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Han X, Xu H, Weng Y, Chen R, Xu J, Cao T, Sun R, Shan Y, He F, Fang W, Li X. N pro of classical swine fever virus enhances HMGB1 acetylation and its degradation by lysosomes to evade from HMGB1-mediated antiviral immunity. Virus Res 2024; 339:199280. [PMID: 37995963 PMCID: PMC10709370 DOI: 10.1016/j.virusres.2023.199280] [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: 08/28/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 11/25/2023]
Abstract
Classical swine fever virus (CSFV) can dampen the host innate immunity by destabilizing IRF3 upon its binding with viral Npro. High mobility group box 1 (HMGB1), a non-histone nuclear protein, has diverse functions, including inflammation, innate immunity, etc., which are closely related to its cellular localization. We investigated potential mutual interactions between CSFV and HMGB1 and their effects on virus replication. We found that HMGB1 at the protein level, but not at mRNA level, was markedly reduced in CSFV-infected or Npro-expressing IPEC-J2 cells. HMGB1 in the nuclear compartment is anti-CSFV by promoting IFN-mediated innate immune response, as evidenced by overexpression of nuclear or cytoplasmic dominant HMGB1 mutant in IPEC-J2 cells stimulated with poly(I:C). However, CSFV Npro upregulates HMGB1 acetylation, a modification that promotes HMGB1 translocation into the cytoplasmic compartment where it is degraded by lysosomes. Ethyl pyruvate could downregulate HMGB1 acetylation and prevent Npro-mediated HMGB1 reduction. Inhibition of deacetylase HDAC1 with MS275 or by RNA silencing could promote Npro-mediated HMGB1 degradation. Taken together, our study elucidates the mechanism with which HMGB1 in the nuclei initiates antiviral innate immune response to suppress CSFV replication and elaborates the pathway by which CSFV uses its Npro to evade from HMGB1-mediated antiviral immunity through upregulating HMGB1 acetylation with subsequent translocation into cytoplasm for lysosomal degradation.
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Affiliation(s)
- Xiao Han
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Hankun Xu
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Yifan Weng
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Rong Chen
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Jidong Xu
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Tong Cao
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Renjie Sun
- Zhejiang Provincial Center for Animal Disease Prevention & Control, Hangzhou, Zhejiang 311199, China
| | - Ying Shan
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Fang He
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China
| | - Weihuan Fang
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China.
| | - Xiaoliang Li
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang 310058, China.
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Chen R, Han X, Xu H, Xu J, Cao T, Shan Y, He F, Fang W, Li X. N-terminal domain of classical swine fever virus N pro induces proteasomal degradation of specificity protein 1 with reduced HDAC1 expression to evade from innate immune responses. J Virol 2023; 97:e0111523. [PMID: 37796122 PMCID: PMC10617410 DOI: 10.1128/jvi.01115-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/25/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Of the flaviviruses, only CSFV and bovine viral diarrhea virus express Npro as the non-structural protein which is not essential for viral replication but functions to dampen host innate immunity. We have deciphered a novel mechanism with which CSFV uses to evade the host antiviral immunity by the N-terminal domain of its Npro to facilitate proteasomal degradation of Sp1 with subsequent reduction of HDAC1 and ISG15 expression. This is distinct from earlier findings involving Npro-mediated IRF3 degradation via the C-terminal domain. This study provides insights for further studies on how HDAC1 plays its role in antiviral immunity, and if and how other viral proteins, such as the core protein of CSFV, the nucleocapsid protein of porcine epidemic diarrhea virus, or even other coronaviruses, exert antiviral immune responses via the Sp1-HDAC1 axis. Such research may lead to a deeper understanding of viral immune evasion strategies as part of their pathogenetic mechanisms.
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Affiliation(s)
- Rong Chen
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Xiao Han
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Hankun Xu
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Jidong Xu
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Tong Cao
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Ying Shan
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Fang He
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Weihuan Fang
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Xiaoliang Li
- Zhejiang University Institute of Preventive Veterinary Medicine & Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
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Gao F, Li P, Yin Y, Du X, Cao G, Wu S, Zhao Y. Molecular breeding of livestock for disease resistance. Virology 2023; 587:109862. [PMID: 37562287 DOI: 10.1016/j.virol.2023.109862] [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: 06/02/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023]
Abstract
Animal infectious diseases pose a significant threat to the global agriculture and biomedicine industries, leading to significant economic losses and public health risks. The emergence and spread of viral infections such as African swine fever virus (ASFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea virus (PEDV), and avian influenza virus (AIV) have highlighted the need for innovative approaches to develop resilient and disease-resistant animal populations. Gene editing technologies, such as CRISPR/Cas9, offer a promising avenue for generating animals with enhanced disease resistance. This review summarizes recent advances in molecular breeding strategies for generating disease-resistant animals, focusing on the development of disease-resistant livestock. We also highlight the potential applications of genome-wide CRISPR/Cas9 library screening and base editors in producing precise gene modified livestock for disease resistance in the future. Overall, gene editing technologies have the potential to revolutionize animal breeding and improve animal health and welfare.
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Affiliation(s)
- Fei Gao
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, Frontiers Science Center for Molecular Design Breeding, China Agricultural University, Beijing, China; Sanya Institute of China Agricultural University, Sanya, 572025, China
| | - Pan Li
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, Frontiers Science Center for Molecular Design Breeding, China Agricultural University, Beijing, China; College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Ye Yin
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, Frontiers Science Center for Molecular Design Breeding, China Agricultural University, Beijing, China
| | - Xuguang Du
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, Frontiers Science Center for Molecular Design Breeding, China Agricultural University, Beijing, China; Sanya Institute of China Agricultural University, Sanya, 572025, China
| | - Gengsheng Cao
- Henan Livestock Genome Editing and Biobreeding Engineering Research Center, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Sen Wu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, Frontiers Science Center for Molecular Design Breeding, China Agricultural University, Beijing, China; Sanya Institute of China Agricultural University, Sanya, 572025, China.
| | - Yaofeng Zhao
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, Frontiers Science Center for Molecular Design Breeding, China Agricultural University, Beijing, China.
