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Díaz-Carballo D, Saka S, Acikelli AH, Homp E, Erwes J, Demmig R, Klein J, Schröer K, Malak S, D'Souza F, Noa-Bolaño A, Menze S, Pano E, Andrioff S, Teipel M, Dammann P, Klein D, Nasreen A, Tannapfel A, Grandi N, Tramontano E, Ochsenfarth C, Strumberg D. Enhanced antitumoral activity of TLR7 agonists via activation of human endogenous retroviruses by HDAC inhibitors. Commun Biol 2021; 4:276. [PMID: 33658617 PMCID: PMC7930250 DOI: 10.1038/s42003-021-01800-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 01/25/2021] [Indexed: 12/18/2022] Open
Abstract
In this work, we are reporting that "Shock and Kill", a therapeutic approach designed to eliminate latent HIV from cell reservoirs, is extrapolatable to cancer therapy. This is based on the observation that malignant cells express a spectrum of human endogenous retroviral elements (HERVs) which can be transcriptionally boosted by HDAC inhibitors. The endoretroviral gene HERV-V2 codes for an envelope protein, which resembles syncytins. It is significantly overexpressed upon exposure to HDAC inhibitors and can be effectively targeted by simultaneous application of TLR7/8 agonists, triggering intrinsic apoptosis. We demonstrated that this synergistic cytotoxic effect was accompanied by the functional disruption of the TLR7/8-NFκB, Akt/PKB, and Ras-MEK-ERK signalling pathways. CRISPR/Cas9 ablation of TLR7 and HERV-V1/V2 curtailed apoptosis significantly, proving the pivotal role of these elements in driving cell death. The effectiveness of this new approach was confirmed in ovarian tumour xenograft studies, revealing a promising avenue for future cancer therapies.
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Affiliation(s)
- David Díaz-Carballo
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany.
| | - Sahitya Saka
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Ali H Acikelli
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Ekaterina Homp
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Julia Erwes
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Rebecca Demmig
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Jacqueline Klein
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Katrin Schröer
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Sascha Malak
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Flevy D'Souza
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Adrien Noa-Bolaño
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Saskia Menze
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Emilio Pano
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Swetlana Andrioff
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Marc Teipel
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
| | - Philip Dammann
- Central Animal Laboratory, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Diana Klein
- Institute of Cell Biology, Cancer Research, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Amber Nasreen
- Visceral Surgery Department, Marien Hospital Herne, Ruhr University Bochum Medical School, Herne, Germany
| | | | - Nicole Grandi
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, Italy
| | - Crista Ochsenfarth
- Department of Anesthesia, Intensive Care, Pain and Palliative Medicine, Marien Hospital Herne, Ruhr-University Bochum Medical School, Herne, Germany
| | - Dirk Strumberg
- Ruhr University Bochum, Faculty of Medicine, Department of Haematology and Oncology, Institute of Molecular Oncology and Experimental Therapeutics, Marien Hospital Herne, Herne, Germany
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Niu G, Jin Z, Zhang C, He D, Gao X, Zou C, Zhang W, Ding J, Das BC, Severinov K, Hitzeroth II, Debata PR, Ma X, Tian X, Gao Q, Wu J, You Z, Tian R, Cui Z, Fan W, Xie W, Huang Z, Cao C, Xu W, Xie H, Xu H, Tang X, Wang Y, Yu Z, Han H, Tan S, Chen S, Hu Z. An effective vaginal gel to deliver CRISPR/Cas9 system encapsulated in poly (β-amino ester) nanoparticles for vaginal gene therapy. EBioMedicine 2020; 58:102897. [PMID: 32711250 PMCID: PMC7387785 DOI: 10.1016/j.ebiom.2020.102897] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Gene therapy has held promises for treating specific genetic diseases. However, the key to clinical application depends on effective gene delivery. METHODS Using a large animal model, we developed two pharmaceutical formulations for gene delivery in the pigs' vagina, which were made up of poly (β-amino ester) (PBAE)-plasmid polyplex nanoparticles (NPs) based two gel materials, modified montmorillonite (mMMT) and hectorite (HTT). FINDINGS By conducting flow cytometry of the cervical cells, we found that PBAE-GFP-NPs-mMMT gel was more efficient than PBAE-GFP-NPs-HTT gel in delivering exogenous DNA intravaginally. Next, we designed specific CRISPR/SpCas9 sgRNAs targeting porcine endogenous retroviruses (PERVs) and evaluated the genome editing efficacy in vivo. We discovered that PERV copy number in vaginal epithelium could be significantly reduced by the local delivery of the PBAE-SpCas9/sgRNA NPs-mMMT gel. Comparable genome editing results were also obtained by high-fidelity version of SpCas9, SpCas9-HF1 and eSpCas9, in the mMMT gel. Further, we confirmed that the expression of topically delivered SpCas9 was limited to the vagina/cervix and did not diffuse to nearby organs, which was relatively safe with low toxicity. INTERPRETATION Our data suggested that the PBAE-NPs mMMT vaginal gel is an effective preparation for local gene therapy, yielding insights into novel therapeutic approaches to sexually transmitted disease in the genital tract. FUNDING This work was supported by the National Science and Technology Major Project of the Ministry of science and technology of China (No. 2018ZX10301402); the National Natural Science Foundation of China (81761148025, 81871473 and 81402158); Guangzhou Science and Technology Programme (No. 201704020093); National Ten Thousand Plan-Young Top Talents of China, Fundamental Research Funds for the Central Universities (17ykzd15 and 19ykyjs07); Three Big Constructions-Supercomputing Application Cultivation Projects sponsored by National Supercomputer Center In Guangzhou; the National Research FFoundation (NRF) South Africa under BRICS Multilateral Joint Call for Proposals; grant 17-54-80078 from the Russian Foundation for Basic Research.
