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Yoon H, Han J, Jang KL. Hepatitis B Virus X Protein Stimulates Hepatitis C Virus (HCV) Replication by Protecting HCV Core Protein from E6AP-Mediated Proteasomal Degradation. Microbiol Spectr 2022; 10:e0143222. [PMID: 36374094 PMCID: PMC9784765 DOI: 10.1128/spectrum.01432-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
Most clinical and experimental studies have suggested that hepatitis C virus (HCV) is dominant over hepatitis B virus (HBV) during coinfection, although the underlying mechanism remains unclear. In this study, we found that the HBV X protein (HBx) upregulates the levels of the HCV core protein to stimulate HCV replication during coinfection in human hepatoma cells. For this purpose, HBx upregulated both the protein levels and enzyme activities of cellular DNA methyltransferase 1 (DNMT1) and DNMT3b, and this subsequently reduced the expression levels of the E6-associated protein (E6AP), an E3 ligase of the HCV core protein, via DNA methylation. The ubiquitin-dependent proteasomal degradation of the HCV core protein was severely impaired in the presence of HBx, whereas this effect was not observed when E6AP was either ectopically expressed or restored by treatment with 5-aza-2'dC or DNMT1 knockdown. The effect of HBx on the HCV core protein was accurately reproduced in HBV/HCV coinfection systems, which were established by either monoinfection by HCV in Huh7D cells transfected with a 1.2-mer HBV replicon or coinfection by HBV and HCV in Huh7D-Na+-taurocholate cotransporting polypeptide cells, providing evidence for the stimulation of HCV replication by HBx. The present study may provide insights into understanding HCV dominance during HBV/HCV coinfection in patients. IMPORTANCE Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major human pathogens that cause a substantial proportion of liver diseases worldwide. As the two hepatotropic viruses have the same modes of transmission, coinfection is often observed, especially in areas and populations where HBV is endemic. High-risk populations include people who inject drugs. Both clinical and experimental studies have shown that HCV is more dominant than HBV during coinfection, but the underlying mechanism remains unclear. In this study, we show that HBV X protein (HBx) stimulates HCV replication by inhibiting the expression of E6-associated protein (E6AP) via DNA methylation, thereby protecting the HCV core protein from proteasomal degradation, which can contribute to HCV dominance during HBV/HCV coinfection.
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Affiliation(s)
- Hyunyoung Yoon
- Department of Integrated Biological Science, The Graduate School, Pusan National University, Busan, Republic of Korea
| | - Jiwoo Han
- Department of Integrated Biological Science, The Graduate School, Pusan National University, Busan, Republic of Korea
| | - Kyung Lib Jang
- Department of Integrated Biological Science, The Graduate School, Pusan National University, Busan, Republic of Korea
- Department of Microbiology, College of Natural Science, Pusan National University, Busan, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan, Republic of Korea
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Wu S, Yi W, Gao Y, Deng W, Bi X, Lin Y, Yang L, Lu Y, Liu R, Chang M, Shen G, Hu L, Zhang L, Li M, Xie Y. Immune Mechanisms Underlying Hepatitis B Surface Antigen Seroclearance in Chronic Hepatitis B Patients With Viral Coinfection. Front Immunol 2022; 13:893512. [PMID: 35634301 PMCID: PMC9130599 DOI: 10.3389/fimmu.2022.893512] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/11/2022] [Indexed: 12/28/2022] Open
Abstract
It is considered that chronic hepatitis B patients have obtained functional cure if they get hepatitis B surface antigen (HBsAg) seroclearance after treatment. Serum HBsAg is produced by cccDNA that is extremely difficult to clear and dslDNA that is integrated with host chromosome. High HBsAg serum level leads to failure of host immune system, which makes it unable to produce effective antiviral response required for HBsAg seroclerance. Therefore, it is very difficult to achieve functional cure, and fewer than 1% of chronic hepatitis B patients are cured with antiviral treatment annually. Some chronic hepatitis B patients are coinfected with other chronic viral infections, such as HIV, HCV and HDV, which makes more difficult to cure. However, it is found that the probability of obtaining HBsAg seroclearance in patients with coinfection is higher than that in patients with HBV monoinfection, especially in patients with HBV/HIV coinfection who have an up to 36% of HBsAg 5-year-seroclerance rate. The mechanism of this interesting phenomenon is related to the functional reconstruction of immune system after antiretroviral therapy (ART). The quantity increase and function recovery of HBV specific T cells and B cells, and the higher level of cytokines and chemokines such as IP-10, GM-CSF, promote HBsAg seroclearance. This review summarizes recent studies on the immune factors that have influence on HBsAg seroconversion in the chronic hepatitis B patients with viral coinfection, which might provide new insights for the development of therapeutic approaches to partially restore the specific immune response to HBV and other viruses.
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Affiliation(s)
- Shuling Wu
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Wei Yi
- Department of Gynecology and Obstetrics, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Yuanjiao Gao
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Wen Deng
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Xiaoyue Bi
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Yanjie Lin
- Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
| | - Liu Yang
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Yao Lu
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Ruyu Liu
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Min Chang
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Ge Shen
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Leiping Hu
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Lu Zhang
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Minghui Li
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
- Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
| | - Yao Xie
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
- Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
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