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Zhou CM, Jiang ZZ, Liu N, Yu XJ. Current insights into human pathogenic phenuiviruses and the host immune system. Virulence 2024; 15:2384563. [PMID: 39072499 PMCID: PMC11290763 DOI: 10.1080/21505594.2024.2384563] [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: 05/22/2024] [Revised: 07/09/2024] [Accepted: 07/18/2024] [Indexed: 07/30/2024] Open
Abstract
Phenuiviruses are a class of segmented negative-sense single-stranded RNA viruses, typically consisting of three RNA segments that encode four distinct proteins. The emergence of pathogenic phenuivirus strains, such as Rift Valley fever phlebovirus (RVFV) in sub-Saharan Africa, Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) in East and Southeast Asia, and Heartland Virus (HRTV) in the United States has presented considerable challenges to global public health in recent years. The innate immune system plays a crucial role as the initial defense mechanism of the host against invading pathogens. In addition to continued research aimed at elucidating the epidemiological characteristics of phenuivirus, significant advancements have been made in investigating its viral virulence factors (glycoprotein, non-structural protein, and nucleoprotein) and potential host-pathogen interactions. Specifically, efforts have focused on understanding mechanisms of viral immune evasion, viral assembly and egress, and host immune networks involving immune cells, programmed cell death, inflammation, nucleic acid receptors, etc. Furthermore, a plethora of technological advancements, including metagenomics, metabolomics, single-cell transcriptomics, proteomics, gene editing, monoclonal antibodies, and vaccines, have been utilized to further our understanding of phenuivirus pathogenesis and host immune responses. Hence, this review aims to provide a comprehensive overview of the current understanding of the mechanisms of host recognition, viral immune evasion, and potential therapeutic approaches during human pathogenic phenuivirus infections focusing particularly on RVFV and SFTSV.
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Affiliation(s)
- Chuan-Min Zhou
- Gastrointestinal Disease Diagnosis and Treatment Center, The First Hospital of Hebei Medical University, Shijiazhuang, China
- Department of General Surgery, Hebei Key Laboratory of Colorectal Cancer Precision Diagnosis and Treatment, The First Hospital of Hebei Medical University, Shijiazhuang, China
- Central Laboratory, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ze-Zheng Jiang
- State Key Laboratory of Virology, School of Public Health, Wuhan University, Wuhan, China
| | - Ning Liu
- Department of Quality and Operations Management, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xue-Jie Yu
- State Key Laboratory of Virology, School of Public Health, Wuhan University, Wuhan, China
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2
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Scoles DR, Pulst SM. Control of innate immunity and lipid biosynthesis in neurodegeneration. Front Mol Neurosci 2024; 17:1402055. [PMID: 39156128 PMCID: PMC11328406 DOI: 10.3389/fnmol.2024.1402055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 07/09/2024] [Indexed: 08/20/2024] Open
Abstract
The cGAS-STING innate immunity pathway and the SREBP-activated cholesterol and fatty acid synthesis pathway are abnormally co-regulated in neurodegenerative disease. Activation of STING signaling occurs at the endoplasmic reticulum (ER) membrane with STING anchored by INSIG1 along with SREBP and the sterol-bound SREBP cleavage activating protein (SCAP) when sterols are in abundance. When sterols are low, the INSIG-dependent STING pathway is inactivated and the SREBP-SCAP complex is translocated to the Golgi where SREBP is cleaved and translocated to the nucleus to transactivate genes for cholesterol and fatty acid synthesis. Thus, there is inverse activation of STING vs. SREBP: when innate immunity is active, pathways for cholesterol and fatty acid synthesis are suppressed, and vice versa. The STING pathway is stimulated by foreign viral cytoplasmic nucleic acids interacting with the cyclic GMP-AMP synthase (cGAS) DNA sensor or RIG-I and MDA5 dsRNA sensors, but with neurodegeneration innate immunity is also activated by self-DNAs and double-stranded RNAs that accumulate with neuronal death. Downstream, activated STING recruits TBK1 and stimulates the transactivation of interferon stimulated genes and the autophagy pathway, which are both protective. However, chronic activation of innate immunity contributes to microglia activation, neuroinflammation and autophagy failure leading to neurodegeneration. STING is also a proton channel that when activated stimulates proton exit from STING vesicles leading to cell death. Here we review the salient features of the innate immunity and cholesterol and fatty acid synthesis pathways, observations of abnormal STING and SREBP signaling in neurodegenerative disease, and relevant therapeutic approaches.
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Affiliation(s)
- Daniel R. Scoles
- Department of Neurology, University of Utah, Salt Lake City, UT, United States
| | - Stefan M. Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT, United States
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3
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Li M. Innate immune response against vector-borne bunyavirus infection and viral countermeasures. Front Cell Infect Microbiol 2024; 14:1365221. [PMID: 38711929 PMCID: PMC11070517 DOI: 10.3389/fcimb.2024.1365221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 03/29/2024] [Indexed: 05/08/2024] Open
Abstract
Bunyaviruses are a large group of important viral pathogens that cause significant diseases in humans and animals worldwide. Bunyaviruses are enveloped, single-stranded, negative-sense RNA viruses that infect a wide range of hosts. Upon entry into host cells, the components of viruses are recognized by host innate immune system, leading to the activation of downstream signaling cascades to induce interferons (IFNs) and other proinflammatory cytokines. IFNs bind to their receptors and upregulate the expression of hundreds of interferon-stimulated genes (ISGs). Many ISGs have antiviral activities and confer an antiviral state to host cells. For efficient replication and spread, viruses have evolved different strategies to antagonize IFN-mediated restriction. Here, we discuss recent advances in our understanding of the interactions between bunyaviruses and host innate immune response.
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Affiliation(s)
- Minghua Li
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
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Zhang J, Shi H, Zhang L, Feng T, Chen J, Zhang X, Ji Z, Jing Z, Zhu X, Liu D, Yang X, Zeng M, Shi D, Feng L. Swine acute diarrhea syndrome coronavirus nucleocapsid protein antagonizes the IFN response through inhibiting TRIM25 oligomerization and functional activation of RIG-I/TRIM25. Vet Res 2024; 55:44. [PMID: 38589930 PMCID: PMC11000385 DOI: 10.1186/s13567-024-01303-z] [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: 12/27/2023] [Accepted: 03/20/2024] [Indexed: 04/10/2024] Open
Abstract
Swine acute diarrhea syndrome coronavirus (SADS-CoV), an emerging Alpha-coronavirus, brings huge economic loss in swine industry. Interferons (IFNs) participate in a frontline antiviral defense mechanism triggering the activation of numerous downstream antiviral genes. Here, we demonstrated that TRIM25 overexpression significantly inhibited SADS-CoV replication, whereas TRIM25 deficiency markedly increased viral yield. We found that SADS-CoV N protein suppressed interferon-beta (IFN-β) production induced by Sendai virus (SeV) or poly(I:C). Moreover, we determined that SADS-CoV N protein interacted with RIG-I N-terminal two caspase activation and recruitment domains (2CARDs) and TRIM25 coiled-coil dimerization (CCD) domain. The interaction of SADS-CoV N protein with RIG-I and TRIM25 caused TRIM25 multimerization inhibition, the RIG-I-TRIM25 interaction disruption, and consequent the IRF3 and TBK1 phosphorylation impediment. Overexpression of SADS-CoV N protein facilitated the replication of VSV-GFP by suppressing IFN-β production. Our results demonstrate that SADS-CoV N suppresses the host IFN response, thus highlighting the significant involvement of TRIM25 in regulating antiviral immune defenses.
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Affiliation(s)
- Jiyu Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Hongyan Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Liaoyuan Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Tingshuai Feng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Jianfei Chen
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Xin Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Zhaoyang Ji
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Zhaoyang Jing
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Xiaoyuan Zhu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Dakai Liu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Xiaoman Yang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Miaomiao Zeng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China
| | - Da Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China.
| | - Li Feng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xiangfang District, Haping Road 678, Harbin, 150069, China.
