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Fiebig U, Krüger L, Denner J. Determination of the Copy Number of Porcine Endogenous Retroviruses (PERV) in Auckland Island Pigs Repeatedly Used for Clinical Xenotransplantation and Elimination of PERV-C. Microorganisms 2024; 12:98. [PMID: 38257925 PMCID: PMC10820294 DOI: 10.3390/microorganisms12010098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024] Open
Abstract
Auckland Island pigs represent an inbred population of feral pigs isolated on the sub-Antarctic island for over 100 years. The animals have been maintained under pathogen-free conditions in New Zealand; they are well characterized virologically and have been used as donor sources in first clinical trials of porcine neonatal islet cell transplantation for the treatment of human diabetes patients. The animals do not carry any of the xenotransplantation-relevant viruses, and in the first clinical trials, no porcine viruses, including porcine endogenous retroviruses (PERVs) were transmitted to the human recipients. PERVs pose a special risk in xenotransplantation, since they are part of the pig genome. When the copy number of PERVs in these animals was analyzed using droplet digital PCR and primers binding to a conserved region of the polymerase gene (PERVpol), a copy number typical for Western pigs was found. This confirms previous phylogenetic analyses of microsatellites as well as mitochondrial analyses showing a closer relationship to European pigs than to Chinese pigs. When kidney cells from very young piglets were analyzed, only around 20 PERVpol copies were detected. Using these cells as donors in somatic cell nuclear transfer (SCNT), animals were born showing PERVpol copy numbers between 35 and 56. These data indicate that Auckland Island pigs have a similar copy number in comparison with other Western pig breeds and that the copy number is higher in adult animals compared with cells from young piglets. Most importantly, PERV-C-free animals were selected and the absence of an additional eight porcine viruses was demonstrated.
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Affiliation(s)
- Uwe Fiebig
- Robert Koch Institute, 13353 Berlin, Germany; (U.F.); (L.K.)
| | - Luise Krüger
- Robert Koch Institute, 13353 Berlin, Germany; (U.F.); (L.K.)
| | - Joachim Denner
- Robert Koch Institute, 13353 Berlin, Germany; (U.F.); (L.K.)
- Institute of Virology, Free University, 14163 Berlin, Germany
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2
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Chen JQ, Zhang MP, Tong XK, Li JQ, Zhang Z, Huang F, Du HP, Zhou M, Ai HS, Huang LS. Scan of the endogenous retrovirus sequences across the swine genome and survey of their copy number variation and sequence diversity among various Chinese and Western pig breeds. Zool Res 2022; 43:423-441. [PMID: 35437972 PMCID: PMC9113972 DOI: 10.24272/j.issn.2095-8137.2021.379] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 04/12/2022] [Indexed: 11/21/2022] Open
Abstract
In pig-to-human xenotransplantation, the transmission risk of porcine endogenous retroviruses (PERVs) is of great concern. However, the distribution of PERVs in pig genomes, their genetic variation among Eurasian pigs, and their evolutionary history remain unclear. We scanned PERVs in the current pig reference genome (assembly Build 11.1), and identified 36 long complete or near-complete PERVs (lcPERVs) and 23 short incomplete PERVs (siPERVs). Besides three known PERVs (PERV-A, -B, and -C), four novel types (PERV-JX1, -JX2, -JX3, and -JX4) were detected in this study. According to evolutionary analyses, the newly discovered PERVs were more ancient, and PERV-Bs probably experienced a bottleneck ~0.5 million years ago (Ma). By analyzing 63 high-quality porcine whole-genome resequencing data, we found that the PERV copy numbers in Chinese pigs were lower (32.0±4.0) than in Western pigs (49.1±6.5). Additionally, the PERV sequence diversity was lower in Chinese pigs than in Western pigs. Regarding the lcPERV copy numbers, PERV-A and -JX2 in Western pigs were higher than in Chinese pigs. Notably, Bama Xiang (BMX) pigs had the lowest PERV copy number (27.8±5.1), and a BMX individual had no PERV-C and the lowest PERV copy number (23), suggesting that BMX pigs were more suitable for screening and/or modification as xenograft donors. Furthermore, we identified 451 PERV transposon insertion polymorphisms (TIPs), of which 86 were shared by all 10 Chinese and Western pig breeds. Our findings provide systematic insights into the genomic distribution, variation, evolution, and possible biological function of PERVs.
