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Yu R, Dong S, Chen B, Si F, Li C. Developing Next-Generation Live Attenuated Vaccines for Porcine Epidemic Diarrhea Using Reverse Genetic Techniques. Vaccines (Basel) 2024; 12:557. [PMID: 38793808 PMCID: PMC11125984 DOI: 10.3390/vaccines12050557] [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: 04/12/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 05/26/2024] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) is the etiology of porcine epidemic diarrhea (PED), a highly contagious digestive disease in pigs and especially in neonatal piglets, in which a mortality rate of up to 100% will be induced. Immunizing pregnant sows remains the most promising and effective strategy for protecting their neonatal offspring from PEDV. Although half a century has passed since its first report in Europe and several prophylactic vaccines (inactivated or live attenuated) have been developed, PED still poses a significant economic concern to the swine industry worldwide. Hence, there is an urgent need for novel vaccines in clinical practice, especially live attenuated vaccines (LAVs) that can induce a strong protective lactogenic immune response in pregnant sows. Reverse genetic techniques provide a robust tool for virological research from the function of viral proteins to the generation of rationally designed vaccines. In this review, after systematically summarizing the research progress on virulence-related viral proteins, we reviewed reverse genetics techniques for PEDV and their application in the development of PED LAVs. Then, we probed into the potential methods for generating safe, effective, and genetically stable PED LAV candidates, aiming to provide new ideas for the rational design of PED LAVs.
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Affiliation(s)
| | | | | | - Fusheng Si
- Institute of Animal Husbandry and Veterinary Medicine, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (R.Y.); (S.D.); (B.C.)
| | - Chunhua Li
- Institute of Animal Husbandry and Veterinary Medicine, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (R.Y.); (S.D.); (B.C.)
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Niu X, Liu M, Yang S, Xu J, Hou YJ, Liu D, Tang Q, Zhu H, Wang Q. A recombination-resistant genome for live attenuated and stable PEDV vaccines by engineering the transcriptional regulatory sequences. J Virol 2023; 97:e0119323. [PMID: 37971221 PMCID: PMC10734454 DOI: 10.1128/jvi.01193-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/23/2023] [Indexed: 11/19/2023] Open
Abstract
IMPORTANCE Coronaviruses are important pathogens of humans and animals, and vaccine developments against them are imperative. Due to the ability to induce broad and prolonged protective immunity and the convenient administration routes, live attenuated vaccines (LAVs) are promising arms for controlling the deadly coronavirus infections. However, potential recombination events between vaccine and field strains raise a safety concern for LAVs. The porcine epidemic diarrhea virus (PEDV) remodeled TRS (RMT) mutant generated in this study replicated efficiently in both cell culture and in pigs and retained protective immunogenicity against PEDV challenge in pigs. Furthermore, the RMT PEDV was resistant to recombination and genetically stable. Therefore, RMT PEDV can be further optimized as a backbone for the development of safe LAVs.
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Affiliation(s)
- Xiaoyu Niu
- Center for Food Animal Health, Department of Animal Sciences, College of Food, Agricultural and Environmental Sciences, The Ohio State University, Wooster, Ohio, USA
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Mingde Liu
- Center for Food Animal Health, Department of Animal Sciences, College of Food, Agricultural and Environmental Sciences, The Ohio State University, Wooster, Ohio, USA
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Shaomin Yang
- Department of Pain Medicine, Shenzhen Nanshan People’s Hospital and the 6th Affiliated Hospital of Guangdong Medical University, Shenzhen, China
| | - Jiayu Xu
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Yixuan J. Hou
- Center for Food Animal Health, Department of Animal Sciences, College of Food, Agricultural and Environmental Sciences, The Ohio State University, Wooster, Ohio, USA
| | - Dongxiao Liu
- Department of Microbiology, Howard University College of Medicine, Washington, DC, USA
| | - Qiyi Tang
- Department of Microbiology, Howard University College of Medicine, Washington, DC, USA
| | - Hua Zhu
- Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, Newark, New Jersey, USA
| | - Qiuhong Wang
- Center for Food Animal Health, Department of Animal Sciences, College of Food, Agricultural and Environmental Sciences, The Ohio State University, Wooster, Ohio, USA
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
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Park GN, Song S, Choe S, Shin J, An BH, Kim SY, Hyun BH, An DJ. Spike Gene Analysis and Prevalence of Porcine Epidemic Diarrhea Virus from Pigs in South Korea: 2013-2022. Viruses 2023; 15:2165. [PMID: 38005843 PMCID: PMC10674705 DOI: 10.3390/v15112165] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
From late 2013-2022, 1131 cases of porcine epidemic diarrhea (PED) were reported to the Korean Animal Health Integrated System (KAHIS). There were four major outbreaks from winter to spring (2013-2014, 2017-2018, 2018-2019, and 2021-2022), with the main outbreaks occurring in Chungnam (CN), Jeonbuk (JB), and Jeju (JJ). Analysis of the complete spike (S) gene of 140/1131 KAHIS PEDV cases nationwide confirmed that 139 belonged to the G2b genotype and 1 to the G2a genotype. Among them, two strains (K17GG1 and K17GB3) were similar to an S INDEL isolated in the United States (strain OH851), and 12 strains had deletions (nucleotides (nt) 3-99) or insertions (12 nt) within the S gene. PEDVs in JJ formed a regionally independent cluster. The substitution rates (substitutions/site/year) were as follows: 1.5952 × 10-3 in CN, 1.8065 × 10-3 in JB, and 1.5113 × 10-3 in JJ. A Bayesian skyline plot showed that the effective population size of PEDs in JJ fell from 2013-2022, whereas in CN and JB it was maintained. Genotyping of 340 Korean PEDV strains, including the 140 PEDVs in this study and 200 Korean reference strains from GenBank, revealed that only the highly pathogenic non-INDEL type (G2b) was dominant from 2020 onwards. Therefore, it is predicted that the incidence of PED will be maintained by the G2b (non-INDEL) genotype.
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Affiliation(s)
- Gyu-Nam Park
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
| | - Sok Song
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
| | - SeEun Choe
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
| | - Jihye Shin
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
| | - Byung-Hyun An
- College of Veterinary Medicine, Seoul University, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea;
| | - Song-Yi Kim
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
| | - Bang-Hun Hyun
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
| | - Dong-Jun An
- Virus Disease Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea; (G.-N.P.); (S.S.); (S.C.); (J.S.); (S.-Y.K.); (B.-H.H.)
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Jiang H, Wang T, Kong L, Li B, Peng Q. Reverse Genetics Systems for Emerging and Re-Emerging Swine Coronaviruses and Applications. Viruses 2023; 15:2003. [PMID: 37896780 PMCID: PMC10611186 DOI: 10.3390/v15102003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/29/2023] Open
Abstract
Emerging and re-emerging swine coronaviruses (CoVs), including porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome-CoV (SADS-CoV), cause severe diarrhea in neonatal piglets, and CoV infection is associated with significant economic losses for the swine industry worldwide. Reverse genetics systems realize the manipulation of RNA virus genome and facilitate the development of new vaccines. Thus far, five reverse genetics approaches have been successfully applied to engineer the swine CoV genome: targeted RNA recombination, in vitro ligation, bacterial artificial chromosome-based ligation, vaccinia virus -based recombination, and yeast-based method. This review summarizes the advantages and limitations of these approaches; it also discusses the latest research progress in terms of their use for virus-related pathogenesis elucidation, vaccine candidate development, antiviral drug screening, and virus replication mechanism determination.
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Affiliation(s)
- Hui Jiang
- Nanchang Key Laboratory of Animal Virus and Genetic Engineering, Jiangxi Agricultural University, Nanchang 330045, China; (H.J.); (T.W.)
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330045, China
- Department of Avian Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
| | - Ting Wang
- Nanchang Key Laboratory of Animal Virus and Genetic Engineering, Jiangxi Agricultural University, Nanchang 330045, China; (H.J.); (T.W.)
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330045, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China
| | - Lingbao Kong
- Nanchang Key Laboratory of Animal Virus and Genetic Engineering, Jiangxi Agricultural University, Nanchang 330045, China; (H.J.); (T.W.)
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330045, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China
| | - Bin Li
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, Nanjing 210014, China
| | - Qi Peng
- Nanchang Key Laboratory of Animal Virus and Genetic Engineering, Jiangxi Agricultural University, Nanchang 330045, China; (H.J.); (T.W.)
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330045, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330045, China
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, Nanjing 210014, China
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Si F, Song S, Yu R, Li Z, Wei W, Wu C. Coronavirus accessory protein ORF3 biology and its contribution to viral behavior and pathogenesis. iScience 2023; 26:106280. [PMID: 36945252 PMCID: PMC9972675 DOI: 10.1016/j.isci.2023.106280] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
Coronavirus porcine epidemic diarrhea virus (PEDV) is classified in the genus Alphacoronavirus, family Coronaviridae that encodes the only accessory protein, ORF3 protein. However, how ORF3 contributes to viral pathogenicity, adaptability, and replication is obscure. In this review, we summarize current knowledge and identify gaps in many aspects of ORF3 protein in PEDV, with emphasis on its unique biological features, including membrane topology, Golgi retention mechanism, potential intrinsic disordered property, functional motifs, protein glycosylation, and codon usage phenotypes related to genetic evolution and gene expression. In addition, we propose intriguing questions related to ORF3 protein that we hope to stimulate further studies and encourage collaboration among virologists worldwide to provide constructive knowledge about the unique characteristics and biological functions of ORF3 protein, by which their potential role in clarifying viral behavior and pathogenesis can be possible.
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Affiliation(s)
- Fusheng Si
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai 201106, P.R. China
| | - Shuai Song
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture of Rural Affairs, and Key Laboratory of Animal Disease Prevention of Guangdong Province, Guangzhou 510640, P.R. China
| | - Ruisong Yu
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai 201106, P.R. China
| | - Zhen Li
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai 201106, P.R. China
| | - Wenqiang Wei
- Department of Microbiology, School of Basic Medical Sciences, Henan University, Kaifeng, Henan 475004, P.R. China
| | - Chao Wu
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110, USA
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Three Amino Acid Substitutions in the Spike Protein Enable the Coronavirus Porcine Epidemic Diarrhea Virus To Infect Vero Cells. Microbiol Spectr 2023; 11:e0387222. [PMID: 36511700 PMCID: PMC9927491 DOI: 10.1128/spectrum.03872-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV), a continuously evolving pathogen, causes severe diarrhea in piglets, with high mortality rates. To prevent or mitigate the disease, it is common practice to develop live or inactivated PEDV vaccines based on cell-adapted viral variants. Propagating wild-type PEDV in cultured cells is, however, often challenging due to the lack of knowledge about the requirements for the cell adaptation of PEDV. In the present study, by using the RNA-targeted reverse genetic system for PEDV to apply S protein swapping followed by the rescue of the recombinant viruses, three key amino acid mutations in the S protein, A605E, E633Q, and R891G, were identified, which enable attenuated PEDV strain DR13 (DR13att) to efficiently and productively infect Vero cells, in contrast to the parental DR13 strain (DR13par). The former two key mutations reside inside and in the vicinity of the receptor binding domain (RBD), respectively, while the latter occurs at the N-terminal end of the fusion peptide (FP). Besides the three key mutations, other mutations in the S protein further enhanced the infection efficiency of the recombinant viruses. We hypothesize that the three mutations changed PEDV tropism by altering the S2' cleavage site and the RBD structure. This study provides basic molecular insight into cell adaptation by PEDV, which is also relevant for vaccine design. IMPORTANCE Porcine epidemic diarrhea virus (PEDV) is a lethal pathogen for newborn piglets, and an efficient vaccine is needed urgently. However, propagating wild-type PEDV in cultured cells for vaccine development is still challenging due to the lack of knowledge about the mechanism of the cell adaptation of PEDV. In this study, we found that three amino acid mutations, A605E, E633Q, and R891G, in the spike protein of the Vero cell-adapted PEDV strain DR13att were critical for its cell adaptation. After analyzing the mutation sites in the spike protein, we hypothesize that the cell adaptation of DR13att was achieved by altering the S2' cleavage site and the RBD structure. This study provides new molecular insight into the mechanism of PEDV culture adaptation and new strategies for PEDV vaccine design.
