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Sun Q, Song SY, Ma J, Li D, Wang Y, Yang Z, Wang Y. Cutting edge of genetically modified pigs targeting complement activation for xenotransplantation. Front Immunol 2024; 15:1383936. [PMID: 38638432 PMCID: PMC11024274 DOI: 10.3389/fimmu.2024.1383936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 03/15/2024] [Indexed: 04/20/2024] Open
Abstract
In the quest to address the critical shortage of donor organs for transplantation, xenotransplantation stands out as a promising solution, offering a more abundant supply of donor organs. Yet, its widespread clinical adoption remains hindered by significant challenges, chief among them being immunological rejection. Central to this issue is the role of the complement system, an essential component of innate immunity that frequently triggers acute and chronic rejection through hyperacute immune responses. Such responses can rapidly lead to transplant embolism, compromising the function of the transplanted organ and ultimately causing graft failure. This review delves into three key areas of xenotransplantation research. It begins by examining the mechanisms through which xenotransplantation activates both the classical and alternative complement pathways. It then assesses the current landscape of xenotransplantation from donor pigs, with a particular emphasis on the innovative strides made in genetically engineering pigs to evade complement system activation. These modifications are critical in mitigating the discordance between pig endogenous retroviruses and human immune molecules. Additionally, the review discusses pharmacological interventions designed to support transplantation. By exploring the intricate relationship between the complement system and xenotransplantation, this retrospective analysis not only underscores the scientific and clinical importance of this field but also sheds light on the potential pathways to overcoming one of the major barriers to the success of xenografts. As such, the insights offered here hold significant promise for advancing xenotransplantation from a research concept to a viable clinical reality.
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Affiliation(s)
- Qin Sun
- Department of Endocrinology, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Si-Yuan Song
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Jiabao Ma
- School of Pharmacy, Guangxi University of Chinese Medicine, Nanning, China
| | - Danni Li
- Department of Pharmacy, Longquanyi District of Chengdu Maternity & Child Health Care Hospital, Chengdu, China
| | - Yiping Wang
- Department of Critical Care Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Zhengteng Yang
- School of Pharmacy, Guangxi University of Chinese Medicine, Nanning, China
| | - Yi Wang
- Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Center of Organ Transplantation, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, Chengdu, Sichuan, China
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2
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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: 3] [Impact Index Per Article: 3.0] [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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Chabukswar S, Grandi N, Lin LT, Tramontano E. Envelope Recombination: A Major Driver in Shaping Retroviral Diversification and Evolution within the Host Genome. Viruses 2023; 15:1856. [PMID: 37766262 PMCID: PMC10536682 DOI: 10.3390/v15091856] [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: 07/06/2023] [Revised: 08/21/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Endogenous retroviruses (ERVs) are integrated into host DNA as the result of ancient germ line infections, primarily by extinct exogenous retroviruses. Thus, vertebrates' genomes contain thousands of ERV copies, providing a "fossil" record for ancestral retroviral diversity and its evolution within the host genome. Like other retroviruses, the ERV proviral sequence consists of gag, pro, pol, and env genes flanked by long terminal repeats (LTRs). Particularly, the env gene encodes for the envelope proteins that initiate the infection process by binding to the host cellular receptor(s), causing membrane fusion. For this reason, a major element in understanding ERVs' evolutionary trajectory is the characterization of env changes over time. Most of the studies dedicated to ERVs' env have been aimed at finding an "actual" physiological or pathological function, while few of them have focused on how these genes were once acquired and modified within the host. Once acquired into the organism, genome ERVs undergo common cellular events, including recombination. Indeed, genome recombination plays a role in ERV evolutionary dynamics. Retroviral recombination events that might have been involved in env divergence include the acquisition of env genes from distantly related retroviruses, env swapping facilitating multiple cross-species transmission over millions of years, ectopic recombination between the homologous sequences present in different positions in the chromosomes, and template switching during transcriptional events. The occurrence of these recombinational events might have aided in shaping retroviral diversification and evolution until the present day. Hence, this review describes and discusses in detail the reported recombination events involving ERV env to provide the basis for further studies in the field.
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Affiliation(s)
- Saili Chabukswar
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (S.C.); (N.G.)
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (S.C.); (N.G.)
| | - Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (S.C.); (N.G.)
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Flecks M, Fischer N, Krijnse Locker J, Tönjes RR, Godehardt AW. Analysis of PERV-C superinfection resistance using HA-tagged viruses. Retrovirology 2023; 20:14. [PMID: 37605152 PMCID: PMC10440901 DOI: 10.1186/s12977-023-00630-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/09/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND Using pigs as organ donors has advanced xenotransplantation to the point that it is almost ready for clinical use. However, there is still a zoonotic risk associated with xenotransplantation, and the potential transmission of porcine endogenous retroviruses needs to be surveyed. Despite significant attempts to eliminate this risk, by the selection of PERV-C free pigs with low expression of PERV-A, -B, and by the genome-wide inactivation of PERV using CRISPR/Cas9, the impact of superinfection resistance (SIR) was not investigated. SIR is a viral trait that prevents reinfection (superinfection). For PERV, the underlying mechanism is unclear, whether and how cells, that harbor functional PERV, are protected. Using PERV-C(5683) as a reference virus, we investigated SIR in a newly developed in vitro model to pursue the mechanism and confirm its protective effect. RESULTS We developed three PERV-C constructs on the basis of PERV-C(5683), each of which carries a hemagglutinin tag (HA-tag) at a different position of the envelope gene (SP-HA, HA-VRA, and RPep-HA), to distinguish between primary infection and superinfection. The newly generated PERV-C(5683)-HA viruses were characterized while quantifying the viral RNA, reverse transcriptase activity, protein expression analysis, and infection studies. It was demonstrated that SP-HA and RPep-HA were comparable to PERV-C(5683), whereas HA-VRA was not replication competent. SP-HA and RPep-HA were chosen to challenge PERV-C(5683)-positive ST-IOWA cells demonstrating that PERV-C-HA viruses are not able to superinfect those cells. They do not integrate into the genome and are not expressed. CONCLUSIONS The mechanism of SIR applies to PERV-C. The production of PERV-C particles serves as a defense mechanism from superinfection with exogenous PERV-C. It was demonstrated by newly generated PERV-C(5683)-HA clones that might be used as a cutting-edge tool. The HA-tagging of PERV-C is novel, providing a blueprint for the tagging of other human tropic PERV viruses. The tagged viruses are suitable for additional in vitro and in vivo infection studies and will contribute, to basic research on viral invasion and pathogenesis. It will maintain the virus safety of XTx.
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Affiliation(s)
- Merle Flecks
- Division of Haematology, Cell and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Nicole Fischer
- Division of Haematology, Cell and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Jacomina Krijnse Locker
- Loewe-DRUID Research Group, Electron Microscopy of Pathogens, Paul-Ehrlich-Institut, Langen, Germany
| | - Ralf R. Tönjes
- Division of Haematology, Cell and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Antonia W. Godehardt
- Division of Haematology, Cell and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
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Liu Y, Niu Y, Ma X, Xiang Y, Wu D, Li W, Wang T, Niu D. Porcine endogenous retrovirus: classification, molecular structure, regulation, function, and potential risk in xenotransplantation. Funct Integr Genomics 2023; 23:60. [PMID: 36790562 DOI: 10.1007/s10142-023-00984-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/16/2023]
Abstract
Xenotransplantation with porcine organs has been recognized as a promising solution to alleviate the shortage of organs for human transplantation. Porcine endogenous retrovirus (PERV), whose proviral DNAs are integrated in the genome of all pig breeds, is a main microbiological risk for xenotransplantation. Over the last decades, some advances on PERVs' studies have been achieved. Here, we reviewed the current progress of PERVs including the classification, molecular structure, regulation, function in immune system, and potential risk in xenotransplantation. We also discussed the problem of insufficient study on PERVs as well as the questions need to be answered in the future work.