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Weber F, Bouloy M, Lozach PY. An Introduction to Rift Valley Fever Virus. Methods Mol Biol 2024; 2824:1-14. [PMID: 39039402 DOI: 10.1007/978-1-0716-3926-9_1] [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] [Indexed: 07/24/2024]
Abstract
Rift Valley fever virus (RVFV) is a pathogen transmitted to humans and livestock via mosquito bites. This virus, which was discovered in Kenya in 1930, is considered by the World Health Organization (WHO) and the World Organisation for Animal Health (WOAH) to be associated with a high risk of causing large-scale epidemics. However, means dedicated to fighting RVFV have been limited, and despite recent research efforts, the virus remains poorly understood at both the molecular and cellular levels as well as at a broader scale of research in the field and in animal and human populations. In this introductory chapter of a methods book, we aim to provide readers with a concise overview of RVFV, from its ecology and transmission to the structural and genomic organization of virions and its life cycle in host cells.
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Affiliation(s)
- Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Michèle Bouloy
- Institut Pasteur, Université Paris Cité, Bunyavirus Molecular Genetics Unit, Paris, France
| | - Pierre-Yves Lozach
- IVPC UMR754, INRAE, Université Claude Bernard Lyon 1, EPHE, PSL Research University, Lyon, France.
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Schoen A, Hölzer M, Müller MA, Wallerang KB, Drosten C, Marz M, Lamp B, Weber F. Functional comparisons of the virus sensor RIG-I from humans, the microbat Myotis daubentonii, and the megabat Rousettus aegyptiacus, and their response to SARS-CoV-2 infection. J Virol 2023; 97:e0020523. [PMID: 37728614 PMCID: PMC10653997 DOI: 10.1128/jvi.00205-23] [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: 02/07/2023] [Accepted: 07/09/2023] [Indexed: 09/21/2023] Open
Abstract
IMPORTANCE A common hypothesis holds that bats (order Chiroptera) are outstanding reservoirs for zoonotic viruses because of a special antiviral interferon (IFN) system. However, functional studies about key components of the bat IFN system are rare. RIG-I is a cellular sensor for viral RNA signatures that activates the antiviral signaling chain to induce IFN. We cloned and functionally characterized RIG-I genes from two species of the suborders Yangochiroptera and Yinpterochiroptera. The bat RIG-Is were conserved in their sequence and domain organization, and similar to human RIG-I in (i) mediating virus- and IFN-activated gene expression, (ii) antiviral signaling, (iii) temperature dependence, and (iv) recognition of RNA ligands. Moreover, RIG-I of Rousettus aegyptiacus (suborder Yinpterochiroptera) and of humans were found to recognize SARS-CoV-2 infection. Thus, members of both bat suborders encode RIG-Is that are comparable to their human counterpart. The ability of bats to harbor zoonotic viruses therefore seems due to other features.
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Affiliation(s)
- Andreas Schoen
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Martin Hölzer
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University Jena, Jena, Germany
- European Virus Bioinformatics Center, Jena, Germany
| | - Marcel A. Müller
- German Centre for Infection Research (DZIF), Partner Sites Giessen and Charité, Berlin, Germany
- Institute of Virology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Kai B. Wallerang
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Christian Drosten
- European Virus Bioinformatics Center, Jena, Germany
- German Centre for Infection Research (DZIF), Partner Sites Giessen and Charité, Berlin, Germany
- Institute of Virology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Manja Marz
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University Jena, Jena, Germany
- European Virus Bioinformatics Center, Jena, Germany
| | - Benjamin Lamp
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
- European Virus Bioinformatics Center, Jena, Germany
- German Centre for Infection Research (DZIF), Partner Sites Giessen and Charité, Berlin, Germany
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7
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Mohamed AA, Soler S, Wegner J, Bartok E, Stankovic S, Brooks AG, Schlee M. Influenza A Infection Stimulates RIG-I and Enhances Effector Function of Primary Human NK Cells. Int J Mol Sci 2023; 24:12220. [PMID: 37569596 PMCID: PMC10419028 DOI: 10.3390/ijms241512220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
Immune surveillance by natural killer (NK) cells and their recruitment to sites of inflammation renders them susceptible to viral infection, potentially modulating their effector function. Here, we analyzed innate RNA receptor signaling in NK cells downstream of direct Influenza A virus (IAV) infection and its impact on NK cell effector function. Infection of NK cells with IAV resulted in the activation of TBK1, NF-ϰB and subsequent type-I IFN secretion. CRISPR-generated knockouts in primary human NK cells revealed that this effect depended on the antiviral cytosolic RNA receptor RIG-I. Transfection of NK cells with synthetic 3p-dsRNA, a strong RIG-I agonist that mimics viral RNA, resulted in a similar phenotype and rendered NK cells resistant to subsequent IAV infection. Strikingly, both IAV infection and 3p-dsRNA transfection enhanced degranulation and cytokine production by NK cells when exposed to target cells. Thus, RIG-I activation in NK cells both supports their cell intrinsic viral defense and enhances their cytotoxic effector function against target cells.
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Affiliation(s)
- Adham Abuelola Mohamed
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53127 Bonn, Germany; (A.A.M.); (J.W.)
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3000, Australia; (S.S.); (A.G.B.)
| | - Sofía Soler
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, 53127 Bonn, Germany; (S.S.)
| | - Julia Wegner
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53127 Bonn, Germany; (A.A.M.); (J.W.)
| | - Eva Bartok
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, 53127 Bonn, Germany; (S.S.)
- Unit of Experimental Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
| | - Sanda Stankovic
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3000, Australia; (S.S.); (A.G.B.)
- Department of Respiratory Medicine, Alfred Hospital, Melbourne, VIC 3004, Australia
| | - Andrew G. Brooks
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3000, Australia; (S.S.); (A.G.B.)
| | - Martin Schlee
- Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53127 Bonn, Germany; (A.A.M.); (J.W.)
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Dinda B, Dinda M, Dinda S, De UC. An overview of anti-SARS-CoV-2 and anti-inflammatory potential of baicalein and its metabolite baicalin: Insights into molecular mechanisms. Eur J Med Chem 2023; 258:115629. [PMID: 37437351 DOI: 10.1016/j.ejmech.2023.115629] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/26/2023] [Accepted: 07/06/2023] [Indexed: 07/14/2023]
Abstract
The current Coronavirus Disease 2019 (COVID-19) pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is highly contagious infection that breaks the healthcare systems of several countries worldwide. Till to date, no effective antiviral drugs against COVID-19 infection have reached the market, and some repurposed drugs and vaccines are prescribed for the treatment and prevention of this disease. The currently prescribed COVID-19 vaccines are less effective against the newly emergent variants of concern of SARS-CoV-2 due to several mutations in viral spike protein and obviously there is an urgency to develop new antiviral drugs against this disease. In this review article, we systematically discussed the anti-SARS-CoV-2 and anti-inflammatory efficacy of two flavonoids, baicalein and its 7-O-glucuronide, baicalin, isolated from Scutellaria baicalensis, Oroxylum indicum, and other plants as well as their pharmacokinetics and oral bioavailability, for development of safe and effective drugs for COVID-19 treatment. Both baicalein and baicalin target the activities of viral S-, 3CL-, PL-, RdRp- and nsp13-proteins, and host mitochondrial OXPHOS for suppression of viral infection. Moreover, these compounds prevent sepsis-related inflammation and organ injury by modulation of host innate immune responses. Several nanoformulated and inclusion complexes of baicalein and baicalin have been reported to increase oral bioavailability, but their safety and efficacy in SARS-CoV-2-infected transgenic animals are not yet evaluated. Future studies on these compounds are required for use in clinical trials of COVID-19 patients.
