic mice manifest chronic liver injury that culminates in cirrhosis and tumor development with age. Notably, agonistic anti-Fas treatment induces fulminant hepatitis in these mice even at a negligible dose. As the BCP mutant exhibits a striking increase in HBV core protein (HBc) expression, we posit that HBc is actively involved in hepatocellular injury. Accordingly, HBc interferes with Fis1-stimulated mitochondrial recruitment of Tre-2/Bub2/Cdc16 domain family member 15 (TBC1D15). HBc may also inhibit multiple Rab GTPase-activating proteins, including Rab7-specific TBC1D15 and TBC1D5, by binding to their conserved catalytic domain. In cells under mitochondrial stress, HBc thus perturbs mitochondrial dynamics and prevents the recycling of damaged mitochondria. Moreover, sustained HBc expression causes lysosomal consumption via Rab7 hyperactivation, which further hampers late-stage autophagy and substantially increases apoptotic cell death. Finally, we show that adenovirally expressed HBc in a mouse model is directly cytopathic and causes profound liver injury, independent of antigen-specific immune clearance. These findings reveal an unexpected cytopathic role of HBc, making it a pivotal target for HBV-associated liver disease treatment. The BCP-mutated HBV transgenic mice also provide a valuable model for understanding chronic hepatitis B progression and for the assessment of therapeutic strategies.
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Affiliation(s)
- Yu Su
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Fan Bu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Yuanfei Zhu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China; Laboratory of Cellular Immunity, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Le Yang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Qiong Wu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Yuan Zheng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Jianjin Zhao
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Lin Yu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Nan Jiang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Yongxiang Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
| | - Jian Wu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
| | - Youhua Xie
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China
| | - Xinxin Zhang
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yueqiu Gao
- Laboratory of Cellular Immunity, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Qiang Deng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China; Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Fudan University, Shanghai 200032, China.
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2
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Kong X, Liu Z, Zhang R, Xie F, Liang R, Zhang Y, Yu L, Yang W, Li X, Chen Q, Li B, Hong Y, Li M, Xia X, Gu L, Fu L, Li X, Shen Y, Wu T, Yu C, Li W. JMJD2D stabilises and cooperates with HBx protein to promote HBV transcription and replication. JHEP Rep 2023; 5:100849. [PMID: 37701334 PMCID: PMC10494471 DOI: 10.1016/j.jhepr.2023.100849] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/16/2023] [Accepted: 07/01/2023] [Indexed: 09/14/2023] Open
Abstract
Background & Aims HBV infection is a global health burden. Covalently closed circular DNA (cccDNA) transcriptional regulation is a major cause of poor cure rates of chronic hepatitis B (CHB) infection. Herein, we evaluated whether targeting host factors to achieve functional silencing of cccDNA may represent a novel strategy for the treatment of HBV infection. Methods To evaluate the effects of Jumonji C domain-containing (JMJD2) protein subfamily JMJD2A-2D proteins on HBV replication, we used lentivirus-based RNA interference to suppress the expression of isoforms JMJD2A-2D in HBV-infected cells. JMJD2D-knockout mice were generated to obtain an HBV-injected model for in vivo experiments. Co-immunoprecipitation and ubiquitylation assays were used to detect JMJD2D-HBx interactions and HBx stability modulated by JMJD2D. Chromatin immunoprecipitation assays were performed to investigate JMJD2D-cccDNA and HBx-cccDNA interactions. Results Among the JMJD2 family members, JMJD2D was significantly upregulated in mouse livers and human hepatoma cells. Downregulation of JMJD2D inhibited cccDNA transcription and HBV replication. Molecularly, JMJD2D sustained HBx stability by suppressing the TRIM14-mediated ubiquitin-proteasome degradation pathway and acted as a key co-activator of HBx to augment HBV replication. The JMJD2D-targeting inhibitor, 5C-8-HQ, suppressed cccDNA transcription and HBV replication. Conclusion Our study clarified the mechanism by which JMJD2D regulates HBV transcription and replication and identified JMJD2D as a potential diagnostic biomarker and promising drug target against CHB, and HBV-associated hepatocarcinoma. Impact and implications HBV cccDNA is central to persistent infection and is a major obstacle to healing CHB. In this study, using cellular and animal HBV models, JMJD2D was found to stabilise and cooperate with HBx to augment HBV transcription and replication. This study reveals a potential novel translational target for intervention in the treatment of chronic hepatitis B infection.