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Affiliation(s)
- Gang Niu
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Zhuang Jin
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Chong Zhang
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dan He
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
| | - Xueqin Gao
- Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chenming Zou
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wei Zhang
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jiahui Ding
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Bhudev C Das
- Amity Institute of Molecular Medicine & Stem Cell Research, Amity University, Uttar Pradesh, Noida 201313, India
| | - Konstantin Severinov
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143025, Russian Federation
| | - Inga Isabel Hitzeroth
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town 7701, South Africa
| | - Priya Ranjan Debata
- Department of Zoology, North Orissa University, Takatpur, Baripada, Odisha 757003, India
| | - Xin Ma
- Department of Urology, General Hospital of People's Liberation Army, Beijing 100039, China
| | - Xun Tian
- Department of Obstetrics and Gynecology, Academician expert workstation, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, Hubei, China
| | - Qinglei Gao
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Jun Wu
- School of Biomedical Engineering, Sun Yat-sen University, Guangzhou 510006, Guangdong, China
| | - Zeshan You
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Rui Tian
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Zifeng Cui
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Weiwen Fan
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Weiling Xie
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Zhaoyue Huang
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Chen Cao
- Department of Obstetrics and Gynecology, Academician expert workstation, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430014, Hubei, China
| | - Wei Xu
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Hongxian Xie
- Generulor Company Bio-X Lab, Guangzhou 510006, Guangdong, China
| | - Hongyan Xu
- Department of Obstetrics and Gynecology, Yuebei People's Hospital, Medical College of Shantou University, Shaoguan 512026, Guangdong, China
| | - Xiongzhi Tang
- Department of Obstetrics and Gynecology, Guilin People's Hospital, Guilin, The Guangxi Zhuang Autonomous Region, 541002, China
| | - Yan Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Zhiying Yu
- Department of Obstetrics & Gynecology, First Affiliated Hospital of Shenzhen University, Shenzhen 518000, Guangdong, China
| | - Hui Han
- State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine & Department of Urology, Yat-sen University Cancer Center, Guangzhou 510080, Guangdong Province, China
| | - Songwei Tan
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Shuqin Chen
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
| | - Zheng Hu
- Department of Obstetrics and Gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; Precision Medicine Institute, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
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Curtin F, Bernard C, Levet S, Perron H, Porchet H, Médina J, Malpass S, Lloyd D, Simpson R. A new therapeutic approach for type 1 diabetes: Rationale for GNbAC1, an anti-HERV-W-Env monoclonal antibody. Diabetes Obes Metab 2018; 20:2075-2084. [PMID: 29749030 DOI: 10.1111/dom.13357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
We describe a newly identified therapeutic target for type 1 diabetes (T1D): an envelope protein of endogenous retroviral origin, human endogenous retrovirus W envelope (HERV-W-Env). HERV-W-Env was found to be detected in the blood of ~60% of patients with T1D and is expressed in acinar pancreatic cells of 75% of patients with T1D at post mortem examination. Preclinical experiments showed that this protein displays direct cytotoxicity on human β-islet cells. In vivo HERV-W-Env impairs the insulin and glucose metabolism in transgenic mice expressing HERV-W-Env. GNbAC1, an IgG4 monoclonal antibody, has been developed to specifically target HERV-W-Env and to neutralize the effect of HERV-W-Env in vitro and in vivo. GNbAC1 is currently in clinical development for multiple sclerosis and > 300 subjects have been administered with GNbAC1 so far. GNbAC1 is now being tested in T1D in the RAINBOW-T1D study, which is a randomized placebo-controlled study with the objective of showing the safety and pharmacodynamic response of GNbAC1 in patients who have had T1D with a maximum of 4 years' duration. GNbAC1 is being tested vs placebo at the dose of 6 mg/kg in 60 patients during six repeated administrations for 6 months; a 6-month open-label extension will follow. The primary endpoint is to assess safety, and secondary endpoints are the pharmacodynamic responses to GNbAC1. GNbAC1 targeting HERV-W-Env is currently in clinical development in T1D, with the first safety and pharmacodynamic study. If the study results are positive, this may open the door to the development of an innovative non-immunomodulatory disease-modifying treatment for T1D.