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Affiliation(s)
- Biswanath Dinda
- Department of Chemistry, Tripura University, Suryamaninagar, Agartala, Tripura, India.
| | - Manikarna Dinda
- Department of Biochemistry and Molecular Genetics, University of Virginia, School of Medicine, Charlottesville, VA, USA
| | - Subhajit Dinda
- Department of Chemistry, Government Degree College, Kamalpur, Dhalai, Tripura, India
| | - Utpal Chandra De
- Department of Chemistry, Tripura University, Suryamaninagar, Agartala, Tripura, India
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Fu C, Zhu W, Cao N, Liu W, Lu Z, Wong Z, Guan K, Hu C, Han B, Zeng S, Fan S. Role of CIV NS1 Protein in Innate Immunity and Viral Replication. Int J Mol Sci 2023; 24:10056. [PMID: 37373204 DOI: 10.3390/ijms241210056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/23/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
The innate immune pathway serves as the first line of defense against viral infections and plays a crucial role in the host's immune response in clearing viruses. Prior research has indicated that the influenza A virus has developed various strategies to avoid host immune responses. Nevertheless, the role of the NS1 protein of the canine influenza virus (CIV) in the innate immune pathway remains unclear. In this study, eukaryotic plasmids of NS1, NP, PA, PB1, and PB2 were constructed, and it was found that these proteins interact with melanoma differentiation-associated gene 5 (MDA5) and antagonize the activation of IFN-β promoters by MDA5. We selected the NS1 protein for further study and found that NS1 does not affect the interaction between the viral ribonucleoprotein (RNP) subunit and MDA5, but that it downregulates the expression of the laboratory of genetics and physiology 2 (LGP2) and retinoic acid-inducible gene-I (RIG-I) receptors in the RIG-I pathway. Additionally, NS1 was found to inhibit the expression of several antiviral proteins and cytokines, including MX dynamin like GTPase 1 (MX1), 2'-5'oligoadenylate synthetase (OAS), Signal Transducers and Activators of Transcription (STAT1), tripartite motif 25 (TRIM25), interleukin-2 (IL-2), IFN, IL-8, and IL-1β. To further investigate the role of NS1, a recombinant H3N2 virus strain (rH3N2) and an NS1-null virus (rH3N2ΔNS1) were rescued using reverse-genetic technology. The rH3N2ΔNS1 virus exhibited lower viral titers compared to rH3N2, but had a stronger activation effect on the receptors LGP2 and RIG-I. Furthermore, when compared to rH3N2, rH3N2ΔNS1 exhibited a more pronounced activation of antiviral proteins such as MX1, OAS, STAT1, and TRIM25, as well as antiviral cytokines such as IL-6, IFN-β, and IL-1β. These findings suggest a new mechanism by which NS1, a nonstructural protein of CIV, facilitates innate immune signaling and provides new avenues for the development of antiviral strategies.
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Affiliation(s)
- Cheng Fu
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Wenhui Zhu
- College of Veterinary Medicine, South China Agricultural University, No. 483, Wushan Road, Tianhe District, Guangzhou 510000, China
| | - Nan Cao
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Wenjun Liu
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Zhier Lu
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Ziyuan Wong
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Kaiting Guan
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Chunyan Hu
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Baoting Han
- College of Animal Science & Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Sen Zeng
- College of Veterinary Medicine, South China Agricultural University, No. 483, Wushan Road, Tianhe District, Guangzhou 510000, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, No. 483, Wushan Road, Tianhe District, Guangzhou 510000, China
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Oh S, Lee S. Recent advances in ZBP1-derived PANoptosis against viral infections. Front Immunol 2023; 14:1148727. [PMID: 37261341 PMCID: PMC10228733 DOI: 10.3389/fimmu.2023.1148727] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/03/2023] [Indexed: 06/02/2023] Open
Abstract
Innate immunity is an important first line of defense against pathogens, including viruses. These pathogen- and damage-associated molecular patterns (PAMPs and DAMPs, respectively), resulting in the induction of inflammatory cell death, are detected by specific innate immune sensors. Recently, Z-DNA binding protein 1 (ZBP1), also called the DNA-dependent activator of IFN regulatory factor (DAI) or DLM1, is reported to regulate inflammatory cell death as a central mediator during viral infection. ZBP1 is an interferon (IFN)-inducible gene that contains two Z-form nucleic acid-binding domains (Zα1 and Zα2) in the N-terminus and two receptor-interacting protein homotypic interaction motifs (RHIM1 and RHIM2) in the middle, which interact with other proteins with the RHIM domain. By sensing the entry of viral RNA, ZBP1 induces PANoptosis, which protects host cells against viral infections, such as influenza A virus (IAV) and herpes simplex virus (HSV1). However, some viruses, particularly coronaviruses (CoVs), induce PANoptosis to hyperactivate the immune system, leading to cytokine storm, organ failure, tissue damage, and even death. In this review, we discuss the molecular mechanism of ZBP1-derived PANoptosis and pro-inflammatory cytokines that influence the double-edged sword of results in the host cell. Understanding the ZBP1-derived PANoptosis mechanism may be critical for improving therapeutic strategies.
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Zheng J, Shi W, Yang Z, Chen J, Qi A, Yang Y, Deng Y, Yang D, Song N, Song B, Luo D. RIG-I-like receptors: Molecular mechanism of activation and signaling. Adv Immunol 2023; 158:1-74. [PMID: 37453753 DOI: 10.1016/bs.ai.2023.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
During RNA viral infection, RIG-I-like receptors (RLRs) recognize the intracellular pathogenic RNA species derived from viral replication and activate antiviral innate immune response by stimulating type 1 interferon expression. Three RLR members, namely, RIG-I, MDA5, and LGP2 are homologous and belong to a subgroup of superfamily 2 Helicase/ATPase that is preferably activated by double-stranded RNA. RLRs are significantly different in gene architecture, RNA ligand preference, activation, and molecular functions. As switchable macromolecular sensors, RLRs' activities are tightly regulated by RNA ligands, ATP, posttranslational modifications, and cellular cofactors. We provide a comprehensive review of the structure and function of the RLRs and summarize the molecular understanding of sensing and signaling events during the RLR activation process. The key roles RLR signaling play in both anti-infection and immune disease conditions highlight the therapeutic potential in targeting this important molecular pathway.
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Affiliation(s)
- Jie Zheng
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, China; Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Wenjia Shi
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ziqun Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jin Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ao Qi
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, China; Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yulin Yang
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, China; Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ying Deng
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Dongyuan Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ning Song
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Bin Song
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Dahai Luo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore.
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12
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Labzin LI, Chew KY, Eschke K, Wang X, Esposito T, Stocks CJ, Rae J, Patrick R, Mostafavi H, Hill B, Yordanov TE, Holley CL, Emming S, Fritzlar S, Mordant FL, Steinfort DP, Subbarao K, Nefzger CM, Lagendijk AK, Gordon EJ, Parton RG, Short KR, Londrigan SL, Schroder K. Macrophage ACE2 is necessary for SARS-CoV-2 replication and subsequent cytokine responses that restrict continued virion release. Sci Signal 2023; 16:eabq1366. [PMID: 37098119 DOI: 10.1126/scisignal.abq1366] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Macrophages are key cellular contributors to the pathogenesis of COVID-19, the disease caused by the virus SARS-CoV-2. The SARS-CoV-2 entry receptor ACE2 is present only on a subset of macrophages at sites of SARS-CoV-2 infection in humans. Here, we investigated whether SARS-CoV-2 can enter macrophages, replicate, and release new viral progeny; whether macrophages need to sense a replicating virus to drive cytokine release; and, if so, whether ACE2 is involved in these mechanisms. We found that SARS-CoV-2 could enter, but did not replicate within, ACE2-deficient human primary macrophages and did not induce proinflammatory cytokine expression. By contrast, ACE2 overexpression in human THP-1-derived macrophages permitted SARS-CoV-2 entry, processing and replication, and virion release. ACE2-overexpressing THP-1 macrophages sensed active viral replication and triggered proinflammatory, antiviral programs mediated by the kinase TBK-1 that limited prolonged viral replication and release. These findings help elucidate the role of ACE2 and its absence in macrophage responses to SARS-CoV-2 infection.