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Hong T, Yang Y, Wang P, Zhu G, Zhu C. Pestiviruses infection: Interferon-virus mutual regulation. Front Cell Infect Microbiol 2023; 13:1146394. [PMID: 36936761 PMCID: PMC10018205 DOI: 10.3389/fcimb.2023.1146394] [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: 01/17/2023] [Accepted: 02/17/2023] [Indexed: 03/06/2023] Open
Abstract
Pestiviruses are a class of viruses that in some cases can cause persistent infection of the host, thus posing a threat to the livestock industry. Interferons (IFNs) are a group of secreted proteins that play a crucial role in antiviral defense. In this review, on the one hand, we elaborate on how pestiviruses are recognized by the host retinoic acid-inducible gene-I (RIG-I), melanoma-differentiation-associated protein 5 (MDA5), and Toll-like receptor 3 (TLR3) proteins to induce the synthesis of IFNs. On the other hand, we focus on reviewing how pestiviruses antagonize the production of IFNs utilizing various strategies mediated by self-encoded proteins, such as the structural envelope protein (Erns) and non-structural protein (Npro). Hence, the IFN signal transduction pathway induced by pestiviruses infection and the process of pestiviruses blockade on the production of IFNs intertwines into an intricate regulatory network. By reviewing the interaction between IFN and pestiviruses (based on studies on BVDV and CSFV), we expect to provide a theoretical basis and reference for a better understanding of the mechanisms of induction and evasion of the innate immune response during infection with these viruses.
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Affiliation(s)
- Tianqi Hong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Yi Yang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Pengzhi Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Guoqiang Zhu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
- *Correspondence: Guoqiang Zhu, ; Congrui Zhu,
| | - Congrui Zhu
- College of Animal Science, South China Agricultural University, Guangzhou, China
- *Correspondence: Guoqiang Zhu, ; Congrui Zhu,
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Mou C, Pan S, Wu H, Chen Z. Disruption of interferon-β production by the N pro of atypical porcine pestivirus. Virulence 2021; 12:654-665. [PMID: 33538238 PMCID: PMC7872032 DOI: 10.1080/21505594.2021.1880773] [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] [Indexed: 01/05/2023] Open
Abstract
Atypical porcine pestivirus (APPV) is an emerging porcine virus that threatens global swine production. Pestiviruses can prevent interferon (IFN) production to avoid the host innate immune response, and the Npro viral protein can play a critical role. Knowledge of the host immune response to APPV infection is limited. Here, we showed that the IFN-β production was suppressed by APPV-Npro and the IFN regulatory factor 3 (IRF3) promoter activity stimulated by adaptor molecules of the IFN-β signaling pathway was also inhibited in the APPV-Npro-expressed cells. The APPV-Npro was able to interact with IRF3 and interfere the phosphorylation of IRF3, indicated that the IFN-β antagonism of APPV-Npro mainly depended on blocking IRF3 activity. To identify the functional region of APPV-Npro, a panel of truncated APPV-Npro was constructed, and its influence on the IRF3 activation was investigated. The results showed that the N-terminal 31–51 amino acids of APPV-Npro were mainly associated with inhibition of the IFN-β response. Taken together, this is the first study focusing on elucidating the function of APPV protein by revealing a novel mechanism of Npro in disruption of host IFN-β production, which will enlighten future study in addressing APPV pathogenesis and immune evasion.
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Affiliation(s)
- Chunxiao Mou
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
| | - Shuonan Pan
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
| | - Huiguang Wu
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
| | - Zhenhai Chen
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
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6
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Kalaiyarasu S, Mishra N, Jayalakshmi K, Selvaraj P, Sudhakar SB, Jhade SK, Sood R, Premalatha N, Singh VP. Molecular characterization of recent HoBi-like pestivirus isolates from cattle showing mucosal disease-like signs in India reveals emergence of a novel genetic lineage. Transbound Emerg Dis 2021; 69:308-326. [PMID: 33411944 DOI: 10.1111/tbed.13981] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/17/2020] [Accepted: 01/03/2021] [Indexed: 12/15/2022]
Abstract
Natural infections with HoBi-like pestivirus (HoBiPeV) have been detected in cattle in South America, Europe and Asia with a range of clinical manifestations including fatal mucosal disease (MD). In India, although HoBiPeV in cattle has been reported, there is no information on currently circulating HoBiPeV strains and associated severe clinical disease. Between September 2018 and December 2019, suspected cases of bovine viral diarrhoea with severe disease in cattle were noticed in farmers' small holdings in Tamil Nadu State. To determine the extent of pestivirus infection, blood, serum, nasal or oral swab samples of 46 cattle from 18 villages were tested. Based on the real-time RT-PCR, antigen ELISA and nucleotide sequencing results, pestivirus was detected in nine cattle from eight villages in two districts and all pestiviruses were identified as HoBiPeV. All nine HoBiPeV-infected cattle displayed clinical signs resembling MD and HoBiPeV isolates (n = 9) obtained were characterized at genetic and antigenic level. Phylogenetic analyses based on 5'-untranslated regions (5'-UTR), Npro and combined 5'-UTR-Npro gene sequences revealed that eight HoBiPeV isolates clustered into a clade, distinct from all reported HoBiPeV clades (a-d), whereas one belonged to HoBiPeV-d clade, thus providing evidence of emergence of a novel HoBiPeV clade (e). This was also supported by HoBiPeV-e clade-specific amino acid substitutions in Npro and the antigenic reactivity patterns. The study demonstrates the existence and independent evolution of five HoBiPeV clades (four main clades) globally and surprisingly three exclusive to India. Also we confirm first HoBiPeV occurrence in southern India with predominant prevalence of HoBiPeV-e strains. Besides demonstrating increased HoBiPeV genetic diversity, here we show association of HoBiPeV with severe clinical disease involving fatalities highlighting impact of HoBiPeV on cattle health. The emergence of a novel HoBiPeV lineage provides new insights on global HoBiPeV epidemiology and genetic diversity reiterating the need for continuous monitoring of HoBiPeV in India.