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Affiliation(s)
- Francois Curtin
- GeNeuro SA, Plan-les-Ouates, Switzerland
- Division of Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | | | - Hervé Perron
- GeNeuro SA, Plan-les-Ouates, Switzerland
- Geneuro-Innovation, Lyon, France
- Laboratory of Immune Deficiencies, Faculty of Medicine Laënnec, University of Lyon, Lyon, France
| | - Hervé Porchet
- GeNeuro SA, Plan-les-Ouates, Switzerland
- Department of Pharmacology, University of Pretoria, Pretoria, South Africa
| | | | - Sam Malpass
- Southern Star Research Pty Ltd, Gordon, Australia
| | - David Lloyd
- Southern Star Research Pty Ltd, Gordon, Australia
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Mercorio R, Bonzini M, Angelici L, Iodice S, Delbue S, Mariani J, Apostoli P, Pesatori AC, Bollati V. Effects of metal-rich particulate matter exposure on exogenous and endogenous viral sequence methylation in healthy steel-workers. Environ Res 2017; 159:452-457. [PMID: 28858759 DOI: 10.1016/j.envres.2017.08.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Inhaled particles have been shown to produce systemic changes in DNA methylation. Global hypomethylation has been associated to viral sequence reactivation, possibly linked to the activation of pro-inflammatory pathways occurring after exposure. This observation provides a rationale to investigate viral sequence (both exogenous and endogenous) methylation in association to metal-rich particulate matter exposure. To verify this hypothesis, we chose the Wp promoter of the Epstein-Barr Virus (EBV-Wp) and the promoter of the human-endogenous-retrovirus w (HERV-w), respectively as a paradigm of an exogenous and an endogenous retroviral sequence, to be investigated by bisulfite PCR Pyrosequencing. We enrolled 63 male workers in an electric furnace steel plant, exposed to high level of metal-rich particulate matter. RESULTS Comparing samples obtained in the first day of a work week (time 0-baseline, after 2 days off work) and the samples obtained after 3 days of work (time 1-post exposure), the mean methylation of EBV-Wp was significantly higher at baseline compared to post-exposure (meanbaseline = 56.7%5mC; meanpost-exposure = 47.9%5mC; p-value = 0.009), whereas the mean methylation of HERV-w did not significantly differ. Individual exposure to inhalable particles and metals was estimated based on measures in all working areas and time spent by the study subjects in each area. In a regression model adjusted for age, body mass index and smoking, PM and metal components had a positive association with EBV-Wp methylation (i.e. PM10: β = 5.99, p-value < 0.038; nickel: β = 17.82, p-value = 0.02; arsenic: β = 13.59, p-value < 0.015). CONCLUSIONS The difference observed comparing baseline and post-exposure samples may be suggestive of a rapid change in EBV methylation induced by air particles, while correlation between EBV methylation and PM/metal exposure may represent a more stable adaptive mechanism. Future studies investigating a larger panel of viral sequences could better elucidate possible mechanisms and their role in pro-inflammatory pathways leading to systemic health effects.
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Affiliation(s)
- Roberta Mercorio
- EPIGET LAB, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via san Barnaba 8, 20122 Milan, Italy
| | - Matteo Bonzini
- EPIGET LAB, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via san Barnaba 8, 20122 Milan, Italy; Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Laura Angelici
- EPIGET LAB, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via san Barnaba 8, 20122 Milan, Italy
| | - Simona Iodice
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Serena Delbue
- Department of Biomedical, Surgical and Dental Sciences, University of Milano, Via Pascal, 36-20133 Milan, Italy
| | - Jacopo Mariani
- EPIGET LAB, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via san Barnaba 8, 20122 Milan, Italy
| | - Pietro Apostoli
- Occupational Medicine and Industrial Hygiene, University of Brescia, Department of Experimental and Applied Medicine, Brescia, Italy
| | - Angela Cecilia Pesatori
- EPIGET LAB, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via san Barnaba 8, 20122 Milan, Italy; Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Valentina Bollati
- EPIGET LAB, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via san Barnaba 8, 20122 Milan, Italy.
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Denner J. Can Antiretroviral Drugs Be Used to Treat Porcine Endogenous Retrovirus (PERV) Infection after Xenotransplantation? Viruses 2017; 9:v9080213. [PMID: 28786944 PMCID: PMC5580470 DOI: 10.3390/v9080213] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/02/2017] [Accepted: 08/02/2017] [Indexed: 01/09/2023] Open
Abstract
Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pigs; they are released as infectious particles, and under certain conditions they can infect human cells. Therefore, they represent a risk when pigs are used as sources of cells, tissues, or organs for xenotransplantation. Xenotransplantation is under development due to the increasing shortage of human transplants. Whereas most porcine microorganisms which may be able to induce a disease (zoonosis) in the transplant recipient can be eliminated, this is not possible in the case of PERVs. Antiretroviral drugs which had been developed for the treatment of human immunodeficiency virus-1 (HIV-1) infections have been tested in vitro for their efficacy in inhibiting PERV replication. Inhibitors of the viral reverse transcriptase and of the integrase have been found effective. The most effective inhibitor of the reverse transcriptase was azidothymidine (AZT); the integrase inhibitors were the most potent inhibitors of PERV. Although in the past PERV transmission has not been observed after experimental or clinical xenotransplantation of pig cells or organs, and although PERVs may one day be inactivated in pigs by genome editing using CRISPR/Cas, knowing which antiretroviral drugs can effectively restrict PERV infection will still be important.