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Affiliation(s)
- Larisa I Labzin
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Keng Yih Chew
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Kathrin Eschke
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Xiaohui Wang
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
| | - Tyron Esposito
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
| | - Claudia J Stocks
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
| | - James Rae
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD 4072, Australia
| | - Ralph Patrick
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Helen Mostafavi
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Brittany Hill
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Teodor E Yordanov
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Caroline L Holley
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
| | - Stefan Emming
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
| | - Svenja Fritzlar
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Francesca L Mordant
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Daniel P Steinfort
- Department of Medicine, University of Melbourne, Parkville, VIC 3010, Australia
- Department of Respiratory Medicine, Royal Melbourne Hospital, Parkville, VIC 3052, Australia
| | - Kanta Subbarao
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Christian M Nefzger
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Anne K Lagendijk
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Emma J Gordon
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD 4072, Australia
| | - Kirsty R Short
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Sarah L Londrigan
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Kate Schroder
- Institute for Molecular Bioscience (IMB), University of Queensland, Brisbane, QLD 4072, Australia
- IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia
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13
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Ke PY. Crosstalk between Autophagy and RLR Signaling. Cells 2023; 12:cells12060956. [PMID: 36980296 PMCID: PMC10047499 DOI: 10.3390/cells12060956] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Autophagy plays a homeostatic role in regulating cellular metabolism by degrading unwanted intracellular materials and acts as a host defense mechanism by eliminating infecting pathogens, such as viruses. Upon viral infection, host cells often activate retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling to induce the transcription of type I interferons, thus establishing the first line of the innate antiviral response. In recent years, numerous studies have shown that virus-mediated autophagy activation may benefit viral replication through different actions on host cellular processes, including the modulation of RLR-mediated innate immunity. Here, an overview of the functional molecules and regulatory mechanism of the RLR antiviral immune response as well as autophagy is presented. Moreover, a summary of the current knowledge on the biological role of autophagy in regulating RLR antiviral signaling is provided. The molecular mechanisms underlying the crosstalk between autophagy and RLR innate immunity are also discussed.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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14
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You H, Wang L, Wang J, Lv C, Xu L, Yuan F, Li J, Wu M, Zhou S, Da Z, Qian J, Wei H, Yan W, Zhou L, Wang Y, Yin S, Zhou D, Wu J, Lu Y, Su D, Liu Z, Liu L, Ma L, Xu X, Zang Y, Liu H, Ren T, Wang F, Zhang M, Tan W. Time-dependent changes in RPILD and mortality risk in anti-MDA5+ DM patients: a cohort study of 272 cases in China. Rheumatology (Oxford) 2023; 62:1216-1226. [PMID: 35961045 DOI: 10.1093/rheumatology/keac450] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/04/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Anti-melanoma differentiation-associated gene 5 positive (anti-MDA5+) DM has a close relationship with rapidly progressive interstitial lung disease (RPILD) and is associated with high mortality. However, data regarding the time-dependent risk of RPILD and deaths during disease progression are limited. We conducted this study to investigate whether the risk of RPILD and death were time-dependent or not in anti-MDA5+ DM. METHODS We assessed a cohort of 272 patients with anti-MDA5+ DM. The clinical characteristics of patients with anti-MDA5+ were collected, and COX regression was used to analyse independent risk factors for RPILD and death. We also described changes in risk of RPILD and death over time and their potential clinical implications. RESULTS There were 272 anti-MDA5+ DM patients enrolled in this study. According to the multivariate cox regression analysis, short disease course, high CRP level, anti-Ro52 positive and anti-MDA5 titre (++∼+++) were independent risk factors of RPILD. High creatine kinase level, high CRP level and RPILD were independent risk factors for death, and >90% RPILD and 84% mortality occurred in the first 6 months after disease onset. Notably, the first 3 months is a particularly high-risk period, with 50% of RPILD and 46% of deaths occurring. Hazards regarding RPILD and mortality diminished over time during a median follow-up of 12 months. CONCLUSION These results suggest significant, time-dependent changes in RPILD and mortality risk in anti-MDA5+ DM patients, providing a cut-off time window to estimate disease progression and poor prognosis.
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Affiliation(s)
- Hanxiao You
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Lei Wang
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Jiajia Wang
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Chengyin Lv
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Lingxiao Xu
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Fenghong Yuan
- Department of Rheumatology and Immunology, the Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi
| | - Ju Li
- Department of Rheumatology, Huai'an First People's Hospital, Huai'an
| | - Min Wu
- Department of Rheumatology, The First People's Hospital of Changzhou, Changzhou
| | - Shiliang Zhou
- Department of Rheumatology, The First People's Hospital of Changzhou, Changzhou
| | - Zhanyun Da
- Department of Rheumatology, Affiliated Hospital of Nantong University, Nantong
| | - Jie Qian
- Department of Rheumatology, Affiliated Hospital of Nantong University, Nantong
| | - Hua Wei
- Department of Rheumatology, Northern Jiangsu People's Hospital, Yangzhou
| | - Wei Yan
- Department of Rheumatology, Northern Jiangsu People's Hospital, Yangzhou
| | - Lei Zhou
- Department of Rheumatology, Changzhou No.2 People's Hospital, Changzhou
| | - Yan Wang
- Department of Rheumatology, Changzhou No.2 People's Hospital, Changzhou
| | - Songlou Yin
- Department of Rheumatology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou
| | - Dongmei Zhou
- Department of Rheumatology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou
| | - Jian Wu
- Department of Rheumatology, The First Affiliated Hospital of Soochow University, Suzhou
| | - Yan Lu
- Department of Rheumatology, Jiangsu Province Hospital of Chinese Medicine
| | - Dinglei Su
- Department of Rheumatology, Nanjing First Hospital, Nanjing
| | - Zhichun Liu
- Department of Rheumatology, The Second Affiliated Hospital of Soochow University, Suzhou
| | - Lin Liu
- Department of Rheumatology, Xuzhou Central Hospital, Xuzhou
| | - Longxin Ma
- Department of Rheumatology, Yancheng No.1 People's Hospital, Yancheng
| | - Xiaoyan Xu
- Department of Rheumatology, Zhongda Hospital Southeast University, Nanjing
| | - Yinshan Zang
- Department of Rheumatology, The Affiliated Suqian First People's Hospital of Nanjing Medical University, Suqian
| | - Huijie Liu
- Department of Rheumatology, The First People's Hospital of Lianyungang, Lianyungang
| | - Tianli Ren
- Department of Rheumatology, Wuxi No.2 People's Hospital, Wuxi
| | - Fang Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, China, Nanjing, Jiangsu, China
| | - Miaojia Zhang
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
| | - Wenfeng Tan
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing
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15
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Tercero B, Terasaki K, Narayanan K, Makino S. Mechanistic insight into the efficient packaging of antigenomic S RNA into Rift Valley fever virus particles. Front Cell Infect Microbiol 2023; 13:1132757. [PMID: 36875526 PMCID: PMC9978001 DOI: 10.3389/fcimb.2023.1132757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 02/06/2023] [Indexed: 02/18/2023] Open
Abstract
Rift Valley fever virus (RVFV), a bunyavirus, has a single-stranded, negative-sense tri-segmented RNA genome, consisting of L, M and S RNAs. An infectious virion carries two envelope glycoproteins, Gn and Gc, along with ribonucleoprotein complexes composed of encapsidated viral RNA segments. The antigenomic S RNA, which serves as the template of the mRNA encoding a nonstructural protein, NSs, an interferon antagonist, is also efficiently packaged into RVFV particles. An interaction between Gn and viral ribonucleoprotein complexes, including the direct binding of Gn to viral RNAs, drives viral RNA packaging into RVFV particles. To understand the mechanism of efficient antigenomic S RNA packaging in RVFV, we identified the regions in viral RNAs that directly interact with Gn by performing UV-crosslinking and immunoprecipitation of RVFV-infected cell lysates with anti-Gn antibody followed by high-throughput sequencing analysis (CLIP-seq analysis). Our data suggested the presence of multiple Gn-binding sites in RVFV RNAs, including a prominent Gn-binding site within the 3' noncoding region of the antigenomic S RNA. We found that the efficient packaging of antigenomic S RNA was abrogated in a RVFV mutant lacking a part of this prominent Gn-binding site within the 3' noncoding region. Also, the mutant RVFV, but not the parental RVFV, triggered the early induction of interferon-β mRNA expression after infection. These data suggest that the direct binding of Gn to the RNA element within the 3' noncoding region of the antigenomic S RNA promoted the efficient packaging of antigenomic S RNA into virions. Furthermore, the efficient packaging of antigenomic S RNA into RVFV particles, driven by the RNA element, facilitated the synthesis of viral mRNA encoding NSs immediately after infection, resulting in the suppression of interferon-β mRNA expression.