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Affiliation(s)
- Yu Liu
- College of Animal Science and Technology & College of Veterinary Medicine, Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Yifan Niu
- College of Animal Science and Technology & College of Veterinary Medicine, Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Xiang Ma
- College of Animal Science and Technology & College of Veterinary Medicine, Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China.,College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.,Jinhua Jinfan Feed Co., Ltd, Jinhua, Zhejiang, 321000, China
| | - Yun Xiang
- Jinhua Academy of Agricultural Sciences, Jinhua, Zhejiang, 321000, China
| | - De Wu
- Postdoctoral Research Station, Jinhua Development Zone, Jinhua, Zhejiang, 321000, China
| | - Weifen Li
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
| | - Tao Wang
- Nanjing Kgene Genetic Engineering Co., Ltd, Nanjing, Jiangsu, 211300, China.
| | - Dong Niu
- College of Animal Science and Technology & College of Veterinary Medicine, Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China.
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Niemann H. Xenotransplantate vom Schwein – ist das Ende des Organmangels
in Sicht? TRANSFUSIONSMEDIZIN 2022. [DOI: 10.1055/a-1814-8440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
ZusammenfassungUnter „Xenotransplantation“ wird die Übertragung von
funktionsfähigen Zellen, Geweben oder Organen zwischen verschiedenen
Spezies verstanden, insbesondere von Schweinen auf den Menschen. In den meisten
Industrieländern klafft eine große Lücke zwischen der
Anzahl geeigneter Spenderorgane und der Anzahl benötigter Transplantate.
Weltweit können nur etwa 10% des Organbedarfs durch Spenden
gedeckt werden. Eine erfolgreiche Xenotransplantation könnte diesen
Mangel mildern oder sogar weitgehend vermeiden. Das Schwein wird aus
verschiedenen Erwägungen heraus als am besten geeignete Spenderspezies
angesehen. Bei einer Übertragung porziner Organe auf Primaten treten
verschiedene immunologisch bedingte Abstoßungsreaktionen auf, die das
übertragene Organ innerhalb kurzer Zeit zerstören
können, wie die HAR (hyperakute Abstoßung), die AVR (akute
vaskuläre Abstoßung) und die spätere zelluläre
Abstoßung. Diese Abstoßungsreaktionen müssen durch
genetische Modifikationen im Schwein und eine geeignete immunsuppressive
Behandlung des Empfängers kontrolliert werden. Dazu müssen Tiere
mit mehrfachen genetischen Veränderungen produziert und im Hinblick auf
ihre Eignung für eine erfolgreiche Xenotransplantation geprüft
werden. Inzwischen können die HAR und auch die AVR durch Knockouts von
antigenen Oberflächenepitopen (z. B. αGal
[Galaktose-α1,3-Galaktose]) und transgene Expression humaner Gene mit
antiinflammatorischer, antiapoptotischer oder antikoagulativer Wirkung
zuverlässig kontrolliert werden. Nach orthotopen Transplantationen in
nicht humane Primaten konnten inzwischen mit Schweineherzen
Überlebensraten von bis zu 264 Tagen und mit porzinen Nieren von 435
Tagen erzielt werden. Eine Übertragung pathogener Erreger auf den
Empfänger kann bei Einhaltung einschlägiger
Hygienemaßnahmen ausgeschlossen werden. PERV (porzine endogene
Retroviren) können durch RNA-(Ribonukleinsäure-)Interferenz oder
Gen-Knockout ausgeschaltet werden. Sie stellen damit kein
Übertragungsrisiko für den Empfänger mehr dar. Anfang
2022 wurde in Baltimore (USA) ein Schweineherz mit 10 genetischen Modifikationen
auf einen Patienten mit schwerem Herzleiden übertragen, mit dem der
Empfänger 2 Monate offenbar ohne größere Probleme lebte.
Es wird erwartet, dass Xenotransplantate vom Schwein in absehbarer Zeit zur
klinischen Anwendungsreife kommen werden. Dazu werden klinische Versuche zur
systematischen Erfassung aller Auswirkungen solcher Transplantate auf den
Patienten sowie geeignete rechtliche und finanzielle Rahmenbedingungen
benötigt.
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Detection of non-reference porcine endogenous retrovirus loci in the Vietnamese native pig genome. Sci Rep 2022; 12:10485. [PMID: 35729348 PMCID: PMC9213404 DOI: 10.1038/s41598-022-14654-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/09/2022] [Indexed: 11/09/2022] Open
Abstract
The Vietnamese native pig (VnP)-a porcine breed with a small body-has proven suitable as a biomedical animal model. Here, we demonstrate that, compared to other breeds, VnPs have fewer copies of porcine endogenous retroviruses (PERVs), which pose a risk for xenotransplantation of pig organs to humans. More specifically, we sought to characterize non-reference PERVs (nrPERVs) that were previously unidentified in the reference genome. To this end, we used whole-genome sequencing data to identify nrPERV loci with long terminal repeat (LTR) sequences in VnPs. RetroSeq was used to estimate nrPERV loci based on the most current porcine reference genome (Sscrofa11.1). LTRs were detected using de novo sequencing read assembly near the loci containing the target site duplication sequences in the inferred regions. A total of 21 non-reference LTR loci were identified and separated into two subtypes based on phylogenetic analysis. Moreover, PERVs within the detected LTR loci were identified, the presence of which was confirmed using conventional PCR and Sanger sequencing. These novel loci represent previously unknown PERVs as they have not been identified in the porcine reference genome. Thus, our RetroSeq method accurately detects novel PERV loci, and can be applied for development of a useful biomedical model.
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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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9
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Infectivity assessment of porcine endogenous retrovirus using high-throughput sequencing technologies. Biologicals 2021; 71:1-8. [PMID: 34039532 DOI: 10.1016/j.biologicals.2021.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 11/20/2022] Open
Abstract
Xenogenic cell-based therapeutic products are expected to alleviate the chronic shortage of human donor organs. For example, porcine islet cell products are currently under development for the treatment of human diabetes. As porcine cells possess endogenous retrovirus (PERV), which can replicate in human cells in vitro, the potential transmission of PERV has raised concerns in the case of products that use living pig cells as raw materials. Although several PERV sequences exist in the porcine genome, not all have the ability to infect human cells. Therefore, polymerase chain reaction analysis, which amplifies a portion of the target gene, may not accurately assess the infection risk. Here, we determined porcine genome sequences and evaluated the infectivity of PERVs using high-throughput sequencing technologies. RNA sequencing was performed on both PERV-infected human cells and porcine cells, and reads mapped to PERV sequences were examined. The normalized number of the reads mapped to PERV regions was able to predict the infectivity of PERVs, indicating that it would be useful for evaluation of the PERV infection risk prior to transplantation of porcine products.
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10
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Denner J. The origin of porcine endogenous retroviruses (PERVs). Arch Virol 2021; 166:1007-1013. [PMID: 33547957 DOI: 10.1007/s00705-020-04925-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/05/2020] [Indexed: 12/21/2022]
Abstract
Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pigs, and they produce viral particles that are able to infect human cells and therefore pose a special risk for xenotransplantation. In contrast to other pig microorganisms that also pose a risk, such as porcine cytomegalovirus and hepatitis E virus, PERVs cannot be eliminated from pigs by vaccines, antiviral drugs, early weaning, or embryo transfer. Since PERVs are relevant for xenotransplantation, their biology and origin are of great interest. Recent studies have shown that PERVs are the result of a transspecies transmission of precursor retroviruses from different animals and further evolution in the pig genome. PERVs acquired different long terminal repeats (LTRs), and recombination took place. In parallel, it has been shown that the activity of the LTRs and recombination in the envelope are important for the transmissibility and pathogenesis of PERVs. Transspecies transmission of retroviruses is common, a well-known example being the transmission of precursor retroviruses from non-human primates to humans, resulting in human immunodeficiency virus (HIV). Here, recent findings concerning the origin of PERVs, their LTRs, and recombination events that occurred during evolution are reviewed and compared with other findings regarding transspecies transmission of retroviruses.
