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Lu H, Liu Z, Deng X, Chen S, Zhou R, Zhao R, Parandaman R, Thind A, Henley J, Tian L, Yu J, Comai L, Feng P, Yuan W. Potent NKT cell ligands overcome SARS-CoV-2 immune evasion to mitigate viral pathogenesis in mouse models. PLoS Pathog 2023; 19:e1011240. [PMID: 36961850 PMCID: PMC10128965 DOI: 10.1371/journal.ppat.1011240] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 04/25/2023] [Accepted: 02/24/2023] [Indexed: 03/25/2023] Open
Abstract
One of the major pathogenesis mechanisms of SARS-CoV-2 is its potent suppression of innate immunity, including blocking the production of type I interferons. However, it is unknown whether and how the virus interacts with different innate-like T cells, including NKT, MAIT and γδ T cells. Here we reported that upon SARS-CoV-2 infection, invariant NKT (iNKT) cells rapidly trafficked to infected lung tissues from the periphery. We discovered that the envelope (E) protein of SARS-CoV-2 efficiently down-regulated the cell surface expression of the antigen-presenting molecule, CD1d, to suppress the function of iNKT cells. E protein is a small membrane protein and a viroporin that plays important roles in virion packaging and envelopment during viral morphogenesis. We showed that the transmembrane domain of E protein was responsible for suppressing CD1d expression by specifically reducing the level of mature, post-ER forms of CD1d, suggesting that it suppressed the trafficking of CD1d proteins and led to their degradation. Point mutations demonstrated that the putative ion channel function was required for suppression of CD1d expression and inhibition of the ion channel function using small chemicals rescued the CD1d expression. Importantly, we discovered that among seven human coronaviruses, only E proteins from highly pathogenic coronaviruses including SARS-CoV-2, SARS-CoV and MERS suppressed CD1d expression, whereas the E proteins of human common cold coronaviruses, HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1, did not. These results suggested that E protein-mediated evasion of NKT cell function was likely an important pathogenesis factor, enhancing the virulence of these highly pathogenic coronaviruses. Remarkably, activation of iNKT cells with their glycolipid ligands, both prophylactically and therapeutically, overcame the putative viral immune evasion, significantly mitigated viral pathogenesis and improved host survival in mice. Our results suggested a novel NKT cell-based anti-SARS-CoV-2 therapeutic approach.
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Affiliation(s)
- Hongjia Lu
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Graduate Programs in Biomedical and Biological Sciences, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Zhewei Liu
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Xiangxue Deng
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Siyang Chen
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Ruiting Zhou
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Rongqi Zhao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Ramya Parandaman
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Amarjot Thind
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Jill Henley
- The Hastings and Wright Laboratories, Keck School of Medicine, University Southern California, California, United States of America
| | - Lei Tian
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, California, United States of America
| | - Jianhua Yu
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, California, United States of America
| | - Lucio Comai
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- The Hastings and Wright Laboratories, Keck School of Medicine, University Southern California, California, United States of America
| | - Pinghui Feng
- Section of Infection and Immunity, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, United States of America
| | - Weiming Yuan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
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Ghosh K, Amin SA, Gayen S, Jha T. Unmasking of crucial structural fragments for coronavirus protease inhibitors and its implications in COVID-19 drug discovery. J Mol Struct 2021; 1237:130366. [PMID: 33814612 PMCID: PMC7997030 DOI: 10.1016/j.molstruc.2021.130366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 03/19/2021] [Accepted: 03/20/2021] [Indexed: 12/19/2022]
Abstract
Fragment based drug discovery (FBDD) by the aid of different modelling techniques have been emerged as a key drug discovery tool in the area of pharmaceutical science and technology. The merits of employing these methods, in place of other conventional molecular modelling techniques, endorsed clear detection of the possible structural fragments present in diverse set of investigated compounds and can create alternate possibilities of lead optimization in drug discovery. In this work, two fragment identification tools namely SARpy and Laplacian-corrected Bayesian analysis were used for previous SARS-CoV PLpro and 3CLpro inhibitors. A robust and predictive SARpy based fragments identification was performed which have been validated further by Laplacian-corrected Bayesian model. These comprehensive approaches have advantages since fragments are straight forward to interpret. Moreover, distinguishing the key molecular features (with respect to ECFP_6 fingerprint) revealed good or bad influences for the SARS-CoV protease inhibitory activities. Furthermore, the identified fragments could be implemented in the medicinal chemistry endeavors of COVID-19 drug discovery.