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Affiliation(s)
- Breanna Tercero
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, United States
| | - Kaori Terasaki
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, The University of Texas Medical Branch, Galveston, TX, United States
| | - Krishna Narayanan
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, United States
| | - Shinji Makino
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, The University of Texas Medical Branch, Galveston, TX, United States
- Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch, Galveston, TX, United States
- UTMB Center for Tropical Diseases, The University of Texas Medical Branch, Galveston, TX, United States
- The Sealy Institute for Vaccine Sciences, The University of Texas Medical Branch, Galveston, TX, United States
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16
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Malet H, Williams HM, Cusack S, Rosenthal M. The mechanism of genome replication and transcription in bunyaviruses. PLoS Pathog 2023; 19:e1011060. [PMID: 36634042 PMCID: PMC9836281 DOI: 10.1371/journal.ppat.1011060] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Bunyaviruses are negative sense, single-strand RNA viruses that infect a wide range of vertebrate, invertebrate and plant hosts. WHO lists three bunyavirus diseases as priority diseases requiring urgent development of medical countermeasures highlighting their high epidemic potential. While the viral large (L) protein containing the RNA-dependent RNA polymerase is a key enzyme in the viral replication cycle and therefore a suitable drug target, our knowledge on the structure and activities of this multifunctional protein has, until recently, been very limited. However, in the last few years, facilitated by the technical advances in the field of cryogenic electron microscopy, many structures of bunyavirus L proteins have been solved. These structures significantly enhance our mechanistic understanding of bunyavirus genome replication and transcription processes and highlight differences and commonalities between the L proteins of different bunyavirus families. Here, we provide a review of our current understanding of genome replication and transcription in bunyaviruses with a focus on the viral L protein. Further, we compare within bunyaviruses and with the related influenza virus polymerase complex and highlight open questions.
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Affiliation(s)
- Hélène Malet
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
- Institut Universitaire de France (IUF), Paris, France
| | - Harry M. Williams
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
| | | | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
- * E-mail:
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17
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Thoresen DT, Galls D, Götte B, Wang W, Pyle AM. A rapid RIG-I signaling relay mediates efficient antiviral response. Mol Cell 2023; 83:90-104.e4. [PMID: 36521492 PMCID: PMC9825657 DOI: 10.1016/j.molcel.2022.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/11/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022]
Abstract
RIG-I is essential for host defense against viral pathogens, as it triggers the release of type I interferons upon encounter with viral RNA molecules. In this study, we show that RIG-I is rapidly and efficiently activated by small quantities of incoming viral RNA and that it relies exclusively on the constitutively expressed resident pool of RIG-I receptors for a strong antiviral response. Live-cell imaging of RIG-I following stimulation with viral or synthetic dsRNA reveals that RIG-I signaling occurs without mass aggregation at the mitochondrial membrane. By contrast, interferon-induced RIG-I protein becomes embedded in cytosolic aggregates that are functionally unrelated to signaling. These findings suggest that endogenous RIG-I efficiently recognizes viral RNA and rapidly relays an antiviral signal to MAVS via a transient signaling complex and that cellular aggregates of RIG-I have a function that is distinct from signaling.
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Affiliation(s)
- Daniel T Thoresen
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Drew Galls
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Benjamin Götte
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Wenshuai Wang
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Anna M Pyle
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA; Department of Chemistry, Yale University, New Haven, CT, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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18
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Yang K, Feng S, Luo Z. Oncolytic Adenovirus, a New Treatment Strategy for Prostate Cancer. Biomedicines 2022; 10:biomedicines10123262. [PMID: 36552019 PMCID: PMC9775875 DOI: 10.3390/biomedicines10123262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Prostate cancer is the most common cancer and one of the leading causes of cancer mortality in males. Androgen-deprivation therapy (ADT) is an effective strategy to inhibit tumour growth at early stages. However, 10~50% of cases are estimated to progress to metastatic castration-resistant prostate cancer (mCRPC) which currently lacks effective treatments. Clinically, salvage treatment measures, such as endocrine therapy and chemotherapy, are mostly used for advanced prostate cancer, but their clinical outcomes are not ideal. When the existing clinical therapeutic methods can no longer inhibit the development of advanced prostate cancer, human adenovirus (HAdV)-based gene therapy and viral therapy present promising effects. Pre-clinical studies have shown its powerful oncolytic effect, and clinical studies are ongoing to further verify its effect and safety in prostate cancer treatment. Targeting the prostate by HAdV alone or in combination with radiotherapy and chemotherapy sheds light on patients with castration-resistant and advanced prostate cancer. This review summarizes the advantages of oncolytic virus-mediated cancer therapy, strategies of HAdV modification, and existing preclinical and clinical investigations of HAdV-mediated gene therapy to further evaluate the potential of oncolytic adenovirus in prostate cancer treatment.
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Affiliation(s)
- Kaiyi Yang
- Department of Urology, Xiangya Hospital, Central South University, Changsha 410008, China
- Correspondence: (K.Y.); (Z.L.)
| | - Shenghui Feng
- Provincial Key Laboratory of Tumour Pathogens and Molecular Pathology, Queen Mary School, Nanchang University, Nanchang 330031, China
| | - Zhijun Luo
- Provincial Key Laboratory of Tumour Pathogens and Molecular Pathology, Queen Mary School, Nanchang University, Nanchang 330031, China
- Correspondence: (K.Y.); (Z.L.)
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19
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Avian Influenza NS1 Proteins Inhibit Human, but Not Duck, RIG-I Ubiquitination and Interferon Signaling. J Virol 2022; 96:e0077622. [PMID: 36069546 PMCID: PMC9517716 DOI: 10.1128/jvi.00776-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The nonstructural protein 1 (NS1) of influenza A viruses is an important virulence factor that controls host cell immune responses. In human cells, NS1 proteins inhibit the induction of type I interferon by several mechanisms, including potentially, by preventing the activation of the retinoic acid-inducible gene I (RIG-I) receptor by the ubiquitin ligase tripartite motif-containing protein 25 (TRIM25). It is unclear whether the inhibition of human TRIM25 is a universal function of all influenza A NS1 proteins or is strain dependent. It is also unclear if NS1 proteins similarly target the TRIM25 of mallard ducks, a natural reservoir host of avian influenza viruses with a long coevolutionary history and unique disease dynamics. To answer these questions, we compared the ability of five different NS1 proteins to interact with human and duck TRIM25 using coimmunoprecipitation and microscopy and assessed the consequence of this on RIG-I ubiquitination and signaling in both species. We show that NS1 proteins from low-pathogenic and highly pathogenic avian influenza viruses potently inhibit RIG-I ubiquitination and reduce interferon promoter activity and interferon-beta protein secretion in transfected human cells, while the NS1 of the mouse-adapted PR8 strain does not. However, all the NS1 proteins, when cloned into recombinant viruses, suppress interferon in infected alveolar cells. In contrast, avian NS1 proteins do not suppress duck RIG-I ubiquitination and interferon promoter activity, despite interacting with duck TRIM25. IMPORTANCE Influenza A viruses are a major cause of human and animal disease. Periodically, avian influenza viruses from wild waterfowl, such as ducks, pass through intermediate agricultural hosts and emerge into the human population as zoonotic diseases with high mortality rates and epidemic potential. Because of their coevolution with influenza A viruses, ducks are uniquely resistant to influenza disease compared to other birds, animals, and humans. Here, we investigate a mechanism of influenza A virus interference in an important antiviral signaling pathway that is orthologous in humans and ducks. We show that NS1 proteins from four avian influenza strains can block the coactivation and signaling of the human RIG-I antiviral receptor, while none block the coactivation and signaling of duck RIG-I. Understanding host-pathogen dynamics in the natural reservoir will contribute to our understanding of viral disease mechanisms, viral evolution, and the pressures that drive it, which benefits global surveillance and outbreak prevention.