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Affiliation(s)
| | - Niranjan Mishra
- ICAR-National Institute of High Security Animal Diseases, Bhopal, India
| | - Konappan Jayalakshmi
- Veterinary College and Research Institute (VC&RI), Tamil Nadu Veterinary and Animal Sciences University, Thanjavur, India
| | - Palanisamy Selvaraj
- Veterinary College and Research Institute (VC&RI), Tamil Nadu Veterinary and Animal Sciences University, Thanjavur, India
| | | | | | - Richa Sood
- ICAR-National Institute of High Security Animal Diseases, Bhopal, India
| | - Narayanasammi Premalatha
- Veterinary College and Research Institute (VC&RI), Tamil Nadu Veterinary and Animal Sciences University, Thanjavur, India
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Regions of conformational flexibility in the proprotein convertase PCSK9 and design of antagonists for LDL cholesterol lowering. Biochem Soc Trans 2020; 48:1323-1336. [DOI: 10.1042/bst20190672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 07/08/2020] [Accepted: 07/20/2020] [Indexed: 12/29/2022]
Abstract
The proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates plasma LDL cholesterol levels by binding to the liver LDL receptor (LDLR) and promoting its degradation. Therefore, PCSK9 has become a compelling new therapeutic target for lipid lowering and the prevention of cardiovascular disease. PCSK9 contains two regions of conformational flexibility, the N-terminal regions of the prodomain and of the catalytic domain. The recognition that the latter region, the so-called P′ helix, is able to transition from an α-helical to a disordered state gave rise to new strategies to develop small molecule inhibitors of PCSK9 for lipid lowering. In the ordered state the P′ helix is buried in a groove of the PCSK9 catalytic domain located next to the main LDLR binding site. The transition to a disordered state leaves the groove site vacated and accessible for compounds to antagonize LDLR binding. By use of a groove-directed phage display strategy we were able to identify several groove-binding peptides. Based on structural information of PCSK9-peptide complexes, a minimized groove-binding peptide was generated and utilized as an anchor to extend towards the adjacent main LDLR binding site, either by use of a phage-displayed peptide extension library, or by appending organic moieties to yield organo-peptides. Both strategies led to antagonists with pharmacologic activities in cell-based assays. The intricate bipartite mechanism of the potent organo-peptide inhibitors was revealed by structural studies, showing that the core peptide occupies the N-terminal groove, while the organic moiety interacts with the LDLR binding site to create antagonism. These findings validate the PCSK9 groove as an attractive target site and should inspire the development of a new class of small molecule antagonists of PCSK9.
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Itakura Y, Matsuno K, Ito A, Gerber M, Liniger M, Fujimoto Y, Tamura T, Kameyama KI, Okamatsu M, Ruggli N, Kida H, Sakoda Y. A cloned classical swine fever virus derived from the vaccine strain GPE - causes cytopathic effect in CPK-NS cells via type-I interferon-dependent necroptosis. Virus Res 2019; 276:197809. [PMID: 31715204 DOI: 10.1016/j.virusres.2019.197809] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 01/03/2023]
Abstract
Classical swine fever viruses (CSFVs) do typically not show cytopathic effect (CPE) in cell culture, while some strains such as vaccine strain the GPE- induce CPE in the swine kidney-derived CPK-NS cell line cultured in serum-free medium. These latter strains commonly lack Npro-mediated inhibition of type-I interferon (IFN) induction. In order to explore the molecular mechanisms of GPE--induced CPE, we analyzed the cellular pathways involved. In CPK-NS cells infected with the attenuated-vaccine-derived vGPE- strain, both, apoptosis and necroptosis were induced. Necroptosis was type-I IFN-dependent and critical for visible CPE. In contrast, the parental virulent vALD-A76 strain did not induce any of these pathways nor CPE. We used reverse genetics to investigate which viral factors regulate these cell-death pathways. Interestingly, a mutant vGPE- in which the Npro function was restored to inhibit type-I IFN induction did not induce necroptosis nor CPE but still induced apoptosis, while an Npro-mutant vALD-A76 incapable of inhibiting type-I IFN production induced necroptosis and CPE. Although Erns of CSFV is reportedly involved in controlling apoptosis, apoptosis induction by vGPE- or apoptosis inhibition by vALD-A76 were independent of the unique amino acid difference found in Erns of these two strains. Altogether, these results demonstrate that type-I IFN-dependent necroptosis related to non-functional Npro is the main mechanism for CPE induction by vGPE-, and that viral factor(s) other than Erns may induce or inhibit apoptosis in vGPE- or vALD-A76 infected CPK-NS cells, respectively.
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Affiliation(s)
- Yukari Itakura
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Keita Matsuno
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Global Station for Zoonotic Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Hokkaido, Japan
| | - Asako Ito
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Markus Gerber
- Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
| | - Matthias Liniger
- Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
| | - Yuri Fujimoto
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Tomokazu Tamura
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Ken-Ichiro Kameyama
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Masatoshi Okamatsu
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Nicolas Ruggli
- Institute of Virology and Immunology (IVI), Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
| | - Hiroshi Kida
- Global Station for Zoonotic Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Hokkaido, Japan; Laboratory of Biologics Development, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yoshihiro Sakoda
- Laboratory of Microbiology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Global Station for Zoonotic Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Hokkaido, Japan.