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Wang X, Chen B, Yu R, Si F, Xie C, Li Z, Dong S, Zhang D. Magnolol, a Neolignan-like Drug, Inhibits Porcine Epidemic Diarrhea Virus Replication in Cultured Cells. Pathogens 2023; 12:pathogens12020263. [PMID: 36839535 PMCID: PMC9965036 DOI: 10.3390/pathogens12020263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) is a destructive pathogen that continues to adversely affect the swine industry worldwide due to a current lack of vaccines and drugs capable of effective disease control. In the present study, the neolignan-like drug, magnolol (MAG), was tested for its ability to inhibit a Vero-cell adapted PEDV strain DR13att. Our data revealed that MAG exhibited anti-PEDV activity in vitro, with IC50 and CC50 values of 28.21 μM and 57.28 μM, respectively. MAG was an efficient inhibitor of viral replication, and repression of viral proliferation was strongest when the host cells were exposed to MAG and the virus at the same time. Although our data indicate that MAG has the potential to be a useful PEDV control agent, in vivo testing of the drug, using animal hosts, is required.
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Affiliation(s)
- Xiaoting Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology (ECUST), Shanghai 200237, China
| | - Bingqing Chen
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Ruisong Yu
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Fusheng Si
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Chunfang Xie
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Zhen Li
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
| | - Shijuan Dong
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Institute of Animal Husbandry and Veterinary Science, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China
- Correspondence: (S.D.); (D.Z.); Tel.: +86-21-62207858 (S.D.); +86-21-64252324 (D.Z.)
| | - Daojing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology (ECUST), Shanghai 200237, China
- Correspondence: (S.D.); (D.Z.); Tel.: +86-21-62207858 (S.D.); +86-21-64252324 (D.Z.)
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Development of a Next-Generation Vaccine Platform for Porcine Epidemic Diarrhea Virus Using a Reverse Genetics System. Viruses 2022; 14:v14112319. [PMID: 36366417 PMCID: PMC9692715 DOI: 10.3390/v14112319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/14/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
For the past three decades, the porcine epidemic diarrhea virus (PEDV) has remained an enormous threat to the South Korean swine industry. The scarcity of an effective method for manipulating viral genomes has impeded research progress in PEDV biology and vaccinology. Here, we report the development of reverse genetics systems using two novel infectious full-length cDNA clones of a Korean highly pathogenic-G2b strain, KNU-141112, and its live attenuated vaccine strain, S DEL5/ORF3, in a bacterial artificial chromosome (BAC) under the control of a eukaryotic promoter. Direct transfection of cells with each recombinant BAC clone induced cytopathic effects and produced infectious progeny. The reconstituted viruses, icKNU-141112 and icS DEL5/ORF3, harboring genetic markers, displayed phenotypic and genotypic properties identical to their respective parental viruses. Using the DNA-launched KNU-141112 infectious cDNA clone as a backbone, two types of recombinant viruses were generated. First, we edited the open reading frame 3 (ORF3) gene, as cell-adapted strains lose full-length ORF3, and replaced this region with an enhanced green fluorescent protein (EGFP) gene to generate icPEDV-EGFP. This mutant virus presented parental virus-like growth kinetics and stably retained robust EGFP expression, indicating that ORF3 is dispensable for PEDV replication in cell culture and is a tolerant location for exogeneous gene acceptance. However, the plaque size and syncytia phenotypes of ORF3-null icPEDV-EGFP were larger than those of icKNU-141112 but similar to ORF3-null icS DEL5/ORF3, suggesting a potential role of ORF3 in PEDV cytopathology. Second, we substituted the spike (S) gene with a heterologous S protein, designated S51, from a variant of interest (VOI), which was the most genetically and phylogenetically distant from KNU-141112. The infectious recombinant VOI, named icPEDV-S51, could be recovered, and the rescued virus showed indistinguishable growth characteristics compared to icKNU-141112. Virus cross-neutralization and structural analyses revealed antigenic differences in S between icKNU-141112 and icPEDV-S51, suggesting that genetic and conformational changes mapped within the neutralizing epitopes of S51 could impair the neutralization capacity and cause considerable immune evasion. Collectively, while the established molecular clones afford convenient, versatile platforms for PEDV genome manipulation, allowing for corroborating the molecular basis of viral replication and pathogenesis, they also provide key infrastructural frameworks for developing new vaccines and coronaviral vectors.
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Visual and Rapid Detection of Porcine Epidemic Diarrhea Virus (PEDV) Using Reverse Transcription Loop-Mediated Isothermal Amplification Method. Animals (Basel) 2022; 12:ani12192712. [PMID: 36230453 PMCID: PMC9558507 DOI: 10.3390/ani12192712] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/29/2022] [Accepted: 10/06/2022] [Indexed: 11/20/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) can cause severe infectious porcine epidemic diarrhea (PED) and infect different ages of pigs, resulting in sickness and death among suckling pigs. For PEDV detection, finding an effective and rapid method is a priority. In this study, we established an effective reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for PEDV detection. Three sets of primers, specific for eight different sequences of the PEDV N gene, were designed in this study. The optimized RT-LAMP amplification program was as follows: 59 min at 61.9 °C and 3 min at 80 °C. The RT-LAMP results were confirmed with the addition of SYBR Green I fluorescence dye and with the detection of a ladder-like band by conventional gel electrophoresis analysis, which demonstrated a significant agreement between the two methods. The LOD of PEDV by RT-LAMP was 0.0001 ng/μL. Compared with RT-LAMP, the traditional RT-PCR method is 100-fold less sensitive. The RT-LAMP results had no cross-reaction with porcine parvovirus (PPV), porcine circovirus type 1 (PCV1), porcine pseudorabies virus (PRV), porcine circovirus type 2 (PCV2), rotavirus (RV), transmissible gastroenteritis virus (TGEV) and porcine reproductive and respiratory syndrome virus (PRRSV). Consequently, the newly developed RT-LAMP method could provide an accurate and reliable tool for PEDV diagnosis.
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Development of a Genetically Engineered Bivalent Vaccine against Porcine Epidemic Diarrhea Virus and Porcine Rotavirus. Viruses 2022; 14:v14081746. [PMID: 36016368 PMCID: PMC9413861 DOI: 10.3390/v14081746] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/06/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) is an enteric coronavirus that causes acute diarrhea, vomiting, dehydration, and a high mortality rate in neonatal piglets. In recent years, PEDV has been associated with co-infections with other swine enteric viruses, including porcine rotavirus (PoRV), resulting in increased mortality among newborn piglets. In this paper, we developed a bivalent vaccine against PEDV and PoRV by constructing a recombinant PEDV encoding PoRV VP7 (rPEDV-PoRV-VP7). The recombinant virus was constructed by replacing the entire open reading frame 3 (ORF3) in the genome of an attenuated PEDV strain YN150 with the PoRV VP7 gene using reverse genetic systems. Similar plaque morphology and replication kinetics were observed in Vero cells with the recombinant PEDV compared to the wild-type PEDV. It is noteworthy that the VP7 protein could be expressed stably in rPEDV-PoRV-VP7-infected cells. To evaluate the immunogenicity and safety of rPEDV-PoRV-VP7, 10-day-old piglets were vaccinated with the recombinant virus. After inoculation, no piglet displayed clinical symptoms such as vomiting, diarrhea, or anorexia. The PoRV VP7- and PEDV spike-specific IgG in serum and IgA in saliva were detected in piglets after rPEDV-PoRV-VP7 vaccination. Moreover, both PoRV and PEDV neutralizing antibodies were produced simultaneously in the inoculated piglets. Collectively, we engineered a recombinant PEDV expressing PoRV VP7 that could be used as an effective bivalent vaccine against PEDV and PoRV.
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Dong S, Yu R, Wang X, Chen B, Si F, Zhou J, Xie C, Li Z, Zhang D. Bis-Benzylisoquinoline Alkaloids Inhibit Porcine Epidemic Diarrhea Virus In Vitro and In Vivo. Viruses 2022; 14:v14061231. [PMID: 35746702 PMCID: PMC9228057 DOI: 10.3390/v14061231] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 02/01/2023] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) belongs to the genus Alphacoronavirus of the family Coronaviridae that causes severe diarrhea and high mortality in neonatal suckling piglets. Currently, there is no effective medication against this pathogen. Cepharanthine (CEP), tetrandrine (TET), and fangchinoline (FAN) are natural bis-benzylisoquinoline alkaloids with anti-inflammatory, antitumor, and antiviral properties. Here, we first found that CEP, TET, and FAN had anti-PEDV activity with IC50 values of 2.53, 3.50, and 6.69 μM, respectively. The compounds could block all the processes of viral cycles, but early application of the compounds before or during virus infection was advantageous over application at a late stage of virus replication. FAN performed inhibitory function more efficiently through interfering with the virus entry and attachment processes or through attenuating the virus directly. CEP had a more notable effect on virus entry. With the highest SI index of 11.8 among the three compounds, CEP was chosen to carry out animal experiments. CEP in a safe dosage of 11.1 mg/kg of body weight could reduce viral load and pathological change of piglet intestinal tracts caused by PEDV field strain challenge, indicating that CEP efficiently inhibited PEDV infection in vivo. All of these results demonstrated that the compounds of bis-benzylisoquinoline alkaloids could inhibit PEDV proliferation efficiently and had the potential of being developed for PED prevention and treatment.
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Affiliation(s)
- Shijuan Dong
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (S.D.); (R.Y.); (B.C.); (F.S.); (C.X.)
| | - Ruisong Yu
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (S.D.); (R.Y.); (B.C.); (F.S.); (C.X.)
| | - Xiaoting Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology (ECUST), Shanghai 200237, China;
| | - Bingqing Chen
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (S.D.); (R.Y.); (B.C.); (F.S.); (C.X.)
| | - Fusheng Si
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (S.D.); (R.Y.); (B.C.); (F.S.); (C.X.)
| | - Jiaming Zhou
- Shanghai Jinshan District Animal Center of Disease Control, Shanghai 201540, China;
| | - Chunfang Xie
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (S.D.); (R.Y.); (B.C.); (F.S.); (C.X.)
| | - Zhen Li
- Institute of Animal Husbandry and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai 201106, China; (S.D.); (R.Y.); (B.C.); (F.S.); (C.X.)
- Correspondence: (Z.L.); (D.Z.); Tel.: +86-21-62206391 (Z.L.); +86-21-64252324 (D.Z.)
| | - Daojing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology (ECUST), Shanghai 200237, China;
- Correspondence: (Z.L.); (D.Z.); Tel.: +86-21-62206391 (Z.L.); +86-21-64252324 (D.Z.)
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12
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Wang W, Peng X, Jin Y, Pan JA, Guo D. Reverse genetics systems for SARS-CoV-2. J Med Virol 2022; 94:3017-3031. [PMID: 35324008 PMCID: PMC9088479 DOI: 10.1002/jmv.27738] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/18/2022] [Indexed: 11/29/2022]
Abstract
The ongoing pandemic of coronavirus disease 2019 (COVID‐19) has caused severe public health crises and heavy economic losses. Limited knowledge about this deadly virus impairs our capacity to set up a toolkit against it. Thus, more studies on severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) biology are urgently needed. Reverse genetics systems, including viral infectious clones and replicons, are powerful platforms for viral research projects, spanning many aspects such as the rescues of wild‐type or mutant viral particles, the investigation of viral replication mechanism, the characterization of viral protein functions, and the studies on viral pathogenesis and antiviral drug development. The operations on viral infectious clones are strictly limited in the Biosafety Level 3 (BSL3) facilities, which are insufficient, especially during the pandemic. In contrast, the operation on the noninfectious replicon can be performed in Biosafety Level 2 (BSL2) facilities, which are widely available. After the outbreak of COVID‐19, many reverse genetics systems for SARS‐CoV‐2, including infectious clones and replicons are developed and given plenty of options for researchers to pick up according to the requirement of their research works. In this review, we summarize the available reverse genetics systems for SARS‐CoV‐2, by highlighting the features of these systems, and provide a quick guide for researchers, especially those without ample experience in operating viral reverse genetics systems.