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Affiliation(s)
- Joachim Denner
- Robert Koch Fellow, Robert Koch Institute, Berlin, Germany.
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Mameli G, Poddighe L, Mei A, Uleri E, Sotgiu S, Serra C, Manetti R, Dolei A. Expression and activation by Epstein Barr virus of human endogenous retroviruses-W in blood cells and astrocytes: inference for multiple sclerosis. PLoS One 2012; 7:e44991. [PMID: 23028727 PMCID: PMC3459916 DOI: 10.1371/journal.pone.0044991] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 08/15/2012] [Indexed: 11/20/2022] Open
Abstract
Background Proposed co-factors triggering the pathogenesis of multiple sclerosis (MS) are the Epstein Barr virus (EBV), and the potentially neuropathogenic MSRV (MS-associated retrovirus) and syncytin-1, of the W family of human endogenous retroviruses. Methodology/Principal Findings In search of links, the expression of HERV-W/MSRV/syncytin-1, with/without exposure to EBV or to EBV glycoprotein350 (EBVgp350), was studied on peripheral blood mononuclear cells (PBMC) from healthy volunteers and MS patients, and on astrocytes, by discriminatory env-specific RT-PCR assays, and by flow cytometry. Basal expression of HERV-W/MSRV/syncytin-1 occurs in astrocytes and in monocytes, NK, and B, but not in T cells. This uneven expression is amplified in untreated MS patients, and dramatically reduced during therapy. In astrocytes, EBVgp350 stimulates the expression of HERV-W/MSRV/syncytin-1, with requirement of the NF-κB pathway. In EBVgp350-treated PBMC, MSRVenv and syncytin-1 transcription is activated in B cells and monocytes, but not in T cells, nor in the highly expressing NK cells. The latter cells, but not the T cells, are activated by proinflammatory cytokines. Conclusions/Significance In vitro EBV activates the potentially immunopathogenic and neuropathogenic HERV-W/MSRV/syncytin-1, in cells deriving from blood and brain. In vivo, pathogenic outcomes would depend on abnormal situations, as in late EBV primary infection, that is often symptomatic, or/and in the presence of particular host genetic backgrounds. In the blood, HERV-Wenv activation might induce immunopathogenic phenomena linked to its superantigenic properties. In the brain, toxic mechanisms against oligodendrocytes could be established, inducing inflammation, demyelination and axonal damage. Local stimulation by proinflammatory cytokines and other factors might activate further HERV-Ws, contributing to the neuropathogenity. In MS pathogenesis, a possible model could include EBV as initial trigger of future MS, years later, and HERV-W/MSRV/syncytin-1 as actual contributor to MS pathogenicity, in striking parallelism with disease behaviour.
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Affiliation(s)
- Giuseppe Mameli
- Department of Biomedical Sciences and Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy
| | - Luciana Poddighe
- Department of Biomedical Sciences and Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy
| | - Alessandra Mei
- Department of Biomedical Sciences and Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy
| | - Elena Uleri
- Department of Biomedical Sciences and Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy
| | - Stefano Sotgiu
- Department of Neurosciences and MIS, University of Sassari, Sassari, Italy
| | - Caterina Serra
- Department of Biomedical Sciences and Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy
| | - Roberto Manetti
- Department of Clinical, Experimental and Oncological Medicine, University of Sassari, Sassari, Italy
| | - Antonina Dolei
- Department of Biomedical Sciences and Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy
- * E-mail:
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Leroy V, Kihara M, Baudino L, Brighouse G, Evans LH, Izui S. Sgp3 and TLR7 stimulation differentially alter the expression profile of modified polytropic retroviruses implicated in murine systemic lupus. J Autoimmun 2012; 38:361-8. [PMID: 22503566 DOI: 10.1016/j.jaut.2012.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 02/27/2012] [Accepted: 03/07/2012] [Indexed: 12/24/2022]
Abstract
The envelope glycoprotein, gp70, of endogenous retroviruses represents one of the major nephritogenic autoantigens implicated in murine systemic lupus erythematosus. Among different endogenous retroviruses (ecotropic, xenotropic and polytropic), lupus-prone mice express remarkably high levels of modified polytropic (mPT) retroviruses, which are controlled by the Sgp3 (serum gp70 production) locus. To define the contribution of the Sgp3 locus derived from lupus-prone mice to the expression of the specific mPT proviruses, the genetic origin of different mPT viruses expressed in livers and thymi of wild-type and Sgp3 congenic C57BL/6 mice was determined through clonal analysis of their transcripts. Among 13 mPT proviruses present in the C57BL/6 genome, only 3 proviruses (Mpmv6, Mpmv10 and Mpmv13) were selectively but differentially expressed in livers and thymi. This was likely a result of co-regulated expression with host genes because of their integration in the same transcriptional direction. In contrast, Sgp3 induced the steady-state expression of an additional select group of mPT proviruses and, after stimulation of TLR7, the highly upregulated expression of a potentially replication-competent mPT virus Mpmv4. These results indicated that the expression of distinct subpopulations of mPT retroviruses was regulated by Sgp3- and TLR7-dependent mechanisms. The induction of potentially replication-competent mPT viruses and the upregulation of one such virus after stimulation with TLR7 in Sgp3 congenic mice further highlight the implication of Sgp3 in autoimmune responses against nephritogenic serum gp70 through the activation of TLR7.
