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Wen J, Wu J, Cao T, Zhi S, Chen Y, Aagaard L, Zhen P, Huang Y, Zhong J, Huang J. Methylation silencing and reactivation of exogenous genes in lentivirus-mediated transgenic mice. Transgenic Res 2021; 30:63-76. [PMID: 33394315 DOI: 10.1007/s11248-020-00224-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/24/2020] [Indexed: 12/27/2022]
Abstract
Taking advantage of their ability to integrate their genomes into the host genome, lentiviruses have been used to rapidly produce transgenic mice in biomedical research. In most cases, transgenes delivered by lentiviral vectors have resisted silencing mediated by epigenetic modifications in mice. However, some studies revealed that methylation caused decreased transgene expression in mice. Therefore, there is conflicting evidence regarding the methylation-induced silencing of transgenes delivered by lentiviral transduction in mice. In this study, we present evidence that the human TTR transgene was silenced by DNA methylation in the liver of a transgenic mouse model generated by lentiviral transduction. The density of methylation on the transgene was increased during reproduction, and the expression of the transgene was completely silenced in mice of the F2 generation. Interestingly, 5-azacytidine (5-AzaC), a methyltransferase inhibitor, potently reactivated the silenced genes in neonatal mice whose hepatocytes were actively proliferating and led to stable transgene expression during development. However, 5-AzaC did not rescue liver transgene expression when administered to adult mice. Moreover, 5-AzaC at the given dose had low developmental toxicity in the newborn mice. In summary, we demonstrate the methylation-induced silencing of an exogenous gene in the liver of a mouse model generated by lentiviral transduction and show that the silenced transgene can be safely and efficiently reactivated by 5-AzaC treatment, providing an alternative way to obtain progeny with stable transgene expression in the case of the methylation of exogenous genes in transgenic mice generated by lentiviral transduction.
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Affiliation(s)
- Jinkun Wen
- Department of Neurology, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-Sen University, Jiangmen, 529030, China.,MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Jinni Wu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Tianqi Cao
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Shengyao Zhi
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Yuxi Chen
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Lars Aagaard
- Department of Biomedicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Peilin Zhen
- Department of Infectious Diseases, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-Sen University, Jiangmen, 529030, China
| | - Yanming Huang
- Clinical Experimental Center, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-Sen University, Jiangmen, 529030, China
| | - Jianxin Zhong
- Department of Neurology, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-Sen University, Jiangmen, 529030, China
| | - Junjiu Huang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China. .,Clinical Experimental Center, Jiangmen Central Hospital, Affiliated Jiangmen Hospital of Sun Yat-Sen University, Jiangmen, 529030, China. .,Key Laboratory of Reproductive Medicine of Guangdong Province, First Affiliated Hospital and School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China.
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Yip WK, Cheng ASL, Zhu R, Lung RWM, Tsang DPF, Lau SSK, Chen Y, Sung JG, Lai PBS, Ng EKO, Yu J, Wong N, To KF, Wong VWS, Sung JJY, Chan HLY. Carboxyl-terminal truncated HBx regulates a distinct microRNA transcription program in hepatocellular carcinoma development. PLoS One 2011; 6:e22888. [PMID: 21829663 PMCID: PMC3150371 DOI: 10.1371/journal.pone.0022888] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 07/07/2011] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The biological pathways and functional properties by which misexpressed microRNAs (miRNAs) contribute to liver carcinogenesis have been intensively investigated. However, little is known about the upstream mechanisms that deregulate miRNA expressions in this process. In hepatocellular carcinoma (HCC), hepatitis B virus (HBV) X protein (HBx), a transcriptional trans-activator, is frequently expressed in truncated form without carboxyl-terminus but its role in miRNA expression and HCC development is unclear. METHODS Human non-tumorigenic hepatocytes were infected with lentivirus-expressing full-length and carboxyl-terminal truncated HBx (Ct-HBx) for cell growth assay and miRNA profiling. Chromatin immunoprecipitation microarray was performed to identify the miRNA promoters directly associated with HBx. Direct transcriptional control was verified by luciferase reporter assay. The differential miRNA expressions were further validated in a cohort of HBV-associated HCC tissues using real-time PCR. RESULTS Hepatocytes expressing Ct-HBx grew significantly faster than the full-length HBx counterparts. Ct-HBx decreased while full-length HBx increased the expression of a set of miRNAs with growth-suppressive functions. Interestingly, Ct-HBx bound to and inhibited the transcriptional activity of some of these miRNA promoters. Notably, some of the examined repressed-miRNAs (miR-26a, -29c, -146a and -190) were also significantly down-regulated in a subset of HCC tissues with carboxyl-terminal HBx truncation compared to their matching non-tumor tissues, highlighting the clinical relevance of our data. CONCLUSION Our results suggest that Ct-HBx directly regulates miRNA transcription and in turn promotes hepatocellular proliferation, thus revealing a viral contribution of miRNA deregulation during hepatocarcinogenesis.