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Affiliation(s)
- Xu Kong
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Zuofeng Liu
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatology, Affiliated Hospital of Panzhihua University, Panzhihua, China
| | - Ruyi Zhang
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Fu’an Xie
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Rubing Liang
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Yong Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Lingling Yu
- Department of Cardiology, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, China
| | - Wensheng Yang
- Department of Pathology, Chenggong Hospital of Xiamen University, Xiamen, China
| | - Xi Li
- College of Arts and Sciences, Boston University, Boston, MA, USA
| | - Qiang Chen
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Bei Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yilin Hong
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Ming Li
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
- Key Laboratory of Natural Medicine Research and Developing, Xiamen Medicine Research Institute, Xiamen, China
| | - Xiaogang Xia
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Lingwei Gu
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Management, Jiang Xia Blood Technology Co., Ltd., Shanghai, China
| | - Lijuan Fu
- Department of Infectious Diseases, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Xiaohua Li
- Department of Surgery, Affiliated Fuzhou First Hospital of Fujian Medical University, Fuzhou, China
| | - Ye Shen
- Department of Management, Jiang Xia Blood Technology Co., Ltd., Shanghai, China
| | - Ting Wu
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
| | - Chundong Yu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Wengang Li
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, China
- Department of Hepatobiliary Surgery, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
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Hojatizadeh M, Amiri MM, Mobini M, Hassanzadeh Makoui M, Ghaedi M, Ghotloo S, Peyghami K, Jeddi-Tehrani M, Golsaz-Shirazi F, Shokri F. Cross-Reactivity of HBe Antigen-Specific Polyclonal Antibody with HBc Antigen. Viral Immunol 2023; 36:378-388. [PMID: 37294935 DOI: 10.1089/vim.2022.0196] [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: 06/11/2023] Open
Abstract
Hepatitis B virus (HBV) infection is a major health problem worldwide and causes almost one million deaths annually. The HBV core gene codes for two related antigens, known as core antigen (HBcAg) and e-antigen (HBeAg), sharing 149 residues but having different amino- and carboxy-terminals. HBeAg is a soluble variant of HBcAg and a clinical marker for determining the disease severity and patients' screening. Currently available HBeAg assays have a shortcoming of showing cross-reactivity with HBcAg. In this study, for the first time, we evaluated whether HBcAg-adsorbed anti-HBe polyclonal antibodies could specifically recognize HBeAg or still show cross-reactivity with HBcAg. Recombinant HBeAg was cloned in pCold1 vector and successfully expressed in Escherichia coli and after purification by Ni-NTA resin was used to generate polyclonal anti-HBe antibodies in rabbit. Purified HBeAg was further characterized by assessing its reactivity with anti-HBe in the sera of chronically infected patients and HBeAg-immunized rabbit. Sera from patients with chronic HBV infection, containing anti-HBe, specifically reacted with recombinant HBeAg, implying antigenic similarity between the prokaryotic and native HBeAg in the serum of HBV-infected patients. In addition, the designed enzyme-linked immunosorbent assay (ELISA) with rabbit anti-HBe polyclonal antibodies could detect recombinant HBeAg with high sensitivity, while high cross-reactivity with HBcAg was observed. It is noteworthy that HBcAg-adsorbed anti-HBe polyclonal antibodies still showed high cross-reactivity with HBcAg, implying that due to the presence of highly similar epitopes in both antigens, HBcAg-adsorbed polyclonal antibodies cannot differentiate between the two antigens.