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9
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Npro of Classical Swine Fever Virus Suppresses Type III Interferon Production by Inhibiting IRF1 Expression and Its Nuclear Translocation. Viruses 2019; 11:v11110998. [PMID: 31683525 PMCID: PMC6893713 DOI: 10.3390/v11110998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 10/25/2019] [Accepted: 10/29/2019] [Indexed: 12/23/2022] Open
Abstract
Classical swine fever virus (CSFV) causes a contagious disease of pigs. The virus can break the mucosal barrier to establish its infection. Type III interferons (IFN-λs) play a crucial role in maintaining the antiviral state in epithelial cells. Limited information is available on whether or how CSFV modulates IFN-λs production. We found that IFN-λ3 showed dose-dependent suppression of CSFV replication in IPEC-J2 cells. Npro-deleted CSFV mutant (∆Npro) induced significantly higher IFN-λs transcription from 24 h post-infection (hpi) than its parental strain (wtCSFV). The strain wtCSFV strongly inhibited IFN-λs transcription and IFN-λ3 promoter activity in poly(I:C)-stimulated IPEC-J2 cells, whereas ∆Npro did not show such inhibition. Npro overexpression caused significant reduction of IFN-λs transcription and IFN-λ3 promoter activity. Both wtCSFV and ∆Npro infection induced time-dependent IRF1 expression in IPEC-J2 cells, with ΔNpro showing more significant induction, particularly at 24 hpi. However, infection with wtCSFV or Npro overexpression led not only to significant reduction of IRF1 expression and its promoter activity in poly(I:C)-treated IPEC-J2 cells but also to blockage of IRF1 nuclear translocation. This study provides clear evidence that CSFV Npro suppresses IRF1-mediated type III IFNs production by inhibiting IRF1 expression and its nuclear translocation.
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Genetically modified pigs are protected from classical swine fever virus. PLoS Pathog 2018; 14:e1007193. [PMID: 30543715 PMCID: PMC6292579 DOI: 10.1371/journal.ppat.1007193] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/31/2018] [Indexed: 01/01/2023] Open
Abstract
Classical swine fever (CSF) caused by classical swine fever virus (CSFV) is one of the most detrimental diseases, and leads to significant economic losses in the swine industry. Despite efforts by many government authorities to stamp out the disease from national pig populations, the disease remains widespread. Here, antiviral small hairpin RNAs (shRNAs) were selected and then inserted at the porcine Rosa26 (pRosa26) locus via a CRISPR/Cas9-mediated knock-in strategy. Finally, anti-CSFV transgenic (TG) pigs were produced by somatic nuclear transfer (SCNT). Notably, in vitro and in vivo viral challenge assays further demonstrated that these TG pigs could effectively limit the replication of CSFV and reduce CSFV-associated clinical signs and mortality, and disease resistance could be stably transmitted to the F1-generation. Altogether, our work demonstrated that RNA interference (RNAi) technology combining CRISPR/Cas9 technology offered the possibility to produce TG animal with improved resistance to viral infection. The use of these TG pigs can reduce CSF-related economic losses and this antiviral strategy may be useful for future antiviral research. Classical swine fever (CSF), caused by classical swine fever virus (CSFV), and is a highly contagious, often fatal porcine disease that causes significant economic losses. Due to the economic importance of this virus to the pig industry, the biology and pathogenesis of CSFV have been investigated extensively. Despite efforts by many government authorities to stamp out the disease from national pig populations, the disease remains widespread, and it is only a matter of time before the virus is reintroduced and the next round of disease outbreaks occurs. These findings highlight the necessity and urgency for developing effective approaches to eradicate the challenging CSFV. In this study, we successfully produced anti-CSFV TG pigs by combining RNAi technology and CRISPR/Cas9 technologies, and viral challenge results confirmed that these TG pigs could effectively limit the replication of CSFV in vivo and in vitro. Additionally, we confirmed that the disease resistance traits in the TG founders were stably transmitted to their F1-generation offspring. Altogether, our work reported the combinational application of CRISPR/Cas9 and RNA interference (RNAi) technology in the generation of anti-CSFV TG pigs, it provided an alternative strategy to change the virus. The results of this study suggested that these TG pigs offered potential benefits over commercial vaccination and reduced CSFV-related economic losses.
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11
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Tucakov AK, Yavuz S, Schürmann EM, Mischler M, Klingebeil A, Meyers G. Restoration of glycoprotein E rns dimerization via pseudoreversion partially restores virulence of classical swine fever virus. J Gen Virol 2017; 99:86-96. [PMID: 29235980 DOI: 10.1099/jgv.0.000990] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The classical swine fever virus (CSFV) represents one of the most important pathogens of swine. The CSFV glycoprotein Erns is an essential structural protein and an important virulence factor. The latter is dependent on the RNase activity of this envelope protein and, most likely, its secretion from the infected cell. A further important feature with regard to its function as a virulence factor is the formation of disulfide-linked Erns homodimers that are found in virus-infected cells and virions. Mutant CSFV lacking cysteine (Cys) 171, the residue responsible for intermolecular disulfide bond formation, were found to be attenuated in pigs (Tews BA, Schürmann EM, Meyers G. J Virol 2009;83:4823-4834). In the course of an animal experiment with such a dimerization-negative CSFV mutant, viruses were reisolated from pigs that contained a mutation of serine (Ser) 209 to Cys. This mutation restored the ability to form disulphide-linked Erns homodimers. In transient expression studies Erns mutants carrying the S209C change were found to form homodimers with about wt efficiency. Also the secretion level of the mutated proteins was equivalent to that of wt Erns. Virus mutants containing the Cys171Ser/Ser209Cys configuration exhibited wt growth rates and increased virulence when compared with the Cys171Ser mutant. These results provide further support for the connection between CSFV virulence and Erns dimerization.