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Affiliation(s)
- Wenhao Wang
- The Center for Infection and Immunity Study and Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, Guangdong, 518107, China
| | - Xiaoxue Peng
- The Center for Infection and Immunity Study and Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, Guangdong, 518107, China
| | - Yunyun Jin
- The Center for Infection and Immunity Study and Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, Guangdong, 518107, China
| | - Ji-An Pan
- The Center for Infection and Immunity Study and Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, Guangdong, 518107, China
| | - Deyin Guo
- The Center for Infection and Immunity Study and Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, Guangdong, 518107, China
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13
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Zhou Y, Li C, Ren C, Hu J, Song C, Wang X, Li Y. One-Step Assembly of a Porcine Epidemic Diarrhea Virus Infectious cDNA Clone by Homologous Recombination in Yeast: Rapid Manipulation of Viral Genome With CRISPR/Cas9 Gene-Editing Technology. Front Microbiol 2022; 13:787739. [PMID: 35222326 PMCID: PMC8870625 DOI: 10.3389/fmicb.2022.787739] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV), a swine enteric coronavirus causing acute diarrhea in piglets, is one of the major threatens to the pork industry globally. Reverse genetics is a valuable tool for the virological study and vaccine development for coronaviruses. Due to the large size and unstable problem in Escherichia coli of coronavirus genome, construction and manipulation of reverse genetics system for coronaviruses remain laborious and time-consuming. In this study, a reverse genetics system of the genotype II PEDV strain HM was generated using the transformation-associated recombination (TAR) technology in yeast within 1 week. The rescued virus (rPEDV) exhibited similar growth properties to the wild-type virus in vitro. With this PEDV infectious cDNA clone, CRISPR/Cas9 technology and homologous recombination were combined to generate a recombinant virus rPEDV-EGFP in which the ORF3 gene was swapped with an EGFP gene. The reporter virus displayed similar growth properties to the parental virus rPEDV and remained stable during serial passage in vitro. Of note, the strategies of construction and manipulation of PEDV infectious cDNA clone are extremely simple and efficient, which could be applied for other RNA viruses and DNA viruses.
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Affiliation(s)
- Yanyang Zhou
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Chenxi Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou, China
| | - Cicheng Ren
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Jingbo Hu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Changxu Song
- College of Animal Science & National Engineering Center for Swine Breeding Industry, South China Agriculture University, Guangzhou, China
| | - Xinjie Wang
- Guangdong Key Laboratory of Mental Health and Cognitive Science, Center for Studies of Psychological Application, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Yanhua Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Comparative Medicine Research Institute, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou, China
- *Correspondence: Yanhua Li,
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Antiviral Activities of Carbazole Derivatives against Porcine Epidemic Diarrhea Virus In Vitro. Viruses 2021; 13:v13122527. [PMID: 34960796 PMCID: PMC8703851 DOI: 10.3390/v13122527] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/11/2021] [Accepted: 12/12/2021] [Indexed: 11/17/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV), an enteric coronavirus, causes neonatal pig acute gastrointestinal infection with a characterization of severe diarrhea, vomiting, high morbidity, and high mortality, resulting in tremendous damages to the swine industry. Neither specific antiviral drugs nor effective vaccines are available, posing a high priority to screen antiviral drugs. The aim of this study is to investigate anti-PEDV effects of carbazole alkaloid derivatives. Eighteen carbazole derivatives (No.1 to No.18) were synthesized, and No.5, No.7, and No.18 were identified to markedly reduce the replication of enhanced green fluorescent protein (EGFP) inserted-PEDV, and the mRNA level of PEDV N. Flow cytometry assay, coupled with CCK8 assay, confirmed No.7 and No.18 carbazole derivatives displayed high inhibition effects with low cell toxicity. Furthermore, time course analysis indicated No.7 and No.18 carbazole derivatives exerted inhibition at the early stage of the viral life cycle. Collectively, the analysis underlines the benefit of carbazole derivatives as potential inhibitors of PEDV, and provides candidates for the development of novel therapeutic agents.
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15
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Ebob OT, Babiaka SB, Ntie-Kang F. Natural Products as Potential Lead Compounds for Drug Discovery Against SARS-CoV-2. NATURAL PRODUCTS AND BIOPROSPECTING 2021; 11:611-628. [PMID: 34515981 PMCID: PMC8435765 DOI: 10.1007/s13659-021-00317-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/01/2021] [Indexed: 05/09/2023]
Abstract
For the past 2 years, the coronavirus responsible for the COVID-19 infection has become a world pandemic, ruining the lives and economies of several nations in the world. This has scaled up research on the virus and the resulting infection with the goal of developing new vaccines and therapies. Natural products are known to be a rich source of lead compounds for drug discovery, including against infectious diseases caused by microbes (viruses, bacteria and fungi). In this review article, we conducted a literature survey aimed at identifying natural products with inhibitory concentrations against the coronaviruses or their target proteins, which lie below 10 µM. This led to the identification of 42 compounds belonging to the alkaloid, flavonoid, terpenoid, phenolic, xanthone and saponin classes. The cut off concentration of 10 µM was to limit the study to the most potent chemical entities, which could be developed into therapies against the viral infection to make a contribution towards limiting the spread of the disease.
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Affiliation(s)
- Oyere Tanyi Ebob
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Smith B. Babiaka
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Fidele Ntie-Kang
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
- Institute for Pharmacy, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
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16
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Construction of a Recombinant Porcine Epidemic Diarrhea Virus Encoding Nanoluciferase for High-Throughput Screening of Natural Antiviral Products. Viruses 2021; 13:v13091866. [PMID: 34578449 PMCID: PMC8473292 DOI: 10.3390/v13091866] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 02/06/2023] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) is the predominant cause of an acute, highly contagious enteric disease in neonatal piglets. There are currently no approved drugs against PEDV infection. Here, we report the development of a nanoluciferase (NLuc)-based high-throughput screening (HTS) platform to identify novel anti-PEDV compounds. We constructed a full-length cDNA clone for a cell-adapted PEDV strain YN150. Using reverse genetics, we replaced the open reading frame 3 (ORF3) in the viral genome with an NLuc gene to engineer a recombinant PEDV expressing NLuc (rPEDV-NLuc). rPEDV-NLuc produced similar plaque morphology and showed similar growth kinetics compared with the wild-type PEDV in vitro. Remarkably, the level of luciferase activity could be stably detected in rPEDV-NLuc-infected cells and exhibited a strong positive correlation with the viral titers. Given that NLuc expression represents a direct readout of PEDV replication, anti-PEDV compounds could be easily identified by quantifying the NLuc activity. Using this platform, we screened for the anti-PEDV compounds from a library of 803 natural products and identified 25 compounds that could significantly inhibit PEDV replication. Interestingly, 7 of the 25 identified compounds were natural antioxidants, including Betulonic acid, Ursonic acid, esculetin, lithocholic acid, nordihydroguaiaretic acid, caffeic acid phenethyl ester, and grape seed extract. As expected, all of the antioxidants could potently reduce PEDV-induced oxygen species production, which, in turn, inhibit PEDV replication in a dose-dependent manner. Collectively, our findings provide a powerful platform for the rapid screening of promising therapeutic compounds against PEDV infection.
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Dong S, Wang R, Yu R, Chen B, Si F, Xie C, Li Z. Identification of cellular proteins interacting with PEDV M protein through APEX2 labeling. J Proteomics 2021; 240:104191. [PMID: 33757879 PMCID: PMC7980486 DOI: 10.1016/j.jprot.2021.104191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 11/24/2022]
Abstract
Membrane (M) proteins of coronaviruses are the most abundant component of the virus envelope and play crucial roles in virus assembly, virus budding and the regulation of host immunity. To understand more about these functions in the context of PEDV M protein, forty host cell proteins interacting with the M protein were identified in the present study by exploiting the proximity-labeling enzyme APEX2 (a mutant soybean ascorbate peroxidase). Bioinformatic analysis showed that the identified host cell proteins were related to fifty-four signal pathways and a wide diversity of biological processes. Interaction between M and five of the identified proteins (RIG-I, PPID, NHE-RF1, S100A11, CLDN4) was confirmed by co-immunoprecipitation (Co-IP). In addition, knockdown of PPID and S100A11 genes by siRNA significantly improved virus production, indicating that the proteins encoded by the two genes were interfering with or down-regulating virus replication in infected cells. Identification of the host cell proteins accomplished in this study provides new information about the mechanisms underlying PEDV replication and immune evasion. SIGNIFICANCE: PEDV M protein is an essential structural protein implicated in viral infection, replication and assembly although the precise mechanisms underlying these functions remain enigmatic. In this study, we have identified 40 host cell proteins that interact with PEDV M protein using the proximity-labeling enzyme APEX2. Co-immunoprecipitation subsequently confirmed interactions between PEDV M protein and five host cell proteins, two of which (S100A11 and PPID) were involved in down-regulating virus replication in infected cells. This study is significant in that it formulates a strategy to provide new information about the mechanisms relating to the novel functions of PEDV M protein.
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Affiliation(s)
- Shijuan Dong
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China,Shanghai Engineering Research Center of Breeding Pigs, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China
| | - Ruiyang Wang
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China
| | - Ruisong Yu
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China
| | - Bingqing Chen
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China,Shanghai Engineering Research Center of Breeding Pigs, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China
| | - Fusheng Si
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China,Shanghai Engineering Research Center of Breeding Pigs, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China
| | - Chunfang Xie
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China
| | - Zhen Li
- Institute of Animal Science and Veterinary Science, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China; Shanghai Engineering Research Center of Breeding Pigs, Shanghai Academy of Agricultural Sciences (SAAS), Shanghai, PR China.
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18
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Porcine Epidemic Diarrhea Virus ORF3 Protein Is Transported through the Exocytic Pathway. J Virol 2020; 94:JVI.00808-20. [PMID: 32554695 DOI: 10.1128/jvi.00808-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/08/2020] [Indexed: 11/20/2022] Open
Abstract
Accessory genes occurring between the S and E genes of coronaviruses have been studied quite intensively during the last decades. In porcine epidemic diarrhea virus (PEDV), the only gene at this location, ORF3, encodes a 224-residue membrane protein shown to exhibit ion channel activity and to enhance virus production. However, little is known about its intracellular trafficking or about its function during PEDV infection. In this study, two recombinant PEDVs were rescued by targeted RNA recombination, one carrying the full-length ORF3 gene and one from which the gene had been deleted entirely. These viruses as well as a PEDV encoding a naturally truncated ORF3 protein were employed to study the ORF3 protein's subcellular trafficking. In addition, ORF3 expression vectors were constructed to study the protein's independent transport. Our results show that the ORF3 protein uses the exocytic pathway to move to and accumulate in the Golgi area of the cell similarly in infected and transfected cells. Like the S protein, but unlike the other structural proteins M and N, the ORF3 protein was additionally observed at the surface of PEDV-infected cells. In addition, the C-terminally truncated ORF3 protein entered the exocytic pathway but it was unable to leave the endoplasmic reticulum (ER) and ER-to-Golgi intermediate compartment (ERGIC). Consistently, a YxxØ motif essential for ER exit was identified in the C-terminal domain. Finally, despite the use of sensitive antibodies and assays no ORF3 protein could be detected in highly purified PEDV particles, indicating that the protein is not a structural virion component.IMPORTANCE Coronaviruses typically express several accessory proteins. They vary in number and nature, and only one is conserved among most of the coronaviruses, pointing at an important biological function for this protein. PEDV is peculiar in that it expresses just this one accessory protein, termed the ORF3 protein. While its analogs in other coronaviruses have been studied to different extents, and these studies have indicated that they share an ion channel property, little is still known about the features and functions of the PEDV ORF3 protein except for its association with virulence. In this investigation, we studied the intracellular trafficking of the ORF3 protein both in infected cells and when expressed independently. In addition, we analyzed the effects of mutations in five sorting motifs in its C-terminal domain and investigated whether the protein, found to follow the same exocytic route by which the viral structural membrane proteins travel, is also incorporated into virions.
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19
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Lu Y, Su X, Du C, Mo L, Ke P, Wang R, Zhong L, Yang C, Chen Y, Wei Z, Huang W, Liao Y, Ouyang K. Genetic Diversity of Porcine Epidemic Diarrhea Virus With a Naturally Occurring Truncated ORF3 Gene Found in Guangxi, China. Front Vet Sci 2020; 7:435. [PMID: 32793651 PMCID: PMC7393948 DOI: 10.3389/fvets.2020.00435] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 06/16/2020] [Indexed: 11/13/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) is one of the major enteric pathogens, causing severe enteric disease, resulting in enormous economic losses. The ORF3 gene encodes an accessory protein which is related to the infectivity and virulence of PEDV. In this study, 33 PEDV positive field samples were collected from Guangxi, from 2017 to 2019, and the genetic diversity of ORF3 was investigated. Thirty-eight strains of ORF3 were obtained, and these were composed of five strains of ORF3 named Guangxi naturally truncated strains that were 293 bp in length, with continuous deletions from 172 to 554 bp. The Guangxi naturally truncated strains encoded a truncated protein of 89 amino acids, which had clustered into a new group referred to as Group 3, and these might be involved in the variations of virulence. Three genotypes (G1-1 subgroup, G1-3 subgroup, and Group 3) existed simultaneously in Guangxi based on the genetic and evolutionary analysis of the ORF3 gene. The sequence information in the current study will hopefully facilitate the establishment of a diagnostic method that can differentiate the PEDV field stains. Continued surveillance will be useful for monitoring PEDV transmission. Differentiation of the ORF3 genes in PEDV field strains can help us to choose an appropriate PEDV vaccine candidate in the future and prevent outbreaks of PED more effectively.