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Affiliation(s)
- Maryam Hojatizadeh
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Mehdi Amiri
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Mobini
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Hassanzadeh Makoui
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mojgan Ghaedi
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Ghotloo
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - Kiana Peyghami
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Jeddi-Tehrani
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACER, Tehran, Iran
| | - Forough Golsaz-Shirazi
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fazel Shokri
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACER, Tehran, Iran
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4
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Zheng Y, Yang L, Yu L, Zhu Y, Wu Y, Zhang Z, Xia T, Deng Q. Canocapavir Is a Novel Capsid Assembly Modulator Inducing a Conformational Change of the Linker Region of HBV Core Protein. Viruses 2023; 15:v15051195. [PMID: 37243280 DOI: 10.3390/v15051195] [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: 04/15/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
Canocapavir is a novel antiviral agent with characteristics of core protein allosteric modulators (CpAMs) that is currently in a phase II clinical trial for treatment of hepatitis B virus (HBV) infection. Herein, we show that Canocapavir prevented the encapsidation of HBV pregenomic RNA and increased the accumulation of cytoplasmic empty capsids, presumably by targeting the hydrophobic pocket at the dimer-dimer interface of HBV core protein (HBc). Canocapavir treatment markedly reduced the egress of naked capsids, which could be reversed by Alix overexpression through a mechanism other than direct association of Alix with HBc. Moreover, Canocapavir interfered with the interaction between HBc and HBV large surface protein, resulting in diminished production of empty virions. Of particular note, Canocapavir induced a conformational change of capsids, with the C-terminus of HBc linker region fully exposed on the exterior of capsids. We posit that the allosteric effect may have great importance in the anti-HBV activity of Canocapavir, given the emerging virological significance of HBc linker region. In support of this notion, the mutation at HBc V124W typically recapitulated the conformational change of the empty capsid with aberrant cytoplasmic accumulation. Collectively, our results indicate Canocapavir as a mechanistically distinct type of CpAMs against HBV infection.
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Affiliation(s)
- Yuan Zheng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China
| | - Le Yang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China
| | - Lin Yu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China
| | - Yuanfei Zhu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Zhijun Zhang
- Shanghai Zhimeng Biopharma, Inc., 1976 Gaoke Middle Road, Suite A-302, Pudong District, Shanghai 201210, China
| | - Tian Xia
- Shanghai Zhimeng Biopharma, Inc., 1976 Gaoke Middle Road, Suite A-302, Pudong District, Shanghai 201210, China
| | - Qiang Deng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai 200032, China
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5
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Viral Diagnosis of Hepatitis B and Delta: What We Know and What Is Still Required? Specific Focus on Low- and Middle-Income Countries. Microorganisms 2022; 10:microorganisms10112096. [PMID: 36363693 PMCID: PMC9694472 DOI: 10.3390/microorganisms10112096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 10/11/2022] [Accepted: 10/18/2022] [Indexed: 01/25/2023] Open
Abstract
To achieve the World Health Organization's (WHO) goals of eradicating viral hepatitis globally by 2030, the regional prevalence and epidemiology of hepatitis B virus (HBV) and hepatitis delta virus (HDV) coinfection must be known in order to implement preventiveon and treatment strategies. HBV/HDV coinfection is considered the most severe form of vira l hepatitis due to it's rapid progression towards cirrhosis, hepatocellular carcinoma, and liver-related death. The role of simplified diagnosticsis tools for screening and monitoring HBV/HDV-coinfected patients is crucial. Many sophisticated tools for diagnoses have been developed for detection of HBV alone as well as HBV/HDV coinfection. However, these advanced techniques are not widely available in low-income countries and there is no standardization for HDV detection assays, which are used for monitoring the response to antiviral therapy. More accessible and affordable alternative methods, such as rapid diagnostic tests (RDTs), are being developed and validated for equipment-free and specific detection of HBV and HDV. This review will provide some insight into both existing and diagnosis tools under development, their applicability in developing countries and how they could increase screening, patient monitoring and treatment eligibility.
