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Fan C, Su H, Liao Z, Su J, Yang C, Zhang Y, Su J. Teleost-Specific MxG, a Traitor in the Mx Family, Negatively Regulates Antiviral Responses by Targeting IPS-1 for Proteasomal Degradation and STING for Lysosomal Degradation. THE JOURNAL OF IMMUNOLOGY 2021; 207:281-295. [PMID: 34135063 DOI: 10.4049/jimmunol.2000555] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 04/29/2021] [Indexed: 11/19/2022]
Abstract
IFN-β promoter stimulator-1 (IPS-1)- and stimulator of IFN genes (STING)-mediated type I IFNs play a critical role in antiviral responses. Myxovirus resistance (Mx) proteins are pivotal components of the antiviral effectors induced by IFNs in many species. An unprecedented expansion of Mx genes has occurred in fish. However, the functions and mechanisms of Mx family members remain largely unknown in fish. In this study, we found that grass carp (Ctenopharyngodon idella) MxG, a teleost-specific Mx protein, is induced by IFNs and viruses, and it negatively regulates both IPS-1- and STING-mediated antiviral responses to facilitate grass carp reovirus, spring viremia of carp virus, and cyprinid herpesvirus-2 replication. MxG binds and degrades IPS-1 via the proteasomal pathway and STING through the lysosomal pathway, thereby negatively regulating IFN1 antiviral responses and NF-κB proinflammatory cytokines. MxG also suppresses the phosphorylation of STING IFN regulatory factor 3/7, and it subsequently downregulates IFN1 and NF-κB1 at the promoter, transcription, and protein levels. GTPase and GTPase effector domains of MxG contribute to the negative regulatory function. On the contrary, MxG knockdown weakens virus replication and cytopathic effect. Therefore, MxG can be an ISG molecule induced by IFNs and viruses, and degrade IPS-1 and STING proteins in a negative feedback manner to maintain homeostasis and avoid excessive immune responses after virus infection. To our knowledge, this is the first identification of a negative regulator in the Mx family, and our findings clarify a novel mechanism by which the IFN response is regulated.
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Affiliation(s)
- Chengjian Fan
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Hang Su
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Zhiwei Liao
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Juanjuan Su
- Key Laboratory of Marine Drugs (Ministry of Education), Shandong Provincial Key Laboratory of Glycoscience and Glycoengineering, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China; and
| | - Chunrong Yang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yongan Zhang
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Jianguo Su
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China; .,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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Rao Y, Wang TY, Qin C, Espinosa B, Liu Q, Ekanayake A, Zhao J, Savas AC, Zhang S, Zarinfar M, Liu Y, Zhu W, Graham N, Jiang T, Zhang C, Feng P. Targeting CTP Synthetase 1 to Restore Interferon Induction and Impede Nucleotide Synthesis in SARS-CoV-2 Infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.02.05.429959. [PMID: 33564769 PMCID: PMC7872357 DOI: 10.1101/2021.02.05.429959] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The newly emerged SARS-CoV-2 caused a global pandemic with astonishing mortality and morbidity. The mechanisms underpinning its highly infectious nature remain poorly understood. We report here that SARS-CoV-2 exploits cellular CTP synthetase 1 (CTPS1) to promote CTP synthesis and suppress interferon (IFN) induction. Screening a SARS-CoV-2 expression library identified ORF7b and ORF8 that suppressed IFN induction via inducing the deamidation of interferon regulatory factor 3 (IRF3). Deamidated IRF3 fails to bind the promoters of classic IRF3-responsible genes, thus muting IFN induction. Conversely, a shRNA-mediated screen focused on cellular glutamine amidotransferases corroborated that CTPS1 deamidates IRF3 to inhibit IFN induction. Functionally, ORF7b and ORF8 activate CTPS1 to promote de novo CTP synthesis while shutting down IFN induction. De novo synthesis of small-molecule inhibitors of CTPS1 enabled CTP depletion and IFN induction in SARS-CoV-2 infection, thus impeding SARS-CoV-2 replication. Our work uncovers a strategy that a viral pathogen couples immune evasion to metabolic activation to fuel viral replication. Inhibition of the cellular CTPS1 offers an attractive means for developing antiviral therapy that would be resistant to SARS-CoV-2 mutation.