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Affiliation(s)
- Anna Katharina Tucakov
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
| | - Sabine Yavuz
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany.,Present address: Fachdienst Verbraucherschutz und Veterinärangelegenheiten, Landratsamt Alb-Donau-Kreis, Ulm, Germany
| | - Eva-Maria Schürmann
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany.,Present address: Landesamt für Gesundheit und Lebensmittelsicherheit, Oberschleissheim, Germany
| | - Manjula Mischler
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
| | - Anne Klingebeil
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
| | - Gregor Meyers
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
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12
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Lei J, Hilgenfeld R. RNA-virus proteases counteracting host innate immunity. FEBS Lett 2017; 591:3190-3210. [PMID: 28850669 PMCID: PMC7163997 DOI: 10.1002/1873-3468.12827] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 01/20/2023]
Abstract
Virus invasion triggers host immune responses, in particular, innate immune responses. Pathogen‐associated molecular patterns of viruses (such as dsRNA, ssRNA, or viral proteins) released during virus replication are detected by the corresponding pattern‐recognition receptors of the host, and innate immune responses are induced. Through production of type‐I and type‐III interferons as well as various other cytokines, the host innate immune system forms the frontline to protect host cells and inhibit virus infection. Not surprisingly, viruses have evolved diverse strategies to counter this antiviral system. In this review, we discuss the multiple strategies used by proteases of positive‐sense single‐stranded RNA viruses of the families Picornaviridae, Coronaviridae, and Flaviviridae, when counteracting host innate immune responses.
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Affiliation(s)
- Jian Lei
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Germany
| | - Rolf Hilgenfeld
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Germany.,German Center for Infection Research (DZIF), Hamburg - Lübeck - Borstel - Riems Site, University of Lübeck, Germany
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13
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Tao J, Li B, Chen J, Zhang C, Ma Y, Zhu G, Liu H. N pro His49 and E rns Lys412 mutations in pig bovine viral diarrhea virus type 2 synergistically enhance the cellular antiviral response. Virus Genes 2017; 54:57-66. [PMID: 28852929 DOI: 10.1007/s11262-017-1506-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/17/2017] [Indexed: 01/01/2023]
Abstract
Type I interferons are major components of the innate immune response of hosts, and accordingly, many viruses have evolved mechanisms to modulate the host response during infection. Bovine viral diarrhea virus (BVDV) nonstructural protein Npro and structural protein Erns play important roles in inhibiting type I interferon. The aim of this study was to explore the epistatic effects of amino acid mutations in Npro and Erns in porcine ST cells to characterize the immune response induced by BVDV-2. Plasmids with mutant amino acids His49 (H49), Glu22 (E22) in Npro, and His300 (H300), Lys412 (K412) in Erns which had been changed to Alanine (A) had similar effects on type I interferon production in MDBK and ST cells, but resulted in much greater ISG15, OAS, and Mx production in ST cells. The rescued vASH/NproH49ErnsK412 virus showed the best efficiency with respect to modulating antiviral cytokines, indicating that the amino acids Npro H49 and Erns K412 had highly synergistic effects in abolishing the ability to inhibit type I interferon. These findings have importance practical implications owing to the increasing prevalence of BVDV infections, including persistent infections, in domestic pigs.
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Affiliation(s)
- Jie Tao
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Engineering Research Center of Breeding Pig, BeiDi Rd 2901, Shanghai, 201106, China.,Municipal Key Laboratory of Agri-Genetics and Breedings, Shanghai, 201106, China
| | - Benqiang Li
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Engineering Research Center of Breeding Pig, BeiDi Rd 2901, Shanghai, 201106, China.,Municipal Key Laboratory of Agri-Genetics and Breedings, Shanghai, 201106, China
| | - Jinghua Chen
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Engineering Research Center of Breeding Pig, BeiDi Rd 2901, Shanghai, 201106, China.,Municipal Key Laboratory of Agri-Genetics and Breedings, Shanghai, 201106, China
| | - Chunling Zhang
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Engineering Research Center of Breeding Pig, BeiDi Rd 2901, Shanghai, 201106, China.,Municipal Key Laboratory of Agri-Genetics and Breedings, Shanghai, 201106, China
| | - Yufei Ma
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Engineering Research Center of Breeding Pig, BeiDi Rd 2901, Shanghai, 201106, China.,Municipal Key Laboratory of Agri-Genetics and Breedings, Shanghai, 201106, China
| | - Guoqiang Zhu
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Huili Liu
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Engineering Research Center of Breeding Pig, BeiDi Rd 2901, Shanghai, 201106, China. .,Municipal Key Laboratory of Agri-Genetics and Breedings, Shanghai, 201106, China.
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14
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Pestivirus Npro Directly Interacts with Interferon Regulatory Factor 3 Monomer and Dimer. J Virol 2016; 90:7740-7. [PMID: 27334592 DOI: 10.1128/jvi.00318-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/06/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Interferon regulatory factor 3 (IRF3) is a transcription factor involved in the activation of type I alpha/beta interferon (IFN-α/β) in response to viral infection. Upon viral infection, the IRF3 monomer is activated into a phosphorylated dimer, which induces the transcription of interferon genes in the nucleus. Viruses have evolved several ways to target IRF3 in order to subvert the innate immune response. Pestiviruses, such as classical swine fever virus (CSFV), target IRF3 for ubiquitination and subsequent proteasomal degradation. This is mediated by the viral protein N(pro) that interacts with IRF3, but the molecular details for this interaction are largely unknown. We used recombinant N(pro) and IRF3 proteins and show that N(pro) interacts with IRF3 directly without additional proteins and forms a soluble 1:1 complex. The full-length IRF3 but not merely either of the individual domains is required for this interaction. The interaction between N(pro) and IRF3 is not dependent on the activation state of IRF3, since N(pro) binds to a constitutively active form of IRF3 in the presence of its transcriptional coactivator, CREB-binding protein (CBP). The results indicate that the N(pro)-binding site on IRF3 encompasses a region that is unperturbed by the phosphorylation and subsequent activation of IRF3 and thus excludes the dimer interface and CBP-binding site. IMPORTANCE The pestivirus N-terminal protease, N(pro), is essential for evading the host's immune system by facilitating the degradation of interferon regulatory factor 3 (IRF3). However, the nature of the N(pro) interaction with IRF3, including the IRF3 species (inactive monomer versus activated dimer) that N(pro) targets for degradation, is largely unknown. We show that classical swine fever virus N(pro) and porcine IRF3 directly interact in solution and that full-length IRF3 is required for interaction with N(pro) Additionally, N(pro) interacts with a constitutively active form of IRF3 bound to its transcriptional cofactor, the CREB-binding protein. This is the first study to demonstrate that N(pro) is able to bind both inactive IRF3 monomer and activated IRF3 dimer and thus likely targets both IRF3 species for ubiquitination and proteasomal degradation.