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Affiliation(s)
- Ying Lu
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Xueli Su
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Chen Du
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Liyuan Mo
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Purui Ke
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Ruomu Wang
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Lian Zhong
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Cui Yang
- Laboratory of Poultry, Guangxi Institute of Animal Science, Nanning, China
| | - Ying Chen
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Zuzhang Wei
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Weijian Huang
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Yuying Liao
- Laboratory of Poultry, Guangxi Institute of Animal Science, Nanning, China
| | - Kang Ouyang
- Laboratory of Animal Infectious Disease and Molecular Immunology, College of Animal Science and Technology, Guangxi University, Nanning, China
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Abstract
Since the end of 2019, the global COVID-19 outbreak has once again made coronaviruses a hot topic. Vaccines are hoped to be an effective way to stop the spread of the virus. However, there are no clinically approved vaccines available for coronavirus infections. Reverse genetics technology can realize the operation of RNA virus genomes at the DNA level and provide new ideas and strategies for the development of new vaccines. In this review, we systematically describe the role of reverse genetics technology in studying the effects of coronavirus proteins on viral virulence and innate immunity, cell and tissue tropism and antiviral drug screening. An efficient reverse genetics platform is useful for obtaining the ideal attenuated strain to prepare an attenuated live vaccine.
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Porcine Epidemic Diarrhea Virus and the Host Innate Immune Response. Pathogens 2020; 9:pathogens9050367. [PMID: 32403318 PMCID: PMC7281546 DOI: 10.3390/pathogens9050367] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 04/27/2020] [Accepted: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV), a swine enteropathogenic coronavirus (CoV), is the causative agent of porcine epidemic diarrhea (PED). PED causes lethal watery diarrhea in piglets, which has led to substantial economic losses in many countries and is a great threat to the global swine industry. Interferons (IFNs) are major cytokines involved in host innate immune defense, which induce the expression of a broad range of antiviral effectors that help host to control and antagonize viral infections. PEDV infection does not elicit a robust IFN response, and some of the mechanisms used by the virus to counteract the host innate immune response have been unraveled. PEDV evades the host innate immune response by two main strategies including: (1) encoding IFN antagonists to disrupt innate immune pathway, and (2) hiding its viral RNA to avoid the exposure of viral RNA to immune sensors. This review highlights the immune evasion mechanisms employed by PEDV, which provides insights for the better understanding of PEDV-host interactions and developing effective vaccines and antivirals against CoVs.
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22
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Malik YS, Singh RK, Yadav MP, Langel SN, Malik YS, Saif LJ. Porcine Coronaviruses. EMERGING AND TRANSBOUNDARY ANIMAL VIRUSES 2020. [PMCID: PMC7123000 DOI: 10.1007/978-981-15-0402-0_4] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhoea virus (PEDV), and porcine deltacoronavirus (PDCoV) are enteropathogenic coronaviruses (CoVs) of swine. TGEV appearance in 1946 preceded identification of PEDV (1971) and PDCoV (2009) that are considered as emerging CoVs. A spike deletion mutant of TGEV associated with respiratory tract infection in piglets appeared in 1984 in pigs in Belgium and was designated porcine respiratory coronavirus (PRCV). PRCV is considered non-pathogenic because the infection is very mild or subclinical. Since PRCV emergence and rapid spread, most pigs have become immune to both PRCV and TGEV, which has significantly reduced the clinical and economic importance of TGEV. In contrast, PDCoV and PEDV are currently expanding their geographic distribution, and there are reports on the circulation of TGEV-PEDV recombinants that cause a disease clinically indistinguishable from that associated with the parent viruses. TGEV, PEDV and PDCoV cause acute gastroenteritis in pigs (most severe in neonatal piglets) and matches in their clinical signs and pathogenesis. Necrosis of the infected intestinal epithelial cells causes villous atrophy and malabsorptive diarrhoea. Profuse diarrhoea frequently combined with vomiting results in dehydration, which can lead to the death of piglets. Strong immune responses following natural infection protect against subsequent homologous challenge; however, these viruses display no cross-protection. Adoption of advance biosecurity measures and effective vaccines control and prevent the occurrence of diseases due to these porcine-associated CoVs. Recombination and reversion to virulence are the risks associated with generally highly effective attenuated vaccines necessitating further research on alternative vaccines to ensure their safe application in the field.
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Affiliation(s)
- Yashpal Singh Malik
- grid.417990.20000 0000 9070 5290Biological Standardization, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh India
| | - Raj Kumar Singh
- grid.417990.20000 0000 9070 5290ICAR-Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh India
| | - Mahendra Pal Yadav
- grid.444573.5ICAR-Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut, Uttar Pradesh India
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Porcine Epidemic Diarrhea Virus (PEDV) ORF3 Enhances Viral Proliferation by Inhibiting Apoptosis of Infected Cells. Viruses 2020; 12:v12020214. [PMID: 32075094 PMCID: PMC7077256 DOI: 10.3390/v12020214] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 02/03/2023] Open
Abstract
The genomes of coronaviruses carry accessory genes known to be associated with viral virulence. The single accessory gene of porcine epidemic diarrhea virus (PEDV), ORF3, is dispensable for virus replication in vitro, while viral mutants carrying ORF3 truncations exhibit an attenuated phenotype of which the underlying mechanism is unknown. Here, we studied the effect of ORF3 deletion on the proliferation of PEDV in Vero cells. To this end, four recombinant porcine epidemic diarrhea viruses (PEDVs) were rescued using targeted RNA recombination, three carrying the full-length ORF3 gene from different PEDV strains, and one from which the ORF3 gene had been deleted entirely. Our results showed that PEDVs with intact or naturally truncated ORF3 replicated to significantly higher titers than PEDV without an ORF3. Further characterization revealed that the extent of apoptosis induced by PEDV infection was significantly lower with the viruses carrying an intact or C-terminally truncated ORF3 than with the virus lacking ORF3, indicating that the ORF3 protein as well as its truncated form interfered with the apoptosis process. Collectively, we conclude that PEDV ORF3 protein promotes virus proliferation by inhibiting cell apoptosis caused by virus infection. Our findings provide important insight into the role of ORF3 protein in the pathogenicity of PEDV.
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Won H, Lee DU, Jang G, Noh YH, Lee SC, Choi HW, Yoon IJ, Yoo HS, Lee C. Generation and protective efficacy of a cold-adapted attenuated genotype 2b porcine epidemic diarrhea virus. J Vet Sci 2019; 20:e32. [PMID: 31364317 PMCID: PMC6669205 DOI: 10.4142/jvs.2019.20.e32] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/29/2019] [Accepted: 05/13/2019] [Indexed: 11/21/2022] Open
Abstract
The recent emergence and re-emergence of porcine epidemic diarrhea virus (PEDV) underscore the urgent need for the development of novel, safe, and effective vaccines against the prevailing strain. In this study, we generated a cold-adapted live attenuated vaccine candidate (Aram-P29-CA) by short-term passage of a virulent PEDV isolate at successively lower temperatures in Vero cells. Whole genome sequencing identified 12 amino acid changes in the cold-adapted strain with no insertions and deletions throughout the genome. Animal inoculation experiments confirmed the attenuated phenotype of Aram-P29-CA virus in the natural host. Pregnant sows were orally administered P29-CA live vaccines two doses at 2-week intervals prior to parturition, and the newborn piglets were challenged with the parental virus. The oral homologous prime-boost vaccination of P29-CA significantly improved the survival rate of the piglets and notably mitigated the severity of diarrhea and PEDV fecal shedding after the challenge. Furthermore, strong antibody responses to PEDV were detected in the sera and colostrum of immunized sows and in the sera of their offspring. These results demonstrated that the cold-adapted attenuated virus can be used as a live vaccine in maternal vaccination strategies to provide durable lactogenic immunity and confer passive protection to litters against PEDV.
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Affiliation(s)
- Hokeun Won
- ChoongAng Vaccine Laboratories, Daejeon 34055, Korea.,Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Dong Uk Lee
- ChoongAng Vaccine Laboratories, Daejeon 34055, Korea
| | - Guehwan Jang
- Animal Virology Laboratory, School of Life Sciences, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea
| | - Yun Hee Noh
- ChoongAng Vaccine Laboratories, Daejeon 34055, Korea
| | | | - Hwan Won Choi
- ChoongAng Vaccine Laboratories, Daejeon 34055, Korea
| | - In Joong Yoon
- ChoongAng Vaccine Laboratories, Daejeon 34055, Korea
| | - Han Sang Yoo
- Department of Infectious Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Changhee Lee
- Animal Virology Laboratory, School of Life Sciences, BK21 plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea.
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25
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Rapid manipulation of the porcine epidemic diarrhea virus genome by CRISPR/Cas9 technology. J Virol Methods 2019; 276:113772. [PMID: 31712093 PMCID: PMC7113866 DOI: 10.1016/j.jviromet.2019.113772] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 11/23/2022]
Abstract
A reverse genetics system for highly virulent PEDV strain AJ1102 was established. A recombinant PEDV was generated using CRISPR/Cas9 technology. Recombinant PEDV can be created within one week using this strategy. Provides an efficient platform for PEDV genome manipulation and vaccine development.
Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic enteric coronavirus causing lethal watery diarrhea in suckling piglets. Reverse genetics is a valuable tool to study the functions of viral genes and to generate vaccine candidates. In this study, a full-length infectious cDNA clone of the highly virulent PEDV strain AJ1102 was assembled in a bacterial artificial chromosome (BAC). The rescued virus (rAJ1102) exhibited similar proliferation characteristics in vitro to the wildtype AJ1102. Using CRISPR/Cas9 technology, a recombinant virus rAJ1102-ΔORF3-EGFP in which the ORF3 gene was replaced with an EGFP gene, was successfully generated, and its proliferation characteristics were compared with the parental rAJ1102. Importantly, it just took one week to construct the recombinant PEDV rAJ1102-ΔORF3-EGFP using this method, providing a more efficient platform for PEDV genome manipulation, which could also be applied to other RNA viruses.
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26
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Hou Y, Wang Q. Emerging Highly Virulent Porcine Epidemic Diarrhea Virus: Molecular Mechanisms of Attenuation and Rational Design of Live Attenuated Vaccines. Int J Mol Sci 2019; 20:E5478. [PMID: 31689903 PMCID: PMC6862049 DOI: 10.3390/ijms20215478] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/23/2019] [Accepted: 10/28/2019] [Indexed: 12/24/2022] Open
Abstract
The highly virulent porcine epidemic diarrhea virus (PEDV) emerged in China in 2010. It infects pigs of all ages, and causes severe diarrhea and high mortality rates in newborn pigs, leading to devastating economic losses in the pork industry worldwide. Effective and safe vaccines against highly virulent PEDV strains are still unavailable, hampering the further prevention, control and eradication of the disease in herds. Vaccination of pregnant sows with live attenuated vaccines (LAVs) is the most effective strategy to induce lactogenic immunity in the sows, which provides A passive protection of suckling piglets against PEDV via the colostrum (beestings, or first milk) and milk. Several LAV candidates have been developed via serially passaging the highly virulent PEDV isolates in non-porcine Vero cells. However, their efficacies in the induction of sufficient protection against virulent PEDV challenge vary in vivo. In this review, we summarize the current knowledge of the virulence-related mutations of PEDV and their potential roles in PEDV attenuation in vivo. With the successful development of reverse genetics systems for PEDV, we also discuss how to use them to generate promising LAV candidates that are safe, effective and genetically stable. This article provides timely insight into the rational design of effective and safe PEDV LAV candidates.
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Affiliation(s)
- Yixuan Hou
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agriculture and Environmental Sciences, Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Wooster, OH 44691, USA.
| | - Qiuhong Wang
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agriculture and Environmental Sciences, Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Wooster, OH 44691, USA.