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Affiliation(s)
- Youliang Rao
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Ting-Yu Wang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Chao Qin
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Bianca Espinosa
- Department of Chemistry, Dornsife College of Arts, Letters and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Qizhi Liu
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Arunika Ekanayake
- Department of Chemistry, Dornsife College of Arts, Letters and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Jun Zhao
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
- Florida Research and Innovation Center, Cleveland Clinic, FL 34987, USA
| | - Ali Can Savas
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Shu Zhang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Mehrnaz Zarinfar
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Yongzhen Liu
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Wenjie Zhu
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123; Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), 510005 Guangzhou, China
| | - Nicholas Graham
- Mork Family Department of Chemical Engineering and Materials Science, Norris Comprehensive Cancer Center, Los Angeles, CA 90089, USA
| | - Taijiao Jiang
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123; Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), 510005 Guangzhou, China
| | - Chao Zhang
- Department of Chemistry, Dornsife College of Arts, Letters and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Pinghui Feng
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
- Lead Contact
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Su H, Fan C, Liao Z, Yang C, Clarke JL, Zhang Y, Su J. Grass Carp Reovirus Major Outer Capsid Protein VP4 Interacts with RNA Sensor RIG-I to Suppress Interferon Response. Biomolecules 2020; 10:biom10040560. [PMID: 32268551 PMCID: PMC7226501 DOI: 10.3390/biom10040560] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 01/02/2023] Open
Abstract
Diseases caused by viruses threaten the production industry and food safety of aquaculture which is a great animal protein source. Grass carp reovirus (GCRV) has caused tremendous loss, and the molecular function of viral proteins during infection needs further research, as for most aquatic viruses. In this study, interaction between GCRV major outer capsid protein VP4 and RIG-I, a critical viral RNA sensor, was screened out by GST pull-down, endogenous immunoprecipitation and subsequent LC-MS/MS, and then verified by co-IP and an advanced far-red fluorescence complementation system. VP4 was proved to bind to the CARD and RD domains of RIG-I and promoted K48-linked ubiquitination of RIG-I to degrade RIG-I. VP4 reduced mRNA and promoter activities of key genes of RLR pathway and sequential IFN production. As a consequence, antiviral effectors were suppressed and GCRV replication increased, resulting in intensified cytopathic effect. Furthermore, results of transcriptome sequencing of VP4 stably expressed CIK (C. idella kidney) cells indicated that VP4 activated the MyD88-dependent TLR pathway. Knockdown of VP4 obtained opposite effects. These results collectively revealed that VP4 interacts with RIG-I to restrain interferon response and assist GCRV invasion. This study lays the foundation for anti-dsRNA virus molecular function research in teleost and provides a novel insight into the strategy of immune evasion for aquatic virus.
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Affiliation(s)
- Hang Su
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (H.S.); (C.F.); (Z.L.); (Y.Z.)
- Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Norwegian Institute for Bioeconomy Research, 1430 Ås, Norway;
| | - Chengjian Fan
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (H.S.); (C.F.); (Z.L.); (Y.Z.)
| | - Zhiwei Liao
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (H.S.); (C.F.); (Z.L.); (Y.Z.)
| | - Chunrong Yang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan,430070, China;
| | | | - Yongan Zhang
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (H.S.); (C.F.); (Z.L.); (Y.Z.)
| | - Jianguo Su
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (H.S.); (C.F.); (Z.L.); (Y.Z.)
- Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Correspondence: ; Tel./Fax: +86-27-87282227
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Zhu D, Huang R, Chen L, Fu P, Luo L, He L, Li Y, Liao L, Zhu Z, Wang Y. Cloning and characterization of the LEF/TCF gene family in grass carp (Ctenopharyngodon idella) and their expression profiles in response to grass carp reovirus infection. FISH & SHELLFISH IMMUNOLOGY 2019; 86:335-346. [PMID: 30500548 DOI: 10.1016/j.fsi.2018.11.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 09/05/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) proteins from the High Mobility Group (HMG) box family act as the main downstream effectors of the Wnt signaling pathway. HMGB proteins play multifaceted roles in the immune system of mammals. To clarify the immunological characteristics of LEF/TCF genes in grass carp (Ctenopharyngodon idella), five LEF/TCF genes (TCF7, LEF1, TCF7L1A, TCF7L1B, and TCF7L2) were identified and characterized. All five LEF/TCF proteins contained two characteristic domains: a HMG-BOX domain and a CTNNB1_binding region. Phylogenetic tree analysis revealed that the LEF/TCF proteins were represented different lineages. These results of subcellular localization showed that four of the LEF/TCF genes were localized exclusively within the nucleus, while TCF7L2 was localized in the cytoplasm and nucleus. The mRNA expression profiles of these LEF/TCF family genes differed across different tissues. The mRNA expression levels of TCF7, TCF7L1A, and TCF7L2 changed significantly in liver after grass carp reovirus (GCRV) challenge; TCF7 and TCF7L1A responded early while TCF7L2 responded late. This suggests that these genes may participate in GCRV-related immune responses. Moreover, TCF7 promoted Bcl6 transcription in response to the GCRV challenge. These findings further our understanding of the function of LEF/TCF genes in teleosts.
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Affiliation(s)
- Denghui Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Rong Huang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Liangming Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peipei Fu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lifei Luo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Libo He
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yongming Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Lanjie Liao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zuoyan Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yaping Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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Rao Y, Wan Q, Su H, Xiao X, Liao Z, Ji J, Yang C, Lin L, Su J. ROS-induced HSP70 promotes cytoplasmic translocation of high-mobility group box 1b and stimulates antiviral autophagy in grass carp kidney cells. J Biol Chem 2018; 293:17387-17401. [PMID: 30237170 DOI: 10.1074/jbc.ra118.003840] [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: 05/05/2018] [Revised: 09/11/2018] [Indexed: 12/20/2022] Open
Abstract
Autophagy plays many physiological and pathophysiological roles. However, the roles and the regulatory mechanisms of autophagy in response to viral infections are poorly defined in teleost fish, such as grass carp (Ctenopharyngodon idella), which is one of the most important aquaculture species in China. In this study, we found that both grass carp reovirus (GCRV) infection and hydrogen peroxide (H2O2) treatment induced the accumulation of reactive oxygen species (ROS) in C. idella kidney cells and stimulate autophagy. Suppressing ROS accumulation with N-acetyl-l-cysteine significantly inhibited GCRV-induced autophagy activation and enhanced GCRV replication. Although ROS-induced autophagy, in turn, restricted GCRV replication, further investigation revealed that the multifunctional cellular protein high-mobility group box 1b (HMGB1b) serves as a heat shock protein 70 (HSP70)-dependent, pro-autophagic protein in grass carp. Upon H2O2 treatment, cytoplasmic HSP70 translocated to the nucleus, where it interacted with HMGB1b and promoted cytoplasmic translocation of HMGB1b. Overexpression and siRNA-mediated knockdown assays indicated that HSP70 and HMGB1b synergistically enhance ROS-induced autophagic activation in the cytoplasm. Moreover, HSP70 reinforced an association of HMGB1b with the C. idella ortholog of Beclin 1 (a mammalian ortholog of the autophagy-associated yeast protein ATG6) by directly interacting with C. idella Beclin 1. In summary, this study highlights the antiviral function of ROS-induced autophagy in response to GCRV infection and reveals the positive role of HSP70 in HMGB1b-mediated autophagy initiation in teleost fish.