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15
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Npro fusion technology: On-column complementation to improve efficiency in biopharmaceutical production. Protein Expr Purif 2016; 120:42-50. [DOI: 10.1016/j.pep.2015.11.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 11/18/2015] [Accepted: 11/24/2015] [Indexed: 11/21/2022]
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16
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Summerfield A, Ruggli N. Immune Responses Against Classical Swine Fever Virus: Between Ignorance and Lunacy. Front Vet Sci 2015; 2:10. [PMID: 26664939 PMCID: PMC4672165 DOI: 10.3389/fvets.2015.00010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/20/2015] [Indexed: 11/14/2022] Open
Abstract
Classical swine fever virus infection of pigs causes disease courses from life-threatening to asymptomatic, depending on the virulence of the virus strain and the immunocompetence of the host. The virus targets immune cells, which are central in orchestrating innate and adaptive immune responses such as macrophages and conventional and plasmacytoid dendritic cells. Here, we review current knowledge and concepts aiming to explain the immunopathogenesis of the disease at both the host and the cellular level. We propose that the interferon type I system and in particular the interaction of the virus with plasmacytoid dendritic cells and macrophages is crucial to understand elements governing the induction of protective rather than pathogenic immune responses. The review also concludes that despite the knowledge available many aspects of classical swine fever immunopathogenesis are still puzzling.
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Affiliation(s)
| | - Nicolas Ruggli
- Institute of Virology and Immunology - IVI , Bern , Switzerland
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17
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Abstract
Pestiviruses are among the economically most important pathogens of livestock. The biology of these viruses is characterized by unique and interesting features that are both crucial for their success as pathogens and challenging from a scientific point of view. Elucidation of these features at the molecular level has made striking progress during recent years. The analyses revealed that major aspects of pestivirus biology show significant similarity to the biology of human hepatitis C virus (HCV). The detailed molecular analyses conducted for pestiviruses and HCV supported and complemented each other during the last three decades resulting in elucidation of the functions of viral proteins and RNA elements in replication and virus-host interaction. For pestiviruses, the analyses also helped to shed light on the molecular basis of persistent infection, a special strategy these viruses have evolved to be maintained within their host population. The results of these investigations are summarized in this chapter.
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Affiliation(s)
- Norbert Tautz
- Institute for Virology and Cell Biology, University of Lübeck, Lübeck, Germany
| | - Birke Andrea Tews
- Institut für Immunologie, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Gregor Meyers
- Institut für Immunologie, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany.
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18
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Ning P, An L, Liang W, Zhang Y. Identification of inhibition of protein disulphide isomerase expression related to classical swine fever virus infection by using real-time PCR analysis. BIOTECHNOL BIOTEC EQ 2015. [DOI: 10.1080/13102818.2015.1018840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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19
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Mine J, Tamura T, Mitsuhashi K, Okamatsu M, Parchariyanon S, Pinyochon W, Ruggli N, Tratschin JD, Kida H, Sakoda Y. The N-terminal domain of Npro of classical swine fever virus determines its stability and regulates type I IFN production. J Gen Virol 2015; 96:1746-56. [PMID: 25809915 DOI: 10.1099/vir.0.000132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The viral protein Npro is unique to the genus Pestivirus within the family Flaviviridae. After autocatalytic cleavage from the nascent polyprotein, Npro suppresses type I IFN (IFN-α/β) induction by mediating proteasomal degradation of IFN regulatory factor 3 (IRF-3). Previous studies found that the Npro-mediated IRF-3 degradation was dependent of a TRASH domain in the C-terminal half of Npro coordinating zinc by means of the amino acid residues C112, C134, D136 and C138. Interestingly, four classical swine fever virus (CSFV) isolates obtained from diseased pigs in Thailand in 1993 and 1998 did not suppress IFN-α/β induction despite the presence of an intact TRASH domain. Through systematic analyses, it was found that an amino acid mutation at position 40 or mutations at positions 17 and 61 in the N-terminal half of Npro of these four isolates were related to the lack of IRF-3-degrading activity. Restoring a histidine at position 40 or both a proline at position 17 and a lysine at position 61 based on the sequence of a functional Npro contributed to higher stability of the reconstructed Npro compared with the Npro from the Thai isolate. This led to enhanced interaction of Npro with IRF-3 along with its degradation by the proteasome. The results of the present study revealed that amino acid residues in the N-terminal domain of Npro are involved in the stability of Npro, in interaction of Npro with IRF-3 and subsequent degradation of IRF-3, leading to downregulation of IFN-α/β production.