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Affiliation(s)
- Jia-Qi Chen
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Ming-Peng Zhang
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Xin-Kai Tong
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Jing-Quan Li
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Zhou Zhang
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Fei Huang
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Hui-Peng Du
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Meng Zhou
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Hua-Shui Ai
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China. E-mail:
| | - Lu-Sheng Huang
- State Key Laboratory for Swine Genetic Improvement and Production Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China. E-mail:
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3
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Denner J. What does the PERV copy number tell us? Xenotransplantation 2022; 29:e12732. [PMID: 35112403 DOI: 10.1111/xen.12732] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/05/2022] [Accepted: 01/12/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Joachim Denner
- Institute of Virology, Free University Berlin, Berlin, Germany
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4
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Ishihara S, Dang‐Nguyen TQ, Kikuchi K, Arakawa A, Mikawa S, Osaki M, Otoi T, Luu QM, Nguyen TS, Taniguchi M. Characteristic features of porcine endogenous retroviruses in Vietnamese native pigs. Anim Sci J 2020; 91:e13336. [PMID: 32219916 DOI: 10.1111/asj.13336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/25/2019] [Accepted: 12/06/2019] [Indexed: 12/14/2022]
Abstract
We aimed to clarify the genomic characteristics of porcine endogenous retroviruses (PERVs) in Vietnamese native pig (VnP) breeds. First, we investigated genetic polymorphisms in β- and γ-like PERVs, and we then measured the copy numbers of infectious γ-like PERVs (PERV-A, B, and C). We purified genomic DNA from 15 VnP breeds from 12 regions all over the country and three Western pig breeds as controls, and investigated genetic polymorphisms in all known PERVs, including the beta (β)1-4 and gamma (γ)1-5 groups. PERVs of β1, β2, β3, and γ4 were highly polymorphic with VnP-specific haplotypes. We did not identify genetic polymorphisms in β4, γ1, or γ2 PERVs. We then applied a real-time polymerase chain reaction-based method to estimate copy numbers of the gag, pol, and env genes of γ1 PERVs (defined as A, B, and C). VnP breeds showed significantly lower copy number of the PERV genes compared with the Western pig breeds (on average, 16.2 and 35.7 copies, respectively, p < .05). Two VnP breeds showed significantly higher copy number compared with the other VnPs (p < .05). Our results elucidated that VnPs have specific haplotypes and a low copy number of PERV genes.
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Affiliation(s)
- Shinya Ishihara
- Institute of Agrobiological Sciences National Agriculture and Food Research Organization Tsukuba Japan
| | - Thanh Q. Dang‐Nguyen
- Institute of Agrobiological Sciences National Agriculture and Food Research Organization Tsukuba Japan
| | - Kazuhiro Kikuchi
- Institute of Agrobiological Sciences National Agriculture and Food Research Organization Tsukuba Japan
| | - Aisaku Arakawa
- Institute of Livestock and Grassland Science National Agriculture and Food Research Organization Tsukuba Japan
| | - Satoshi Mikawa
- Institute of Agrobiological Sciences National Agriculture and Food Research Organization Tsukuba Japan
| | - Makoto Osaki
- National Institute of Animal Health National Agriculture and Food Research Organization Tsukuba Japan
| | - Takeshige Otoi
- Faculty of Bioscience and Bioindustry Tokushima University Tokushima Japan
| | - Quang Minh Luu
- Key Laboratory of Animal Cell Technology National Institute of Animal Science Hanoi Vietnam
| | - Thanh Son Nguyen
- Key Laboratory of Animal Cell Technology National Institute of Animal Science Hanoi Vietnam
| | - Masaaki Taniguchi
- Institute of Livestock and Grassland Science National Agriculture and Food Research Organization Tsukuba Japan
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5
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Abstract
The shortage of organs for transplantation is probably the biggest unmet medical need. A potential problem with the clinical use of porcine xenografts is the risk that porcine endogenous retroviruses (PERVs) could infect human cells. In the past, we determined the PERV copy number in the porcine kidney epithelial cell line PK15 and in primary fibroblasts. Using CRISPR-Cas9, we disrupted the catalytic center of pol, which is essential for virus replication. Next, we isolated cells in which 100% of the PERV elements had been inactivated. This method enables the possibility of eradicating PERVs in vitro for application to pig-to-human xenotransplantation. Here we describe the methodological bases of this work.