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Affiliation(s)
- Youliang Rao
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.,the Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Quanyuan Wan
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.,the College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China, and
| | - Hang Su
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Xun Xiao
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiwei Liao
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Jianfei Ji
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Chunrong Yang
- the College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Li Lin
- the College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China, and
| | - Jianguo Su
- From the College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China, .,the Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
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Yan X, Xiong L, Li J, Wang Y, Wu Z, Jian J, Ding Y. GCRV 096 VP6 protein and its impacts on GCRV replication with different genotypes in CIK cells. AQUACULTURE AND FISHERIES 2018. [DOI: 10.1016/j.aaf.2018.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Cytoplasmic Translocation of Nucleolar Protein NOP53 Promotes Viral Replication by Suppressing Host Defense. Viruses 2018; 10:v10040208. [PMID: 29677136 PMCID: PMC5923502 DOI: 10.3390/v10040208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 12/15/2022] Open
Abstract
NOP53 is a tumor suppressor protein located in the nucleolus and is translocated to the cytoplasm during infection by vesicular stomatitis virus (VSV) and herpes simplex virus type 1 (HSV-1), as shown in our previous study. Cytoplasmic NOP53 interacts with the retinoic acid-inducible gene I (RIG-I) to remove its K63-linked ubiquitination, leading to attenuation of type I interferon IFN-β. In the present study, we found no obvious translocation of NOP53 in infection by a mutant virus lacking ICP4 (HSV-1/d120, replication inadequate). Blocking cytoplasmic translocation of NOP53 by the deletion of its nuclear export sequence (NES) abrogated its ability to support viral replication. These results demonstrated that NOP53 redistribution is related to viral replication. It is interesting that treatment with poly (I:C) or RIG-I-N (a constitutively-active variant) directly induced NOP53 cytoplasmic translocation. To better assess the function of cytoplasmic NOP53 in viral replication, the NOP53-derived protein N3-T, which contains a human immunodeficiency virus (HIV)-derived cell-penetrating Tat peptide at the C-terminal region of N3 (residues 330–432), was constructed and expressed. The recombinant N3-T protein formed trimers, attenuated the expression of IFN-β and IFN-stimulated genes, as well as decreased the phosphorylation level of interferon regulatory factor 3 (IRF3). Furthermore, N3-T promoted the efficient replication of enveloped and non-enveloped DNA and RNA viruses belonging to 5 families. Our findings expand the understanding of the mechanism by which viruses utilize the nucleolar protein NOP53 for optimal viral replication.
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Rao Y, Wan Q, Yang C, Su J. Grass Carp Laboratory of Genetics and Physiology 2 Serves As a Negative Regulator in Retinoic Acid-Inducible Gene I- and Melanoma Differentiation-Associated Gene 5-Mediated Antiviral Signaling in Resting State and Early Stage of Grass Carp Reovirus Infection. Front Immunol 2017; 8:352. [PMID: 28396670 PMCID: PMC5366347 DOI: 10.3389/fimmu.2017.00352] [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: 01/20/2017] [Accepted: 03/13/2017] [Indexed: 12/22/2022] Open
Abstract
Laboratory of genetics and physiology 2 (LGP2) is a key component of RIG-I-like receptors (RLRs). However, the lack of the caspase recruitment domains (CARDs) results in its controversial functional performance as a negative or positive regulator in antiviral responses. Especially, no sufficient evidence uncovers the functional mechanisms of LGP2 in RLR signaling pathways in teleost. Here, negative regulation mechanism of LGP2 in certain situations in retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5)-mediated antiviral responses was identified in Ctenopharyngodon idella kidney cells. LGP2 overexpression inhibits synthesis and phosphorylation of interferon regulatory factor 3/7 (IRF3/7), and mRNA levels and promoter activities of IFNs and NF-κBs in resting state and early phase of grass carp reovirus (GCRV) infection. Knockdown of LGP2 obtains opposite effects. Luciferase report assay indicates that LGP2 works at the upstream of RIG-I and MDA5. LGP2 binds to RIG-I and MDA5 with diverse domain preference and which is independent of GCRV infection. Furthermore, LGP2 restrains K63-linked ubiquitination of RIG-I and MDA5 in various degrees. These differences result in disparate repressive mechanisms of LGP2 to RIG-I- and MDA5-mediated signal activations of IFN-β promoter stimulator 1 and mediator of IRF3 activation. Interestingly, LGP2 also inhibits K48-linked RIG-I and MDA5 ubiquitination to suppress proteins degradation, which guarantees the basal protein levels for subsequently rapid signal activation. All these results reveal a mechanism that LGP2 functions as a suppressor in RLR signaling pathways to maintain cellular homeostasis in resting state and early phase during GCRV infection.