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Affiliation(s)
- Junki Mine
- 1Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Tomokazu Tamura
- 1Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Kazuya Mitsuhashi
- 1Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Masatoshi Okamatsu
- 1Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Sujira Parchariyanon
- 2National Institute of Animal Health, Kaset Klang, Chatuchak, Bangkok 10900, Thailand
| | - Wasana Pinyochon
- 2National Institute of Animal Health, Kaset Klang, Chatuchak, Bangkok 10900, Thailand
| | - Nicolas Ruggli
- 3The Institute of Virology and Immunology IVI, Sensemattstrasse 293, 3147 Mittelhäusern, Switzerland
| | - Jon-Duri Tratschin
- 3The Institute of Virology and Immunology IVI, Sensemattstrasse 293, 3147 Mittelhäusern, Switzerland
| | - Hiroshi Kida
- 1Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan 4Research Center for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan 5Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 001-0020, Japan
| | - Yoshihiro Sakoda
- 5Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 001-0020, Japan 1Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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20
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X-ray structure of the pestivirus NS3 helicase and its conformation in solution. J Virol 2015; 89:4356-71. [PMID: 25653438 DOI: 10.1128/jvi.03165-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
UNLABELLED Pestiviruses form a genus in the Flaviviridae family of small enveloped viruses with a positive-sense single-stranded RNA genome. Viral replication in this family requires the activity of a superfamily 2 RNA helicase contained in the C-terminal domain of nonstructural protein 3 (NS3). NS3 features two conserved RecA-like domains (D1 and D2) with ATPase activity, plus a third domain (D3) that is important for unwinding nucleic acid duplexes. We report here the X-ray structure of the pestivirus NS3 helicase domain (pNS3h) at a 2.5-Å resolution. The structure deviates significantly from that of NS3 of other genera in the Flaviviridae family in D3, as it contains two important insertions that result in a narrower nucleic acid binding groove. We also show that mutations in pNS3h that rescue viruses from which the core protein is deleted map to D3, suggesting that this domain may be involved in interactions that facilitate particle assembly. Finally, structural comparisons of the enzyme in different crystalline environments, together with the findings of small-angle X-ray-scattering studies in solution, show that D2 is mobile with respect to the rest of the enzyme, oscillating between closed and open conformations. Binding of a nonhydrolyzable ATP analog locks pNS3h in a conformation that is more compact than the closest apo-form in our crystals. Together, our results provide new insight and bring up new questions about pNS3h function during pestivirus replication. IMPORTANCE Although pestivirus infections impose an important toll on the livestock industry worldwide, little information is available about the nonstructural proteins essential for viral replication, such as the NS3 helicase. We provide here a comparative structural and functional analysis of pNS3h with respect to its orthologs in other viruses of the same family, the flaviviruses and hepatitis C virus. Our studies reveal differences in the nucleic acid binding groove that could have implications for understanding the unwinding specificity of pNS3h, which is active only on RNA duplexes. We also show that pNS3h has a highly dynamic behavior--a characteristic probably shared with NS3 helicases from all Flaviviridae members--that could be targeted for drug design by using recent algorithms to specifically block molecular motion. Compounds that lock the enzyme in a single conformation or limit its dynamic range of conformations are indeed likely to block its helicase function.
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21
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Ji W, Guo Z, Ding NZ, He CQ. Studying classical swine fever virus: Making the best of a bad virus. Virus Res 2015; 197:35-47. [DOI: 10.1016/j.virusres.2014.12.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 01/04/2023]
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22
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Kozasa T, Abe Y, Mitsuhashi K, Tamura T, Aoki H, Ishimaru M, Nakamura S, Okamatsu M, Kida H, Sakoda Y. Analysis of a pair of END+ and END- viruses derived from the same bovine viral diarrhea virus stock reveals the amino acid determinants in Npro responsible for inhibition of type I interferon production. J Vet Med Sci 2014; 77:511-8. [PMID: 25648277 PMCID: PMC4478729 DOI: 10.1292/jvms.14-0420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The Exaltation of Newcastle disease virus (END) phenomenon is induced by the
inhibition of type I interferon in pestivirus-infected cells in vitro,
via proteasomal degradation of cellular interferon regulatory factor (IRF)-3 with the
property of the viral autoprotease protein Npro. Reportedly, the amino acid
residues in the zinc-binding TRASH motif of Npro determine the difference in
characteristics between END-phenomenon-positive (END+) and
END-phenomenon-negative (END−) classical swine fever viruses (CSFVs). However,
the basic mechanism underlying this function in bovine viral diarrhea virus (BVDV) has not
been elucidated from the genomic differences between END+ and END−
viruses using reverse genetics till date. In the present study, comparison of complete
genome sequences of a pair of END+ and END− viruses isolated from
the same virus stock revealed that there were only four amino acid substitutions (D136G,
I2623V, D3148G and D3502Y) between two viruses. Based on these differences, viruses with
and without mutations at these positions were generated using reverse genetics. The END
assay, measurements of induced type I interferon and IRF-3 detection in cells infected
with these viruses revealed that the aspartic acid at position 136 in the zinc-binding
TRASH motif of Npro was required to inhibit the production of type I interferon
via the degradation of cellular IRF-3, consistently with CSFV.
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Affiliation(s)
- Takashi Kozasa
- Food Safety and Consumer Affairs Bureau, Ministry of Agriculture, Forestry and Fisheries, Chiyoda-ku, Tokyo 100-8950, Japan
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23
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Abstract
Hepatitis E virus (HEV) causes both endemic and epidemic human hepatitis by fecal-oral transmission in many parts of the world. Zoonotic transmission of HEV from animals to humans has been reported. Due to the lack of an efficient cell culture system, the molecular mechanisms of HEV infection remain largely unknown. In this study, we found that HEV replication in hepatoma cells inhibited poly(I·C)-induced beta interferon (IFN-β) expression and that the HEV open reading frame 1 (ORF1) product was responsible for this inhibition. Two domains, X and the papain-like cysteine protease domain (PCP), of HEV ORF1 were identified as the putative IFN antagonists. When overexpressed in HEK293T cells, the X domain (or macro domain) inhibited poly(I·C)-induced phosphorylation of interferon regulatory factor 3 (IRF-3), which is the key transcription factor for IFN induction. The PCP domain was shown to have deubiquitinase activity for both RIG-I and TBK-1, whose ubiquitination is a key step in their activation in poly(I·C)-induced IFN induction. Furthermore, replication of a HEV replicon containing green fluorescent protein (GFP) (E2-GFP) in hepatoma cells led to impaired phosphorylation of IRF-3 and reduced ubiquitination of RIG-I and TBK-1, which confirmed our observations of X and PCP inhibitory effects in HEK293T cells. Altogether, our study identified the IFN antagonists within the HEV ORF1 polyprotein and expanded our understanding of the functions of several of the HEV ORF1 products, as well as the mechanisms of HEV pathogenesis. Importance: Type I interferons (IFNs) are important components of innate immunity and play a crucial role against viral infection. They also serve as key regulators to evoke an adaptive immune response. Virus infection can induce the synthesis of interferons; however, viruses have evolved many strategies to antagonize the induction of interferons. There is little knowledge about how hepatitis E virus (HEV) inhibits induction of host IFNs, though the viral genome was sequenced more than 2 decades ago. This is the first report of identification of the potential IFN antagonists encoded by HEV. By screening all the domains in the open reading frame 1 (ORF1) polyprotein, we identified two IFN antagonists and performed further research to determine how and at which step in the IFN induction pathway they antagonize host IFN induction. Our work provides valuable information about HEV-cell interaction and pathogenesis.