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Affiliation(s)
- Joachim Denner
- Robert Koch Institute, Berlin, Germany. .,Institute for Virology, Free University, Berlin, Germany.
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11
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Niu D, Ma X, Yuan T, Niu Y, Xu Y, Sun Z, Ping Y, Li W, Zhang J, Wang T, Church GM. Porcine genome engineering for xenotransplantation. Adv Drug Deliv Rev 2021; 168:229-245. [PMID: 32275950 DOI: 10.1016/j.addr.2020.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/28/2020] [Accepted: 04/06/2020] [Indexed: 02/06/2023]
Abstract
The extreme shortage of human donor organs for treatment of patients with end-stage organ failures is well known. Xenotransplantation, which might provide unlimited organ supply, is a most promising strategy to solve this problem. Domestic pigs are regarded as ideal organ-source animals owing to similarity in anatomy, physiology and organ size to humans as well as high reproductive capacity and low maintenance cost. However, several barriers, which include immune rejection, inflammation and coagulative dysfunctions, as well as the cross-species transmission risk of porcine endogenous retrovirus, blocked the pig-to-human xenotransplantation. With the rapid development of genome engineering technologies and the potent immunosuppressive medications in recent years, these barriers could be eliminated through genetic modification of pig genome together with the administration of effective immunosuppressants. A number of candidate genes involved in the regulation of immune response, inflammation and coagulation have been explored to optimize porcine xenograft survival in non-human primate recipients. PERV inactivation in pigs has also been accomplished to firmly address the safety issue in pig-to-human xenotransplantation. Many encouraging preclinical milestones have been achieved with some organs surviving for years. Therefore, the clinical trials of some promising organs, such as islet, kidney and heart, are aimed to be launched in the near future.
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Affiliation(s)
- Dong Niu
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, China-Australian Joint Laboratory for Animal Health Big Data Analytics, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection & Internet Technology, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, Hangzhou, P.R. China
| | - Xiang Ma
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, China-Australian Joint Laboratory for Animal Health Big Data Analytics, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection & Internet Technology, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, Hangzhou, P.R. China
| | - Taoyan Yuan
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021, China
| | - Yifan Niu
- Nanjing Kgene Genetic Engineering Co., Ltd, Nanjing, Jiangsu 211300, China
| | - Yibin Xu
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Zhongxin Sun
- Cosmetic & Plastic Surgery Department, Hangzhou First People's Hospital, Hangzhou, Zhejiang 310006, China
| | - Yuan Ping
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Weifen Li
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jufang Zhang
- Cosmetic & Plastic Surgery Department, Hangzhou First People's Hospital, Hangzhou, Zhejiang 310006, China.
| | - Tao Wang
- Nanjing Kgene Genetic Engineering Co., Ltd, Nanjing, Jiangsu 211300, China.
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA.
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12
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Yu XH, Deng WY, Jiang HT, Li T, Wang Y. Kidney xenotransplantation: Recent progress in preclinical research. Clin Chim Acta 2020; 514:15-23. [PMID: 33301767 DOI: 10.1016/j.cca.2020.11.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 01/23/2023]
Abstract
Kidney transplantation is the most effective treatment for end-stage renal disease, but is limited by the increasing shortage of deceased and living human donor kidneys. Xenotransplantation using pig organs provides the possibility to resolve the issue of organ supply shortage and is regarded as the next great medical revolution. In the past five years, there have been sequential advances toward the prolongation of life-supporting pig kidney xenograft survival in non-human primates, with the longest survival being 499 days. This progress is due to the growing availability of pigs with multi-layered genetic modifications to overcome the pathobiological barriers and the application of a costimulation blockade-based immunosuppressive regimen. These encouraging results bring the hope to initiate the clinical trials of pig kidney transplantation in the near future. In this review, we summarized the latest advances regarding pig kidney xenotransplantation in preclinical models to provide a basis for future investigation and potential clinical translation.
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Affiliation(s)
- Xiao-Hua Yu
- Institute of Clinical Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China; The Transplantation Institute of Hainan Medical University, Haikou, Hainan 460106, China
| | - Wen-Yi Deng
- Institute of Clinical Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China; The Transplantation Institute of Hainan Medical University, Haikou, Hainan 460106, China
| | - Hong-Tao Jiang
- Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China; The Transplantation Institute of Hainan Medical University, Haikou, Hainan 460106, China
| | - Tao Li
- Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China; The Transplantation Institute of Hainan Medical University, Haikou, Hainan 460106, China
| | - Yi Wang
- Institute of Clinical Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China; Department of Organ Transplantation, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 460106, China; The Transplantation Institute of Hainan Medical University, Haikou, Hainan 460106, China.
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Krüger L, Stillfried M, Prinz C, Schröder V, Neubert LK, Denner J. Copy Number and Prevalence of Porcine Endogenous Retroviruses (PERVs) in German Wild Boars. Viruses 2020; 12:v12040419. [PMID: 32276520 PMCID: PMC7232352 DOI: 10.3390/v12040419] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/02/2020] [Accepted: 04/04/2020] [Indexed: 01/25/2023] Open
Abstract
Porcine endogenous retroviruses (PERVs) are integrated in the genome of pigs and are transmitted like cellular genes from parents to the offspring. Whereas PERV-A and PERV-B are present in all pigs, PERV-C was found to be in many, but not all pigs. When PERV-C is present, recombination with PERV-A may happen and the PERV-A/C recombinants are characterized by a high replication rate. Until now, nothing has been known about the copy number of PERVs in wild boars and little is known about the prevalence of the phylogenetically youngest PERV-C in ancient wild boars. Here we investigated for the first time the copy number of PERVs in different populations of wild boars in and around Berlin using droplet digital PCR. Copy numbers between 3 and 69 per genome have been measured. A lower number but a higher variability was found compared to domestic pigs, including minipigs reported earlier (Fiebig et al., Xenotransplantation, 2018). The wild boar populations differed genetically and had been isolated during the existence of the Berlin wall. Despite this, the variations in copy number were larger in a single population compared to the differences between the populations. PERV-C was found in all 92 analyzed animals. Differences in the copy number of PERV in different organs of a single wild boar indicate that PERVs are also active in wild boars, replicating and infecting new cells as has been shown in domestic pigs.
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Affiliation(s)
- Luise Krüger
- Robert Koch Fellow, Robert Koch Institute, 13353 Berlin, Germany; (L.K.); (C.P.); (V.S.); (L.K.N.)
| | - Milena Stillfried
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany;
| | - Carolin Prinz
- Robert Koch Fellow, Robert Koch Institute, 13353 Berlin, Germany; (L.K.); (C.P.); (V.S.); (L.K.N.)
| | - Vanessa Schröder
- Robert Koch Fellow, Robert Koch Institute, 13353 Berlin, Germany; (L.K.); (C.P.); (V.S.); (L.K.N.)
| | - Lena Katharina Neubert
- Robert Koch Fellow, Robert Koch Institute, 13353 Berlin, Germany; (L.K.); (C.P.); (V.S.); (L.K.N.)
| | - Joachim Denner
- Robert Koch Fellow, Robert Koch Institute, 13353 Berlin, Germany; (L.K.); (C.P.); (V.S.); (L.K.N.)