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Affiliation(s)
- Kalyan Ghosh
- Laboratory of Drug Design and Discovery, Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, MP, India
| | - Sk Abdul Amin
- Natural Science Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India
| | - Shovanlal Gayen
- Laboratory of Drug Design and Discovery, Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, MP, India
| | - Tarun Jha
- Natural Science Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India
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Gorkhali R, Koirala P, Rijal S, Mainali A, Baral A, Bhattarai HK. Structure and Function of Major SARS-CoV-2 and SARS-CoV Proteins. Bioinform Biol Insights 2021; 15:11779322211025876. [PMID: 34220199 PMCID: PMC8221690 DOI: 10.1177/11779322211025876] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 05/25/2021] [Indexed: 01/20/2023] Open
Abstract
SARS-CoV-2 virus, the causative agent of COVID-19 pandemic, has a genomic organization consisting of 16 nonstructural proteins (nsps), 4 structural proteins, and 9 accessory proteins. Relative of SARS-CoV-2, SARS-CoV, has genomic organization, which is very similar. In this article, the function and structure of the proteins of SARS-CoV-2 and SARS-CoV are described in great detail. The nsps are expressed as a single or two polyproteins, which are then cleaved into individual proteins using two proteases of the virus, a chymotrypsin-like protease and a papain-like protease. The released proteins serve as centers of virus replication and transcription. Some of these nsps modulate the host’s translation and immune systems, while others help the virus evade the host immune system. Some of the nsps help form replication-transcription complex at double-membrane vesicles. Others, including one RNA-dependent RNA polymerase and one exonuclease, help in the polymerization of newly synthesized RNA of the virus and help minimize the mutation rate by proofreading. After synthesis of the viral RNA, it gets capped. The capping consists of adding GMP and a methylation mark, called cap 0 and additionally adding a methyl group to the terminal ribose called cap1. Capping is accomplished with the help of a helicase, which also helps remove a phosphate, two methyltransferases, and a scaffolding factor. Among the structural proteins, S protein forms the receptor of the virus, which latches on the angiotensin-converting enzyme 2 receptor of the host and N protein binds and protects the genomic RNA of the virus. The accessory proteins found in these viruses are small proteins with immune modulatory roles. Besides functions of these proteins, solved X-ray and cryogenic electron microscopy structures related to the function of the proteins along with comparisons to other coronavirus homologs have been described in the article. Finally, the rate of mutation of SARS-CoV-2 residues of the proteome during the 2020 pandemic has been described. Some proteins are mutated more often than other proteins, but the significance of these mutation rates is not fully understood.