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27
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Serological Screening for Coronavirus Infections in Cats. Viruses 2019; 11:v11080743. [PMID: 31412572 PMCID: PMC6723642 DOI: 10.3390/v11080743] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 12/21/2022] Open
Abstract
Coronaviruses (CoVs) are widespread among mammals and birds and known for their potential for cross-species transmission. In cats, infections with feline coronaviruses (FCoVs) are common. Several non-feline coronaviruses have been reported to infect feline cells as well as cats after experimental infection, supported by their ability to engage the feline receptor ortholog for cell entry. However, whether cats might become naturally infected with CoVs of other species is unknown. We analyzed coronavirus infections in cats by serological monitoring. In total 137 cat serum samples and 25 FCoV type 1 or type 2-specific antisera were screened for the presence of antibodies against the S1 receptor binding subunit of the CoV spike protein, which is immunogenic and possesses low amino acid sequence identity among coronavirus species. Seventy-eight sera were positive for antibodies that recognized one or more coronavirus S1s whereas 1 serum exclusively reacted with human coronavirus 229E (HCoV-229E) and two sera exclusively reacted with porcine delta coronavirus (PDCoV). We observed antigenic cross-reactivity between S1s of type 1 and type 2 FCoVs, and between FCoV type 1 and porcine epidemic diarrhea virus (PEDV). Domain mapping of antibody epitopes indicated the presence of conserved epitope(s) particularly in the CD domains of S1. The cross-reactivity of FCoV type 1 and PEDV was also observed at the level of virus neutralization. To conclude, we provide the first evidence of antigenic cross-reactivity among S1 proteins of coronaviruses, which should be considered in the development of serological diagnoses. In addition, the potential role of cats in cross-species transmission of coronaviruses cannot be excluded.
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28
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Cho HM, Ha TKQ, Dang LH, Pham HTT, Tran VO, Huh J, An JP, Oh WK. Prenylated Phenolic Compounds from the Leaves of Sabia limoniacea and Their Antiviral Activities against Porcine Epidemic Diarrhea Virus. JOURNAL OF NATURAL PRODUCTS 2019; 82:702-713. [PMID: 30888811 DOI: 10.1021/acs.jnatprod.8b00435] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Porcine epidemic diarrhea virus (PEDV), a serious swine epidemic, has been rampant in Asia since the 1990s. Despite the widespread use of PEDV vaccines, the occurrence of PEDV variants requires the discovery of new substances that inhibit these viruses. During a search for PEDV inhibitory materials from natural sources, seven new sabphenosides (1-7) and a new flavonoid (8), as well as eight known phenolic compounds (9-16), were obtained from the leaves of Sabia limoniacea. The structural determination of the new phenolic derivatives (1-8) was accomplished using comprehensive spectroscopic methods. Their absolute configurations were assigned by a combination of the ECD exciton chirality method following selective reduction and calculation of their ECD spectra. The bioactivities of the isolated compounds were measured based on their abilities to inhibit viral replication of PEDV. Among the test compounds, 15 and 16 exhibited the most promising antiviral activities, with IC50 values of 7.5 ± 0.7 μM and 8.0 ± 2.5 μM against PEDV replication. This study suggests that compounds 15 and 16 could serve as new scaffolds for the treatment of PEDV infection through the inhibition of PEDV replication.
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Affiliation(s)
- Hyo-Moon Cho
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Thi-Kim-Quy Ha
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Lan-Huong Dang
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Ha-Thanh-Tung Pham
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Van-On Tran
- Department of Botany , Hanoi University of Pharmacy , Hanoi , Vietnam
| | - Jungmoo Huh
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Jin-Pyo An
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Won-Keun Oh
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy , Seoul National University , Seoul 08826 , Republic of Korea
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29
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Wang G, Liang R, Liu Z, Shen Z, Shi J, Shi Y, Deng F, Xiao S, Fu ZF, Peng G. The N-Terminal Domain of Spike Protein Is Not the Enteric Tropism Determinant for Transmissible Gastroenteritis Virus in Piglets. Viruses 2019; 11:v11040313. [PMID: 30935078 PMCID: PMC6520731 DOI: 10.3390/v11040313] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/24/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022] Open
Abstract
Transmissible gastroenteritis virus (TGEV) is the etiologic agent of transmissible gastroenteritis in pigs, and the N-terminal domain of TGEV spike protein is generally recognized as both the virulence determinant and enteric tropism determinant. Here, we assembled a full-length infectious cDNA clone of TGEV in a bacterial artificial chromosome. Using a novel approach, the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) systems efficiently and rapidly rescued another recombinant virus with a 224-amino-acid deletion in the N-terminal domain of the TGEV Spike gene (S_NTD224), which is analogous to the N-terminal domain of porcine respiratory coronavirus. S_NTD224 notably affected the TGEV growth kinetics in PK-15 cells but was not essential for recombinant virus survival. In animal experiments with 13 two-day-old piglets, the TGEV recombinant viruses with/without S_NTD224 deletion induced obvious clinical signs and mortality. Together, our results directly demonstrated that S_NTD224 of TGEV mildly influenced TGEV virulence but was not the enteric tropism determinant and provide new insights for the development of a new attenuated vaccine against TGEV. Importantly, the optimized reverse genetics platform used in this study will simplify the construction of mutant infectious clones and help accelerate progress in coronavirus research.
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Affiliation(s)
- Gang Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Rui Liang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Ziwei Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Zhou Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Jiale Shi
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Yuejun Shi
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Feng Deng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Shaobo Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
| | - Zhen F Fu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
- Departments of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| | - Guiqing Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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30
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Koonpaew S, Teeravechyan S, Frantz PN, Chailangkarn T, Jongkaewwattana A. PEDV and PDCoV Pathogenesis: The Interplay Between Host Innate Immune Responses and Porcine Enteric Coronaviruses. Front Vet Sci 2019; 6:34. [PMID: 30854373 PMCID: PMC6395401 DOI: 10.3389/fvets.2019.00034] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 01/28/2019] [Indexed: 12/24/2022] Open
Abstract
Enteropathogenic porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV), members of the coronavirus family, account for the majority of lethal watery diarrhea in neonatal pigs in the past decade. These two viruses pose significant economic and public health burdens, even as both continue to emerge and reemerge worldwide. The ability to evade, circumvent or subvert the host’s first line of defense, namely the innate immune system, is the key determinant for pathogen virulence, survival, and the establishment of successful infection. Unfortunately, we have only started to unravel the underlying viral mechanisms used to manipulate host innate immune responses. In this review, we gather current knowledge concerning the interplay between these viruses and components of host innate immunity, focusing on type I interferon induction and signaling in particular, and the mechanisms by which virus-encoded gene products antagonize and subvert host innate immune responses. Finally, we provide some perspectives on the advantages gained from a better understanding of host-pathogen interactions. This includes their implications for the future development of PEDV and PDCoV vaccines and how we can further our knowledge of the molecular mechanisms underlying virus pathogenesis, virulence, and host coevolution.
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Affiliation(s)
- Surapong Koonpaew
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
| | - Samaporn Teeravechyan
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
| | - Phanramphoei Namprachan Frantz
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
| | - Thanathom Chailangkarn
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
| | - Anan Jongkaewwattana
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
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31
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Ye Y, Zhu J, Ai Q, Wang C, Liao M, Fan H. Quantitative Proteomics Reveals Changes in Vero Cells in Response to Porcine Epidemic Diarrhea Virus. J Proteome Res 2019; 18:1623-1633. [PMID: 30730140 DOI: 10.1021/acs.jproteome.8b00897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Outbreaks of porcine epidemic diarrhea virus (PEDV) have caused significant lethality rates in neonatal piglets, which pose a serious threat to the swine industry worldwide. Available commercial vaccines fail to protect against the emergence of high virulence of PEDV variants. Therefore, the endemic state of the PEDV infection in suckling piglets highlights the urgent need for uncovering the molecular determinants of the disease pathogenesis. In this study, stable isotope labeling by amino acids in cell culture (SILAC), combined with high-performance liquid chromatography/tandem mass spectrometry was performed to determine proteomic differences between PEDV-infected and mock-infected Vero cells at 18 h postinfection. The SILAC-based approach identified 4508 host-cell proteins, of which 120 were significantly up-regulated and 103 were significantly down-regulated at ≥95% confidence. Alterations in the expression of selected proteins were verified by Western blot. Several signaling metabolic pathways including mevalonate pathway I and the superpathway of cholesterol biosynthesis were triggered by the infection of the highly virulent strain and are linked to host innate immunity. 25-HC, an inhibitor of the mevalonate pathway, exhibited potent antiviral activity against PEDV infection. Meanwhile, the cell-cycle-related functions were significantly regulated, which may likely be responsible for the viral replication and pathogenicity of PEDV.
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Affiliation(s)
- Yu Ye
- College of Veterinary Medicine , South China Agricultural University , Guangzhou 510642 , China.,Department of Preventive Veterinary Medicine, College of Animal Science and Technology , Jiangxi Agricultural University , Nanchang 330045 , China
| | - Jun Zhu
- College of Veterinary Medicine , South China Agricultural University , Guangzhou 510642 , China.,National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control , Guangzhou 510642 , China
| | - Qiangyun Ai
- College of Veterinary Medicine , South China Agricultural University , Guangzhou 510642 , China.,Key Laboratory of Animal Vaccine Development , Ministry of Agriculture , Guangzhou 510642 , China.,Key Laboratory of Zoonoses Control and Prevention of Guangdong , Guangzhou 510642 , China
| | - Chengcheng Wang
- College of Veterinary Medicine , South China Agricultural University , Guangzhou 510642 , China.,Key Laboratory of Animal Vaccine Development , Ministry of Agriculture , Guangzhou 510642 , China.,Key Laboratory of Zoonoses Control and Prevention of Guangdong , Guangzhou 510642 , China
| | - Ming Liao
- College of Veterinary Medicine , South China Agricultural University , Guangzhou 510642 , China.,National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control , Guangzhou 510642 , China.,Key Laboratory of Animal Vaccine Development , Ministry of Agriculture , Guangzhou 510642 , China.,Key Laboratory of Zoonoses Control and Prevention of Guangdong , Guangzhou 510642 , China
| | - Huiying Fan
- College of Veterinary Medicine , South China Agricultural University , Guangzhou 510642 , China.,National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control , Guangzhou 510642 , China.,Key Laboratory of Animal Vaccine Development , Ministry of Agriculture , Guangzhou 510642 , China.,Key Laboratory of Zoonoses Control and Prevention of Guangdong , Guangzhou 510642 , China
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32
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Tsai TL, Su CC, Hsieh CC, Lin CN, Chang HW, Lo CY, Lin CH, Wu HY. Gene Variations in Cis-Acting Elements between the Taiwan and Prototype Strains of Porcine Epidemic Diarrhea Virus Alter Viral Gene Expression. Genes (Basel) 2018; 9:E591. [PMID: 30501108 PMCID: PMC6316102 DOI: 10.3390/genes9120591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/20/2018] [Accepted: 11/26/2018] [Indexed: 01/30/2023] Open
Abstract
In 2013, the outbreak of porcine epidemic diarrhea (PED) in Taiwan caused serious economic losses. In this study, we examined whether the variations of the cis-acting elements between the porcine epidemic diarrhea virus (PEDV) Taiwan (TW) strain and the prototype strain CV777 alter gene expression. For this aim, we analyzed the variations of the cis-acting elements in the 5' and 3' untranslated regions (UTRs) between the PEDV TW, CV777, and other reference strains. We also determined the previously unidentified transcription regulatory sequence (TRS), a sequence motif required for coronavirus transcription, and found that a nucleotide deletion in the TW strain, in comparison with CV777 strain, immediately downstream of the leader core sequence alters the identity between the leader TRS and the body TRS. Functional analyses using coronavirus defective interfering (DI) RNA revealed that such variations in cis-acting elements for the TW strain compared with the CV777 strain have an influence on the efficiency of gene expression. The current data show for the first time the evolution of PEDV in terms of cis-acting elements and their effects on gene expression, and thus may contribute to our understanding of recent PED outbreaks worldwide.
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Affiliation(s)
- Tsung-Lin Tsai
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Chen-Chang Su
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Ching-Chi Hsieh
- Division of Chest Medicine, Department of Internal Medicine, Chang Bing Show Chwan Memorial Hospital, Changhua 505, Taiwan.
| | - Chao-Nan Lin
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Neipu, Pingtung 91201, Taiwan.
| | - Hui-Wen Chang
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Chen-Yu Lo
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Ching-Houng Lin
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Hung-Yi Wu
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan.