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20
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Tanaka Y, Morita N, Kitagawa Y, Gotoh B, Komatsu T. Human metapneumovirus M2-2 protein inhibits RIG-I signaling by preventing TRIM25-mediated RIG-I ubiquitination. Front Immunol 2022; 13:970750. [PMID: 36045682 PMCID: PMC9421128 DOI: 10.3389/fimmu.2022.970750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 07/21/2022] [Indexed: 11/13/2022] Open
Abstract
Retinoic acid-inducible gene I (RIG-I) is a receptor that senses viral RNA and interacts with mitochondrial antiviral signaling (MAVS) protein, leading to the production of type I interferons and inflammatory cytokines to establish an antiviral state. This signaling axis is initiated by the K63-linked RIG-I ubiquitination, mediated by E3 ubiquitin ligases such as TRIM25. However, many viruses, including several members of the family Paramyxoviridae and human respiratory syncytial virus (HRSV), a member of the family Pneumoviridae, escape the immune system by targeting RIG-I/TRIM25 signaling. In this study, we screened human metapneumovirus (HMPV) open reading frames (ORFs) for their ability to block RIG-I signaling reconstituted in HEK293T cells by transfection with TRIM25 and RIG-I CARD (an N-terminal CARD domain that is constitutively active in RIG-I signaling). HMPV M2-2 was the most potent inhibitor of RIG-I/TRIM25-mediated interferon (IFN)-β activation. M2-2 silencing induced the activation of transcription factors (IRF and NF-kB) downstream of RIG-I signaling in A549 cells. Moreover, M2-2 inhibited RIG-I ubiquitination and CARD-dependent interactions with MAVS. Immunoprecipitation revealed that M2-2 forms a stable complex with RIG-I CARD/TRIM25 via direct interaction with the SPRY domain of TRIM25. Similarly, HRSV NS1 also formed a stable complex with RIG-I CARD/TRIM25 and inhibited RIG-I ubiquitination. Notably, the inhibitory actions of HMPV M2-2 and HRSV NS1 are similar to those of V proteins of several members of the Paramyxoviridae family. In this study, we have identified a novel mechanism of immune escape by HMPV, similar to that of Pneumoviridae and Paramyxoviridae family members.
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Affiliation(s)
- Yukie Tanaka
- Department of Integrative Vascular Biology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Naoko Morita
- Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
| | - Yoshinori Kitagawa
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Shiga, Japan
| | - Bin Gotoh
- Division of Microbiology and Infectious Diseases, Department of Pathology, Shiga University of Medical Science, Shiga, Japan
| | - Takayuki Komatsu
- Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
- *Correspondence: Takayuki Komatsu,
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21
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Kannan A, Suomalainen M, Volle R, Bauer M, Amsler M, Trinh HV, Vavassori S, Schmid JP, Vilhena G, Marín-González A, Perez R, Franceschini A, von Mering C, Hemmi S, Greber UF. Sequence-Specific Features of Short Double-Strand, Blunt-End RNAs Have RIG-I- and Type 1 Interferon-Dependent or -Independent Anti-Viral Effects. Viruses 2022; 14:v14071407. [PMID: 35891387 PMCID: PMC9322957 DOI: 10.3390/v14071407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/17/2022] [Accepted: 06/23/2022] [Indexed: 02/08/2023] Open
Abstract
Pathogen-associated molecular patterns, including cytoplasmic DNA and double-strand (ds)RNA trigger the induction of interferon (IFN) and antiviral states protecting cells and organisms from pathogens. Here we discovered that the transfection of human airway cell lines or non-transformed fibroblasts with 24mer dsRNA mimicking the cellular micro-RNA (miR)29b-1* gives strong anti-viral effects against human adenovirus type 5 (AdV-C5), influenza A virus X31 (H3N2), and SARS-CoV-2. These anti-viral effects required blunt-end complementary RNA strands and were not elicited by corresponding single-strand RNAs. dsRNA miR-29b-1* but not randomized miR-29b-1* mimics induced IFN-stimulated gene expression, and downregulated cell adhesion and cell cycle genes, as indicated by transcriptomics and IFN-I responsive Mx1-promoter activity assays. The inhibition of AdV-C5 infection with miR-29b-1* mimic depended on the IFN-alpha receptor 2 (IFNAR2) and the RNA-helicase retinoic acid-inducible gene I (RIG-I) but not cytoplasmic RNA sensors MDA5 and ZNFX1 or MyD88/TRIF adaptors. The antiviral effects of miR29b-1* were independent of a central AUAU-motif inducing dsRNA bending, as mimics with disrupted AUAU-motif were anti-viral in normal but not RIG-I knock-out (KO) or IFNAR2-KO cells. The screening of a library of scrambled short dsRNA sequences identified also anti-viral mimics functioning independently of RIG-I and IFNAR2, thus exemplifying the diverse anti-viral mechanisms of short blunt-end dsRNAs.
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Affiliation(s)
- Abhilash Kannan
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
- Neurimmune AG, Wagistrasse 18, 8952 Schlieren, Switzerland
| | - Maarit Suomalainen
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
| | - Romain Volle
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
| | - Michael Bauer
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Marco Amsler
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
| | - Hung V. Trinh
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
- Genezen, 9900 Westpoint Dr, Suite 128, Indianapolis, IN 46256, USA
| | - Stefano Vavassori
- Division of Immunology, University Children’s Hospital Zürich, 8032 Zürich, Switzerland; (S.V.); (J.P.S.)
| | - Jana Pachlopnik Schmid
- Division of Immunology, University Children’s Hospital Zürich, 8032 Zürich, Switzerland; (S.V.); (J.P.S.)
- Faculty of Medicine, University of Zürich, 8006 Zürich, Switzerland
| | - Guilherme Vilhena
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain; (G.V.); (R.P.)
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Alberto Marín-González
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Cantoblanco, E-28049 Madrid, Spain;
| | - Ruben Perez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain; (G.V.); (R.P.)
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Andrea Franceschini
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, 20139 Milano, Italy
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Christian von Mering
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Silvio Hemmi
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
| | - Urs F. Greber
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland; (A.K.); (M.S.); (R.V.); (M.B.); (M.A.); (H.V.T.); (A.F.); (C.v.M.); (S.H.)
- Correspondence:
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22
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Nair S, Wu Y, Nguyen TM, Fink K, Luo D, Ruedl C. Intranasal Delivery of RIG-I Agonist Drives Pulmonary Myeloid Cell Activation in Mice. Front Immunol 2022; 13:910192. [PMID: 35784329 PMCID: PMC9241514 DOI: 10.3389/fimmu.2022.910192] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/13/2022] [Indexed: 11/30/2022] Open
Abstract
Viral respiratory infections cause substantial health and economic burden. There is a pressing demand for efficacious vaccination strategies and, therefore, a need for a better understanding of the mechanisms of action of novel potential adjuvants. Here we investigated the effect of a synthetic RIG-I agonist, the dsRNA hairpin 3p10LA9, on the activation of pulmonary myeloid cells. Analysis of early innate immune responses revealed that a single intranasal 3p10LA9 dose induces a transient pulmonary interferon-stimulated gene (ISG) and pro-inflammatory cytokine/chemokine response, which leads to the maturation of three distinct dendritic cell subpopulations in the lungs. While lung resident dendritic cell decrease shortly after 3p10LA9 delivery, their numbers increase in the draining mediastinal lymph node, where they have migrated, maintaining their activated phenotype. At the same time, dsRNA hairpin-induced chemokines attract transiently infiltrating monocytes into the lungs, which causes a short temporary pulmonary inflammation. However, these monocytes are dispensable in controlling influenza infection since in CCR2 deficient mice, lacking these infiltrating cells, the virus load was similar to the wild type mice when infected with the influenza virus at a sublethal dose. In summary, our data suggest that intranasal delivery of dsRNA hairpins, used as a RIG-I targeting adjuvant, represents an attractive strategy to boost type I inteferon-mediated lung dendritic cell maturation, which supports viral reduction in the lungs during infection.
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Affiliation(s)
- Sajith Nair
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yilun Wu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Trinh Mai Nguyen
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Katja Fink
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Dahai Luo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Christiane Ruedl
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- *Correspondence: Christiane Ruedl,
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23
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White LA, Bisom TC, Grimes HL, Hayashi M, Lanchy JM, Lodmell JS. Tra2beta-Dependent Regulation of RIO Kinase 3 Splicing During Rift Valley Fever Virus Infection Underscores the Links Between Alternative Splicing and Innate Antiviral Immunity. Front Cell Infect Microbiol 2022; 11:799024. [PMID: 35127560 PMCID: PMC8807687 DOI: 10.3389/fcimb.2021.799024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/28/2021] [Indexed: 12/14/2022] Open
Abstract
Rift Valley fever virus (RVFV) is an emerging pathogen that has potential to cause severe disease in humans and domestic livestock. Propagation of RVFV strain MP-12 is negatively impacted by the actions of RIOK3, a protein involved in the cellular immune response to viral infection. During RVFV infection, RIOK3 mRNA is alternatively spliced to produce an isoform that correlates with the inhibition of interferon β signaling. Here, we identify splicing factor TRA2-β (also known as TRA2beta and hTRA2-β) as a key regulator governing the relative abundance of RIOK3 splicing isoforms. Using RT-PCR and minigenes, we determined that TRA2-β interaction with RIOK3 pre-mRNA was necessary for constitutive splicing of RIOK3 mRNA, and conversely, lack of TRA2-β engagement led to increased alternative splicing. Expression of TRA2-β was found to be necessary for RIOK3's antiviral effect against RVFV. Intriguingly, TRA2-β mRNA is also alternatively spliced during RVFV infection, leading to a decrease in cellular TRA2-β protein levels. These results suggest that splicing modulation serves as an immune evasion strategy by RVFV and/or is a cellular mechanism to prevent excessive immune response. Furthermore, the results suggest that TRA2-β can act as a key regulator of additional steps of the innate immune response to viral infection.