- Correspondence: ; Tel.: +49-30-18754-2800
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14
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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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15
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Chung HC, Nguyen VG, Moon HJ, Park YH, Park BK. Regulation of porcine endogenous retrovirus by dual LTR1+2 (Long Terminal Region) miRNA in primary porcine kidney cells. J Vet Sci 2020; 20:e50. [PMID: 31565893 PMCID: PMC6769330 DOI: 10.4142/jvs.2019.20.e50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/18/2019] [Accepted: 08/05/2019] [Indexed: 11/20/2022] Open
Abstract
Porcine endogenous retroviruses (PERVs) integrate into germline DNA as proviral genome that enables vertical transmission from parents to their offspring. The provirus usually survives as part of the host genome rather than as an infectious agent, but may become pathogenic if it crosses species barriers. Therefore, replication-competent PERV should be controlled through selective breeding or knockout technologies. Two microRNAs (miRNAs), dual LTR1 and LTR2, were selected to inhibit the expression of PERV in primary porcine kidney cells. The inhibition efficiency of the miRNAs was compared based on their inhibition of different PERV regions, specifically long terminal repeats (LTRs), gag, pol, and env. Gene expression was quantified using real-time polymerase chain reaction and the C-type reverse transcriptase (RT) activity was determined. The messenger RNA (mRNA) expression of the PERV LTR and env regions was determined in HeLa cells co-cultured with primary porcine kidney cells. The mRNA expression of the LTR, gag, pol, and env regions of PERV was dramatically inhibited by dual miRNA from 24 to 144 h after transfection, with the highest inhibition observed for the LTR and pol regions at 120 h. Additionally, the RT activity of PERV in the co-culture experiment of porcine and human cells was reduced by 84.4% at the sixth passage. The dual LTR 1+2 miRNA efficiently silences PERV in primary porcine kidney cells.
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Affiliation(s)
- Hee Chun Chung
- Department of Veterinary Medicine Virology Lab, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Van Giap Nguyen
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam
| | - Hyung Joon Moon
- Research Unit, Green Cross Veterinary Products, Yongin 17066, Korea
| | - Yong Ho Park
- Department of Veterinary Microbiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Bong Kyun Park
- Department of Veterinary Medicine Virology Lab, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
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16
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Dzobo K, Motaung KSCM, Adesida A. Recent Trends in Decellularized Extracellular Matrix Bioinks for 3D Printing: An Updated Review. Int J Mol Sci 2019; 20:E4628. [PMID: 31540457 PMCID: PMC6788195 DOI: 10.3390/ijms20184628] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/01/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023] Open
Abstract
The promise of regenerative medicine and tissue engineering is founded on the ability to regenerate diseased or damaged tissues and organs into functional tissues and organs or the creation of new tissues and organs altogether. In theory, damaged and diseased tissues and organs can be regenerated or created using different configurations and combinations of extracellular matrix (ECM), cells, and inductive biomolecules. Regenerative medicine and tissue engineering can allow the improvement of patients' quality of life through availing novel treatment options. The coupling of regenerative medicine and tissue engineering with 3D printing, big data, and computational algorithms is revolutionizing the treatment of patients in a huge way. 3D bioprinting allows the proper placement of cells and ECMs, allowing the recapitulation of native microenvironments of tissues and organs. 3D bioprinting utilizes different bioinks made up of different formulations of ECM/biomaterials, biomolecules, and even cells. The choice of the bioink used during 3D bioprinting is very important as properties such as printability, compatibility, and physical strength influence the final construct printed. The extracellular matrix (ECM) provides both physical and mechanical microenvironment needed by cells to survive and proliferate. Decellularized ECM bioink contains biochemical cues from the original native ECM and also the right proportions of ECM proteins. Different techniques and characterization methods are used to derive bioinks from several tissues and organs and to evaluate their quality. This review discusses the uses of decellularized ECM bioinks and argues that they represent the most biomimetic bioinks available. In addition, we briefly discuss some polymer-based bioinks utilized in 3D bioprinting.
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Affiliation(s)
- Kevin Dzobo
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Wernher and Beit Building (South), UCT Medical Campus, Anzio Road, Observatory, Cape Town 7925, South Africa.
- Division of Medical Biochemistry and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town 7925, South Africa.
| | | | - Adetola Adesida
- Department of Surgery, Faculty of Medicine and Dentistry, Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, AB T6G 2E1, Canada.
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17
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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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18
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Pan D, Liu T, Lei T, Zhu H, Wang Y, Deng S. Progress in multiple genetically modified minipigs for xenotransplantation in China. Xenotransplantation 2019; 26:e12492. [PMID: 30775816 DOI: 10.1111/xen.12492] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2019] [Indexed: 12/18/2022]
Abstract
Pig-to-human organ transplantation provides an alternative for critical shortage of human organs worldwide. Genetically modified pigs are promising donors for xenotransplantation as they show many anatomical and physiological similarities to humans. However, immunological rejection including hyperacute rejection (HAR), acute humoral xenograft rejection (AHXR), immune cell-mediated rejection, and other barriers associated with xenotransplantation must be overcome with various strategies for the genetic modification of pigs. In this review, we summarize the outcomes of genetically modified and cloned pigs achieved by Chinese scientists to resolve the above-mentioned problems in xenotransplantation. It is now possible to knockout several porcine genes associated with the expression of sugar residues, antigens for (naturally) existing antibodies in humans, including GGTA1, CMAH, and β4GalNT2, and thereby preventing the antigen-antibody response. Moreover, insertion of human complement- and coagulation-regulatory transgenes, such as CD46, CD55, CD59, and hTBM, can further overcome effects of the humoral immune response and coagulation dysfunction, while expression of regulatory factors of immune responses can inhibit the adaptive immune rejection. Furthermore, transgenic strategies have been developed by Chinese scientists to reduce the potential risk of infections by endogenous porcine retroviruses (PERVs). Breeding of multi-gene low-immunogenicity pigs in China is also presented in this review. Lastly, we will briefly mention the preclinical studies on pig-to-non-human primate xenotransplantation conducted in several centers in China.
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Affiliation(s)
- Dengke Pan
- Organ Transplant and Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Sichuan Academy of an Transplant Science & Sichuan Provincial People's Hospital, Chengdu, China
| | - Ting Liu
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Tiantian Lei
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Huibin Zhu
- Chengdu Clonorgan Biotechnology Co., LTD, Chengdu, China
| | - Yi Wang
- Health Management Center, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, China
| | - Shaoping Deng
- Organ Transplant and Clinical Immunology Translational Medicine Key Laboratory of Sichuan Province, Sichuan Academy of an Transplant Science & Sichuan Provincial People's Hospital, Chengdu, China
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19
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McGregor CGA, Takeuchi Y, Scobie L, Byrne G. PERVading strategies and infectious risk for clinical xenotransplantation. Xenotransplantation 2019; 25:e12402. [PMID: 30264876 PMCID: PMC6174873 DOI: 10.1111/xen.12402] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/16/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Christopher G A McGregor
- Institute of Cardiovascular Science, University College London, London, UK.,Department of Surgery, University of Alabama Birmingham, Birmingham, AL, USA.,Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA
| | - Yasu Takeuchi
- Division of Infection and Immunity, University College London, London, UK.,Division of Advanced Therapies, National Institute for Biological Standards and Control, South Mims, UK
| | - Linda Scobie
- School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Guerard Byrne
- Institute of Cardiovascular Science, University College London, London, UK.,Department of Surgery, University of Alabama Birmingham, Birmingham, AL, USA.,Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA
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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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21
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Choudhury D, Tun HW, Wang T, Naing MW. Organ-Derived Decellularized Extracellular Matrix: A Game Changer for Bioink Manufacturing? Trends Biotechnol 2018; 36:787-805. [DOI: 10.1016/j.tibtech.2018.03.003] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/17/2018] [Accepted: 03/19/2018] [Indexed: 12/13/2022]
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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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23
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Weiss RA. Infection hazards of xenotransplantation: Retrospect and prospect. Xenotransplantation 2018; 25:e12401. [PMID: 29756309 DOI: 10.1111/xen.12401] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/29/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Robin A Weiss
- Division of Infection & Immunity, University College London, London, UK
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24
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Denner J. Why was PERV not transmitted during preclinical and clinical xenotransplantation trials and after inoculation of animals? Retrovirology 2018; 15:28. [PMID: 29609635 PMCID: PMC5879552 DOI: 10.1186/s12977-018-0411-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/22/2018] [Indexed: 01/27/2023] Open
Abstract
Porcine endogenous retroviruses (PERVs) are present in the genome of all pigs, they infect certain human cells and therefore pose a special risk for xenotransplantation using pig cells, tissues and organs. Xenotransplantation is being developed in order to alleviate the reduced availability of human organs. Despite the fact that PERVs are able to infect certain human cells and cells from other species, transmission of PERVs has not been observed when animals (including non-human primates) were inoculated with PERV preparations or during preclinical xenotransplantations. The data indicate that PERVs were not transmitted because they were not released from the transplant or were inhibited by intracellular restriction factors and innate immunity in the recipient. In a single study in guinea pigs, a transient PERV infection and anti-PERV antibodies were described, indicating that in this case at least, the immune system may also have been involved.