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Affiliation(s)
- Wing-Kit Yip
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Alfred Sze-Lok Cheng
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ranxu Zhu
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Raymond Wai-Ming Lung
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Daisy Pui-Fong Tsang
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Suki Shuk-Kei Lau
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yangchao Chen
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jonathan Gabriel Sung
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Paul Bo-San Lai
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Enders Kai-On Ng
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jun Yu
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Nathalie Wong
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ka-Fai To
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Vincent Wai-Sun Wong
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Joseph Jao-Yiu Sung
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Henry Lik-Yuen Chan
- Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, China
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Kim JW, Lee SH, Park YS, Hwang JH, Jeong SH, Kim N, Lee DH. Replicative activity of hepatitis B virus is negatively associated with methylation of covalently closed circular DNA in advanced hepatitis B virus infection. Intervirology 2011; 54:316-25. [PMID: 21242658 DOI: 10.1159/000321450] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 09/20/2010] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES The aim of this study was to examine the methylation status of intrahepatic hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) and to elucidate the possible relationship between the cccDNA methylation and viral replicative activity in patients with HBV-related liver cirrhosis (HBV-LC). METHODS The methylation status of HBV cccDNA was investigated by bisulfite sequencing in nonneoplastic tissues from 12 patients with HBV-LC who underwent surgical resection for combined hepatocellular carcinoma. Clinical, biochemical and virologic factors were evaluated with respect to the degrees of cccDNA methylation. We also examined the effect of methylation of cccDNA on viral transcription by an in vitro transcription assay. RESULTS Variable degrees of CpG methylation were present in the HBV cccDNA from patients with HBV-LC. Old age, low serum HBV DNA levels and low virion productivity were significantly associated with elevated cccDNA methylation. Virion productivity of cccDNA was also lower in HepAD38 cells with a higher degree of cccDNA methylation. In vitro transcription assays showed that the transcriptional activity of HBV cccDNA was suppressed by increased methylation of cccDNA. CONCLUSIONS Increased CpG methylation of cccDNA is associated with old age, low serum HBV DNA levels and suppressed replicative activity in HBV-LC.
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Affiliation(s)
- Jin-Wook Kim
- Department of Medicine, Seoul National University Bundang Hospital, Seongnam, South
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Abstract
Epigenetics represents a new frontier in cancer research. Methylation is the best studied of the epigenetic mechanisms that regulate gene expression. Regulation of gene expression by means of methylation has been reported for tumor suppressor genes, oncogenes, viral promoters, and age-related genes. In this review, the regulation of viral gene expression by methylation is discussed, with particular emphasis on: (1) the virus-specific factors that bind to promoter regions; (2) the implications of this knowledge for designing viral vectors that can be used to deliver genes for the purpose of gene therapy; and (3) the use of this knowledge for the early detection and prevention of cancer. Since methylation can be reversed by a variety of exogenous agents, great potential exists to develop interventions that target cancer-associated aberrant methylation in an effort to reverse or prevent carcinogenesis.