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Affiliation(s)
- Ritesh Gorkhali
- Department of Biotechnology, Kathmandu University, Dhulikhel, Nepal
| | | | - Sadikshya Rijal
- Department of Biotechnology, Kathmandu University, Dhulikhel, Nepal
| | - Ashmita Mainali
- Department of Biotechnology, Kathmandu University, Dhulikhel, Nepal
| | - Adesh Baral
- Department of Biotechnology, Kathmandu University, Dhulikhel, Nepal
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Shang J, Han N, Chen Z, Peng Y, Li L, Zhou H, Ji C, Meng J, Jiang T, Wu A. Compositional diversity and evolutionary pattern of coronavirus accessory proteins. Brief Bioinform 2021; 22:1267-1278. [PMID: 33126244 PMCID: PMC7665327 DOI: 10.1093/bib/bbaa262] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/29/2020] [Indexed: 12/11/2022] Open
Abstract
Accessory proteins play important roles in the interaction between coronaviruses and their hosts. Accordingly, a comprehensive study of the compositional diversity and evolutionary patterns of accessory proteins is critical to understanding the host adaptation and epidemic variation of coronaviruses. Here, we developed a standardized genome annotation tool for coronavirus (CoroAnnoter) by combining open reading frame prediction, transcription regulatory sequence recognition and homologous alignment. Using CoroAnnoter, we annotated 39 representative coronavirus strains to form a compositional profile for all of the accessary proteins. Large variations were observed in the number of accessory proteins of 1–10 for different coronaviruses, with SARS-CoV-2 and SARS-CoV having the most (9 and 10, respectively). The variation between SARS-CoV and SARS-CoV-2 accessory proteins could be traced back to related coronaviruses in other hosts. The genomic distribution of accessory proteins had significant intra-genus conservation and inter-genus diversity and could be grouped into 1, 4, 2 and 1 types for alpha-, beta-, gamma-, and delta-coronaviruses, respectively. Evolutionary analysis suggested that accessory proteins are more conservative locating before the N-terminal of proteins E and M (E-M), while they are more diverse after these proteins. Furthermore, comparison of virus-host interaction networks of SARS-CoV-2 and SARS-CoV accessory proteins showed that they share multiple antiviral signaling pathways, those involved in the apoptotic process, viral life cycle and response to oxidative stress. In summary, our study provides a tool for coronavirus genome annotation and builds a comprehensive profile for coronavirus accessory proteins covering their composition, classification, evolutionary pattern and host interaction.
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Affiliation(s)
- Jingzhe Shang
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
| | - Na Han
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
| | - Ziyi Chen
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
| | | | - Liang Li
- Linyi people's hospital, Shandong, China
| | - Hangyu Zhou
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
| | - Chengyang Ji
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
| | - Jing Meng
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
| | - Taijiao Jiang
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Aiping Wu
- Suzhou Institute of Systems Medicine, Center for Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, Suzhou, China
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Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome contains nine open reading frames (ORFs) that encode for accessory proteins which, although dispensable for viral replication, are important for the modulation of the host infected cell metabolism and innate immunity evasion. Among those, the ORF8 gene encodes for the homonymous multifunctional, highly immunogenic, immunoglobulin-like protein that was recently found to inhibit presentation of viral antigens by class I major histocompatibility complex, suppress the type I interferon antiviral response and interact with host factors involved in pulmonary inflammation and fibrogenesis. Moreover, the ORF8 is a hypervariable gene rapidly evolving among SARS-related coronaviruses, with a tendency to recombine and undergo deletions that are deemed to facilitate the virus adaptation to the human host. Intriguingly, SARS-CoV-2 variants isolated in the beginning of the coronavirus disease 2019 (Covid-19) pandemic that were deleted of the ORF8 gene have been associated to milder symptoms and better disease outcome. This minireview summarizes the current knowledge on the SARS-CoV-2 ORF8 protein in perspective to its potential as antiviral target and with special emphasis on the biochemical, biophysical and structural aspects of its molecular biology.
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Mohammad S, Bouchama A, Mohammad Alharbi B, Rashid M, Saleem Khatlani T, Gaber NS, Malik SS. SARS-CoV-2 ORF8 and SARS-CoV ORF8ab: Genomic Divergence and Functional Convergence. Pathogens 2020; 9:E677. [PMID: 32825438 PMCID: PMC7558349 DOI: 10.3390/pathogens9090677] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 01/18/2023] Open
Abstract
The COVID-19 pandemic, in the first seven months, has led to more than 15 million confirmed infected cases and 600,000 deaths. SARS-CoV-2, the causative agent for COVID-19, has proved to be a great challenge for its ability to spread in asymptomatic stages and the diverse disease spectrum it has generated. This has created a challenge of unimaginable magnitude, not only affecting human health and life but also potentially generating a long-lasting socioeconomic impact. Both medical sciences and biomedical research have also been challenged, consequently leading to a large number of clinical trials and vaccine initiatives. While known proteins of pathobiological importance are targets for these therapeutic approaches, it is imperative to explore other factors of viral significance. Accessory proteins are one such trait that have diverse roles in coronavirus pathobiology. Here, we analyze certain genomic characteristics of SARS-CoV-2 accessory protein ORF8 and predict its protein features. We have further reviewed current available literature regarding its function and comparatively evaluated these and other features of ORF8 and ORF8ab, its homolog from SARS-CoV. Because coronaviruses have been infecting humans repeatedly and might continue to do so, we therefore expect this study to aid in the development of holistic understanding of these proteins. Despite low nucleotide and protein identity and differentiating genome level characteristics, there appears to be significant structural integrity and functional proximity between these proteins pointing towards their high significance. There is further need for comprehensive genomics and structural-functional studies to lead towards definitive conclusions regarding their criticality and that can eventually define their relevance to therapeutics development.