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Affiliation(s)
- Joachim Denner
- Robert Koch Institute, Nordufer 20, 13353, Berlin, Germany.
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25
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Denner J. The porcine virome and xenotransplantation. Virol J 2017; 14:171. [PMID: 28874166 PMCID: PMC5585927 DOI: 10.1186/s12985-017-0836-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/27/2017] [Indexed: 12/29/2022] Open
Abstract
The composition of the porcine virome includes viruses that infect pig cells, ancient virus-derived elements including endogenous retroviruses inserted in the pig chromosomes, and bacteriophages that infect a broad array of bacteria that inhabit pigs. Viruses infecting pigs, among them viruses also infecting human cells, as well as porcine endogenous retroviruses (PERVs) are of importance when evaluating the virus safety of xenotransplantation. Bacteriophages associated with bacteria mainly in the gut are not relevant in this context. Xenotransplantation using pig cells, tissues or organs is under development in order to alleviate the shortage of human transplants. Here for the first time published data describing the viromes in different pigs and their relevance for the virus safety of xenotransplantation is analysed. In conclusion, the analysis of the porcine virome has resulted in numerous new viruses being described, although their impact on xenotransplantation is unclear. Most importantly, viruses with known or suspected zoonotic potential were often not detected by next generation sequencing, but were revealed by more sensitive methods.
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Affiliation(s)
- Joachim Denner
- Robert Koch Fellow, Robert Koch Institute, Nordufer, 20, Berlin, Germany.
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26
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Niu D, Wei HJ, Lin L, George H, Wang T, Lee IH, Zhao HY, Wang Y, Kan Y, Shrock E, Lesha E, Wang G, Luo Y, Qing Y, Jiao D, Zhao H, Zhou X, Wang S, Wei H, Güell M, Church GM, Yang L. Inactivation of porcine endogenous retrovirus in pigs using CRISPR-Cas9. Science 2017; 357:1303-1307. [PMID: 28798043 DOI: 10.1126/science.aan4187] [Citation(s) in RCA: 450] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/03/2017] [Indexed: 12/14/2022]
Abstract
Xenotransplantation is a promising strategy to alleviate the shortage of organs for human transplantation. In addition to the concerns about pig-to-human immunological compatibility, the risk of cross-species transmission of porcine endogenous retroviruses (PERVs) has impeded the clinical application of this approach. We previously demonstrated the feasibility of inactivating PERV activity in an immortalized pig cell line. We now confirm that PERVs infect human cells, and we observe the horizontal transfer of PERVs among human cells. Using CRISPR-Cas9, we inactivated all of the PERVs in a porcine primary cell line and generated PERV-inactivated pigs via somatic cell nuclear transfer. Our study highlights the value of PERV inactivation to prevent cross-species viral transmission and demonstrates the successful production of PERV-inactivated animals to address the safety concern in clinical xenotransplantation.
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Affiliation(s)
- Dong Niu
- eGenesis, Cambridge, MA 02139, USA.,College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hong-Jiang Wei
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China.,College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China
| | - Lin Lin
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Tao Wang
- eGenesis, Cambridge, MA 02139, USA
| | | | - Hong-Ye Zhao
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
| | - Yong Wang
- Department of Laboratory Animal Science, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038, China
| | | | - Ellen Shrock
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | | | - Yonglun Luo
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Yubo Qing
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China.,College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China
| | - Deling Jiao
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China.,College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China
| | - Heng Zhao
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China.,College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China
| | - Xiaoyang Zhou
- Department of Laboratory Animal Science, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038, China
| | - Shouqi Wang
- Research Institute of Shenzhen Jinxinnong Technology, Shenzhen 518106, China
| | - Hong Wei
- Department of Laboratory Animal Science, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038, China
| | | | - George M Church
- eGenesis, Cambridge, MA 02139, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA
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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: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [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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28
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Three cysteine residues of SLC52A1, a receptor for the porcine endogenous retrovirus-A (PERV-A), play a critical role in cell surface expression and infectivity. Virology 2017; 507:140-150. [PMID: 28437635 DOI: 10.1016/j.virol.2017.04.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 11/22/2022]
Abstract
Porcine endogenous retrovirus-A (PERV-A), a gammaretrovirus, infects human cells in vitro, thus raising the potential risk of cross-species transmission in xenotransplantation. Two members of the solute carrier family 52 (SLC52A1 and SLC52A2) are PERV-A receptors. Site-directed mutagenesis of the cDNA encoding SLC52A1 identified that only one of two putative glycosylation signals is occupied by glycans. In addition, we showed that glycosylation of SLC52A1 is not necessary for PERV-A receptor function. We also identified that at a minimum, three cysteine residues are sufficient for SLC52A1 cell surface expression. Mutation of cysteine at position 365 and either of the two cysteine residues in the C-terminal tail at positions 442 or 446 reduced SLC52A1 surface expression and PERV-A infection suggesting that these residues may contribute to overall structural stability and receptor function. Understanding interactions between PERV-A and its cellular receptor may provide novel strategies to prevent zoonotic infection in the setting of xenotransplantation.
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29
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Nascimento FF, Rodrigo AG. Computational Evaluation of the Strict Master and Random Template Models of Endogenous Retrovirus Evolution. PLoS One 2016; 11:e0162454. [PMID: 27649303 PMCID: PMC5029938 DOI: 10.1371/journal.pone.0162454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 08/02/2016] [Indexed: 02/05/2023] Open
Abstract
Transposable elements (TEs) are DNA sequences that are able to replicate and move within and between host genomes. Their mechanism of replication is also shared with endogenous retroviruses (ERVs), which are also a type of TE that represent an ancient retroviral infection within animal genomes. Two models have been proposed to explain TE proliferation in host genomes: the strict master model (SMM), and the random template (or transposon) model (TM). In SMM only a single copy of a given TE lineage is able to replicate, and all other genomic copies of TEs are derived from that master copy. In TM, any element of a given family is able to replicate in the host genome. In this paper, we simulated ERV phylogenetic trees under variations of SMM and TM. To test whether current phylogenetic programs can recover the simulated ERV phylogenies, DNA sequence alignments were simulated and maximum likelihood trees were reconstructed and compared to the simulated phylogenies. Results indicate that visual inspection of phylogenetic trees alone can be misleading. However, if a set of statistical summaries is calculated, we are able to distinguish between models with high accuracy by using a data mining algorithm that we introduce here. We also demonstrate the use of our data mining algorithm with empirical data for the porcine endogenous retrovirus (PERV), an ERV that is able to replicate in human and pig cells in vitro.
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Affiliation(s)
| | - Allen G. Rodrigo
- National Evolutionary Synthesis Center, Durham, NC, United States of America
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30
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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: 62] [Impact Index Per Article: 7.8] [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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31
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Garcia-Etxebarria K, Jugo BM. Genome-wide reexamination of endogenous retroviruses in Rattus norvegicus. Virology 2016; 494:119-28. [PMID: 27107945 DOI: 10.1016/j.virol.2016.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 04/02/2016] [Accepted: 04/04/2016] [Indexed: 01/18/2023]
Abstract
Endogenous retroviruses (ERVs) are remnants of retroviral infections that are present in a large number of vertebrate genomes. Based on the proposal that the rat could act as a reservoir of retroviruses, rat ERVs were analysed in silico using a whole-genome approach. To enrich the detected ERV groups, we applied an upgraded approach based on the hidden Markov model. We found 2637 elements that were classified into the following groups: 9 groups of Class I; 15 of Class II, 7 of them previously described; 1 of Class III; and 3 groups whose classification was unclear but were distantly related to Class I. Sixteen ERV groups seemed to be specific to rat. The high number of rat-specific groups might be related to the contact of rats with retroviruses and their role as a reservoir. In addition, the env gene of the more extended groups seemed to be undetectable.