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33
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Kao CF, Chiou HY, Chang YC, Hsueh CS, Jeng CR, Tsai PS, Cheng IC, Pang VF, Chang HW. The Characterization of Immunoprotection Induced by a cDNA Clone Derived from the Attenuated Taiwan Porcine Epidemic Diarrhea Virus Pintung 52 Strain. Viruses 2018; 10:E543. [PMID: 30287770 PMCID: PMC6213177 DOI: 10.3390/v10100543] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 09/27/2018] [Accepted: 10/02/2018] [Indexed: 12/11/2022] Open
Abstract
The porcine epidemic diarrhea virus (PEDV) poses a great threat to the global swine industries and the unreliable protection induced by the currently available vaccines remains a major challenge. We previously generated a genogroup 2b (G2b) PEDV Taiwan Pintung 52 (PEDVPT) strain, PEDVPT-P96, and determined its promising host immune response against the virulent PEDVPT-P5 strain. To study the attenuation determinants of PEDVPT-P96 and establish a PEDVPT-P96-based recombinant vector as a vaccine platform for further antigenicity modification, iPEDVPT-P96, a full-length cDNA clone of PEDVPT-P96, was established. Comparing to the parental PEDVPT-P96 virus, the iPEDVPT-P96 virus showed efficient replication kinetics with a delayed decline of viral load and similar but much more uniform plaque sizes in Vero cells. In the 5-week-old piglet model, fecal viral shedding was observed in the PEDVPT-P96-inoculated piglets, whereas those inoculated with iPEDVPT-P96 showed neither detectable fecal viral shedding nor PEDV-associated clinical signs. Moreover, inoculation with iPEDVPT-P96 elicited comparable levels of anti-PEDV specific plasma IgG and fecal/salivary IgA, neutralizing antibody titers, and similar but less effective immunoprotection against the virulent PEDVPT-P5 challenge compared to the parental PEDVPT-P96. In the present study, an infectious cDNA clone of an attenuated G2b PEDV strain was successfully generated for the first time, and the in vitro and in vivo data indicate that iPEDVPT-P96 is further attenuated but remains immunogenic compared to its parental PEDVPT-P96 viral stock. The successful development of the iPEDVPT-P96 cDNA clone could allow for the manipulation of the viral genome to study viral pathogenesis and facilitate the rapid development of effective vaccines.
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Affiliation(s)
- Chi-Fei Kao
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Hue-Ying Chiou
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 250 Kuo Kuang Rd, Taichung 402, Taiwan.
| | - Yen-Chen Chang
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Cheng-Shun Hsueh
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Chian-Ren Jeng
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Pei-Shiue Tsai
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Ivan-Chen Cheng
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Victor Fei Pang
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
| | - Hui-Wen Chang
- School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
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The S Gene Is Necessary but Not Sufficient for the Virulence of Porcine Epidemic Diarrhea Virus Novel Variant Strain BJ2011C. J Virol 2018; 92:JVI.00603-18. [PMID: 29695430 DOI: 10.1128/jvi.00603-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 04/17/2018] [Indexed: 01/02/2023] Open
Abstract
The recently emerged highly virulent variants of porcine epidemic diarrhea virus (PEDV) have caused colossal economic losses to the worldwide swine industry. In this study, we investigated the viral virulence determinants by constructing a series of chimeric mutants between the highly virulent strain BJ2011C and the avirulent strain CHM2013. When tested in the 2-day-old piglet model, wild-type (WT) BJ2011C caused severe diarrhea and death of the piglets within 72 h. In contrast, its chimeric derivative carrying the S gene from CHM2013 (BJ2011C-SCHM) was avirulent to the piglets. Moreover, reciprocal substitution of the BJ2011C S gene (CHM2013-SBJ) did not enable CHM2013 to gain any virulence. However, when the whole structural protein-coding region of BJ2011C (CHM2013-SPBJ) was swapped, CHM2013 started to gain the ability to efficiently colonize the intestinal tract and caused diarrhea in piglets. A further gain of virulence required additional acquisition of the 3' untranslated region (UTR) of BJ2011C, and the resultant virus (CHM2013-SP + 3UTRBJ) caused more severe diarrhea and death of piglets. Together, our findings suggest that the virulence of PEDV epidemic strains is a multigenic event and that the S gene is only one of the necessary determinants.IMPORTANCE The recently emerged highly virulent PEDV variants are the major cause of the global porcine epidemic diarrhea (PED) pandemic. The S gene of the variants undergoes remarkable variations and has been thought to be the virulence determinant for the enhanced pathogenesis. Our studies here showed that the S gene is only part of the story and that full virulence requires cooperation from other genes. Our findings provide insight into the pathogenic mechanism of the highly virulent PEDV variants and have implications for future vaccine development.
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Dortmans JCFM, Li W, van der Wolf PJ, Buter GJ, Franssen PJM, van Schaik G, Houben M, Bosch BJ. Porcine epidemic diarrhea virus (PEDV) introduction into a naive Dutch pig population in 2014. Vet Microbiol 2018; 221:13-18. [PMID: 29981699 PMCID: PMC7117506 DOI: 10.1016/j.vetmic.2018.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 12/21/2022]
Abstract
PEDV G1b was not circulating in the Netherlands before November 2014. Description of the first PEDV G1b outbreak in the Netherlands in 2014. PEDV sequences suggests a one event introduction of PEDV G1b in Europe in 2014.
Porcine epidemic diarrhea virus (PEDV) is the highly contagious, causative agent of an economically important acute enteric disease in pigs of all ages. The disease is characterized by diarrhea and dehydration causing mortality and growth retardation. In the last few decades, only classical PEDV was reported sporadically in Europe, but in 2014 outbreaks of PEDV were described in Germany. Phylogenetic analysis showed a very high nucleotide similarity with a variant of PEDV that was isolated in the US in January 2014. The epidemiological situation of PEDV infections in the Netherlands in 2014 was unknown and a seroprevalence study in swine was performed. In total, 838 blood samples from sows from 267 farms and 101 samples from wild boars were collected from May till November 2014 and tested for antibodies against PEDV by ELISA. The apparent herd prevalence of 0.75% suggests that PEDV was not circulating on a large scale in the Netherlands at this time. However, in November 2014 a clinical outbreak of PEDV was diagnosed in a fattener farm by PCR testing. This was the first confirmed PEDV outbreak since the early nineties. Sequence analyses showed that the viruses isolated in 2014 and 2015 in the Netherlands cluster with recently found European G1b strains. This suggests a one event introduction of PEDV G1b strains in Europe in 2014, which made the Netherlands and other European countries endemic for this type of strains since then.
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Affiliation(s)
| | - W Li
- Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - P J van der Wolf
- GD Animal Health, 7400 AA, Deventer, The Netherlands; Present address: IDT-Biologika Benelux, Breda, The Netherlands
| | - G J Buter
- GD Animal Health, 7400 AA, Deventer, The Netherlands
| | | | - G van Schaik
- GD Animal Health, 7400 AA, Deventer, The Netherlands; Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - M Houben
- GD Animal Health, 7400 AA, Deventer, The Netherlands
| | - B J Bosch
- Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Sun M, Ma J, Yu Z, Pan Z, Lu C, Yao H. Identification of two mutation sites in spike and envelope proteins mediating optimal cellular infection of porcine epidemic diarrhea virus from different pathways. Vet Res 2017; 48:44. [PMID: 28854955 PMCID: PMC5577753 DOI: 10.1186/s13567-017-0449-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/31/2017] [Indexed: 01/31/2023] Open
Abstract
Entry of the α-coronavirus porcine epidemic diarrhea virus (PEDV) requires specific proteases to activate spike (S) protein for the membrane fusion of the virion to the host cell following receptor binding. Herein, PEDV isolate 85-7 could proliferate and induce cell-cell fusion in a trypsin independent manner on Vero cells, and eight homologous mutation strains were screened by continuous proliferation in the absence of trypsin on Vero cells. According to the whole genome sequence comparative analysis, we identified four major variations located in nonstructural protein 2, S, open reading frame 3, and envelope (E) genes, respectively. Comparative analyses of their genomic variations and proliferation characteristics identified a single mutation within the S2' cleavage site between C30 and C40 mutants: the substitution of conserved arginine (R) by a glycine (G) (R895G). This change resulted in weaker cell-cell fusion, smaller plaque morphology, higher virus titer and serious microfilament condensation. Further analysis confirmed that this mutation was responsible for optimal cell-adaptation, but not the determinant for trypsin-dependent entry of PEDV. Otherwise, a novel variation (16-20 aa deletion and an L25P mutation) in the transmembrane domain of the E protein affected multiple infection processes, including up-regulation of the production of the ER stress indicator GRP78, improving the expression of pro-inflammatory cytokines IL-6 and IL-8, and promoting apoptosis. The results of this study provide a better understanding of the potential mechanisms of viral functional proteins in PEDV replication, infection, and fitness.
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Affiliation(s)
- Min Sun
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jiale Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Zeyanqiu Yu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Zihao Pan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Chengping Lu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Huochun Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China.
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Kim JW, Ha TKQ, Cho H, Kim E, Shim SH, Yang JL, Oh WK. Antiviral escin derivatives from the seeds of Aesculus turbinata Blume (Japanese horse chestnut). Bioorg Med Chem Lett 2017; 27:3019-3025. [PMID: 28527823 PMCID: PMC7127610 DOI: 10.1016/j.bmcl.2017.05.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/04/2017] [Accepted: 05/06/2017] [Indexed: 01/22/2023]
Abstract
Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and high fatality of piglets, influencing the swine industry. Japanese horse chestnut (seed of Aesculus turbinata) contains many saponin mixtures, called escins, and has been used for a long time as a traditional medicinal plant. Structure-activity relationship (SAR) studies on escins have revealed that acylations at C-21 and C-22 with angeloyl or tigloyl groups were important for their cytotoxic effects. However, the strong cytotoxicity of escins makes them hard to utilize for other diseases and to develop as nutraceuticals. In this research, we investigated whether escin derivatives 1-7 (including new compounds 2, 3, 5 and 6), without the angeloyl or tigloyl groups and with modified glycosidic linkages by hydrolysis, have PEDV inhibitory effects with less cytotoxicity. Compounds 1-7 had no cytotoxicity at 20μM on VERO cells, while compounds 8-10 showed strong cytotoxicity at similar concentrations on PEDV. Our results suggest that escin derivatives showed strong inhibitory activities on PEDV replication with lowered cytotoxicity. These studies propose a method to utilize Japanese horse chestnut for treating PEDV and to increase the diversity of its bioactive compounds.
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Affiliation(s)
- Ji Won Kim
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Thi-Kim-Quy Ha
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Hyomoon Cho
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
| | - Eunhee Kim
- Choong Ang Vaccine Laboratory, 59-3 Hwaam-dong, Yuseong-gu, Daejeon 305-348, Republic of Korea
| | - Sang Hee Shim
- College of Pharmacy, Duksung Women's University, Seoul, Republic of Korea
| | - Jun-Li Yang
- Key Laboratory of Chemistry of Northwestern Plant Resources of CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China
| | - Won Keun Oh
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea.
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Lee S, Son KY, Noh YH, Lee SC, Choi HW, Yoon IJ, Lee C. Genetic characteristics, pathogenicity, and immunogenicity associated with cell adaptation of a virulent genotype 2b porcine epidemic diarrhea virus. Vet Microbiol 2017; 207:248-258. [PMID: 28757031 PMCID: PMC7172462 DOI: 10.1016/j.vetmic.2017.06.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 01/31/2023]
Abstract
A virulent G2b PEDV strain KNU-141112 was subjected to Vero cell culture passage. Deletions (DEL) in S and ORF3 of KNU-141112 at high passage levels were identified. Cell-adapted KNU-141112 DEL strains were highly attenuated and immunogenic in pigs. Large deletions in ORF3 appear to be associated with PEDV attenuation in pigs. High-cell-passage KNU-141112 DEL strains can be live, attenuated vaccine candidates.
Porcine epidemic diarrhea virus (PEDV) has emerged or re-emerged worldwide, posing a significant financial threat to major pig-producing countries. In the present study, a virulent Korean pandemic PEDV strain, KNU-141112, was serially propagated in Vero cells for up to 100 passages. Through cell culture adaptation, we obtained four distinct deletion (DEL) mutants by plaque purification followed by nucleotide sequencing of the spike (S)/ORF3 gene-coding region, which were designated KNU-141112-S DEL2, −S DEL5, −S DEL2/ORF3, and −S DEL5/ORF3. Further whole genome sequencing identified 12 or 14 amino acid changes in the cell-adapted DEL strains. Animal inoculation studies revealed that the virulence of both S DEL2/ORF3 and S DEL5/ORF3 viruses with a large 46-nt deletion in the intergenic portion of S and ORF3 was remarkably diminished, indicating viral attenuation in the natural host. Furthermore, these cell-adapted strains elicited potent neutralizing antibody responses in immunized pigs. Taken together, our data indicate that the cell-attenuated S DEL2/ORF3 and S DEL5/ORF3 strains are promising candidates for the development of a safe and effective live PEDV vaccine.
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Affiliation(s)
- Sunhee Lee
- Animal Virology Laboratory, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Kyu-Yeol Son
- Choongang Vaccine Laboratory, Daejeon 34055, Republic of Korea
| | - Yun-Hee Noh
- Choongang Vaccine Laboratory, Daejeon 34055, Republic of Korea
| | - Seung-Chul Lee
- Choongang Vaccine Laboratory, Daejeon 34055, Republic of Korea
| | - Hwan-Won Choi
- Choongang Vaccine Laboratory, Daejeon 34055, Republic of Korea
| | - In-Joong Yoon
- Choongang Vaccine Laboratory, Daejeon 34055, Republic of Korea
| | - Changhee Lee
- Animal Virology Laboratory, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea.