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Affiliation(s)
- Valérie Leroy
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva 4, Switzerland
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Diem O, Schäffner M, Seifarth W, Leib-Mösch C. Influence of antipsychotic drugs on human endogenous retrovirus (HERV) transcription in brain cells. PLoS One 2012; 7:e30054. [PMID: 22253875 PMCID: PMC3256206 DOI: 10.1371/journal.pone.0030054] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 12/08/2011] [Indexed: 01/26/2023] Open
Abstract
Human endogenous retroviruses (HERVs) have been associated with various neurological and neuropsychiatric disorders. Transcripts and proteins of at least three HERV groups, HERV-W, ERV9 and HERV-K(HML-2) have been detected repeatedly in brain samples or cerebrospinal fluid of patients with schizophrenia suggesting that alterations in HERV activity may play a role in etiopathogenesis. Current therapies otherwise include neuroleptics and/or antidepressants that may induce epigenetic alterations and thus influence HERV expression. To investigate the effects of these drugs on HERV transcriptional activity, HERV expression profiles of a broad range of human brain cell lines treated with valproic acid (VPA), haloperidol, risperidone, and clozapine were analyzed using a retrovirus-specific microarray and qRT-PCR. Investigation of 52 HERV subgroups revealed upregulation of several class I and class II HERV elements by VPA in a dose-dependent manner. The strongest effect was observed on HERV-W and ERV9 groups in the human glioblastoma cell lines SK-N-SH and SK-N-MC, respectively. The transcript level of HERV-K(HML-2) elements was not influenced. Transcription of HERV-W, ERV9 and HERV-K(HML-2) taxa was further quantified in postmortem brain samples of patients with schizophrenia, bipolar disorders and a healthy control group with regard to their medication. Patients with schizophrenia showed a significantly higher HERV-W transcription associated with VPA treatment. However in case of ERV9, enhanced transcript levels could not be explained solely by VPA treatment, since a slight increase was also found in untreated patients compared to healthy controls. HERV-K(HML-2) elements appeared to be upregulated in some patients with bipolar disorders independent from medication. In conclusion, these results suggest that antipsychotic medication may contribute to increased expression of distinct HERV taxa in patients with neuropsychiatric diseases.
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Affiliation(s)
- Olivia Diem
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- III. Medizinische Klinik, UMM-Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Marisa Schäffner
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Wolfgang Seifarth
- III. Medizinische Klinik, UMM-Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Christine Leib-Mösch
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- III. Medizinische Klinik, UMM-Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
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Fukuma A, Abe M, Morikawa Y, Miyazawa T, Yasuda J. Cloning and characterization of the antiviral activity of feline Tetherin/BST-2. PLoS One 2011; 6:e18247. [PMID: 21479233 PMCID: PMC3066219 DOI: 10.1371/journal.pone.0018247] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 03/01/2011] [Indexed: 12/22/2022] Open
Abstract
Human Tetherin/BST-2 has recently been identified as a cellular antiviral factor that blocks the release of various enveloped viruses. In this study, we cloned a cDNA fragment encoding a feline homolog of Tetherin/BST-2 and characterized the protein product. The degree of amino acid sequence identity between human Tetherin/BST-2 and the feline homolog was 44.4%. Similar to human Tetherin/BST-2, the expression of feline Tetherin/BST-2 mRNA was inducible by type I interferon (IFN). Exogenous expression of feline Tetherin/BST-2 efficiently inhibited the release of feline endogenous retrovirus RD-114. The extracellular domain of feline Tetherin/BST-2 has two putative N-linked glycosylation sites, N79 and N119. Complete loss of N-linked glycosylation by introduction of mutations into both sites resulted in almost complete abolition of its antiviral activity. In addition, feline Tetherin/BST-2 was insensitive to antagonism by HIV-1 Vpu, although the antiviral activity of human Tetherin/BST-2 was antagonized by HIV-1 Vpu. Our data suggest that feline Tetherin/BST-2 functions as a part of IFN-induced innate immunity against virus infection and that the induction of feline Tetherin/BST-2 in vivo may be effective as a novel antiviral strategy for viral infection.
