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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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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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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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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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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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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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Garcia-Etxebarria K, Sistiaga-Poveda M, Jugo BM. Endogenous retroviruses in domestic animals. Curr Genomics 2014; 15:256-65. [PMID: 25132796 PMCID: PMC4133949 DOI: 10.2174/1389202915666140520003503] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/14/2014] [Accepted: 05/16/2014] [Indexed: 01/15/2023] Open
Abstract
Endogenous retroviruses (ERVs) are genomic elements that are present in a wide range of vertebrates. Although the study of ERVs has been carried out mainly in humans and model organisms, recently, domestic animals have become important, and some species have begun to be analyzed to gain further insight into ERVs. Due to the availability of complete genomes and the development of new computer tools, ERVs can now be analyzed from a genome-wide viewpoint. In addition, more experimental work is being carried out to analyze the distribution, expression and interplay of ERVs within a host genome. Cats, cattle, chicken, dogs, horses, pigs and sheep have been scrutinized in this manner, all of which are interesting species in health and economic terms. Furthermore, several studies have noted differences in the number of endogenous retroviruses and in the variability of these elements among different breeds, as well as their expression in different tissues and the effects of their locations, which, in some cases, are near genes. These findings suggest a complex, intriguing relationship between ERVs and host genomes. In this review, we summarize the most important in silico and experimental findings, discuss their implications and attempt to predict future directions for the study of these genomic elements.
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Affiliation(s)
- Koldo Garcia-Etxebarria
- Genetika, Antropologia Fisikoa eta Animalien Fisiologia Saila. Zientzia eta Teknologia Fakultatea. Euskal Herriko Unibertsitatea (UPV/EHU). 644 Postakutxa , E-48080 Bilbao, Spain
| | - Maialen Sistiaga-Poveda
- Genetika, Antropologia Fisikoa eta Animalien Fisiologia Saila. Zientzia eta Teknologia Fakultatea. Euskal Herriko Unibertsitatea (UPV/EHU). 644 Postakutxa , E-48080 Bilbao, Spain
| | - Begoña Marina Jugo
- Genetika, Antropologia Fisikoa eta Animalien Fisiologia Saila. Zientzia eta Teknologia Fakultatea. Euskal Herriko Unibertsitatea (UPV/EHU). 644 Postakutxa , E-48080 Bilbao, Spain
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Schneider MKJ, Seebach JD. Xenotransplantation literature update, September-October 2012. Xenotransplantation 2012. [PMID: 23198733 DOI: 10.1111/xen.12010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Mårten K J Schneider
- Laboratory of Vascular Immunology, Division of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
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