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Affiliation(s)
- Mukesh Verma
- Cancer Biomarkers Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Rockville, Maryland 20852-7362, USA.
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Xu Z, Yen TSB, Wu L, Madden CR, Tan W, Slagle BL, Ou JH. Enhancement of hepatitis B virus replication by its X protein in transgenic mice. J Virol 2002; 76:2579-84. [PMID: 11836439 PMCID: PMC153824 DOI: 10.1128/jvi.76.5.2579-2584.2002] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) X gene encodes a multifunctional protein that can regulate cellular signaling pathways, interact with cellular transcription factors, and induce hepatocellular oncogenesis. In spite of its diverse activities, the precise role of the X protein in the viral life cycle of HBV remains unclear. To investigate this question, we have produced transgenic mice that carry either the wild-type HBV genome or a mutated HBV genome incapable of expressing the 16.5-kDa X protein. Our results indicate that while the X protein is not absolutely essential for HBV replication or its maturation in transgenic mice, it can enhance viral replication, apparently by activating viral gene expression. These results demonstrate a transactivation role of the X protein in HBV replication in transgenic mice.
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Affiliation(s)
- Zhenming Xu
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Ave., Los Angeles, CA 90033, USA
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Matsuda J, Suzuki M, Nozaki C, Shinya N, Tashiro K, Mizuno K, Uchinuno Y, Yamamura K. Transgenic mouse expressing a full-length hepatitis C virus cDNA. Jpn J Cancer Res 1998; 89:150-8. [PMID: 9548442 PMCID: PMC5921765 DOI: 10.1111/j.1349-7006.1998.tb00543.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Hepatitis C virus (HCV), a major causative agent of post transfusion non-A, non-B hepatitis (NANBH), can only infect humans and chimpanzees. We produced nine transgenic mouse lines carrying a full-length HCV cDNA with the human serum amyloid P component (hSAP) promoter that can direct liver-specific expression. In one of these lines HCV mRNA and HCV core protein were detected in the liver of the transgenic mouse, although the levels of expression were very low. In addition, HCV-related antibody was detected in the serum.
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Affiliation(s)
- J Matsuda
- The Chemo-Sero-Therapeutic Research Institute, Kikuchi Research Center, Pathology Department, Kumamoto
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Dunne JB, Piratvisuth T, Williams R, Tredger JM. Treatment of experimental ischemia/reperfusion injury with S-adenyosylmethionine: evidence that donor pretreatment complements other regimens. Transplantation 1997; 63:500-6. [PMID: 9047141 DOI: 10.1097/00007890-199702270-00003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Triple therapy with S-adenosylmethionine (SAM) (given to the donor animal, included in University of Wisconsin solution [UW], and added to the reperfusing medium) has been shown to reduce the sequential cold and warm ischemia/reperfusion injuries characteristic of the liver transplantation procedure. To clarify the actions of SAM during different stages of ischemia/ reperfusion, we have compared its benefit in five dosage regimens, using perfused rat livers after sequential periods of 24 hr cold and 20 min rewarming ischemia. When added only to UW, the presence of SAM throughout ischemia improved hepatic blood flow by 26% after 15 min of reperfusion versus no treatment (2.32+/-0.18 vs. 1.84+/-0.11 ml/min/g liver, P<0.05). SAM also improved blood flow by 23% during the 3-hr perfusion overall (P<0.05). Oxygen consumption and the release of purine nucleoside phosphorylase (PNP) were decreased (both P<0.05). When added to both UW and the perfusate, SAM additionally increased bile production at 15 min (7.14+/-1.21 vs. 2.31+/-0.74 mg/h/g liver, P<0.01). By pretreating the liver donor with SAM in vivo, and including it in the preservation and reperfusing media, it was possible to prolong and amplify the benefits on blood flow (P<0.001) and bile production (P<0.05) and to sustain glucose uptake (P<0.01). An acute exposure to SAM, when used in saline to flush UW from the graft before reperfusion, increased blood flow at 15 min (by 68%) and over a 3-hr period (both P<0.001), but no indices of metabolic activity were improved. Oxygen consumption and PNP release were both decreased (P<0.05). When added to the perfusate (present throughout reperfusion), SAM increased blood flow at 15 min (58%) and over a 3-hr period (P<0.01 in both cases). Net glucose uptake was increased (P<0.05), whereas oxygen consumption (P<0.001) and PNP release fell (P<0.05). Actions of SAM achieved acutely and over the intermediate- and long-term all seem to underlie its benefits in reducing ischemia/reperfusion injuries.