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Affiliation(s)
- Sameer Mohammad
- Experimental Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia; (S.M.); (A.B.); (B.M.A.); (N.S.G.)
| | - Abderrezak Bouchama
- Experimental Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia; (S.M.); (A.B.); (B.M.A.); (N.S.G.)
| | - Bothina Mohammad Alharbi
- Experimental Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia; (S.M.); (A.B.); (B.M.A.); (N.S.G.)
| | - Mamoon Rashid
- Bioinformatics and Biostatistics Department, King Abdullah International Medical Research Center, King~Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia;
| | - Tanveer Saleem Khatlani
- Stem Cells Unit, Department of Cellular Therapy, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia;
| | - Nusaibah S. Gaber
- Experimental Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia; (S.M.); (A.B.); (B.M.A.); (N.S.G.)
| | - Shuja Shafi Malik
- Experimental Medicine Department, King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, MNGHA, Riyadh 11426, Saudi Arabia; (S.M.); (A.B.); (B.M.A.); (N.S.G.)
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Shi CS, Nabar NR, Huang NN, Kehrl JH. SARS-Coronavirus Open Reading Frame-8b triggers intracellular stress pathways and activates NLRP3 inflammasomes. Cell Death Dis 2019. [PMID: 31231549 DOI: 10.1038/s41420‐019‐0181‐7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The SARS (severe acute respiratory syndrome) outbreak was caused by a coronavirus (CoV) named the SARS-CoV. SARS pathology is propagated both by direct cytotoxic effects of the virus and aberrant activation of the innate immune response. Here, we identify several mechanisms by which a SARS-CoV open reading frame (ORF) activates intracellular stress pathways and targets the innate immune response. We show that ORF8b forms insoluble intracellular aggregates dependent on a valine at residue 77. Aggregated ORF8b induces endoplasmic reticulum (ER) stress, lysosomal damage, and subsequent activation of the master regulator of the autophagy and lysosome machinery, Transcription factor EB (TFEB). ORF8b causes cell death in epithelial cells, which is partially rescued by reducing its ability to aggregate. In macrophages, ORF8b robustly activates the NLRP3 inflammasome by providing a potent signal 2 required for activation. Mechanistically, ORF8b interacts directly with the Leucine Rich Repeat domain of NLRP3 and localizes with NLRP3 and ASC in cytosolic dot-like structures. ORF8b triggers cell death consistent with pyroptotic cell death in macrophages. While in those cells lacking NLRP3 accumulating ORF8b cytosolic aggregates cause ER stress, mitochondrial dysfunction, and caspase-independent cell death.