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Zhou J, Chen J, Peng Y, Xie Y, Xiao Y. A Promising Tool in Serological Diagnosis: Current Research Progress of Antigenic Epitopes in Infectious Diseases. Pathogens 2022; 11:1095. [PMID: 36297152 PMCID: PMC9609281 DOI: 10.3390/pathogens11101095] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 07/30/2023] Open
Abstract
Infectious diseases, caused by various pathogens in the clinic, threaten the safety of human life, are harmful to physical and mental health, and also increase economic burdens on society. Infections are a complex mechanism of interaction between pathogenic microorganisms and their host. Identification of the causative agent of the infection is vital for the diagnosis and treatment of diseases. Etiological laboratory diagnostic tests are therefore essential to identify pathogens. However, due to its rapidity and automation, the serological diagnostic test is among the methods of great significance for the diagnosis of infections with the basis of detecting antigens or antibodies in body fluids clinically. Epitopes, as a special chemical group that determines the specificity of antigens and the basic unit of inducing immune responses, play an important role in the study of immune responses. Identifying the epitopes of a pathogen may contribute to the development of a vaccine to prevent disease, the diagnosis of the corresponding disease, and the determination of different stages of the disease. Moreover, both the preparation of neutralizing antibodies based on useful epitopes and the assembly of several associated epitopes can be used in the treatment of disease. Epitopes can be divided into B cell epitopes and T cell epitopes; B cell epitopes stimulate the body to produce antibodies and are therefore commonly used as targets for the design of serological diagnostic experiments. Meanwhile, epitopes can fall into two possible categories: linear and conformational. This article reviews the role of B cell epitopes in the clinical diagnosis of infectious diseases.
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Probing the Hepatitis B Virus E-Antigen with a Nanopore Sensor Based on Collisional Events Analysis. BIOSENSORS 2022; 12:bios12080596. [PMID: 36004992 PMCID: PMC9405897 DOI: 10.3390/bios12080596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 11/24/2022]
Abstract
Real-time monitoring, simple operation, and cheaper methods for detecting immunological proteins hold the potential for a solid influence on proteomics and human biology, as they can promote the onset of timely diagnoses and adequate treatment protocols. In this work we present an exploratory study suggesting the applicability of resistive-pulse sensing technology in conjunction with the α-hemolysin (α-HL) protein nanopore, for the detection of the chronic hepatitis B virus (HBV) e-antigen (HBeAg). In this approach, the recognition between HBeAg and a purified monoclonal hepatitis B e antibody (Ab(HBeAg)) was detected via transient ionic current spikes generated by partial occlusions of the α-HL nanopore by protein aggregates electrophoretically driven toward the nanopore’s vestibule entrance. Despite the steric hindrance precluding antigen, antibody, or antigen–antibody complex capture inside the nanopore, their stochastic bumping with the nanopore generated clear transient blockade events. The subsequent analysis suggested the detection of protein subpopulations in solution, rendering the approach a potentially valuable label-free platform for the sensitive, submicromolar-scale screening of HBeAg targets.