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Affiliation(s)
- Aiko Fukuma
- Department of Emerging Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- Fifth Biology Section for Microbiology, First Department of Forensic Science, National Research Institute of Police Science, Kashiwa, Japan
- Kitasato Institute for Life Sciences and Graduate School for Infection Control, Kitasato University, Tokyo, Japan
| | - Masumi Abe
- Fifth Biology Section for Microbiology, First Department of Forensic Science, National Research Institute of Police Science, Kashiwa, Japan
| | - Yuko Morikawa
- Kitasato Institute for Life Sciences and Graduate School for Infection Control, Kitasato University, Tokyo, Japan
| | - Takayuki Miyazawa
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Jiro Yasuda
- Department of Emerging Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- Fifth Biology Section for Microbiology, First Department of Forensic Science, National Research Institute of Police Science, Kashiwa, Japan
- * E-mail:
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Abstract
Xenotransplantation of porcine cells, tissues, and organs offers a solution to overcome the shortage of human donor materials. In addition to the immunological and physiological barriers, the existence of numerous porcine microorganisms including viruses poses a risk for xenozoonosis. Three classes of functional gamma-type porcine endogenous retroviruses (PERV) have been identified, whereby functional polytropic PERV-A and PERV-B infect human embryonic kidney (HEK 293) and other cell lines in vitro. In the course of risk assessment for xenotransplantation the capacity of human cells to counteract PERV infections should be analyzed. Primates and other mammals display different means of protection against viral infections. APOBEC3 proteins which are cytidine deaminases and a part of the intrinsic immunity mediate potent activity against a wide range of retroviruses including murine leukemia viruses (MLV). As PERV and MLV belong to the same genus, we raised the question as to whether PERV is affected by APOBEC3 proteins. Initial data indicate that human and porcine cytidine deaminases inhibit PERV replication, thereby possibly reducing the risk for infection of human cells by PERV as a consequence of pig-to-human xenotransplantation.
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11
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Shi M, Wang X, De Clercq E, Takao S, Baba M. Selective inhibition of porcine endogenous retrovirus replication in human cells by acyclic nucleoside phosphonates. Antimicrob Agents Chemother 2007; 51:2600-4. [PMID: 17470654 PMCID: PMC1913248 DOI: 10.1128/aac.00212-07] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several anti-human immunodeficiency virus type 1 reverse transcriptase inhibitors were evaluated for their antiviral activities against porcine endogenous retrovirus in human cells. Among the test compounds, zidovudine was found to be the most active. The order of potency was zidovudine > phosphonylmethoxyethoxydiaminopyrimidine = phosphonylmethoxypropyldiaminopurine > tenofovir > or = adefovir > stavudine.
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Affiliation(s)
- Minyi Shi
- Frontier Science Research Center, Kagoshima University, Kagoshima 890-8544, Japan
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Li Z, Ping Y, Shengfu L, Youping L, Jingqiu C, Hong B. The Lack of Inhibition of Porcine Endogenous Retrovirus by Small Interference RNA Designed From the Long Terminal Regions. Transplant Proc 2006; 38:2258-60. [PMID: 16980058 DOI: 10.1016/j.transproceed.2006.06.099] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Xenotransplantation from pigs may offer a potential solution to the organ shortage. However, there remains the risk of xenoinfection by porcine endogenous retroviruses (PERVs) that cannot be eliminated by breeding pigs under specified pathogen-free conditions. RNA interference is a new method to inhibit the expression of a specific gene. Here, we designed two siRNAs from the long terminal repeat of PERV. Our results showed that these siRNAs had no inhibitory effects. The possible reasons for this are an off-target effect or a problem with specific sequence of RNAi. Future work should focus on siRNAs from conserved regions of other PERV genes.
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Affiliation(s)
- Z Li
- Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, P.R. China
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Taruscio D, Mantovani A. Factors regulating endogenous retroviral sequences in human and mouse. Cytogenet Genome Res 2005; 105:351-62. [PMID: 15237223 DOI: 10.1159/000078208] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Accepted: 12/23/2003] [Indexed: 11/19/2022] Open
Abstract
Endogenous retroviruses (ERVs) are stably integrated in the genome of vertebrates and inherited as Mendelian genes. The several human ERV (HERV) families and related elements represent up to 5-8% of the DNA of our species. ERVs may be involved in the regulation of adjacent genomic loci, especially promoting the tissue-specific expression of genes; some HERVs may have functional roles, e.g., coding for the placental fusogenic protein, syncytin. This paper reviews the growing evidence about factors that may modulate ERVs, including: cell and tissue types (with special attention to placenta and germ cells), processes related to differentiation and aging, cytokines, agents that disrupt cell functions (e.g., DNA hypomethylating agents) and steroids. Special attention is given to HERVs, due to their possible involvement in autoimmunity and reproduction, as well as altered expression in some cancer types; moreover, different HERV families may deserve specific attention, due to remarkable differences concerning, e.g., expression in tissues. A comparison with factors interacting with murine ERV-related sequences indicates that the mouse may be a useful model for studying some patterns of HERV regulation. Overall, the available evidence identifies the diverse, potential interactions with endogenous or exogenous factors as a promising field for investigating the roles of ERVs in physiology and disease.
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Affiliation(s)
- D Taruscio
- National Centre on Rare Diseases, Istituto Superiore di Sanità, Rome, Italy
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Abstract
Porcine endogenous retrovirus (PERV) may potentially be transmitted through porcine xenotransplantation products administered to humans. This study examined the feasibility of using guinea pigs as a model to characterize the in vivo infectivity of PERV. To enhance the susceptibility of guinea pigs to retroviral infection or genomic integration, moderate physiological or immunological changes were induced prior to exposing the animals to PERV. Quantitative PERV-specific PCR performed on all tested samples resulted in either undetectable or very low copy numbers of proviruses, even in animals possessing PERV-specific antibody responses. The low copy number of viral DNA detected suggests that PERV infected a limited number of cells. However, PERV DNA levels did not increase over time, suggesting no virus replication occurred. These results in the guinea pig are similar to previous observations of non-human primate cells that allow PERV infection but do not support PERV replication in vitro.