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Affiliation(s)
- Chong-Shan Shi
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Neel R Nabar
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ning-Na Huang
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - John H Kehrl
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
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Shi CS, Nabar NR, Huang NN, Kehrl JH. SARS-Coronavirus Open Reading Frame-8b triggers intracellular stress pathways and activates NLRP3 inflammasomes. Cell Death Discov 2019; 5:101. [PMID: 31231549 PMCID: PMC6549181 DOI: 10.1038/s41420-019-0181-7] [Citation(s) in RCA: 307] [Impact Index Per Article: 61.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/30/2019] [Accepted: 05/13/2019] [Indexed: 12/23/2022] Open
Abstract
The SARS (severe acute respiratory syndrome) outbreak was caused by a coronavirus (CoV) named the SARS-CoV. SARS pathology is propagated both by direct cytotoxic effects of the virus and aberrant activation of the innate immune response. Here, we identify several mechanisms by which a SARS-CoV open reading frame (ORF) activates intracellular stress pathways and targets the innate immune response. We show that ORF8b forms insoluble intracellular aggregates dependent on a valine at residue 77. Aggregated ORF8b induces endoplasmic reticulum (ER) stress, lysosomal damage, and subsequent activation of the master regulator of the autophagy and lysosome machinery, Transcription factor EB (TFEB). ORF8b causes cell death in epithelial cells, which is partially rescued by reducing its ability to aggregate. In macrophages, ORF8b robustly activates the NLRP3 inflammasome by providing a potent signal 2 required for activation. Mechanistically, ORF8b interacts directly with the Leucine Rich Repeat domain of NLRP3 and localizes with NLRP3 and ASC in cytosolic dot-like structures. ORF8b triggers cell death consistent with pyroptotic cell death in macrophages. While in those cells lacking NLRP3 accumulating ORF8b cytosolic aggregates cause ER stress, mitochondrial dysfunction, and caspase-independent cell death.
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Affiliation(s)
- Chong-Shan Shi
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Neel R Nabar
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ning-Na Huang
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - John H Kehrl
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
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Abstract
BACKGROUND Coronaviruses (CoVs) primarily cause enzootic infections in birds and mammals but, in the last few decades, have shown to be capable of infecting humans as well. The outbreak of severe acute respiratory syndrome (SARS) in 2003 and, more recently, Middle-East respiratory syndrome (MERS) has demonstrated the lethality of CoVs when they cross the species barrier and infect humans. A renewed interest in coronaviral research has led to the discovery of several novel human CoVs and since then much progress has been made in understanding the CoV life cycle. The CoV envelope (E) protein is a small, integral membrane protein involved in several aspects of the virus' life cycle, such as assembly, budding, envelope formation, and pathogenesis. Recent studies have expanded on its structural motifs and topology, its functions as an ion-channelling viroporin, and its interactions with both other CoV proteins and host cell proteins. MAIN BODY This review aims to establish the current knowledge on CoV E by highlighting the recent progress that has been made and comparing it to previous knowledge. It also compares E to other viral proteins of a similar nature to speculate the relevance of these new findings. Good progress has been made but much still remains unknown and this review has identified some gaps in the current knowledge and made suggestions for consideration in future research. CONCLUSIONS The most progress has been made on SARS-CoV E, highlighting specific structural requirements for its functions in the CoV life cycle as well as mechanisms behind its pathogenesis. Data shows that E is involved in critical aspects of the viral life cycle and that CoVs lacking E make promising vaccine candidates. The high mortality rate of certain CoVs, along with their ease of transmission, underpins the need for more research into CoV molecular biology which can aid in the production of effective anti-coronaviral agents for both human CoVs and enzootic CoVs.
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Affiliation(s)
- Dewald Schoeman
- Molecular Biology and Virology Research Laboratory, Department of Medical Biosciences, University of the Western Cape, Cape Town, South Africa
| | - Burtram C Fielding
- Molecular Biology and Virology Research Laboratory, Department of Medical Biosciences, University of the Western Cape, Cape Town, South Africa.
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Yue Y, Nabar NR, Shi CS, Kamenyeva O, Xiao X, Hwang IY, Wang M, Kehrl JH. SARS-Coronavirus Open Reading Frame-3a drives multimodal necrotic cell death. Cell Death Dis 2018. [PMID: 30185776 DOI: 10.1038/s41419‐018‐0917‐y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The molecular mechanisms underlying the severe lung pathology that occurs during SARS-CoV infections remain incompletely understood. The largest of the SARS-CoV accessory protein open reading frames (SARS 3a) oligomerizes, dynamically inserting into late endosomal, lysosomal, and trans-Golgi-network membranes. While previously implicated in a non-inflammatory apoptotic cell death pathway, here we extend the range of SARS 3a pathophysiologic targets by examining its effects on necrotic cell death pathways. We show that SARS 3a interacts with Receptor Interacting Protein 3 (Rip3), which augments the oligomerization of SARS 3a helping drive necrotic cell death. In addition, by inserting into lysosomal membranes SARS 3a triggers lysosomal damage and dysfunction. Consequently, Transcription Factor EB (TFEB) translocates to the nucleus increasing the transcription of autophagy- and lysosome-related genes. Finally, SARS 3a activates caspase-1 either directly or via an enhanced potassium efflux, which triggers NLRP3 inflammasome assembly. In summary, Rip3-mediated oligomerization of SARS 3a causes necrotic cell death, lysosomal damage, and caspase-1 activation-all likely contributing to the clinical manifestations of SARS-CoV infection.