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8
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Wang Y, Liao H, Deng Z, Liu Y, Bian D, Ren Y, Yu G, Jiang Y, Bai L, Liu S, Liu M, Zhou L, Chen Y, Duan Z, Lu F, Zheng S. Serum HBV RNA predicts HBeAg clearance and seroconversion in patients with chronic hepatitis B treated with nucleos(t)ide analogues. J Viral Hepat 2022; 29:420-431. [PMID: 35274400 PMCID: PMC9311425 DOI: 10.1111/jvh.13671] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 01/29/2022] [Accepted: 02/22/2022] [Indexed: 12/12/2022]
Abstract
This study evaluated the predictive value of serum HBV DNA, HBV RNA, HBcrAg, HBsAg, intrahepatic HBV DNA and cccDNA for HBeAg clearance and seroconversion during long-term treatment with nucleos(t)ide analogues (NAs) in patients with chronic hepatitis B (CHB). A single centre, prospective cohort of CHB patients was used for this study. Serum HBV RNA levels were retrospectively measured at baseline, 6, 12, 24, 36, 48, 60, 72 and 84 months post-NAs treatment. Serum HBsAg and HBcrAg levels were quantified at baseline, month 6, 60 and 72. Histological samples from liver biopsy at baseline and month 60 were analysed for intrahepatic HBV DNA and cccDNA. Eighty-three HBeAg-positive patients were enrolled with a median follow-up time of 108 months (range 18-138 months). Of them, 53 (63.86%) patients achieved HBeAg clearance, and 37 (44.58%) achieved HBeAg seroconversion. Cox multivariate analysis showed that only baseline HBV RNA was independently associated with HBeAg clearance and seroconversion (<5.45 log10 copies/mL, HR = 5.06, 95% CI: 1.87-13.71, p = .001; HR = 3.38, 95% CI: 1.28-8.91, p = .01). The independent association with HBeAg clearance and seroconversion remained for HBV RNA levels at month 6 (<4.72 log10 copies/mL, HR = 4.16, 95% CI: 1.61-10.72, p = .003; HR = 6.52, 95% CI: 1.85-22.94, p = .003) and month 12 (<4.08 log10 copies/mL, HR = 3.68, 95% CI: 1.96-6.90, p < .001; HR = 2.79, 95% CI: 1.31-5.94, p = .008). The AUCs of baseline HBV RNA for predicting the HBeAg clearance (0.83, 95% CI: 0.70-0.96, 0.83, 95% CI: 0.70-0.96 and 0.82, 95% CI: 0.69-0.95 respectively) and seroconversion (0.89, 95% CI: 0.77-1.00; 0.81, 95% CI: 0.66-0.95 and 0.84, 95% CI: 0.71-0.98 respectively) at month 36, 60 and 84 were higher than those of HBV DNA, HBsAg and HBcrAg. In conclusion, lower serum HBV RNA at baseline, month 6 and 12 post-NAs treatment could predict HBeAg clearance and seroconversion during long-term NAs treatment.
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Affiliation(s)
- Yang Wang
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Hao Liao
- Department of Microbiology and Infectious Disease CenterSchool of Basic Medical SciencesPeking University Health Science CenterBeijingChina,Intervention and Cell Therapy CenterPeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhenChina
| | - Zhongping Deng
- Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijingChina,Hunan Provincial Key Laboratory of Gene Diagnostic TechnologyChangshaChina
| | - Yanna Liu
- Department of Microbiology and Infectious Disease CenterSchool of Basic Medical SciencesPeking University Health Science CenterBeijingChina
| | - Dandan Bian
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Yan Ren
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Guangxin Yu
- Department of Microbiology and Infectious Disease CenterSchool of Basic Medical SciencesPeking University Health Science CenterBeijingChina
| | - Yingying Jiang
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Li Bai
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Shuang Liu
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Mei Liu
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Li Zhou
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Yu Chen
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Zhongping Duan
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
| | - Fengmin Lu
- Department of Microbiology and Infectious Disease CenterSchool of Basic Medical SciencesPeking University Health Science CenterBeijingChina
| | - Sujun Zheng
- Liver Disease CenterBeijing YouAn HospitalCapital Medical UniversityBeijingChina,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & ResearchBeijing YouAn HospitalCapital Medical UniversityBeijingChina
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9