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Affiliation(s)
- Marc Güell
- Translational Synthetic Biology Laboratory, Department of Experimental and Health Sciences, Pompeu Fabra University, PRBB, Barcelona, Spain.
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6
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Hirata M, Wittayarat M, Hirano T, Nguyen NT, Le QA, Namula Z, Fahrudin M, Tanihara F, Otoi T. The Relationship between Embryonic Development and the Efficiency of Target Mutations in Porcine Endogenous Retroviruses (PERVs) Pol Genes in Porcine Embryos. Animals (Basel) 2019; 9:ani9090593. [PMID: 31443357 PMCID: PMC6770129 DOI: 10.3390/ani9090593] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/30/2019] [Accepted: 08/19/2019] [Indexed: 12/17/2022] Open
Abstract
Porcine endogenous retrovirus (PERV) is a provirus found in the pig genome that may act as an infectious pathogen in humans who receive pig organ xenotransplantation. Inactivation of the PERV pol gene in porcine cells reportedly affects cell growth. Therefore, the mutation of PERV pol gene in porcine embryos using genome editing may affect the embryonic development. The present study was carried out to investigate the relationship between the mutation of the PERV pol gene in porcine embryos and their development. We introduced, either alone or in combination, three different gRNAs (gRNA1, 2, and 3) into porcine zygotes by genome editing using electroporation of the Cas9 protein (GEEP) system. All three gRNAs targeted the PERV pol gene, and we assessed their effects on porcine embryonic development. Our results showed that the blastocyst formation rates of zygotes electroporated with gRNA3-alone and in combination-were significantly lower (p < 0.05) than those of zygotes electroporated with gRNA1. The mutation rates assessed by the PERV pol gene target site sequencing in individual blastocysts and pooled embryos at the 2-to-8-cell stage did not differ among the three gRNAs. However, the frequency of indel mutations in mutant embryos at the 2-to-8-cell stage trended higher in the embryos electroporated with gRNA3 alone and in combination. Embryonic development may be affected by gRNAs that induce high-frequency indel mutations.
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Affiliation(s)
- Maki Hirata
- Faculty of Bioscience and Bioindustry, Tokushima University, Myozai-gun, Tokushima 7793233, Japan
| | - Manita Wittayarat
- Faculty of Veterinary Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand
| | - Takayuki Hirano
- Faculty of Bioscience and Bioindustry, Tokushima University, Myozai-gun, Tokushima 7793233, Japan
| | - Nhien Thi Nguyen
- Faculty of Bioscience and Bioindustry, Tokushima University, Myozai-gun, Tokushima 7793233, Japan
| | - Quynh Anh Le
- Faculty of Bioscience and Bioindustry, Tokushima University, Myozai-gun, Tokushima 7793233, Japan
| | - Zhao Namula
- Faculty of Veterinary Science, Guangdong Ocean University, Zhanjiang, Guangdong 524005, China
| | - Mokhamad Fahrudin
- Faculty of Veterinary Science, Bogor Agricultural University, Dramaga, Bogor 16680, Indonesia
| | - Fuminori Tanihara
- Faculty of Bioscience and Bioindustry, Tokushima University, Myozai-gun, Tokushima 7793233, Japan.