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Affiliation(s)
- Takele Argaw
- Laboratory of Immunology and Virology, Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, 8800 Rockville Pike, HFM-725, Bethesda, MD 20892, USA
| | - Winston Colon-Moran
- Laboratory of Immunology and Virology, Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, 8800 Rockville Pike, HFM-725, Bethesda, MD 20892, USA
| | - Carolyn A Wilson
- Laboratory of Immunology and Virology, Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, 8800 Rockville Pike, HFM-725, Bethesda, MD 20892, USA
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Hazama K, Miyagawa S, Miyazawa T, Yamada J, Tomonaga K, Ota M, Matsuda H, Shirakura R. The significance of N-linked glycosylation in pig endogenous retrovirus infectivity. Biochem Biophys Res Commun 2003; 310:327-33. [PMID: 14521913 DOI: 10.1016/j.bbrc.2003.08.142] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The significance of the envelope glycoprotein in the transmission of pig endogenous retrovirus (PERV) to human cells was investigated. Pig endothelial cells (PEC) were transduced with the LacZ gene by a pseudotype infection and then infected with PERV subtype B. Culture supernatants of the infected PEC previously incubated with several types of drugs were inoculated into HEK293 cells. The inoculated cells were then stained and the number of LacZ-positive foci was counted. PERV from tunicamycin treated PEC was not transmitted to human cells, indicating the importance of N-linked sugars in this process. Moreover, while inhibition of the terminal alpha-glucose residues from the precursor N-glycan by castanospermine and 1-deoxynojirimycin attenuated PERV infectivity, the mannosidase inhibitors, 1-deoxymannojirimycin and swainsonine, upregulated the infectivity. In addition, treatment with alpha-mannosidase and incubation with concanavalin A completely abrogated the transmission of PERV to HEK293. These data imply that the high-mannose type of N-glycan plays a key role in PERV infectivity.
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Affiliation(s)
- Kenji Hazama
- Division of Organ Transplantation, Department of Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
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Scheef G, Fischer N, Flory E, Schmitt I, Tönjes RR. Transcriptional regulation of porcine endogenous retroviruses released from porcine and infected human cells by heterotrimeric protein complex NF-Y and impact of immunosuppressive drugs. J Virol 2002; 76:12553-63. [PMID: 12438581 PMCID: PMC136706 DOI: 10.1128/jvi.76.24.12553-12563.2002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Recent studies revealed a significant promoter activity of porcine endogenous retrovirus (PERV) long terminal repeats (LTRs) in different human and mammalian cell lines, which is mediated by a 39-bp repeat located in the U3 region in different numbers, representing an enhancer (G. Scheef, N. Fischer, U. Krach, and R. R. Tönjes, J. Virol. 75:6933-6940, 2001). A statistical transcription factor analysis revealed putative binding sites for the CCAAT-binding transcription factor NF-Y inside the 39-bp repeat. Specific binding of NF-Y to the repeat sequence was demonstrated by electrophoretic mobility shift assays and supershift assays with specific antibodies directed against the three subunits of NF-Y. To identify further transcription-regulating elements, genetically modified LTRs lacking the repeat box, U3, R, or U5 were investigated. The results indicated a strong inhibitory element in the R region, as the deletion of R caused a significantly increased promoter activity. Since PERV might play a potential role in the application of xenogeneic cell therapy and xenotransplantation techniques, we have investigated whether immunosuppressive drugs that are routinely used in transplantation medicine have an impact on the promoter activity. Neither cyclosporine nor prednisolone had any influence on the promoter strength of the PERV LTRs. By performing a real-time PCR we were able to compare the proviral loads of porcine and infected human cells as well as the amount of released virions, which revealed a direct link between LTR activity and the number of released retroviruses.
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Affiliation(s)
- Gregor Scheef
- Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, D-63225 Langen, Germany
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17
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Abstract
Endogenous retroviral sequences are present as an integral part of eukaryotic genomes. Although the majority of these sequences are defective, a few can produce infectious virus, either spontaneously upon long-term culture or by treatment with various chemical or other agents. Early, extensive studies of retrovirus induction were done in mouse cells; however, similar studies have not been done using state-of-the-art virus detection assays and with cells of other mammalian species. To investigate induction and detection of occult retroviruses in cells of different species, especially primate cells that are used in production of biologics, we have initially determined the optimum conditions for retrovirus induction in chemically treated K-BALB mouse cells using highly sensitive product-enhanced reverse transcriptase (PERT) assays as well as transmission electron microscopy (TEM). Retrovirus induction was detected at day 1 post-drug treatment under all test conditions but was optimum using 30 microg ml(-1) of 5-iododeoxyuridine (IdU) for 24 h. Additionally, the combination of IdU and 5-azacytidine specifically enhanced activation of type C particles. RT activity was detected by PERT assays in one microliter equivalent of test sample and retroviral particle production was seen by TEM analysis. The induction of infectious murine leukemia retroviruses was confirmed by infectivity assays and correlated with PERT activity. These results indicate that strategies for detection of occult viral agents should include optimization of induction conditions using multiple viral detection assays to evaluate virus activation.