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5' preS1 mutations to prevent large envelope protein expression from hepatitis B virus genotype A or genotype D markedly increase polymerase-envelope fusion protein. J Virol 2022; 96:e0172321. [PMID: 35019714 PMCID: PMC8906437 DOI: 10.1128/jvi.01723-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hepatitis B virus (HBV) large (L) envelope protein is translated from 2.4-kb RNA. It contains preS1, preS2, and S domains and is detected in Western blot as p39 and gp42. The 3.5-kb pregenomic RNA produces core and polymerase (P) proteins. We generated L-minus mutants of a genotype A clone and a genotype D clone from 1.1mer or 1.3mer construct, with the former overproducing pregenomic RNA. Surprisingly, mutating preS1 ATG codon(s) or introducing a nonsense mutation soon afterwards switched secreted p39/gp42 into p41/p44 doublet, with its amount further increased by a nonsense mutation in the core gene. A more downstream preS1 nonsense mutation prevented p41/p44 production. Tunicamycin treatment confirmed p44 as glycosylated form of p41. In this regard splicing of 3.5-kb RNA to generate nt2447-nt2902 junction for genotype D enables translation of p43, with N-terminal 47 residues of P protein fused to C-terminal 371 residues of L protein. Indeed p41/p44 were detectable by an antibody against N-terminus of P protein, and eliminated by a nonsense mutation at 5' P gene or a point mutation to prevent that splicing. Therefore, lost L (and core) protein expression from 1.1mer or 1.3mer construct markedly increased p41/p44 (p43), the P-L fusion protein. Co-transfection with an expression construct for L/M proteins reversed high extracellular p41/p44 associated with L-minus mutants, suggesting that L protein retains p43 in wild-type HBV to promote its intracellular degradation. Considering that p43 lacks N-terminal preS1 sequence critical for receptor binding, its physiological significance during natural infection and therapeutic potential warrant further investigation. IMPORTANCE The large (L) envelope protein of hepatitis B virus (HBV) is translated from 2.4-kb RNA and detected in Western blot as p39 and gp42. Polymerase (P) protein is expressed at a low level from 3.5-kb RNA. The major spliced form of 3.5-kb RNA will produce a fusion protein between the first 47 residues of P protein and a short irrelevant sequence, although also at a low level. Another spliced form has the same P protein sequence fused to L protein missing its first 18 residues. We found that some point mutations to eliminate L and core protein expression from overlength HBV DNA constructs converted p39/gp42 into p41/gp44, which turned out to be that P-L fusion protein. Thus, the P-L fusion protein can be expressed at extremely high level when L protein expression is prevented. The underlying mechanism and functional significance of this variant form of L protein warrant further investigation.
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10
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Wang Y, Liu Y, Liao H, Deng Z, Bian D, Ren Y, Yu G, Jiang Y, Bai L, Liu S, Liu M, Zhou L, Chen Y, Chen X, Duan Z, Lu F, Zheng S. Serum HBV DNA plus RNA reflecting cccDNA level before and during NAs treatment in HBeAg positive CHB patients. Int J Med Sci 2022; 19:858-866. [PMID: 35693741 PMCID: PMC9149645 DOI: 10.7150/ijms.71737] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/20/2022] [Indexed: 11/06/2022] Open
Abstract
Background & Aims: Correlations between serum viral markers and intrahepatic cccDNA in patients undergoing long-term nucleos(t)ide analogues (NAs) treatment haven't been fully explored. In this study, we evaluate the correlation between intrahepatic cccDNA and other serum viral markers and intrahepatic HBV DNA in HBeAg positive chronic hepatitis B (CHB) patients during 60-month treatment with NAs. Methods: Fifty-four HBeAg positive CHB patients received long-term NAs treatment were included in this study. Serial serum samples were regularly collected and quantitatively analyzed for HBsAg, HBV DNA, HBV RNA and HBcrAg. Histological samples from liver biopsy at baseline and month 60 were analyzed for intrahepatic HBV DNA and cccDNA. Results: At baseline, serum HBV DNA plus RNA was positively associated with intrahepatic cccDNA in multivariate regression analysis (β=0.205, P<0.001). In the correlation analysis between cccDNA and serum viral markers, HBV DNA plus RNA had the highest correlation coefficient (r=0.698, P<0.001), followed by serum HBV DNA (r=0.641, P<0.001), HBV RNA (r=0.590, P<0.001), and HBcrAg (r=0.564, P<0.001). At month 60, correlations between these serum viral markers and cccDNA were not observed (P>0.05). Multivariate regression analysis showed that only the decreased HBV DNA plus RNA was positively associated with cccDNA decline (β=0.172, P =0.006). Changes of HBV DNA plus RNA (r=0.525, P=0.001) was better correlated with cccDNA decline as compared to HBV RNA (r=0.384, P=0.008), HBV DNA (r=0.431, P=0.003), and HBsAg (r=0.342, P=0.029). Conclusions: Serum HBV DNA plus RNA better correlated with intrahepatic cccDNA than other viral makers before and during NAs treatment in HBeAg positive CHB patients.