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24
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Tamura T, Nagashima N, Ruggli N, Summerfield A, Kida H, Sakoda Y. Npro of classical swine fever virus contributes to pathogenicity in pigs by preventing type I interferon induction at local replication sites. Vet Res 2014; 45:47. [PMID: 24742209 PMCID: PMC4018971 DOI: 10.1186/1297-9716-45-47] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/01/2014] [Indexed: 11/10/2022] Open
Abstract
Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious disease of pigs. The viral protein Npro of CSFV interferes with alpha- and beta-interferon (IFN-α/β) induction by promoting the degradation of interferon regulatory factor 3 (IRF3). During the establishment of the live attenuated CSF vaccine strain GPE-, Npro acquired a mutation that abolished its capacity to bind and degrade IRF3, rendering it unable to prevent IFN-α/β induction. In a previous study, we showed that the GPE- vaccine virus became pathogenic after forced serial passages in pigs, which was attributed to the amino acid substitutions T830A in the viral proteins E2 and V2475A and A2563V in NS4B. Interestingly, during the re-adaptation of the GPE- vaccine virus in pigs, the IRF3-degrading function of Npro was not recovered. Therefore, we examined whether restoring the ability of Npro to block IFN-α/β induction of both the avirulent and moderately virulent GPE--derived virus would enhance pathogenicity in pigs. Viruses carrying the N136D substitution in Npro regained the ability to degrade IRF3 and suppress IFN-α/β induction in vitro. In pigs, functional Npro significantly reduced the local IFN-α mRNA expression in lymphoid organs while it increased quantities of IFN-α/β in the circulation, and enhanced pathogenicity of the moderately virulent virus. In conclusion, the present study demonstrates that functional Npro influences the innate immune response at local sites of virus replication in pigs and contributes to pathogenicity of CSFV in synergy with viral replication.
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Affiliation(s)
| | | | | | | | | | - Yoshihiro Sakoda
- Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
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Gottipati K, Acholi S, Ruggli N, Choi KH. Autocatalytic activity and substrate specificity of the pestivirus N-terminal protease Npro. Virology 2014; 452-453:303-9. [PMID: 24606708 DOI: 10.1016/j.virol.2014.01.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 11/27/2013] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
Abstract
Pestivirus N(pro) is the first protein translated in the viral polypeptide, and cleaves itself off co-translationally generating the N-terminus of the core protein. Once released, N(pro) blocks the host׳s interferon response by inducing degradation of interferon regulatory factor-3. N(pro׳)s intracellular autocatalytic activity and lack of trans-activity have hampered in vitro cleavage studies to establish its substrate specificity and the roles of individual residues. We constructed N(pro)-GFP fusion proteins that carry the authentic cleavage site and determined the autoproteolytic activities of N(pro) proteins containing substitutions at the predicted catalytic sites Glu22 and Cys69, at Arg100 that forms a salt bridge with Glu22, and at the cleavage site Cys168. Contrary to previous reports, we show that N(pro׳)s catalytic activity does not involve Glu22, which may instead be involved in protein stability. Furthermore, N(pro) does not have specificity for Cys168 at the cleavage site even though this residue is conserved throughout the pestivirus genus.
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Affiliation(s)
- Keerthi Gottipati
- Department of Biochemistry & Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0647, USA
| | - Sudheer Acholi
- Department of Biochemistry & Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0647, USA
| | - Nicolas Ruggli
- Institute of Virology and Immunology, CH-3147 Mittelhäusern, Switzerland
| | - Kyung H Choi
- Department of Biochemistry & Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0647, USA.
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N pro of Bungowannah virus exhibits the same antagonistic function in the IFN induction pathway than that of other classical pestiviruses. Vet Microbiol 2013; 168:340-7. [PMID: 24398226 DOI: 10.1016/j.vetmic.2013.11.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 11/22/2013] [Accepted: 11/25/2013] [Indexed: 01/01/2023]
Abstract
Bungowannah virus is the most divergent atypical pestivirus that had been detected up to now, and does not fit into any of the four approved species: Bovine viral diarrhea virus type 1 (BVDV-1) and type 2 (BVDV-2), Classical swine fever virus (CSFV) and Border disease virus (BDV). However, the presence of N(pro) and E(rns) coding regions, which are unique to pestiviruses, provides clear evidence of a pestivirus. Nevertheless, the amino acid identity of Bungowannah virus N(pro) and BVDV-1 N(pro) (strain CP7) is only 51.5%. By using a BVDV-1 backbone, a novel chimeric construct was generated, in which the genomic region encoding the non-structural protein N(pro) was replaced by that of Bungowannah virus (CP7_N(pro)-Bungo). In vitro studies of CP7_N(pro)-Bungo revealed autonomous replication with the same efficacy as the BVDV backbone CP7 and infectious high-titer virus could be collected. In order to compare the ability of interferon (IFN) suppression, two reporter gene assays, specific for type-I IFN, were carried out. In virus-infected cells, no significant difference in blocking of IFN expression between the parental virus CP7, Bungowannah virus and the chimeric construct CP7_N(pro)-Bungo could be detected. In contrast, an N(pro) deletion mutant showed an impaired replication in bovine cells and a marked type-I IFN response. Taken together, our findings reveal the compatibility of non-structural protein N(pro) of atypical Bungowannah virus with a BVDV type 1 backbone and its characteristic feature as an inhibitor of type-I IFN induction with an inhibitor-activity comparable to other pestiviruses.
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