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Deletion of a 197-Amino-Acid Region in the N-Terminal Domain of Spike Protein Attenuates Porcine Epidemic Diarrhea Virus in Piglets. J Virol 2017; 91:JVI.00227-17. [PMID: 28490591 DOI: 10.1128/jvi.00227-17] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/26/2017] [Indexed: 02/06/2023] Open
Abstract
We previously isolated a porcine epidemic diarrhea virus (PEDV) strain, PC177, by blind serial passaging of the intestinal contents of a diarrheic piglet in Vero cell culture. Compared with the highly virulent U.S. PEDV strain PC21A, the tissue culture-adapted PC177 (TC-PC177) contains a 197-amino-acid (aa) deletion in the N-terminal domain of the spike (S) protein. We orally inoculated neonatal, conventional suckling piglets with TC-PC177 or PC21A to compare their pathogenicities. Within 7 days postinoculation, TC-PC177 caused mild diarrhea and lower fecal viral RNA shedding, with no mortality, whereas PC21A caused severe clinical signs and 55% mortality. To investigate whether infection with TC-PC177 can induce cross-protection against challenge with a highly virulent PEDV strain, all the surviving piglets were challenged with PC21A at 3 weeks postinoculation. Compared with 100% protection in piglets initially inoculated with PC21A, 88% and 100% TC-PC177- and mock-inoculated piglets had diarrhea following challenge, respectively, indicating incomplete cross-protection. To investigate whether this 197-aa deletion was the determinant for the attenuation of TC-PC177, we generated a mutant (icPC22A-S1Δ197) bearing the 197-aa deletion from an infectious cDNA clone of the highly virulent PEDV PC22A strain (infectious clone PC22A, icPC22A). In neonatal gnotobiotic pigs, the icPC22A-S1Δ197 virus caused mild to moderate diarrhea, lower titers of viral shedding, and no mortality, whereas the icPC22A virus caused severe diarrhea and 100% mortality. Our data indicate that deletion of this 197-aa fragment in the spike protein can attenuate a highly virulent PEDV, but the virus may lose important epitopes for inducing robust protective immunity.IMPORTANCE The emerging, highly virulent PEDV strains have caused substantial economic losses worldwide. However, the virulence determinants are not established. In this study, we found that a 197-aa deletion in the N-terminal region of the S protein did not alter virus (TC-PC177) tissue tropism but reduced the virulence of the highly virulent PEDV strain PC22A in neonatal piglets. We also demonstrated that the primary infection with TC-PC177 failed to induce complete cross-protection against challenge by the highly virulent PEDV PC21A, suggesting that the 197-aa region may contain important epitopes for inducing protective immunity. Our results provide an insight into the role of this large deletion in virus propagation and pathogenicity. In addition, the reverse genetics platform of the PC22A strain was further optimized for the rescue of recombinant PEDV viruses in vitro This breakthrough allows us to investigate other virulence determinants of PEDV strains and will provide knowledge leading to better control PEDV infections.
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van Beurden SJ, Berends AJ, Krämer-Kühl A, Spekreijse D, Chénard G, Philipp HC, Mundt E, Rottier PJM, Verheije MH. A reverse genetics system for avian coronavirus infectious bronchitis virus based on targeted RNA recombination. Virol J 2017; 14:109. [PMID: 28606144 PMCID: PMC5468965 DOI: 10.1186/s12985-017-0775-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 06/01/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Avian coronavirus infectious bronchitis virus (IBV) is a respiratory pathogen of chickens that causes severe economic losses in the poultry industry worldwide. Major advances in the study of the molecular biology of IBV have resulted from the development of reverse genetics systems for the highly attenuated, cell culture-adapted, IBV strain Beaudette. However, most IBV strains, amongst them virulent field isolates, can only be propagated in embryonated chicken eggs, and not in continuous cell lines. METHODS We established a reverse genetics system for the IBV strain H52, based on targeted RNA recombination in a two-step process. First, a genomic and a chimeric synthetic, modified IBV RNA were co-transfected into non-susceptible cells to generate a recombinant chimeric murinized (m) IBV intermediate (mIBV). Herein, the genomic part coding for the spike glycoprotein ectodomain was replaced by that of the coronavirus mouse hepatitis virus (MHV), allowing for the selection and propagation of recombinant mIBV in murine cells. In the second step, mIBV was used as the recipient. To this end a recombination with synthetic RNA comprising the 3'-end of the IBV genome was performed by introducing the complete IBV spike gene, allowing for the rescue and selection of candidate recombinants in embryonated chicken eggs. RESULTS Targeted RNA recombination allowed for the modification of the 3'-end of the IBV genome, encoding all structural and accessory genes. A wild-type recombinant IBV was constructed, containing several synonymous marker mutations. The in ovo growth kinetics and in vivo characteristics of the recombinant virus were similar to those of the parental IBV strain H52. CONCLUSIONS Targeted RNA recombination allows for the generation of recombinant IBV strains that are not able to infect and propagate in continuous cell lines. The ability to introduce specific mutations holds promise for the development of rationally designed live-attenuated IBV vaccines and for studies into the biology of IBV in general.
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Affiliation(s)
- Steven J van Beurden
- Faculty of Veterinary Medicine, Department of Pathobiology, Utrecht University, Yalelaan 1, 3584 CL, Utrecht, The Netherlands
| | - Alinda J Berends
- Faculty of Veterinary Medicine, Department of Pathobiology, Utrecht University, Yalelaan 1, 3584 CL, Utrecht, The Netherlands
| | - Annika Krämer-Kühl
- Boehringer Ingelheim Veterinary Research Center GmbH & Co. KG, Bemeroder Str. 31, 30559, Hannover, Germany
| | - Dieuwertje Spekreijse
- Boehringer Ingelheim Animal Health Operations, C.J. van Houtenlaan 36, 1381 CP, Weesp, The Netherlands
| | - Gilles Chénard
- Boehringer Ingelheim Animal Health Operations, C.J. van Houtenlaan 36, 1381 CP, Weesp, The Netherlands
| | - Hans-Christian Philipp
- Boehringer Ingelheim Veterinary Research Center GmbH & Co. KG, Bemeroder Str. 31, 30559, Hannover, Germany
| | - Egbert Mundt
- Boehringer Ingelheim Veterinary Research Center GmbH & Co. KG, Bemeroder Str. 31, 30559, Hannover, Germany
| | - Peter J M Rottier
- Faculty of Veterinary Medicine, Department of Pathobiology, Utrecht University, Yalelaan 1, 3584 CL, Utrecht, The Netherlands
| | - M Hélène Verheije
- Faculty of Veterinary Medicine, Department of Pathobiology, Utrecht University, Yalelaan 1, 3584 CL, Utrecht, The Netherlands.
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Wongthida P, Liwnaree B, Wanasen N, Narkpuk J, Jongkaewwattana A. The role of ORF3 accessory protein in replication of cell-adapted porcine epidemic diarrhea virus (PEDV). Arch Virol 2017; 162:2553-2563. [PMID: 28474223 DOI: 10.1007/s00705-017-3390-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/19/2017] [Indexed: 12/01/2022]
Abstract
The ORF3 accessory protein has been shown to impede reverse genetics of cell-culture-adapted porcine epidemic diarrhea virus (PEDV). Its absence or truncated variants are also associated with viral attenuation in vivo. Here, three ORF3 variants (ORF3NP12, ORF3NP14 and ORF3RB14) and their truncated counterparts were investigated for their regulatory role in recovery of cell-adapted PEDV in vitro. We demonstrate that ORF3NP12, but not the truncated form, can inhibit recovery of reverse-genetics-derived PEDV when expressed in trans. When testing with other RNA viruses, ORF3 was found to inhibit rescue of porcine respiratory and reproductive syndrome virus (PRRSV), but not of influenza virus. Interestingly, results from mutagenesis of ORF3NP12 suggest that F81 and M167 are responsible for impairing PEDV rescue in vitro. By changing specific residues of ORF3, the recombinant PEDV bearing the modified ORF3NP12 can be productively propagated in VeroE6-APN cells. These results may provide mechanistic insights into ORF3-mediated inhibition of PEDV replication in new host cells.
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Affiliation(s)
- Phonphimon Wongthida
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin Rd., Klong Nueng, Klong Luang, Pathum Thani, 12120, Thailand
| | - Benjamas Liwnaree
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin Rd., Klong Nueng, Klong Luang, Pathum Thani, 12120, Thailand
| | - Nanchaya Wanasen
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin Rd., Klong Nueng, Klong Luang, Pathum Thani, 12120, Thailand
| | - Jaraspim Narkpuk
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin Rd., Klong Nueng, Klong Luang, Pathum Thani, 12120, Thailand
| | - Anan Jongkaewwattana
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Phahonyothin Rd., Klong Nueng, Klong Luang, Pathum Thani, 12120, Thailand.
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Li W, Luo R, He Q, van Kuppeveld FJM, Rottier PJM, Bosch BJ. Aminopeptidase N is not required for porcine epidemic diarrhea virus cell entry. Virus Res 2017; 235:6-13. [PMID: 28363778 PMCID: PMC7114539 DOI: 10.1016/j.virusres.2017.03.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 12/14/2022]
Abstract
Overexpression of porcine APN in cells does not confer susceptibility to PEDV. Knockout APN expression in PEDV-susceptible cells has no effect on PEDV infection. Results demonstrate that APN is not essential for PEDV cell entry.
Porcine epidemic diarrhea virus (PEDV) is an emerging pathogenic coronavirus that causes a significant economic burden to the swine industry. The virus infects the intestinal epithelium and causes villous atrophy, resulting in diarrhea and dehydration. Interaction of the viral spike (S) surface glycoprotein − through its S1 subunit − with the host cell receptor is the first step in infection and the main determinant for virus tropism. As for several other alphacoronaviruses including the porcine transmissible gastroenteritis virus (TGEV) and the human coronavirus 229E (HCoV-229E), the aminopeptidase N (APN) protein was reported to be a functional receptor for PEDV. In this study we examined the role of APN as a receptor. We show that overexpression of porcine APN renders MDCK cells susceptible to TGEV, but not to PEDV. Consistently, unlike TGEV-S1, PEDV-S1 exhibited no binding to cell-surface expressed APN or to a soluble version of APN. Moreover, preincubation of these viruses with soluble APN or pretreatment of APN expressing ST cells with soluble TGEV-S1 blocked TGEV infection, but had no effect on infection by PEDV. The combined observations indicated that APN is not required for PEDV infection. To definitively prove this conclusion, we applied CRISPR/Cas9 genome engineering to knock out APN expression in PEDV-susceptible porcine (ST) and human cell lines (Huh7 and HeLa). As a consequence these cells no longer bound TGEV-S1 and HCoV-229E-S1 at their surface and were resistant to infection by the corresponding viruses. However, genetic ablation of APN expression had no effect on their infectability by PEDV, demonstrating that APN is not essential for PEDV cell entry.
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Affiliation(s)
- Wentao Li
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Rui Luo
- State Key laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - Qigai He
- State Key laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Peter J M Rottier
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Berend-Jan Bosch
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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Development of the full-length cDNA clones of two porcine epidemic diarrhea disease virus isolates with different virulence. PLoS One 2017; 12:e0173998. [PMID: 28301551 PMCID: PMC5354467 DOI: 10.1371/journal.pone.0173998] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/01/2017] [Indexed: 11/28/2022] Open
Abstract
The recently emerged highly virulent variants of porcine epidemic and diarrhea virus (PEDV) remain a huge threat to the worldwide swine industry. Here, we describe the development of a bacterial artificial chromosome (BAC) reverse genetics system for PEDV based on two recent Chinese field isolates, namely CHM2013 and BJ2011C. Phylogenetically, CHM2013 is closely related to the vaccine strain SM98 whereas the isolate BJ2011C belongs to the GIIb group, a cluster that contains many recent pandemic strains. The full-length cDNA clones of the two isolates were constructed into BAC under the control of CMV promoter. The rescued viruses rBJ2011C and rCHM2013 were found to replicate at the kinetics similar to their respective parental viruses in cell culture. When tested in the 2-day-old pig model, rBJ2011C caused severe diarrhea of piglets with extensive damages to the intestinal epithelium, leading to 100% fatality within 48 hours. In contrast, the rCHM2013-inoculated piglets all survived with only very minor tissue damage observed. Thus, we have successfully established a convenient platform for PEDV genome manipulation. This study also represents the first description of a DNA-launched reverse genetics system for the highly virulent PEDV.