| | - Takeshige Otoi
- Faculty of Bioscience and Bioindustry, Tokushima University, Myozai-gun, Tokushima 7793233, Japan
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7
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Fiebig U, Fischer K, Bähr A, Runge C, Schnieke A, Wolf E, Denner J. Porcine endogenous retroviruses: Quantification of the copy number in cell lines, pig breeds, and organs. Xenotransplantation 2018; 25:e12445. [DOI: 10.1111/xen.12445] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 12/12/2022]
Affiliation(s)
| | - Konrad Fischer
- School of Life Sciences Weihenstephan; Technische Universität München; Freising Germany
| | - Andrea Bähr
- Molecular Animal Breeding and Biotechnology; Gene Center; Ludwig-Maximilians-Universität München; Oberschleißheim Germany
| | | | - Angelika Schnieke
- School of Life Sciences Weihenstephan; Technische Universität München; Freising Germany
| | - Eckhard Wolf
- Molecular Animal Breeding and Biotechnology; Gene Center; Ludwig-Maximilians-Universität München; Oberschleißheim Germany
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Chung HC, Nguyen VG, Oh WT, Huynh TML, Moon HJ, Lee JH, Kim HK, Park SJ, Park BK. Inhibition of Porcine Endogenous Retrovirus by Multi-Targeting Micro RNA Against Long Terminal Region. Transplant Proc 2018; 49:2225-2232. [PMID: 29149987 DOI: 10.1016/j.transproceed.2017.09.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/21/2017] [Accepted: 09/02/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND There might be much benefit in xenotransplantation, however, the risk of infections across species barriers remains, especially porcine endogenous retrovirus (PERV). To date, many attempts have been made to knock down active PERVs by inhibitory RNA (RNAi) and micro RNA (miRNA), which target different genes of PERV. There are a few studies that have explored whether targeting promoter regions of PERV could exert an inhibition effect. METHODS miRNAs were automatically selected based on an online program BLOCK-iT RNAi Designer. The inhibition efficiency between miRNAs was compared based on their inhibition of different PERV genes: long terminal repeats (LTR), gag, and pol. Both relative quantitative real-time polymerase chain reaction (PCR) and C-type reverse transcriptase activity were performed. RESULTS The results demonstrated that miRNA targeting the LTR region degraded the target sequence, and simultaneously inhibited the mRNA expression of both gag and pol genes of PERV. The LTR1, LTR2, and dual LTR1 + LTR2 miRNA inhibited 76.2%, 22%, and 76.8% of gag gene expression, respectively. Similarly, the miRNA was found to knock down the pol gene expression of 69.8%, 25.5%, and 77.7% for single targeting miRNA (LTR1 and LTR2) and multi-targeting miRNA (LTR1 + LTR2), respectively. A stable PK15 clone constitutively expressed dual LTR1 + LTR2 miRNA and exhibited higher inhibitory up to 82.8% and 92.7% of the expressions of the gag and pol genes, respectively. Also, the result of co-cultivation of dual LTR1 + LTR2 miRNA transfected PK15 cell with a human cell line inhibited expression of LTR, gag, and pol genes of PERV. CONCLUSIONS In conclusion, this study suggested that the LTR might be an alternative target for gene silencing of PERV, and that multi-targeting miRNA had better inhibitory effect than single- targeting miRNA. In an in vitro model, the presence of miRNA was able to reduce PERV infectivity in a human cell line.
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Affiliation(s)
- H-C Chung
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - V-G Nguyen
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - W-T Oh
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - T-M-L Huynh
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - H-J Moon
- Research Unit, Green Cross Veterinary Products, Yongin, Republic of Korea
| | - J-H Lee
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - H-K Kim
- Viral Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - S-J Park
- Forensic Medicine Division, Daegu Institute, National Forensic Service, Chilgok, Korea
| | - B-K Park
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea.