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Affiliation(s)
- Luke Adam White
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Thomas C. Bisom
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, United States
| | - Hunter L. Grimes
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Miyuki Hayashi
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, United States
| | - Jean-Marc Lanchy
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - J. Stephen Lodmell
- Division of Biological Sciences, University of Montana, Missoula, MT, United States,Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT, United States,*Correspondence: J. Stephen Lodmell,
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24
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Alem F, Olanrewaju AA, Omole S, Hobbs HE, Ahsan N, Matulis G, Brantner CA, Zhou W, Petricoin EF, Liotta LA, Caputi M, Bavari S, Wu Y, Kashanchi F, Hakami RM. Exosomes originating from infection with the cytoplasmic single-stranded RNA virus Rift Valley fever virus (RVFV) protect recipient cells by inducing RIG-I mediated IFN-B response that leads to activation of autophagy. Cell Biosci 2021; 11:220. [PMID: 34953502 PMCID: PMC8710069 DOI: 10.1186/s13578-021-00732-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/12/2021] [Indexed: 12/12/2022] Open
Abstract
Background Although multiple studies have demonstrated a role for exosomes during virus infections, our understanding of the mechanisms by which exosome exchange regulates immune response during viral infections and affects viral pathogenesis is still in its infancy. In particular, very little is known for cytoplasmic single-stranded RNA viruses such as SARS-CoV-2 and Rift Valley fever virus (RVFV). We have used RVFV infection as a model for cytoplasmic single-stranded RNA viruses to address this gap in knowledge. RVFV is a highly pathogenic agent that causes RVF, a zoonotic disease for which no effective therapeutic or approved human vaccine exist. Results We show here that exosomes released from cells infected with RVFV (designated as EXi-RVFV) serve a protective role for the host and provide a mechanistic model for these effects. Our results show that treatment of both naïve immune cells (U937 monocytes) and naïve non-immune cells (HSAECs) with EXi-RVFV induces a strong RIG-I dependent activation of IFN-B. We also demonstrate that this strong anti-viral response leads to activation of autophagy in treated cells and correlates with resistance to subsequent viral infection. Since we have shown that viral RNA genome is associated with EXi-RVFV, RIG-I activation might be mediated by the presence of packaged viral RNA sequences. Conclusions Using RVFV infection as a model for cytoplasmic single-stranded RNA viruses, our results show a novel mechanism of host protection by exosomes released from infected cells (EXi) whereby the EXi activate RIG-I to induce IFN-dependent activation of autophagy in naïve recipient cells including monocytes. Because monocytes serve as reservoirs for RVFV replication, this EXi-RVFV-induced activation of autophagy in monocytes may work to slow down or halt viral dissemination in the infected organism. These findings offer novel mechanistic insights that may aid in future development of effective vaccines or therapeutics, and that may be applicable for a better molecular understanding of how exosome release regulates innate immune response to other cytoplasmic single-stranded RNA viruses. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-021-00732-z.
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Affiliation(s)
- Farhang Alem
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA
| | - Adeyemi A Olanrewaju
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA
| | - Samson Omole
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA
| | - Heather E Hobbs
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA
| | - Noor Ahsan
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA.,Lentigen Technology, Inc., Gaithersburg, MD, USA
| | - Graham Matulis
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA
| | - Christine A Brantner
- Nanofabrication and Imaging Center, George Washington University, Washington, DC, USA
| | - Weidong Zhou
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, VA, USA
| | - Emanuel F Petricoin
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, VA, USA
| | - Lance A Liotta
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, VA, USA
| | - Massimo Caputi
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | | | - Yuntao Wu
- School of Systems Biology, George Mason University, Manassas, VA, USA.,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA
| | - Fatah Kashanchi
- School of Systems Biology, George Mason University, Manassas, VA, USA
| | - Ramin M Hakami
- School of Systems Biology, George Mason University, Manassas, VA, USA. .,Center for Infectious Disease Research (Formerly, National Center for Biodefense and Infectious Diseases), George Mason University, Manassas, VA, USA.
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25
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Pott F, Postmus D, Brown RJP, Wyler E, Neumann E, Landthaler M, Goffinet C. Single-cell analysis of arthritogenic alphavirus-infected human synovial fibroblasts links low abundance of viral RNA to induction of innate immunity and arthralgia-associated gene expression. Emerg Microbes Infect 2021; 10:2151-2168. [PMID: 34723780 PMCID: PMC8604527 DOI: 10.1080/22221751.2021.2000891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 12/25/2022]
Abstract
Infection by (re-)emerging RNA arboviruses including Chikungunya virus (CHIKV) and Mayaro virus primarily cause acute febrile disease and transient polyarthralgia. However, in a significant subset of infected individuals, debilitating arthralgia persists for weeks over months up to years. The underlying immunopathogenesis of chronification of arthralgia upon primary RNA-viral infection remains unclear. Here, we analysed cell-intrinsic responses to ex vivo arthritogenic alphaviral infection of primary human synovial fibroblasts isolated from knee joints, one the most affected joint types during acute and chronic CHIKV disease. Synovial fibroblasts were susceptible and permissive to alphaviral infection. Base-line and exogenously added type I interferon (IFN) partially and potently restricted infection, respectively. RNA-seq revealed a CHIKV infection-induced transcriptional profile that comprised upregulation of expression of several hundred IFN-stimulated and arthralgia-mediating genes. Single-cell virus-inclusive RNA-seq uncovered a fine-tuned switch from induction to repression of cell-intrinsic immune responses depending on the abundance of viral RNA in an individual cell. Specifically, responses were most pronounced in cells displaying low-to-intermediate amounts of viral RNA and absence of virus-encoded, fluorescent reporter protein expression, arguing for efficient counteraction of innate immunity in cells expressing viral antagonists at sufficient quantities. In summary, cell-intrinsic sensing of viral RNA that potentially persists or replicates at low levels in synovial fibroblasts and other target cell types in vivo may contribute to the chronic arthralgia induced by alphaviral infections. Our findings might advance our understanding of the immunopathophysiology of long-term pathogenesis of RNA-viral infections.
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Affiliation(s)
- Fabian Pott
- Institute of Virology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Dylan Postmus
- Institute of Virology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Berlin, Germany
| | | | - Emanuel Wyler
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
| | - Elena Neumann
- Internal Medicine and Rheumatology, Justus-Liebig-University Giessen, Bad Nauheim, Germany
| | - Markus Landthaler
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Berlin, Germany
- IRI Life Sciences, Institut für Biologie, Humboldt Universität zu Berlin, Berlin, Germany
| | - Christine Goffinet
- Institute of Virology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Berlin, Germany
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26
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Xue M, Zhang Y, Wang H, Kairis EL, Lu M, Ahmad S, Attia Z, Harder O, Zhang Z, Wei J, Chen P, Gao Y, Peeples ME, Sharma A, Boyaka P, He C, Hur S, Niewiesk S, Li J. Viral RNA N6-methyladenosine modification modulates both innate and adaptive immune responses of human respiratory syncytial virus. PLoS Pathog 2021; 17:e1010142. [PMID: 34929018 PMCID: PMC8759664 DOI: 10.1371/journal.ppat.1010142] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/14/2022] [Accepted: 11/19/2021] [Indexed: 12/29/2022] Open
Abstract
Human respiratory syncytial virus (RSV) is the leading cause of respiratory tract infections in humans. A well-known challenge in the development of a live attenuated RSV vaccine is that interferon (IFN)-mediated antiviral responses are strongly suppressed by RSV nonstructural proteins which, in turn, dampens the subsequent adaptive immune responses. Here, we discovered a novel strategy to enhance innate and adaptive immunity to RSV infection. Specifically, we found that recombinant RSVs deficient in viral RNA N6-methyladenosine (m6A) and RSV grown in m6A methyltransferase (METTL3)-knockdown cells induce higher expression of RIG-I, bind more efficiently to RIG-I, and enhance RIG-I ubiquitination and IRF3 phosphorylation compared to wild-type virion RNA, leading to enhanced type I IFN production. Importantly, these m6A-deficient RSV mutants also induce a stronger IFN response in vivo, are significantly attenuated, induce higher neutralizing antibody and T cell immune responses in mice and provide complete protection against RSV challenge in cotton rats. Collectively, our results demonstrate that inhibition of RSV RNA m6A methylation enhances innate immune responses which in turn promote adaptive immunity.