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Novel Porcine Epidemic Diarrhea Virus (PEDV) Variants with Large Deletions in the Spike (S) Gene Coexist with PEDV Strains Possessing an Intact S Gene in Domestic Pigs in Japan: A New Disease Situation. PLoS One 2017; 12:e0170126. [PMID: 28095455 PMCID: PMC5241010 DOI: 10.1371/journal.pone.0170126] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/29/2016] [Indexed: 11/19/2022] Open
Abstract
Since late 2013, after an absence of seven years, outbreaks of porcine epidemic diarrhea virus (PEDV) infection have reemerged and swept rapidly across Japan, resulting in significant economic losses. In this study, we report the emergence, mixed infection, and genetic characterization of 15 novel field PEDV variants with large genomic deletions. The sizes of deletion varied between 582 nt (194 aa) and 648 nt (216 aa) at positions 28-714 (10-238) on the S gene (protein). Among 17 PEDV samples isolated from individual pigs, all of them contained at least two distinct genotypes with large genomic deletions, and 94.1% of them were found to consist of strains with an intact S gene. These variants were found in eight primary and nine recurrent outbreaks, and they might be associated with persistent PEDV infection in the farms. Full-length S and ORF3 genes of eight variants derived from 2 samples were characterized. This is the first report of mixed infections caused by various genotypes of PEDV and would be important for the studies of viral isolation, pathogenesis, and molecular epidemiology of the disease.
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Teeravechyan S, Frantz PN, Wongthida P, Chailangkarn T, Jaru-Ampornpan P, Koonpaew S, Jongkaewwattana A. Deciphering the biology of porcine epidemic diarrhea virus in the era of reverse genetics. Virus Res 2016; 226:152-171. [PMID: 27212685 PMCID: PMC7114553 DOI: 10.1016/j.virusres.2016.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/04/2016] [Accepted: 05/04/2016] [Indexed: 01/01/2023]
Abstract
Emergence of the porcine epidemic diarrhea virus (PEDV) as a global threat to the swine industry underlies the urgent need for deeper understanding of this virus. To date, we have yet to identify functions for all the major gene products, much less grasp their implications for the viral life cycle and pathogenic mechanisms. A major reason is the lack of genetic tools for studying PEDV. In this review, we discuss the reverse genetics approaches that have been successfully used to engineer infectious clones of PEDV as well as other potential and complementary methods that have yet to be applied to PEDV. The importance of proper cell culture for successful PEDV propagation and maintenance of disease phenotype are addressed in our survey of permissive cell lines. We also highlight areas of particular relevance to PEDV pathogenesis and disease that have benefited from reverse genetics studies and pressing questions that await resolution by such studies. In particular, we examine the spike protein as a determinant of viral tropism, entry and virulence, ORF3 and its association with cell culture adaptation, and the nucleocapsid protein and its potential role in modulating PEDV pathogenicity. Finally, we conclude with an exploration of how reverse genetics can help mitigate the global impact of PEDV by addressing the challenges of vaccine development.
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Affiliation(s)
- Samaporn Teeravechyan
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand
| | - Phanramphoei Namprachan Frantz
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand
| | - Phonphimon Wongthida
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand
| | - Thanathom Chailangkarn
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand
| | - Peera Jaru-Ampornpan
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand
| | - Surapong Koonpaew
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand
| | - Anan Jongkaewwattana
- Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120 Thailand.
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Characterization of a pathogenic full-length cDNA clone of a virulent porcine epidemic diarrhea virus strain AH2012/12 in China. Virology 2016; 500:50-61. [PMID: 27770703 PMCID: PMC7111662 DOI: 10.1016/j.virol.2016.10.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/01/2016] [Accepted: 10/12/2016] [Indexed: 12/17/2022]
Abstract
Since 2010, outbreaks of variant porcine epidemic diarrhea virus (PEDV) have swept across the world causing substantial economic losses. The development of new, more effective vaccines has been hampered by difficulties in isolating strains and viral genome manipulation. In the present study, we successfully isolated a highly pathogenic field strain AH2012/12, from a pig farm reporting severe diarrhea in China. Phylogenetic analysis revealed that the new isolate belongs to group G2, which represents epidemic and pandemic field strains. Furthermore, we constructed an infectious cDNA clone of the newly isolated strain, rAH2012/12, and the rescued virus displayed phenotypic properties identical to the parental virus in vitro. In vivo experiments demonstrated that the rescued virus displayed similar pathogenicity to the parental isolate, causing high mortality rates in suckling pigs. This study provided a strong basis for the development of live attenuated vaccines and for research into the pathogenic mechanisms of this virus. We successfully isolated one epidemic PEDV strain AH2012/12 with high virulent in newborn pigs. We firstly generated the infectious cDNA clone of the virulent PEDV strain AH2012/12 in China. The rescued virus has similar biological characteristics with the parent virus in vitro and vivo.
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Li W, van Kuppeveld FJM, He Q, Rottier PJM, Bosch BJ. Cellular entry of the porcine epidemic diarrhea virus. Virus Res 2016; 226:117-127. [PMID: 27317167 PMCID: PMC7114534 DOI: 10.1016/j.virusres.2016.05.031] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/20/2016] [Accepted: 05/20/2016] [Indexed: 01/09/2023]
Abstract
An overview of the interactions of PEDV and its target cells during the initial stage of infection. A description of the multidomain structure of the spike (S) protein. A summary of observations on aminopeptidase N as the PEDV protein receptor. An overview with new data on the significance of the N-terminal S domain in sialic acid binding. A summary of the requirements for proteolytic activation of the fusion function of the S protein.
Porcine epidemic diarrhea virus (PEDV), a coronavirus discovered more than 40 years ago, regained notoriety recently by its devastating outbreaks in East Asia and the Americas, causing substantial economic losses to the swine husbandry. The virus replicates extensively and almost exclusively in the epithelial cells of the small intestine resulting in villus atrophy, malabsorption and severe diarrhea. Cellular entry of this enveloped virus is mediated by the large spike (S) glycoprotein, trimers of which mediate virus attachment to the target cell and subsequent membrane fusion. The S protein has a multidomain architecture and has been reported to bind to carbohydrate (sialic acid) and proteinaceous (aminopeptidase N) cell surface molecules. PEDV propagation in vitro requires the presence of trypsin(-like) proteases in the culture medium, which capacitates the fusion function of the S protein. Here we review the current data on PEDV entry into its host cell, including therein our new observations regarding the functional role of the sialic acid binding activity of the S protein in virus infection. Moreover, we summarize the recent progress on the proteolytic activation of PEDV S proteins, and discuss factors that may determine tissue tropism of PEDV in vivo.
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Affiliation(s)
- Wentao Li
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Qigai He
- State Key laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei province, China
| | - Peter J M Rottier
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Berend-Jan Bosch
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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Zhang Q, Yoo D. Immune evasion of porcine enteric coronaviruses and viral modulation of antiviral innate signaling. Virus Res 2016; 226:128-141. [PMID: 27212682 PMCID: PMC7111337 DOI: 10.1016/j.virusres.2016.05.015] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 12/15/2022]
Abstract
Enteric coronaviruses have evolved to modulate the host innate immunity. Viral IFN antagonists have been identified and they are mostly redundant. For protection of intestinal epithelia from enteric viruses, type III IFN plays a major role.
Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) are emerged and reemerging viruses in pigs, and together with transmissible gastroenteritis virus (TGEV), pose significant economic concerns to the swine industry. These viruses infect epithelial cells of the small intestine and cause watery diarrhea, dehydration, and a high mortality in neonatal piglets. Type I interferons (IFN-α/β) are major antiviral cytokines forming host innate immunity, and in turn, these enteric coronaviruses have evolved to modulate the host innate immune signaling during infection. Accumulating evidence however suggests that IFN induction and signaling in the intestinal epithelial cells differ from other epithelial cells, largely due to distinct features of the gut epithelial mucosal surface and commensal microflora, and it appears that type III interferon (IFN-λ) plays a key role to maintain the antiviral state in the gut. This review describes the recent understanding on the immune evasion strategies of porcine enteric coronaviruses and the role of different types of IFNs for intestinal antiviral innate immunity.
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Affiliation(s)
- Qingzhan Zhang
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana IL, United States
| | - Dongwan Yoo
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana IL, United States.
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Zhang Q, Shi K, Yoo D. Suppression of type I interferon production by porcine epidemic diarrhea virus and degradation of CREB-binding protein by nsp1. Virology 2016; 489:252-68. [PMID: 26773386 PMCID: PMC7111358 DOI: 10.1016/j.virol.2015.12.010] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 10/20/2015] [Accepted: 12/19/2015] [Indexed: 12/25/2022]
Abstract
Type I interferons (IFN-α/β) are the major components of the innate immune response of hosts, and in turn many viruses have evolved to modulate the host response during infection. We found that the IFN-β production was significantly suppressed during PEDV infection in cells. To identify viral IFN antagonists and to study their suppressive function, viral coding sequences for the entire structural and nonstructural proteins were cloned and expressed. Of 16 PEDV nonstructural proteins (nsps), nsp1, nsp3, nsp7, nsp14, nsp15 and nsp16 were found to inhibit the IFN-β and IRF3 promoter activities. The sole accessory protein ORF3, structure protein envelope (E), membrane (M), and nucleocapsid (N) protein were also shown to inhibit such activities. PEDV nsp1 did not interfere the IRF3 phosphorylation and nuclear translocation but interrupted the enhanceosome assembly of IRF3 and CREB-binding protein (CBP) by degrading CBP. A further study showed that the CBP degradation by nsp1 was proteasome-dependent. Our data demonstrate that PEDV modulates the host innate immune responses by degrading CBP and suppressing ISGs expression.
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Affiliation(s)
- Qingzhan Zhang
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana 61802, IL, USA
| | - Kaichuang Shi
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana 61802, IL, USA
| | - Dongwan Yoo
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana 61802, IL, USA.
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Beall A, Yount B, Lin CM, Hou Y, Wang Q, Saif L, Baric R. Characterization of a Pathogenic Full-Length cDNA Clone and Transmission Model for Porcine Epidemic Diarrhea Virus Strain PC22A. mBio 2016; 7:e01451-15. [PMID: 26733065 PMCID: PMC4724997 DOI: 10.1128/mbio.01451-15] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 11/10/2015] [Indexed: 01/18/2023] Open
Abstract
UNLABELLED Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic alphacoronavirus. In the United States, highly virulent PEDV strains cause between 80 and 100% mortality in suckling piglets and are rapidly transmitted between animals and farms. To study the genetic factors that regulate pathogenesis and transmission, we developed a molecular clone of PEDV strain PC22A. The infectious-clone-derived PEDV (icPEDV) replicated as efficiently as the parental virus in cell culture and in pigs, resulting in lethal disease in vivo. Importantly, recombinant PEDV was rapidly transmitted to uninoculated pigs via indirect contact, demonstrating virulence and efficient transmission while replicating phenotypes seen in the wild-type virus. Using reverse genetics, we removed open reading frame 3 (ORF3) and replaced this region with a red fluorescent protein (RFP) gene to generate icPEDV-ΔORF3-RFP. icPEDV-ΔORF3-RFP replicated efficiently in vitro and in vivo, was efficiently transmitted among pigs, and produced lethal disease outcomes. However, the diarrheic scores in icPEDV-ΔORF3-RFP-infected pigs were lower than those in wild-type-virus- or icPEDV-infected pigs, and the virus formed smaller plaques than those of PC22A. Together, these data describe the development of a robust reverse-genetics platform for identifying genetic factors that regulate pathogenic outcomes and transmission efficiency in vivo, providing key infrastructural developments for developing and evaluating the efficacy of live attenuated vaccines and therapeutics in a clinical setting. IMPORTANCE Porcine epidemic diarrhea virus (PEDV) emerged in the United States in 2013 and has since killed 10% of U.S. farm pigs. Though the disease has been circulating internationally for decades, the lack of a rapid reverse-genetics platform for manipulating PEDV and identifying genetic factors that impact transmission and virulence has hindered the study of this important agricultural disease. Here, we present a DNA-based infectious-clone system that replicates the pathogenesis of circulating U.S. strain PC22A both in vitro and in piglets. This infectious clone can be used both to study the genetics, virulence, and transmission of PEDV coronavirus and to inform the creation of a live attenuated PEDV vaccine.
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Affiliation(s)
- Anne Beall
- University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA
| | - Boyd Yount
- University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA
| | - Chun-Ming Lin
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, USA
| | - Yixuan Hou
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, USA
| | - Qiuhong Wang
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, USA
| | - Linda Saif
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, USA
| | - Ralph Baric
- University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA
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