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9
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Bovo S, Mazzoni G, Ribani A, Utzeri VJ, Bertolini F, Schiavo G, Fontanesi L. A viral metagenomic approach on a non-metagenomic experiment: Mining next generation sequencing datasets from pig DNA identified several porcine parvoviruses for a retrospective evaluation of viral infections. PLoS One 2017; 12:e0179462. [PMID: 28662150 PMCID: PMC5491021 DOI: 10.1371/journal.pone.0179462] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/29/2017] [Indexed: 12/14/2022] Open
Abstract
Shot-gun next generation sequencing (NGS) on whole DNA extracted from specimens collected from mammals often produces reads that are not mapped (i.e. unmapped reads) on the host reference genome and that are usually discarded as by-products of the experiments. In this study, we mined Ion Torrent reads obtained by sequencing DNA isolated from archived blood samples collected from 100 performance tested Italian Large White pigs. Two reduced representation libraries were prepared from two DNA pools constructed each from 50 equimolar DNA samples. Bioinformatic analyses were carried out to mine unmapped reads on the reference pig genome that were obtained from the two NGS datasets. In silico analyses included read mapping and sequence assembly approaches for a viral metagenomic analysis using the NCBI Viral Genome Resource. Our approach identified sequences matching several viruses of the Parvoviridae family: porcine parvovirus 2 (PPV2), PPV4, PPV5 and PPV6 and porcine bocavirus 1-H18 isolate (PBoV1-H18). The presence of these viruses was confirmed by PCR and Sanger sequencing of individual DNA samples. PPV2, PPV4, PPV5, PPV6 and PBoV1-H18 were all identified in samples collected in 1998-2007, 1998-2000, 1997-2000, 1998-2004 and 2003, respectively. For most of these viruses (PPV4, PPV5, PPV6 and PBoV1-H18) previous studies reported their first occurrence much later (from 5 to more than 10 years) than our identification period and in different geographic areas. Our study provided a retrospective evaluation of apparently asymptomatic parvovirus infected pigs providing information that could be important to define occurrence and prevalence of different parvoviruses in South Europe. This study demonstrated the potential of mining NGS datasets non-originally derived by metagenomics experiments for viral metagenomics analyses in a livestock species.
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Affiliation(s)
- Samuele Bovo
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
- Department of Biological, Geological, and Environmental Sciences (BiGeA), Biocomputing Group, University of Bologna, Bologna, Italy
| | - Gianluca Mazzoni
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anisa Ribani
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
| | - Valerio Joe Utzeri
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
| | - Francesca Bertolini
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
- Department of Animal Science, Iowa State University, Iowa, United States of America
| | - Giuseppina Schiavo
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
| | - Luca Fontanesi
- Department of Agricultural and Food Sciences (DISTAL), Division of Animal Sciences, University of Bologna, Bologna, Italy
- * E-mail:
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10
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Abstract
Ever since the discovery of the major histocompatibility complex, scientific and clinical understanding in the field of transplantation has been advanced through genetic and genomic studies. Candidate-gene approaches and recent genome-wide association studies (GWAS) have enabled a deeper understanding of the complex interplay of the donor-recipient interactions that lead to transplant tolerance or rejection. Genetic analysis in transplantation, when linked to demographic and clinical outcomes, has the potential to drive personalized medicine by enabling individualized risk stratification and immunosuppression through the identification of variants associated with immune-mediated complications, post-transplant disease or alterations in drug-metabolizing genes.
