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Hepatitis B virus X protein promotes liver cell pyroptosis under oxidative stress through NLRP3 inflammasome activation. Inflamm Res 2020; 69:683-696. [PMID: 32347316 PMCID: PMC7261280 DOI: 10.1007/s00011-020-01351-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 03/11/2020] [Accepted: 04/18/2020] [Indexed: 02/07/2023] Open
Abstract
Objective Hepatitis B virus X protein (HBx) is a pivotal factor for HBV-induced hepatitis. Herein, we sought to investigate HBx-mediated NLR pyrin domain containing 3 (NLRP3) inflammasome activation and pyroptosis under oxidative stress. Methods The effect of HBx on the NLRP3 inflammasome was analyzed by enzyme-linked immunosorbent assays, quantitative reverse transcription-polymerase chain reaction, western blotting, and immunofluorescence in hepatic HL7702 cells. Pyroptosis was evaluated by western blotting, lactate dehydrogenase release, propidium iodide staining, and transmission electron microscopy. NLRP3 expression in the inflammasome from liver tissues was assessed by immunohistochemistry. Results In hydrogen peroxide (H2O2)-stimulated HL7702 cells, HBx triggered the release of pro-inflammatory mediators apoptosis-associated speck-like protein containing a CARD (ASC), interleukin (IL)-1β, IL-18, and high-mobility group box 1 (HMGB1); activated NLRP3; and initiated pro-inflammatory cell death (pyroptosis). HBx localized to the mitochondria, where it induced mitochondrial damage and production of mitochondrial reactive oxygen species (mitoROS). Treatment of HL7702 cells with a mitoROS scavenger attenuated HBx-induced NLRP3 activation and pyroptosis. Expression levels of NLRP3, ASC, and IL-1β in liver tissues from patients were positively correlated with HBV DNA concentration. Conclusions The NLRP3 inflammasome was activated by elevated mitoROS levels and mediated HBx-induced liver inflammation and hepatocellular pyroptosis under H2O2-stress conditions. Electronic supplementary material The online version of this article (10.1007/s00011-020-01351-z) contains supplementary material, which is available to authorized users.
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Salpini R, Surdo M, Cortese MF, Palumbo GA, Carioti L, Cappiello G, Spanò A, Trimoulet P, Fleury H, Vecchiet J, Pasquazzi C, Mirabelli C, Scutari R, Sacco A, Alkhatib M, Missale G, Francioso S, Sarmati L, Andreoni M, Angelico M, Ceccherini-Silberstein F, Levrero M, Perno CF, Belloni L, Svicher V. The novel HBx mutation F30V correlates with hepatocellular carcinoma in vivo, reduces hepatitis B virus replicative efficiency and enhances anti-apoptotic activity of HBx N terminus in vitro. Clin Microbiol Infect 2018; 25:906.e1-906.e7. [PMID: 30472417 DOI: 10.1016/j.cmi.2018.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/06/2018] [Accepted: 11/09/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE We aimed to investigate HBx genetic elements correlated with hepatitis B virus (HBV) -related hepatocellular carcinoma (HCC) and their impact on (a) HBV replicative efficiency, (b) HBx binding to circular covalently closed DNA (cccDNA), (c) apoptosis and cell-cycle progression, and (d) HBx structural stability. METHODS This study included 123 individuals chronically infected with HBV: 27 with HCC (77.9% (21/27) genotype D; 22.1% (6/27) genotype A) and 96 without HCC (75% (72/96) genotype D; 25.0% (24/96) genotype A). HepG2 cells were transfected by wild-type or mutated linear HBV genome to assess pre-genomic RNA (pgRNA) and core-associated HBV-DNA levels, HBx-binding onto cccDNA by chromatin immunoprecipitation-based quantitative assay, and rate of apoptosis and cell-cycle progression by cytofluorimetry. RESULTS F30V was the only HBx mutation correlated with HCC (18.5% (5/27) in HCC patients versus 1.0% (1/96) in non-HCC patients, p 0.002); a result confirmed by multivariate analysis. In vitro, F30V determined a 40% and 60% reduction in pgRNA and core-associated HBV-DNA compared with wild-type (p <0.05), in parallel with a significant decrease of HBx binding to cccDNA and decreased HBx stability. F30V also decreased the percentage of apoptotic cells compared with wild-type (14.8 ± 6.8% versus 19.1 ± 10.1%, p <0.01, without affecting cell-cycle progression) and increased the probability of HBx-Ser-31 being phosphorylated by PI3K-Akt kinase (known to promote anti-apoptotic activity). CONCLUSIONS F30V was closely correlated with HBV-induced HCC in vivo, reduced HBV replicative efficiency by affecting HBx-binding to cccDNA and increased anti-apoptotic HBx activity in vitro. This suggests that F30V (although hampering HBV's replicative capacity) may promote hepatocyte survival, so potentially allowing persistent production of viral progeny and initiating HBV-driven hepatocarcinogenesis. Investigation of viral genetic markers associated with HCC is crucial to identify those patients at higher risk of HCC, who hence deserve intensive liver monitoring and/or early anti-HBV therapy.