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Affiliation(s)
- Yuan Yue
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.,B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Neel R Nabar
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA. .,Department of Molecular, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden, 17165.
| | - Chong-Shan Shi
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Olena Kamenyeva
- Biological Imaging Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xun Xiao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.,B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Il-Young Hwang
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Min Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - John H Kehrl
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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11
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Yue Y, Nabar NR, Shi CS, Kamenyeva O, Xiao X, Hwang IY, Wang M, Kehrl JH. SARS-Coronavirus Open Reading Frame-3a drives multimodal necrotic cell death. Cell Death Dis 2018; 9:904. [PMID: 30185776 PMCID: PMC6125346 DOI: 10.1038/s41419-018-0917-y] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/29/2018] [Accepted: 07/22/2018] [Indexed: 02/05/2023]
Abstract
The molecular mechanisms underlying the severe lung pathology that occurs during SARS-CoV infections remain incompletely understood. The largest of the SARS-CoV accessory protein open reading frames (SARS 3a) oligomerizes, dynamically inserting into late endosomal, lysosomal, and trans-Golgi-network membranes. While previously implicated in a non-inflammatory apoptotic cell death pathway, here we extend the range of SARS 3a pathophysiologic targets by examining its effects on necrotic cell death pathways. We show that SARS 3a interacts with Receptor Interacting Protein 3 (Rip3), which augments the oligomerization of SARS 3a helping drive necrotic cell death. In addition, by inserting into lysosomal membranes SARS 3a triggers lysosomal damage and dysfunction. Consequently, Transcription Factor EB (TFEB) translocates to the nucleus increasing the transcription of autophagy- and lysosome-related genes. Finally, SARS 3a activates caspase-1 either directly or via an enhanced potassium efflux, which triggers NLRP3 inflammasome assembly. In summary, Rip3-mediated oligomerization of SARS 3a causes necrotic cell death, lysosomal damage, and caspase-1 activation—all likely contributing to the clinical manifestations of SARS-CoV infection.
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Affiliation(s)
- Yuan Yue
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.,B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Neel R Nabar
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA. .,Department of Molecular, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden, 17165.
| | - Chong-Shan Shi
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Olena Kamenyeva
- Biological Imaging Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xun Xiao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.,B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Il-Young Hwang
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Min Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - John H Kehrl
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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Wong HH, Fung TS, Fang S, Huang M, Le MT, Liu DX. Accessory proteins 8b and 8ab of severe acute respiratory syndrome coronavirus suppress the interferon signaling pathway by mediating ubiquitin-dependent rapid degradation of interferon regulatory factor 3. Virology 2017; 515:165-175. [PMID: 29294448 PMCID: PMC7112132 DOI: 10.1016/j.virol.2017.12.028] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 12/22/2017] [Accepted: 12/25/2017] [Indexed: 12/28/2022]
Abstract
Severe acute respiratory syndrome coronavirus (SARS-CoV) is an inefficient inducer of interferon (IFN) response. It expresses various proteins that effectively circumvent IFN production at different levels via distinct mechanisms. Through the construction of recombinant IBV expressing proteins 8a, 8b and 8ab encoded by SARS-CoV ORF8, we demonstrate that expression of 8b and 8ab enables the corresponding recombinant viruses to partially overcome the inhibitory actions of IFN activation to achieve higher replication efficiencies in cells. We also found that proteins 8b and 8ab could physically interact with IRF3. Overexpression of 8b and 8ab resulted in the reduction of poly (I:C)-induced IRF3 dimerization and inhibition of the IFN-β signaling pathway. This counteracting effect was partially mediated by protein 8b/8ab-induced degradation of IRF3 in a ubiquitin-proteasome-dependent manner. Taken together, we propose that SARS-CoV may exploit the unique functions of proteins 8b and 8ab as novel mechanisms to overcome the effect of IFN response during virus infection. Recombinant IBV expressing SARS-CoV protein 8b or 8ab replicates better than wild type in cells pre-treated with poly(I:C). 8b interacts with the IAD domain of IRF3. Overexpression of 8b or 8ab reduces poly(I:C)-induced IRF3 dimerization and interferon induction. 8b and 8ab induce degradation of IRF3 in a ubiquitin-proteasome-dependent manner. 8b and 8ab suppress interferon response induced by constitutively active IRF3.