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Affiliation(s)
- Joshua Y C Yang
- Division of Transplant Surgery, University of California San Francisco, 513 Parnassus Avenue, San Francisco, California 94143, USA
| | - Minnie M Sarwal
- Division of Transplant Surgery, University of California San Francisco, 513 Parnassus Avenue, San Francisco, California 94143, USA
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11
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How Active Are Porcine Endogenous Retroviruses (PERVs)? Viruses 2016; 8:v8080215. [PMID: 27527207 PMCID: PMC4997577 DOI: 10.3390/v8080215] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/04/2016] [Accepted: 07/22/2016] [Indexed: 01/12/2023] Open
Abstract
Porcine endogenous retroviruses (PERVs) represent a risk factor if porcine cells, tissues, or organs were to be transplanted into human recipients to alleviate the shortage of human transplants; a procedure called xenotransplantation. In contrast to human endogenous retroviruses (HERVs), which are mostly defective and not replication-competent, PERVs are released from normal pig cells and are infectious. PERV-A and PERV-B are polytropic viruses infecting cells of several species, among them humans; whereas PERV-C is an ecotropic virus infecting only pig cells. Virus infection was shown in co-culture experiments, but also in vivo, in the pig, leading to de novo integration of proviruses in certain organs. This was shown by measurement of the copy number per cell, finding different numbers in different organs. In addition, recombinations between PERV-A and PERV-C were observed and the recombinant PERV-A/C were found to be integrated in cells of different organs, but not in the germ line of the animals. Here, the evidence for such in vivo activities of PERVs, including expression as mRNA, protein and virus particles, de novo infection and recombination, will be summarised. These activities make screening of pigs for provirus number and PERV expression level difficult, especially when only blood or ear biopsies are available for analysis. Highly sensitive methods to measure the copy number and the expression level will be required when selecting pigs with low copy number and low expression of PERV as well as when inactivating PERVs using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease (CRISPR/Cas) technology.
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12
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Yoon JK, Choi J, Lee HJ, Cho Y, Gwon YD, Jang Y, Kim S, Choi H, Lee JH, Kim YB. Distribution of Porcine Endogenous Retrovirus in Different Organs of the Hybrid of a Landrace and a Jeju Domestic Pig in Korea. Transplant Proc 2016; 47:2067-71. [PMID: 26293098 DOI: 10.1016/j.transproceed.2015.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/22/2015] [Indexed: 01/30/2023]
Abstract
Xenotransplantation offers a solution to the shortage of available organs for transplantation, and the pig represents an ideal source of such organs. However, porcine endogenous retrovirus (PERV), whose genome is integrated in pigs, has been suggested to pose a potential risk of xenotransmission. Expression of PERVs in different organs of pigs was carefully measured at DNA, mRNA, and protein levels, providing information valuable for the application of pig organs in xenotransplantation. An analysis of PERV DNA showed that a very similar number of PERV copies was present in the genome of all organs, whereas mRNA and protein levels of PERV varied depending on the organ, with kidney, liver, and spleen expressing high levels of both mRNA and protein. In contrast, mRNA and protein levels were dissimilar in the lung and brain, where mRNA levels were low but protein levels were high. This discrepancy indicates that mRNA levels are not always reflected in protein expression. In addition, the difference between mRNA and protein highlights the importance of choosing the proper analysis method for diagnosing viral infection. In summary, this study provides insight into the distribution of PERV in various organs at the DNA, mRNA, and protein levels, and also informs the proper selection of tissues or organs for future clinical xenotransplantation.
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Affiliation(s)
- J K Yoon
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - J Choi
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - H J Lee
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - Y Cho
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - Y D Gwon
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - Y Jang
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - S Kim
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - H Choi
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea
| | - J H Lee
- College of Veterinary Medicine, Konkuk University, Seoul, Korea
| | - Y B Kim
- Department of Bio-industrial Technologies, Konkuk University, Seoul, Korea.