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Affiliation(s)
- A S Khan
- Laboratory of Retrovirus Research, Division of Viral Products, Center for Biologics Evaluation and Review, US Food and Drug Administration, Bethesda, MD 20892, USA.
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18
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Qari SH, Magre S, García-Lerma JG, Hussain AI, Takeuchi Y, Patience C, Weiss RA, Heneine W. Susceptibility of the porcine endogenous retrovirus to reverse transcriptase and protease inhibitors. J Virol 2001; 75:1048-53. [PMID: 11134319 PMCID: PMC114002 DOI: 10.1128/jvi.75.2.1048-1053.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porcine xenografts may offer a solution to the shortage of human donor allografts. However, all pigs contain the porcine endogenous retrovirus (PERV), raising concerns regarding the transmission of PERV and the possible development of disease in xenotransplant recipients. We evaluated 11 antiretroviral drugs licensed for human immunodeficiency virus type 1 (HIV-1) therapy for their activities against PERV to assess their potential for clinical use. Fifty and 90% inhibitory concentrations (IC(50)s and IC(90)s, respectively) of five nucleoside reverse transcriptase inhibitors (RTIs) were determined enzymatically for PERV and for wild-type (WT) and RTI-resistant HIV-1 reference isolates. In a comparison of IC(50)s, the susceptibilities of PERV RT to lamivudine, stavudine, didanosine, zalcitabine, and zidovudine were reduced >20-fold, 26-fold, 6-fold, 4-fold, and 3-fold, respectively, compared to those of WT HIV-1. PERV was also resistant to nevirapine. Tissue culture-based, single-round infection assays using replication-competent virus confirmed the relative sensitivity of PERV to zidovudine and its resistance to all other RTIs. A Gag polyprotein-processing inhibition assay was developed and used to assess the activities of protease inhibitors against PERV. No inhibition of PERV protease was seen with saquinavir, ritonavir, indinavir, nelfinavir, or amprenavir at concentrations >200-fold the IC(50)s for WT HIV-1. Thus, following screening of many antiretroviral agents, our findings support only the potential clinical use of zidovudine.
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Affiliation(s)
- S H Qari
- HIV and Retrovirology Branch, Division of AIDS, STD, and TB Laboratory Research, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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Abstract
dUTP pyrophosphatase catalyses hydrolysis of deoxyuridine triphosphate (dUTP) to deoxyuridine monophosphate (dUMP) and inorganic pyrophosphate (PPi). Elimination of dUTP is vital since its misincorporation into DNA by DNA polymerases can initiate a damaging iterative repair and misincorporation cycle, resulting in DNA fragmentation and cell death. The anti-tumour activity of folate agonists and thymidylate synthase inhibitors is thought to rely on dUTP misincorporation. Furthermore, retroviral cDNA production may be particularly susceptible to the effects of dUTP misincorporation by virtue of the error-prone nature of reverse trans criptase. Consequently, dUTPase activity is an ideal point of intervention in both chemotherapy and anti-retroviral therapy. In particular, the dUTPase encoded by a human endogenous retrovirus (HERV-K) has been suggested to complement HIV infection and so is an attractive target for specific inhibition. Hence, we used site photoaffinity labelling, site-directed mutagenesis and molecular modelling to assign catalytic roles to the conserved amino acid residues in the active site of the HERV-K dUTPase and to identify structural differences with other dUTPase enzymes. We found that dUTP photoaffinity labelling was specific for a beta-hairpin motif in HERV-K dUTPase. Mutagenesis of aspartate residues Asp84 and 86 to asparagine within this beta-hairpin showed the carboxylate moiety of both residues was required for catalysis but not for dUTP binding. An increase in the pKa of both aspartate residues brought about by substitution of a serine residue with a glutamate residue adjacent to the aspartate residues increased activity by a factor of 1.67 at pH 8.0, implicating general base catalysis as the enzyme's catalytic mechanism. Conservative mutagenesis of Tyr87 to Phe resulted in a sevenfold reduction of dUTPase activity and a 3.3-fold reduction in binding activity, whilst substitution with an isoleucine residue totally abolished both catalytic activity and dUTP binding, suggesting that binding/activity is dependent on an aromatic side-chain at the base of the hairpin. Comparison of a homology-based three-dimensional model structure of HERV-K dUTPase with a crystallographic structure of the human dUTPase revealed displacement of a conserved alpha-helix in the HERV-K enzyme causing expansion of the HERV-K active site. This expansion may be responsible for the ability of the HERV-K enzyme to hydrolyse dTTP and bind the bulkier dNTPs in contrast to the majority of dUTPases which are highly specific for dUTP. Knowledge of the dUTPase catalytic mechanism and the distinctive topography of the HERV-K active site provides a molecular basis for the design of HERV-K dUTPase-specific inhibitors.
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Affiliation(s)
- J M Harris
- Centre for Molecular and Cellular Biology, University of Queensland, St Lucia, Australia.
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