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Affiliation(s)
- Hui Hui Wong
- South China Agricultural University, Guangdong Province Key Laboratory Microbial Signals & Disease Co, and Integrative Microbiology Research Centre, Guangzhou 510642, Guangdong, People's Republic of China; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore
| | - To Sing Fung
- South China Agricultural University, Guangdong Province Key Laboratory Microbial Signals & Disease Co, and Integrative Microbiology Research Centre, Guangzhou 510642, Guangdong, People's Republic of China
| | - Shouguo Fang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore; Agricultural School, Yangtze University, 266 Jingmilu, Jingzhou City, Hubei Province 434025, China
| | - Mei Huang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - My Tra Le
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore
| | - Ding Xiang Liu
- South China Agricultural University, Guangdong Province Key Laboratory Microbial Signals & Disease Co, and Integrative Microbiology Research Centre, Guangzhou 510642, Guangdong, People's Republic of China; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore.
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van Boheemen S, de Graaf M, Lauber C, Bestebroer TM, Raj VS, Zaki AM, Osterhaus AD, Haagmans BL, Gorbalenya AE, Snijder EJ, Fouchier RA. Genomic characterization of a newly discovered coronavirus associated with acute respiratory distress syndrome in humans. mBio 2012; 3:e00473-12. [PMID: 23170002 DOI: 10.1128/mBio.00473-12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED A novel human coronavirus (HCoV-EMC/2012) was isolated from a man with acute pneumonia and renal failure in June 2012. This report describes the complete genome sequence, genome organization, and expression strategy of HCoV-EMC/2012 and its relation with known coronaviruses. The genome contains 30,119 nucleotides and contains at least 10 predicted open reading frames, 9 of which are predicted to be expressed from a nested set of seven subgenomic mRNAs. Phylogenetic analysis of the replicase gene of coronaviruses with completely sequenced genomes showed that HCoV-EMC/2012 is most closely related to Tylonycteris bat coronavirus HKU4 (BtCoV-HKU4) and Pipistrellus bat coronavirus HKU5 (BtCoV-HKU5), which prototype two species in lineage C of the genus Betacoronavirus. In accordance with the guidelines of the International Committee on Taxonomy of Viruses, and in view of the 75% and 77% amino acid sequence identity in 7 conserved replicase domains with BtCoV-HKU4 and BtCoV-HKU5, respectively, we propose that HCoV-EMC/2012 prototypes a novel species in the genus Betacoronavirus. HCoV-EMC/2012 may be most closely related to a coronavirus detected in Pipistrellus pipistrellus in The Netherlands, but because only a short sequence from the most conserved part of the RNA-dependent RNA polymerase-encoding region of the genome was reported for this bat virus, its genetic distance from HCoV-EMC remains uncertain. HCoV-EMC/2012 is the sixth coronavirus known to infect humans and the first human virus within betacoronavirus lineage C. IMPORTANCE Coronaviruses are capable of infecting humans and many animal species. Most infections caused by human coronaviruses are relatively mild. However, the outbreak of severe acute respiratory syndrome (SARS) caused by SARS-CoV in 2002 to 2003 and the fatal infection of a human by HCoV-EMC/2012 in 2012 show that coronaviruses are able to cause severe, sometimes fatal disease in humans. We have determined the complete genome of HCoV-EMC/2012 using an unbiased virus discovery approach involving next-generation sequencing techniques, which enabled subsequent state-of-the-art bioinformatics, phylogenetics, and taxonomic analyses. By establishing its complete genome sequence, HCoV-EMC/2012 was characterized as a new genotype which is closely related to bat coronaviruses that are distant from SARS-CoV. We expect that this information will be vital to rapid advancement of both clinical and vital research on this emerging pathogen.