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Affiliation(s)
- Yang Wang
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Yanna Liu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Hao Liao
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.,Department of Clinical Laboratory, Shenzhen Third People's Hospital, Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, 518112, PR China
| | - Zhongping Deng
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.,Hunan Provincial Key Laboratory of Gene Diagnostic Technology, Changsha 410205, China
| | - Dandan Bian
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Yan Ren
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Guangxin Yu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yingying Jiang
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Li Bai
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Shuang Liu
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Mei Liu
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Li Zhou
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Yu Chen
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Xinyue Chen
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Zhongping Duan
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
| | - Fengmin Lu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Sujun Zheng
- Liver disease center, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China.,Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment & Research, Beijing YouAn Hospital, Capital Medical University, Beijing 100069, China
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11
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Lin J, Yin L, Xu XZ, Sun HC, Huang ZH, Ni XY, Chen Y, Lin X. Bay41-4109-induced aberrant polymers of hepatitis b capsid proteins are removed via STUB1-promoted p62-mediated macroautophagy. PLoS Pathog 2022; 18:e1010204. [PMID: 35030230 PMCID: PMC8824320 DOI: 10.1371/journal.ppat.1010204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 02/08/2022] [Accepted: 12/16/2021] [Indexed: 12/16/2022] Open
Abstract
The hepatitis B virus (HBV) core protein (HBc) functions in multiple steps of the viral life cycle. Heteroaryldihydropyrimidine compounds (HAPs) such as Bay41-4109 are capsid protein allosteric modulators that accelerate HBc degradation and inhibit the virion secretion of HBV, specifically by misleading HBc assembly into aberrant non-capsid polymers. However, the subsequent cellular fates of these HAP-induced aberrant non-capsid polymers are not well understood. Here, we discovered that that the chaperone-binding E3 ubiquitin ligase protein STUB1 is required for the removal of Bay41-4109-induced aberrant non-capsid polymers from HepAD38 cells. Specifically, STUB1 recruits BAG3 to transport Bay41-4109-induced aberrant non-capsid polymers to the perinuclear region of cells, thereby initiating p62-mediated macroautophagy and lysosomal degradation. We also demonstrate that elevating the STUB1 level enhances the inhibitory effect of Bay41-4109 on the production of HBeAg and HBV virions in HepAD38 cells, in HBV-infected HepG2-NTCP cells, and in HBV transgenic mice. STUB1 overexpression also facilitates the inhibition of Bay41-4109 on the cccDNA formation in de novo infection of HBV. Understanding these molecular details paves the way for applying HAPs as a potentially curative regimen (or a component of a combination treatment) for eradicating HBV from hepatocytes of chronic infection patients. Hepatitis B virus (HBV) infects more than 250 million people worldwide chronically. It is a major pathogen causing liver cirrhosis and hepatocellular carcinoma now. The HBV capsid protein (HBc) plays multiple roles in the viral life cycle, and many antivirals targeting HBc such as Heteroaryldihydropyrimidine compounds (HAPs) are under clinical trial recently. This study aimed to investigate how a HAP compound Bay41-4109 induces the degradation of HBc protein. Bay41-4109 induces aberrant non-capsid polymers, which form in complex with the chaperone-binding E3 ubiquitin ligase protein STUB1 and co-chaperone BAG3 and are transported to the perinuclear compartment. Subsequently, Bay41-4109-induced aberrant non-capsid polymers are removed by p62-mediated macroautophagy and lysosomal degradation. STUB1 overexpression accelerates Bay41-4109-induced degradation of HBc protein, and thus enhances the effect of Bay41-4109 on inhibiting secretion of HBeAg and HBV virions. When Bay41-4109 are enforced during HBV infection, de novo cccDNA formation were also negatively regulated by STUB1 overexpression. Altogether, this study provides novel mechanistic insights into developing more potent and safe HAP-based antiviral treatment.