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Affiliation(s)
- Youliang Rao
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
| | - Quanyuan Wan
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
| | - Chunrong Yang
- College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China
| | - Jianguo Su
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
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Wan Q, Yang C, Rao Y, Liao Z, Su J. MDA5 Induces a Stronger Interferon Response than RIG-I to GCRV Infection through a Mechanism Involving the Phosphorylation and Dimerization of IRF3 and IRF7 in CIK Cells. Front Immunol 2017; 8:189. [PMID: 28286505 PMCID: PMC5323377 DOI: 10.3389/fimmu.2017.00189] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/09/2017] [Indexed: 12/22/2022] Open
Abstract
Retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) are critical cytosolic sensors that trigger the production of interferons (IFNs). Though their recognition functions are well identified, their unique roles in the downstream signal transduction remain to be elucidated. Herein, we report the differential effect between grass carp (Ctenopharyngodon idella) MDA5 (CiMDA5) and CiRIG-I on the production of various IFNs upon grass carp reovirus (GCRV) infection in C. idella kidney (CIK) cell line. In CIK cells, grass carp IFN1 (CiIFN1) and CiIFN3 are relatively highly expressed while CiIFN2 and CiIFN4 are relatively slightly expressed. Following GCRV infection, CiMDA5 induces a more extensive type I IFN response than CiRIG-I. Further investigation reveals that both CiMDA5 and CiRIG-I facilitate the expression and total phosphorylation levels of grass carp IFN regulatory factor (IRF) 3 (CiIRF3) and CiIRF7 upon GCRV infection or poly(I:C) stimulation. However, the difference is that CiRIG-I decreases the threonine phosphorylation level of CiIRF7. As a consequence, CiMDA5 enhances the heterodimerization of CiIRF3 and CiIRF7 and homodimerization of CiIRF7, whereas CiRIG-I facilitates the heterodimerization but attenuates homodimerization of CiIRF7. Moreover, the present study suggests that CiIRF3 and CiIRF7 heterodimers and CiIRF7 homodimers are able to induce more extensive IFN-I responses than CiIRF3 homodimers under GCRV infection. Additionally, CiMDA5 induces a stronger type II IFN (IFN-II) response against GCRV infection than CiRIG-I. Collectively, these results demonstrate that CiMDA5 plays a more potent role than CiRIG-I in IFN response to GCRV infection through differentially regulating the phosphorylation and dimerization of CiIRF3 and CiIRF7.
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Affiliation(s)
- Quanyuan Wan
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
| | - Chunrong Yang
- College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China
| | - Youliang Rao
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
| | - Zhiwei Liao
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
| | - Jianguo Su
- College of Fisheries, Huazhong Agricultural University , Wuhan , China
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Insights into the antiviral immunity against grass carp (Ctenopharyngodon idella) reovirus (GCRV) in grass carp. J Immunol Res 2015; 2015:670437. [PMID: 25759845 PMCID: PMC4337036 DOI: 10.1155/2015/670437] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/12/2014] [Indexed: 12/13/2022] Open
Abstract
Global fish production from aquaculture has rapidly grown over the past decades, and grass carp shares the largest portion. However, hemorrhagic disease caused by grass carp reovirus (GCRV) results in tremendous loss of grass carp (Ctenopharyngodon idella) industry. During the past years, development of molecular biology and cellular biology technologies has promoted significant advances in the understanding of the pathogen and the immune system. Immunoprophylaxis based on stimulation of the immune system of fish has also got some achievements. In this review, authors summarize the recent progresses in basic researches on GCRV; viral nucleic acid sensors, high-mobility group box proteins (HMGBs); pattern recognition receptors (PRRs), Toll-like receptors (TLRs) and retinoic acid inducible gene I- (RIG-I-) like receptors (RLRs); antiviral immune responses induced by PRRs-mediated signaling cascades of type I interferon (IFN-I) and IFN-stimulated genes (ISGs) activation. The present review also notices the potential applications of molecule genetic markers. Additionally, authors discuss the current preventive and therapeutic strategies (vaccines, RNAi, and prevention medicine) and highlight the importance of innate immunity in long term control for grass carp hemorrhagic disease.
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