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13
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Denner J. Elimination of porcine endogenous retroviruses from pig cells. Xenotransplantation 2015; 22:411-2. [PMID: 26566739 DOI: 10.1111/xen.12210] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Yang L, Güell M, Niu D, George H, Lesha E, Grishin D, Aach J, Shrock E, Xu W, Poci J, Cortazio R, Wilkinson RA, Fishman JA, Church G. Genome-wide inactivation of porcine endogenous retroviruses (PERVs). Science 2015; 350:1101-4. [PMID: 26456528 DOI: 10.1126/science.aad1191] [Citation(s) in RCA: 387] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/08/2015] [Indexed: 12/28/2022]
Abstract
The shortage of organs for transplantation is a major barrier to the treatment of organ failure. Although porcine organs are considered promising, their use has been checked by concerns about the transmission of porcine endogenous retroviruses (PERVs) to humans. Here we describe the eradication of all PERVs in a porcine kidney epithelial cell line (PK15). We first determined the PK15 PERV copy number to be 62. Using CRISPR-Cas9, we disrupted all copies of the PERV pol gene and demonstrated a >1000-fold reduction in PERV transmission to human cells, using our engineered cells. Our study shows that CRISPR-Cas9 multiplexability can be as high as 62 and demonstrates the possibility that PERVs can be inactivated for clinical application of porcine-to-human xenotransplantation.
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Affiliation(s)
- Luhan Yang
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA. eGenesis Biosciences, Boston, MA 02115, USA.
| | - Marc Güell
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA. eGenesis Biosciences, Boston, MA 02115, USA
| | - Dong Niu
- Department of Genetics, Harvard Medical School, Boston, MA, USA. College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Haydy George
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Emal Lesha
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Dennis Grishin
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - John Aach
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Ellen Shrock
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Weihong Xu
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jürgen Poci
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Rebeca Cortazio
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Robert A Wilkinson
- Transplant Infectious Disease and Compromised Host Program, Massachusetts General Hospital, Boston, MA 02115, USA
| | - Jay A Fishman
- Transplant Infectious Disease and Compromised Host Program, Massachusetts General Hospital, Boston, MA 02115, USA
| | - George Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA. Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA. eGenesis Biosciences, Boston, MA 02115, USA.
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15
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Choi J, Kim HM, Yoon JK, Cho Y, Lee HJ, Kim KC, Kim CK, Kim GW, Kim YB. Identification of Porcine Endogenous Retrovirus (PERV) packaging sequence and development of PERV packaging viral vector system. J Microbiol 2015; 53:348-53. [PMID: 25935307 DOI: 10.1007/s12275-015-5134-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/09/2015] [Accepted: 04/13/2015] [Indexed: 12/11/2022]
Abstract
Studies of the retroviruses have focused on the specific interaction of the nucleocapsid protein with a packaging signal in the viral RNA as important for this selectivity, but the packaging signal in porcine endogenous retrovirus (PERV) has not been defined. Herein, we identified and analyzed this packaging signal in PERV and found hairpin structures with conserved tetranucleotides in their loops and nucleocapsid recognition sequences; both of which are key elements in the viral packaging signal of MLV. We evaluated packaging efficiency of sequence variants isolated from viral and proviral integrated genomes. All viral packaging sequences (Ψ) were identical, while five distinct packaging sequences were identified from proviral sources. One proviral sequence (Ψ1) was identical to that of the viral Ψ and had the highest packaging efficiency. Three variants (Ψ2, Ψ3, Ψ4) maintained key elements of the viral packaging signal, but had nucleotide replacements and consequently demonstrated reduced packaging efficiency. Despite of the same overall hairpin structure, the proviral variant (Ψ5) had only one GACG sequence in the hairpin loop and showed the lowest packaging efficiency other than ∆Ψ, in which the essential packaging sequence was removed. This result, thus, defined the packaging sequences in PERV and emphasized the importance of nucleotide sequence and RNA structure in the determination of packaging efficiency. In addition, we demonstrate efficient infection and gene expression from the PERV based viral vector, which may serve as a novel alternative to current retroviral expression systems.
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Affiliation(s)
- Jiwon Choi
- Department of Bioindustrial Technologies, Konkuk University, Seoul, 143-701, Korea
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16
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Schneider MKJ, Seebach JD. Xenotransplantation literature update, November-December 2011. Xenotransplantation 2012; 19:65-9. [PMID: 22360756 DOI: 10.1111/j.1399-3089.2012.00692.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mårten K J Schneider
- Laboratory of Vascular Immunology, Division of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
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