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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
| | - Begoña M 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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32
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Zhu H, Yu L, He Y, Lyu Y, Wang B. Microencapsulated Pig Islet Xenotransplantation as an Alternative Treatment of Diabetes. TISSUE ENGINEERING PART B-REVIEWS 2015; 21:474-89. [PMID: 26028249 DOI: 10.1089/ten.teb.2014.0499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Haitao Zhu
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi'an Jiaotong University, Xi'an, China
- Heart Center, Northwest Women's and Children's Hospital, Xi'an, China
| | - Liang Yu
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi'an Jiaotong University, Xi'an, China
| | - Yayi He
- Department of Endocrinology, First Affiliated Hospital, Medical College, Xi'an Jiaotong University, Xi'an, China
| | - Yi Lyu
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi'an Jiaotong University, Xi'an, China
- Institute of Advanced Surgical Technology and Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Bo Wang
- Department of Hepatobiliary Surgery, First Affiliated Hospital, Medical College, Xi'an Jiaotong University, Xi'an, China
- Institute of Advanced Surgical Technology and Engineering, Xi'an Jiaotong University, Xi'an, China
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33
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34
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Zhu HT, Yu L, Lyu Y, Wang B. Optimal pig donor selection in islet xenotransplantation: current status and future perspectives. J Zhejiang Univ Sci B 2015; 15:681-91. [PMID: 25091986 DOI: 10.1631/jzus.b1400120] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Islet transplantation is an attractive treatment of type 1 diabetes mellitus. Xenotransplantation, using the pig as a donor, offers the possibility of an unlimited supply of islet grafts. Published studies demonstrated that pig islets could function in diabetic primates for a long time (>6 months). However, pig-islet xenotransplantation must overcome the selection of an optimal pig donor to obtain an adequate supply of islets with high-quality, to reduce xeno-antigenicity of islet and prolong xenograft survival, and to translate experimental findings into clinical application. This review discusses the suitable pig donor for islet xenotransplantation in terms of pig age, strain, structure/function of islet, and genetically modified pig.
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Affiliation(s)
- Hai-tao Zhu
- Department of Hepatobiliary Surgery, the First Affiliated Hospital, Medical College, Xi'an Jiaotong University, Xi'an 710061, China
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35
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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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36
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Aiewsakun P, Katzourakis A. Endogenous viruses: Connecting recent and ancient viral evolution. Virology 2015; 479-480:26-37. [PMID: 25771486 DOI: 10.1016/j.virol.2015.02.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 12/15/2014] [Accepted: 02/04/2015] [Indexed: 12/17/2022]
Abstract
The rapid rates of viral evolution allow us to reconstruct the recent history of viruses in great detail. This feature, however, also results in rapid erosion of evolutionary signal within viral molecular data, impeding studies of their deep history. Thus, the further back in time, the less accurate the inference becomes. Furthermore, reconstructing complex histories of transmission can be challenging, especially where extinct viral lineages are concerned. This problem has been partially solved by the discovery of viruses embedded in host genomes, known as endogenous viral elements (EVEs). Some of these endogenous viruses are derived from ancient relatives of extant viruses, allowing us to better examine ancient viral host range, geographical distribution and transmission routes. Moreover, our knowledge of viral evolutionary timescales and rate dynamics has also been greatly improved by their discovery, thereby bridging the gap between recent and ancient viral evolution.
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Affiliation(s)
| | - Aris Katzourakis
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
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37
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Sang Y, Bergkamp J, Blecha F. Molecular evolution of the porcine type I interferon family: subtype-specific expression and antiviral activity. PLoS One 2014; 9:e112378. [PMID: 25372927 PMCID: PMC4221479 DOI: 10.1371/journal.pone.0112378] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/15/2014] [Indexed: 12/22/2022] Open
Abstract
Type I interferons (IFNs), key antiviral cytokines, evolve to adapt with ever-changing viral threats during vertebrate speciation. Due to novel pathogenic pressure associated with Suidae speciation and domestication, porcine IFNs evolutionarily engender both molecular and functional diversification, which have not been well addressed in pigs, an important livestock species and animal model for biomedical sciences. Annotation of current swine genome assembly Sscrofa10.2 reveals 57 functional genes and 16 pseudogenes of type I IFNs. Subfamilies of multiple IFNA, IFNW and porcine-specific IFND genes are separated into four clusters with ∼ 60 kb intervals within the IFNB/IFNE bordered region in SSC1, and each cluster contains mingled subtypes of IFNA, IFNW and IFND. Further curation of the 57 functional IFN genes indicates that they include 18 potential artifactual duplicates. We performed phylogenetic construction as well as analyses of gene duplication/conversion and natural selection and showed that porcine type I IFN genes have been undergoing active diversification through both gene duplication and conversion. Extensive analyses of the non-coding sequences proximal to all IFN coding regions identified several genomic repetitive elements significantly associated with different IFN subtypes. Family-wide studies further revealed their molecular diversity with respect to differential expression and restrictive activity on the resurgence of a porcine endogenous retrovirus. Based on predicted 3-D structures of representative animal IFNs and inferred activity, we categorized the general functional propensity underlying the structure-activity relationship. Evidence indicates gene expansion of porcine type I IFNs. Genomic repetitive elements that associated with IFN subtypes may serve as molecular signatures of respective IFN subtypes and genomic mechanisms to mediate IFN gene evolution and expression. In summary, the porcine type I IFN profile has been phylogenetically defined family-wide and linked to diverse expression and antiviral activity, which is important information for further biological studies across the porcine type I IFN family.
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Affiliation(s)
- Yongming Sang
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
| | - Joseph Bergkamp
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Frank Blecha
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
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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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39
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Porcine endogenous retroviruses in xenotransplantation--molecular aspects. Viruses 2014; 6:2062-83. [PMID: 24828841 PMCID: PMC4036542 DOI: 10.3390/v6052062] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/15/2014] [Accepted: 04/26/2014] [Indexed: 02/06/2023] Open
Abstract
In the context of the shortage of organs and other tissues for use in human transplantation, xenotransplantation procedures with material taken from pigs have come under increased consideration. However, there are unclear consequences of the potential transmission of porcine pathogens to humans. Of particular concern are porcine endogenous retroviruses (PERVs). Three subtypes of PERV have been identified, of which PERV-A and PERV-B have the ability to infect human cells in vitro. The PERV-C subtype does not show this ability but recombinant PERV-A/C forms have demonstrated infectivity in human cells. In view of the risk presented by these observations, the International Xenotransplantation Association recently indicated the existence of four strategies to prevent transmission of PERVs. This article focuses on the molecular aspects of PERV infection in xenotransplantation and reviews the techniques available for the detection of PERV DNA, RNA, reverse transcriptase activity and proteins, and anti-PERV antibodies to enable carrying out these recommendations. These methods could be used to evaluate the risk of PERV transmission in human recipients, enhance the effectiveness and reliability of monitoring procedures, and stimulate discussion on the development of improved, more sensitive methods for the detection of PERVs in the future.