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Affiliation(s)
- J B Dunne
- Institute of Liver Studies, King's College Hospital, London, England
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Kato T, Ahmed M, Yamamoto T, Takahashi H, Oohara M, Ikeda T, Aida Y, Katsuki M, Arakawa Y, Shikata T, Esumi M. Inactivation of hepatitis C virus cDNA transgene by hypermethylation in transgenic mice. Arch Virol 1996; 141:951-8. [PMID: 8678840 DOI: 10.1007/bf01718169] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Transgenic mice were produced by microinjection of a partial hepatitis C virus (HCV) genome sequence including the structural protein region, under the control of the albumin promoter and enhancer into fertilized eggs of C57BL/6 and BDF1 mice. Three founders carrying at least five copies of the transgene but not expressing HCV-specific RNA were generated. Methylation analysis indicated that the transgene was extensively methylated. Mapping of methylated cytosine residues of the transgenic mouse DNA showed that all C residues of a particular part of the HCV genome but not all the CpG island like sequences were methylated. Transiently expressed HCV cDNA in COS7 cells and the active endogenous albumin gene were not methylated. Furthermore, 5-azacytidine, a potent demethylating agent, induced HCV gene expression in a line of these transgenic mice. These results suggest that methylation of HCV cDNA is a cause of its inactive expression in transgenic mice, and that this phenomenon may occur in other stable systems for expression of the HCV genome.
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Affiliation(s)
- T Kato
- First Department of Pathology, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
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Miyazaki Y, Araki K, Vesin C, Garcia I, Kapanci Y, Whitsett JA, Piguet PF, Vassalli P. Expression of a tumor necrosis factor-alpha transgene in murine lung causes lymphocytic and fibrosing alveolitis. A mouse model of progressive pulmonary fibrosis. J Clin Invest 1995; 96:250-9. [PMID: 7542280 PMCID: PMC185196 DOI: 10.1172/jci118029] [Citation(s) in RCA: 290] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The murine TNF-alpha gene was expressed under the control of the human surfactant protein SP-C promoter in transgenic mice. A number of the SP-C TNF-alpha mice died at birth or after a few weeks with very severe lung lesions. Surviving mice transmitted a pulmonary disease to their offspring, the severity and evolution of which was related to the level of TNF-alpha mRNA in the lung; TNF-alpha RNA was detected in alveolar epithelium, presumably in type II epithelial cells. In a longitudinal study of two independent mouse lines, pulmonary pathology, at 1-2 mo of age, consisted of a leukocytic alveolitis with a predominance of T lymphocytes. Leukocyte infiltration was associated with endothelial changes and increased levels of mRNA for the endothelial adhesion molecule VCAM-1. In the following months, alveolar spaces enlarged in association with thickening of the alveolar walls due to an accumulation of desmin-containing fibroblasts, collagen fibers, and lymphocytes. Alveolar surfaces were lined by regenerating type II epithelial cells, and alveolar spaces contained desquamating epithelial cells in places. Platelet trapping in the damaged alveolar capillaries was observed. Pulmonary pathology in the SP-C TNF-alpha mice bears a striking resemblance to human idiopathic pulmonary fibrosis, in which increased expression of TNF-alpha in type II epithelial cells has also been noted. These mice provide a valuable animal model for understanding the pathogenesis of pulmonary fibrosis and exploring possible therapeutic approaches.
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Affiliation(s)
- Y Miyazaki
- Department of Pathology, University of Geneva, Switzerland
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