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Affiliation(s)
- Jiacheng Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Limin Yin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China
| | - Xia-Zhen Xu
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China
| | - He-Chen Sun
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China
| | - Zhi-Hua Huang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China
| | - Xue-Yun Ni
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China
| | - Yan Chen
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
| | - Xu Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.,Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, Fujian Medical University, Fuzhou, China
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12
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Lost Small Envelope Protein Expression from Naturally Occurring PreS1 Deletion Mutants of Hepatitis B Virus Is Often Accompanied by Increased HBx and Core Protein Expression as Well as Genome Replication. J Virol 2021; 95:e0066021. [PMID: 33910956 PMCID: PMC8223946 DOI: 10.1128/jvi.00660-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatitis B virus (HBV) transcribes coterminal mRNAs of 0.7 to 3.5 kb from the 3.2-kb covalently closed circular DNA, with the 2.1-kb RNA being most abundant. The 0.7-kb RNA produces HBx protein, a transcriptional transactivator, while the 3.5-kb pregenomic RNA (pgRNA) drives core and P protein translation as well as genome replication. The large (L) and small (S) envelope proteins are translated from the 2.4-kb and 2.1-kb RNAs, respectively, with the majority of the S protein being secreted as noninfectious subviral particles and detected as hepatitis B surface antigen (HBsAg). pgRNA transcription could inhibit transcription of subgenomic RNAs. The present study characterized naturally occurring in-frame deletions in the 3' preS1 region, which not only codes for L protein but also serves as the promoter for 2.1-kb RNA. The human hepatoma cell line Huh7 was transiently transfected with subgenomic expression constructs for envelope (and HBx) proteins, dimeric constructs, or constructs mimicking covalently closed circular DNA. The results confirmed lost 2.1-kb RNA transcription and HBsAg production from many deletion mutants, accompanied by increases in other (especially 2.4-kb) RNAs, intracellular HBx and core proteins, and replicative DNA but impaired virion and L protein secretion. The highest intracellular L protein levels were achieved by mutants that had residual S protein expression or retained the matrix domain in L protein. Site-directed mutagenesis of a high replicating deletion mutant suggested that increased HBx protein expression and blocked virion secretion both contributed to the high replication phenotype. Our findings could help explain why such deletions are selected at a late stage of chronic HBV infection and how they contribute to viral pathogenesis. IMPORTANCE Expression of hepatitis B e antigen (HBeAg) and overproduction of HBsAg by wild-type HBV are implicated in the induction of immune tolerance to achieve chronic infection. How HBV survives the subsequent immune clearance phase remains incompletely understood. Our previous characterization of core promoter mutations to reduce HBeAg production revealed the ability of the 3.5-kb pgRNA to diminish transcription of coterminal RNAs of 2.4 kb, 2.1 kb, and 0.7 kb. The later stage of chronic HBV infection often selects for in-frame deletions in the preS region. Here, we found that many 3' preS1 deletions prevented transcription of the 2.1-kb RNA for HBsAg production, which was often accompanied by increases in intracellular 3.5-, 0.7-, and especially 2.4-kb RNAs, HBx and core proteins, and replicative DNA but lost virion secretion. These findings established the biological consequences of preS1 deletions, thus shedding light on why they are selected and how they contribute to hepatocarcinogenesis.
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