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40
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Lamb M, Laugenour K, Liang O, Alexander M, Foster CE, Lakey JRT. In Vitro Maturation of Viable Islets from Partially Digested Young Pig Pancreas. Cell Transplant 2014; 23:263-72. [DOI: 10.3727/096368912x662372] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Isolation of islets from market-sized pigs is costly, with considerable islet losses from fragmentation occurring during isolation and tissue culture. Fetal and neonatal pigs yield insulin unresponsive islet-like cell clusters that become glucose-responsive after extended periods of time. Both issues impact clinical applicability and commercial scale-up. We have focused our efforts on a cost-effective scalable method of isolating viable insulin-responsive islets. Young Yorkshire pigs (mean age 20 days, range 4–30 days) underwent rapid pancreatectomy (<5 min) and partial digestion using low-dose collagenase, followed by in vitro culture at 37°C and 5% CO2 for up to 14 days. Islet viability was assessed using FDA/PI or Newport Green, and function was assessed using a glucose-stimulated insulin release (GSIR) assay. Islet yield was performed using enumeration of dithizonestained aliquots. The young porcine (YP) islet yield at dissociation was 12.6 ± 2.1 × 103 IEQ (mean ± SEM) per organ and increased to 33.3 ± 6.4 × 103 IEQ after 7 days of in vitro culture. Viability was 97.3 ± 7% at dissociation and remained over 90% viable after 11 days in tissue culture ( n = ns). Glucose responsiveness increased throughout maturation in culture. The stimulation index (SI) of the islets increased from 1.7 ± 2 on culture day 3 to 2.58 ± 0.5 on culture day 7. These results suggest that this method is both efficient and scalable for isolating and maturing insulin-responsive porcine islets in culture.
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Affiliation(s)
- Morgan Lamb
- Department of Surgery, University of California Irvine, Orange, CA, USA
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, USA
| | - Kelly Laugenour
- Department of Surgery, University of California Irvine, Orange, CA, USA
| | - Ouwen Liang
- Department of Surgery, University of California Irvine, Orange, CA, USA
| | - Michael Alexander
- Department of Surgery, University of California Irvine, Orange, CA, USA
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, USA
| | | | - Jonathan R. T. Lakey
- Department of Surgery, University of California Irvine, Orange, CA, USA
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, USA
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA, USA
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41
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Jung YD, Lee JR, Kim YJ, Ha HS, Oh KB, Im GS, Choi BH, Kim HS. Promoter activity analysis and methylation characterization of LTR elements of PERVs in NIH miniature pig. Genes Genet Syst 2014; 88:135-42. [PMID: 23832305 DOI: 10.1266/ggs.88.135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The potential risk of porcine endogenous retrovirus (PERV) transmission is an important issue in xenotransplantation (pig-to-human transplantation). Long terminal repeats (LTRs) in PERV elements show promoter activity that could affect neighboring functional genes. The methylation status and promoter activities of 3 LTR structures (PERV-LTR1, LTR2, and LTR3 elements) belonging to the PERV-A family were examined using luciferase reporter genes in human liver cell lines (HepG2 and Hep3B). The PERV LTR3 element exhibited hypomethylation and stronger promoter activity than the other LTR elements in human liver cells. We also performed comparative sequences analysis of the PERV LTR elements by using bioinformatics tools. Our findings showed that several transcription factors such as Nkx2-2 and Elk-1 positively influenced the high transcriptional activity of the PERV LTR3 element.
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Affiliation(s)
- Yi-Deun Jung
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
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42
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Chung HC, Nguyen VG, Moon HJ, Kim HK, Park SJ, Lee JH, Choi MG, Kim AR, Park BK. Inhibition of porcine endogenous retrovirus in PK15 cell line by efficient multitargeting RNA interference. Transpl Int 2013; 27:96-105. [PMID: 24138389 DOI: 10.1111/tri.12219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 08/20/2013] [Accepted: 10/16/2013] [Indexed: 12/30/2022]
Abstract
To effectively suppress porcine endogenous retroviruses (PERV)s, RNAi technique was utilized. RNAi is the up-to-date skill for gene knockdown which simultaneously multitargets both gag and pol genes critical for replication of PERVs. Previously, two of the most effective siRNAs (gag2, pol2) were found to reduce the expression of PERVs. Concurrent treatment of these two siRNAs (gag2+pol2) showed knockdown efficiency of up to 88% compared to negative control. However, despite the high initial knockdown efficiency 48 h after transfection caused by siRNA, it may only be a transient effect of suppressing PERVs. The multitargeting vector was designed, containing both gag and pol genes and making use of POL II miR Expression Vector, which allowed for persistent and multiple targeting. This is the latest shRNA system technique expressing and targeting like miRNA. Through antibiotics resistance characteristics utilizing this vector, miRNA-transfected PK15 cells (gag2-pol2) were selected during 10 days. An 88.1% reduction in the level of mRNA expression was found. In addition, we performed RT-activity analysis and fluorescence in situ hybridization assay, and it demonstrated the highest knockdown efficiency in multitargeting (gag2+pol2) miRNA group. Therefore, according to the results above, gene knockdown system (siRNA and shRNA) through multitargeting strategy could effectively inhibit PERVs.
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Affiliation(s)
- Hee-Chun Chung
- 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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43
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Role of DNA methylation in expression and transmission of porcine endogenous retroviruses. J Virol 2013; 87:12110-20. [PMID: 23986605 DOI: 10.1128/jvi.03262-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Porcine endogenous retroviruses (PERV) represent a major safety concern in pig-to-human xenotransplantation. To date, no PERV infection of a xenograft recipient has been recorded; however, PERVs are transmissible to human cells in vitro. Some recombinants of the A and C PERV subgroups are particularly efficient in infection and replication in human cells. Transcription of PERVs has been described in most pig cells, but their sequence and insertion polymorphism in the pig genome impede identification of transcriptionally active or silenced proviral copies. Furthermore, little is known about the epigenetic regulation of PERV transcription. Here, we report on the transcriptional suppression of PERV by DNA methylation in vitro and describe heavy methylation in the majority of PERV 5' long terminal repeats (LTR) in porcine tissues. In contrast, we have detected sparsely methylated or nonmethylated proviruses in the porcine PK15 cells, which express human cell-tropic PERVs. We also demonstrate the resistance of PERV DNA methylation to inhibitors of methylation and deacetylation. Finally, we show that the high permissiveness of various human cell lines to PERV infection coincides with the inability to efficiently silence the PERV proviruses by 5'LTR methylation. In conclusion, we suggest that DNA methylation is involved in PERV regulation, and that only a minor fraction of proviruses are responsible for the PERV RNA expression and porcine cell infectivity.
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44
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Wolf G, Nielsen AL, Mikkelsen JG, Pedersen FS. Epigenetic marking and repression of porcine endogenous retroviruses. J Gen Virol 2013; 94:960-970. [PMID: 23324470 DOI: 10.1099/vir.0.049288-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Endogenous retroviruses (ERVs) are remnants of retroviral germ line infections and have been identified in all mammals investigated so far. Although the majority of ERVs are degenerated, some mammalian species, such as mice and pigs, carry replication-competent ERVs capable of forming infectious viral particles. In mice, ERVs are silenced by DNA methylation and histone modifications and some exogenous retroviruses were shown to be transcriptionally repressed after integration by a primer-binding site (PBS) targeting mechanism. However, epigenetic repression of porcine ERVs (PERVs) has remained largely unexplored so far. In this study, we screened the pig genome for PERVs using LTRharvest, a tool for de novo detection of ERVs, and investigated various aspects of epigenetic repression of three unrelated PERV families. We found that these PERV families are differentially up- or downregulated upon chemical inhibition of DNA methylation and histone deacetylation in cultured porcine cells. Furthermore, chromatin immunoprecipitation analysis revealed repressive histone methylation marks at PERV loci in primary porcine embryonic germ cells and immortalized embryonic kidney cells. PERV elements belonging to the PERV-γ1 family, which is the only known PERV family that has remained active up to the present, were marked by significantly higher levels of histone methylations than PERV-γ2 and PERV-β3 proviruses. Finally, we tested three PERV-associated PBS sequences for repression activity in murine and porcine cells using retroviral transduction experiments and showed that none of these PBS sequences induced immediate transcriptional silencing in the tested primary porcine cells.