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van Boheemen S, de Graaf M, Lauber C, Bestebroer TM, Raj VS, Zaki AM, Osterhaus AD, Haagmans BL, Gorbalenya AE, Snijder EJ, Fouchier RA. Genomic characterization of a newly discovered coronavirus associated with acute respiratory distress syndrome in humans. mBio 2012; 3:e00473-12. [PMID: 23170002 DOI: 10.1128/mBio.00473-12] [Citation(s) in RCA: 639] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A novel human coronavirus (HCoV-EMC/2012) was isolated from a man with acute pneumonia and renal failure in June 2012. This report describes the complete genome sequence, genome organization, and expression strategy of HCoV-EMC/2012 and its relation with known coronaviruses. The genome contains 30,119 nucleotides and contains at least 10 predicted open reading frames, 9 of which are predicted to be expressed from a nested set of seven subgenomic mRNAs. Phylogenetic analysis of the replicase gene of coronaviruses with completely sequenced genomes showed that HCoV-EMC/2012 is most closely related to Tylonycteris bat coronavirus HKU4 (BtCoV-HKU4) and Pipistrellus bat coronavirus HKU5 (BtCoV-HKU5), which prototype two species in lineage C of the genus Betacoronavirus. In accordance with the guidelines of the International Committee on Taxonomy of Viruses, and in view of the 75% and 77% amino acid sequence identity in 7 conserved replicase domains with BtCoV-HKU4 and BtCoV-HKU5, respectively, we propose that HCoV-EMC/2012 prototypes a novel species in the genus Betacoronavirus. HCoV-EMC/2012 may be most closely related to a coronavirus detected in Pipistrellus pipistrellus in The Netherlands, but because only a short sequence from the most conserved part of the RNA-dependent RNA polymerase-encoding region of the genome was reported for this bat virus, its genetic distance from HCoV-EMC remains uncertain. HCoV-EMC/2012 is the sixth coronavirus known to infect humans and the first human virus within betacoronavirus lineage C. Coronaviruses are capable of infecting humans and many animal species. Most infections caused by human coronaviruses are relatively mild. However, the outbreak of severe acute respiratory syndrome (SARS) caused by SARS-CoV in 2002 to 2003 and the fatal infection of a human by HCoV-EMC/2012 in 2012 show that coronaviruses are able to cause severe, sometimes fatal disease in humans. We have determined the complete genome of HCoV-EMC/2012 using an unbiased virus discovery approach involving next-generation sequencing techniques, which enabled subsequent state-of-the-art bioinformatics, phylogenetics, and taxonomic analyses. By establishing its complete genome sequence, HCoV-EMC/2012 was characterized as a new genotype which is closely related to bat coronaviruses that are distant from SARS-CoV. We expect that this information will be vital to rapid advancement of both clinical and vital research on this emerging pathogen.
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15
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Ruch TR, Machamer CE. The coronavirus E protein: assembly and beyond. Viruses 2012; 4:363-82. [PMID: 22590676 DOI: 10.3390/v4030363] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 02/18/2012] [Accepted: 02/27/2012] [Indexed: 12/14/2022] Open
Abstract
The coronavirus E protein is a small membrane protein that has an important role in the assembly of virions. Recent studies have indicated that the E protein has functions during infection beyond assembly, including in virus egress and in the host stress response. Additionally, the E protein has ion channel activity, interacts with host proteins, and may have multiple membrane topologies. The goal of this review is to highlight the properties and functions of the E protein, and speculate on how they may be related.
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