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Affiliation(s)
- R Salpini
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy
| | - M Surdo
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy
| | - M F Cortese
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy; Liver Pathology Unit, Departments of Biochemistry and Microbiology, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - G A Palumbo
- Department of Internal Medicine-DMISM, Sapienza University, Rome, Italy
| | - L Carioti
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy
| | | | - A Spanò
- 'S. Pertini Hospital', Rome, Italy
| | | | - H Fleury
- Hôpital Pellegrin Tripode, Bordeaux, France
| | | | | | - C Mirabelli
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy; University of Michigan Medical School, Ann Arbor, MI, USA
| | - R Scutari
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy
| | - A Sacco
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy
| | - M Alkhatib
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy
| | | | - S Francioso
- Hepatology Unit, Tor Vergata University Hospital, Rome, Italy
| | - L Sarmati
- Infectious Diseases Unit, Tor Vergata University Hospital, Rome, Italy
| | - M Andreoni
- Infectious Diseases Unit, Tor Vergata University Hospital, Rome, Italy
| | - M Angelico
- Hepatology Unit, Tor Vergata University Hospital, Rome, Italy
| | | | - M Levrero
- Department of Internal Medicine-DMISM, Sapienza University, Rome, Italy; INSERM U1052 - Cancer Research Centre of Lyon, 69008 Lyon, France
| | - C F Perno
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy; Haematology and Oncohaematology, University of Milan, Italy
| | - L Belloni
- Department of Internal Medicine-DMISM, Sapienza University, Rome, Italy; Centre for Life NanoSciences, IIT-Sapienza, Rome, Italy
| | - V Svicher
- Department of Experimental Medicine and Surgery, University of Rome 'Tor Vergata' Rome, Italy.
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Sun W, Zhang J, Chen J. MicroRNA-520a suppresses HBV replication in HepG2.2.15 cells by inactivating AKT. J Int Med Res 2018; 46:4693-4704. [PMID: 30191752 PMCID: PMC6259377 DOI: 10.1177/0300060518792780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Objective To investigate whether the mechanism by which a microRNA, miR-520a, suppresses the replication of hepatitis B virus (HBV) involves the regulation of the serine/threonine kinase (AKT) gene. Methods The effects of miR-520a on the proliferation, mitotic index and apoptosis of the HBV-replicating human hepatocellular carcinoma cell line HepG2.2.15 were measured using standard laboratory methods including flow cytometry. The effects of miR-520a on HBV transcription and replication were assessed using methods including immunoassays and reverse transcription–polymerase chain reaction. The effect of small interfering RNA (siRNA) to AKT on the levels of AKT mRNA and protein were also evaluated. Results In HepG2.2.15 cells, miRNA-520a reduced HBV transcription and replication by reducing AKT levels. MiRNA-520a decreased cell proliferation and mitosis entry of cells and increased apoptosis in HepG2.2.15 cells. AKT levels were reduced significantly by its siRNA, which resulted in suppression of HBV replication in HepG2.2.15 cells. Conclusions MiRNA-520a inhibited AKT gene expression and suppressed HBV transcription and replication. These findings suggest that miRNA-520a may be a novel target for the treatment of HBV infection because miRNA-520a reduced HepG2.2.15 cell survival and inhibited HBV replication associated with the AKT signalling pathway.
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Affiliation(s)
- Wei Sun
- 1 Department of Oncology, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Jinqian Zhang
- 2 Department of Laboratory Medicine, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong Province, China
| | - Jinglong Chen
- 1 Department of Oncology, Beijing Ditan Hospital, Capital Medical University, Beijing, China
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