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Affiliation(s)
- Gernot Wolf
- Department of Molecular Biology and Genetics, University of Aarhus, DK-8000 Aarhus C, Denmark
| | | | | | - Finn Skou Pedersen
- Department of Molecular Biology and Genetics, University of Aarhus, DK-8000 Aarhus C, Denmark
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45
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Semaan M, Rotem A, Barkai U, Bornstein S, Denner J. Screening pigs for xenotransplantation: prevalence and expression of porcine endogenous retroviruses in Göttingen minipigs. Xenotransplantation 2013; 20:148-56. [DOI: 10.1111/xen.12032] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 03/12/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Marwan Semaan
- Robert Koch Institute; HIV and Other Retroviruses; Berlin Germany
| | - Avi Rotem
- Beta-O 2 Technologies Ltd; Petach-Tikva Israel
| | | | - Stefan Bornstein
- Center Internal Medicine; University Clinics Carl Gustav Carus; Technical University; Dresden Germany
| | - Joachim Denner
- Robert Koch Institute; HIV and Other Retroviruses; Berlin Germany
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46
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Song N, Jo H, Choi M, Kim JH, Seo HG, Cha SY, Seo K, Park C. Identification and classification of feline endogenous retroviruses in the cat genome using degenerate PCR and in silico data analysis. J Gen Virol 2013; 94:1587-1596. [PMID: 23515024 DOI: 10.1099/vir.0.051862-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The purpose of this study was to identify and classify endogenous retroviruses (ERVs) in the cat genome. Pooled DNA from five domestic cats was subjected to degenerate PCR with primers specific to the conserved retroviral pro/pol region. The 59 amplified retroviral sequences were used for in silico analysis of the cat genome (Felis_catus-6.2). We identified 219 ERV γ and β elements from cat genome contigs, which were classified into 42 ERV γ and 4 β families and further analysed. Among them, 99 γ and 5 β ERV elements contained the complete retroviral structure. Furthermore, we identified 757 spuma-like ERV elements based on the sequence homology to murine (Mu)ERV-L and human (H)ERV-L. To the best of our knowledge, this is the first detailed genome-scale analysis examining Felis catus endogenous retroviruses (FcERV) and providing advanced insights into their structural characteristics, localization in the genome, and diversity.
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Affiliation(s)
- Ning Song
- Department of Animal Biotechnology, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul, South Korea
| | - Haiin Jo
- Department of Animal Biotechnology, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul, South Korea
| | - Minkyeung Choi
- Department of Animal Biotechnology, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul, South Korea
| | - Jin-Hoi Kim
- Department of Animal Biotechnology, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul, South Korea
| | - Han Geuk Seo
- Department of Animal Biotechnology, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul, South Korea
| | - Se-Yeoun Cha
- College of Veterinary Medicine, Chonbuk National University, Jeonju, South Korea
| | - Kunho Seo
- Colleges of Veterinary Medicine, Konkuk University, Seoul, South Korea
| | - Chankyu Park
- Department of Animal Biotechnology, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul, South Korea
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47
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Jung YD, Ha HS, Park SJ, Oh KB, Im GS, Kim TH, Seong HH, Kim HS. Identification and promoter analysis of PERV LTR subtypes in NIH-miniature pig. Mol Cells 2013; 35:99-105. [PMID: 23456331 PMCID: PMC3887905 DOI: 10.1007/s10059-013-2289-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 11/20/2012] [Accepted: 12/11/2012] [Indexed: 11/28/2022] Open
Abstract
Porcine endogenous retroviruses (PERVs) are integrated into the genomes of all pigs. Since some PERVs can also infect human cells, they represent a potential risk for xenotransplantation involving pig cells or organs. The long terminal repeat (LTR) elements of PERVs show promoter activity that can affect human functional genes; therefore, we examined these elements in this study. We detected several expressed LTRs in the NIH-miniature pig liver, among which we identified 9 different subtypes. When these LTRs were compared, distinct structures that contained several insertion and deletion (INDEL) events and tandem repeats were identified in the U3 region. The transcriptional activity of the 9 LTR subtypes was analyzed in the PK15 porcine cell line and in the HepG2 and Hep3B human liver cell lines, and transcriptional regulation was found to be different in the 3 cell lines. The D LTR subtype was found to have stronger promoter activity than all other types in 4 different human cell lines (HepG2, Hep3B, U251, and 293). Using computational approaches, the D type was shown to contain 4 transcription factor-binding sites distinct from those in the U3 regions of the other subtypes. Therefore, deletion mutants were constructed and examined by a transient transfection luciferase assay. The results of this analysis indicated that the binding site for the Hand1:E47 transcription factor might play a positive role in the transcriptional regulation of PERV LTR subtype D in human liver cell lines.
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Affiliation(s)
- Yi-Deun Jung
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735,
Korea
| | | | - Sang-Je Park
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735,
Korea
| | | | | | | | | | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735,
Korea
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48
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Bittmann I, Mihica D, Plesker R, Denner J. Expression of porcine endogenous retroviruses (PERV) in different organs of a pig. Virology 2012; 433:329-36. [DOI: 10.1016/j.virol.2012.08.030] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 06/21/2012] [Accepted: 08/18/2012] [Indexed: 10/27/2022]
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49
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Kaulitz D, Mihica D, Adlhoch C, Semaan M, Denner J. Improved pig donor screening including newly identified variants of porcine endogenous retrovirus-C (PERV-C). Arch Virol 2012; 158:341-8. [PMID: 23053520 DOI: 10.1007/s00705-012-1490-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/16/2012] [Indexed: 11/30/2022]
Abstract
Porcine endogenous retroviruses (PERV) are widely distributed in the genomes of pigs. PERV-A and PERV-B are present in all pigs. They infect human cells in vitro and therefore represent a risk for xenotransplantation when pig cells, tissues or organs are used. PERV-C infects only pig cells and is not present in the genomes of all pigs. However, PERV-A/C recombinants infecting human cells and characterized by high replication titers were found in pigs. To select PERV-C-free animals that cannot generate such recombinants, PCR-based assays were developed (Kaulitz et al., J Virol Methods, 175:60, 2011). When screening for PERV-C in German wild boars (Sus scrofa scrofa), applying these methods, a new variant of PERV-C was identified. Whereas in all 125 wild boar only the new variant of PERV-C was found, different variants were present in some landrace pigs, and most importantly, some pigs were totally free of PERV-C.
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Affiliation(s)
- Danny Kaulitz
- Centre of HIV and Retrovirology, Robert Koch-Institute, Nordufer 20, 13353, Berlin, Germany
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50
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Blomström AL, Ståhl K, Masembe C, Okoth E, Okurut AR, Atmnedi P, Kemp S, Bishop R, Belák S, Berg M. Viral metagenomic analysis of bushpigs (Potamochoerus larvatus) in Uganda identifies novel variants of Porcine parvovirus 4 and Torque teno sus virus 1 and 2. Virol J 2012; 9:192. [PMID: 22967311 PMCID: PMC3478234 DOI: 10.1186/1743-422x-9-192] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 09/05/2012] [Indexed: 11/19/2022] Open
Abstract
Background As a result of rapidly growing human populations, intensification of livestock production and increasing exploitation of wildlife habitats for animal agriculture, the interface between wildlife, livestock and humans is expanding, with potential impacts on both domestic animal and human health. Wild animals serve as reservoirs for many viruses, which may occasionally result in novel infections of domestic animals and/or the human population. Given this background, we used metagenomics to investigate the presence of viral pathogens in sera collected from bushpigs (Potamochoerus larvatus), a nocturnal species of wild Suid known to move between national parks and farmland, in Uganda. Results Application of 454 pyrosequencing demonstrated the presence of Torque teno sus virus (TTSuV), porcine parvovirus 4 (PPV4), porcine endogenous retrovirus (PERV), a GB Hepatitis C–like virus, and a Sclerotinia hypovirulence-associated-like virus in sera from the bushpigs. PCR assays for each specific virus combined with Sanger sequencing revealed two TTSuV-1 variants, one TTSuV-2 variant as well as PPV4 in the serum samples and thereby confirming the findings from the 454 sequencing. Conclusions Using a viral metagenomic approach we have made an initial analysis of viruses present in bushpig sera and demonstrated for the first time the presence of PPV4 in a wild African Suid. In addition we identified novel variants of TTSuV-1 and 2 in bushpigs.
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Affiliation(s)
- Anne-Lie Blomström
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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