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Affiliation(s)
- Miaoge Xue
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Yuexiu Zhang
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Haitao Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Elizabeth L. Kairis
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Mijia Lu
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Sadeem Ahmad
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Zayed Attia
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Olivia Harder
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Zijie Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, United States of America
| | - Jiangbo Wei
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, United States of America
| | - Phylip Chen
- Center for Vaccines and Immunity, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, United States of America
| | - Youling Gao
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Mark E. Peeples
- Center for Vaccines and Immunity, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Amit Sharma
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Prosper Boyaka
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Chuan He
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, The University of Chicago, Chicago, Illinois, United States of America
| | - Sun Hur
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Stefan Niewiesk
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Jianrong Li
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, United States of America
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27
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Chen YG, Hur S. Cellular origins of dsRNA, their recognition and consequences. Nat Rev Mol Cell Biol 2021; 23:286-301. [PMID: 34815573 DOI: 10.1038/s41580-021-00430-1] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2021] [Indexed: 01/02/2023]
Abstract
Double-stranded RNA (dsRNA) is associated with most viral infections - it either constitutes the viral genome (in the case of dsRNA viruses) or is generated in host cells during viral replication. Hence, nearly all organisms have the capability of recognizing dsRNA and mounting a response, the primary aim of which is to mitigate the potential infection. In vertebrates, a set of innate immune receptors for dsRNA induce a multitude of cell-intrinsic and cell-extrinsic immune responses upon dsRNA recognition. Notably, recent studies showed that vertebrate cells can accumulate self-derived dsRNAs or dsRNA-like species upon dysregulation of several cellular processes, activating the very same immune pathways as in infected cells. On the one hand, such aberrant immune activation in the absence of infection can lead to pathogenesis of immune disorders, such as Aicardi-Goutières syndrome. On the other hand, the same innate immune reaction can be induced in a controlled setting for a therapeutic benefit, as occurs in immunotherapies. In this Review, we describe mechanisms by which immunostimulatory dsRNAs are generated in mammalian cells, either by viruses or by the host cells, and how cells respond to them, with the focus on recent developments regarding the role of cellular dsRNAs in immune modulation.
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Affiliation(s)
- Y Grace Chen
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Sun Hur
- Harvard Medical School & Boston Children's Hospital, Boston, MA, USA.
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28
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Wuerth JD, Weber F. NSs of the mildly virulent sandfly fever Sicilian virus is unable to inhibit interferon signaling and upregulation of interferon-stimulated genes. J Gen Virol 2021; 102. [PMID: 34726591 PMCID: PMC8742993 DOI: 10.1099/jgv.0.001676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Phleboviruses (order Bunyavirales, family Phenuiviridae) are globally emerging arboviruses with a wide spectrum of virulence. Sandfly fever Sicilian virus (SFSV) is one of the most ubiquitous members of the genus Phlebovirus and associated with a self-limited, incapacitating febrile disease in travellers and military troops. The phleboviral NSs protein is an established virulence factor, acting as antagonist of the antiviral interferon (IFN) system. Consistently, we previously reported that SFSV NSs targets the induction of IFN mRNA synthesis by specifically binding to the DNA-binding domain of the IFN transcription factor IRF3. Here, we further characterized the effect of SFSV and its NSs towards IFN induction, and evaluated its potential to affect the downstream IFN-stimulated signalling and the subsequent transactivation of antiviral interferon-stimulated genes (ISGs). We found that SFSV dampened, but did not entirely abolish type I and type III IFN induction. Furthermore, SFSV NSs did not affect IFN signalling, resulting in substantial ISG expression in infected cells. Hence, although SFSV targets IRF3 to reduce IFN induction, it is not capable of entirely disarming the IFN system in the presence of high basal IRF3 and/or IRF7 levels, and we speculate that this significantly contributes to its low level of virulence.
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Affiliation(s)
- Jennifer Deborah Wuerth
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany.,Institute of Innate Immunity, University of Bonn, Bonn, Germany
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
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Bach S, Demper JC, Klemm P, Schlereth J, Lechner M, Schoen A, Kämper L, Weber F, Becker S, Biedenkopf N, Hartmann RK. Identification and characterization of short leader and trailer RNAs synthesized by the Ebola virus RNA polymerase. PLoS Pathog 2021; 17:e1010002. [PMID: 34699554 PMCID: PMC8547711 DOI: 10.1371/journal.ppat.1010002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 10/04/2021] [Indexed: 11/21/2022] Open
Abstract
Transcription of non-segmented negative sense (NNS) RNA viruses follows a stop-start mechanism and is thought to be initiated at the genome’s very 3’-end. The synthesis of short abortive leader transcripts (leaderRNAs) has been linked to transcription initiation for some NNS viruses. Here, we identified the synthesis of abortive leaderRNAs (as well as trailer RNAs) that are specifically initiated opposite to (anti)genome nt 2; leaderRNAs are predominantly terminated in the region of nt ~ 60–80. LeaderRNA synthesis requires hexamer phasing in the 3’-leader promoter. We determined a steady-state NP mRNA:leaderRNA ratio of ~10 to 30-fold at 48 h after Ebola virus (EBOV) infection, and this ratio was higher (70 to 190-fold) for minigenome-transfected cells. LeaderRNA initiation at nt 2 and the range of termination sites were not affected by structure and length variation between promoter elements 1 and 2, nor the presence or absence of VP30. Synthesis of leaderRNA is suppressed in the presence of VP30 and termination of leaderRNA is not mediated by cryptic gene end (GE) signals in the 3’-leader promoter. We further found different genomic 3’-end nucleotide requirements for transcription versus replication, suggesting that promoter recognition is different in the replication and transcription mode of the EBOV polymerase. We further provide evidence arguing against a potential role of EBOV leaderRNAs as effector molecules in innate immunity. Taken together, our findings are consistent with a model according to which leaderRNAs are abortive replicative RNAs whose synthesis is not linked to transcription initiation. Rather, replication and transcription complexes are proposed to independently initiate RNA synthesis at separate sites in the 3’-leader promoter, i.e., at the second nucleotide of the genome 3’-end and at the more internally positioned transcription start site preceding the first gene, respectively, as reported for Vesicular stomatitis virus. The RNA polymerase (RdRp) of Ebola virus (EBOV) initiates RNA synthesis at the 3’-leader promoter of its encapsidated, non-segmented negative sense (NNS) RNA genome, either at the penultimate 3’-end position of the genome in the replicative mode or more internally (position 56) at the transcription start site (TSS) in its transcription mode. Here we identified the synthesis of abortive replicative RNAs that are specifically initiated opposite to genome nt 2 (termed leaderRNAs) and predominantly terminated in the region of nt ~ 60–80 near the TSS. The functional role of abortive leaderRNA synthesis is still enigmatic; a role in interferon induction could be excluded. Our findings indirectly link leaderRNA termination to nucleoprotein (NP) availability for encapsidation of nascent replicative RNA or to NP removal from the template RNA. Our findings further argue against the model that leaderRNA synthesis is a prerequisite for each transcription initiation event at the TSS. Rather, our findings are in line with the existence of distinct replicase and transcriptase complexes of RdRp that interact differently with the 3’-leader promoter and intiate RNA synthesis independently at different sites (position 2 or 56 of the genome), mechanistically similar to another NNS virus, Vesicular stomatitis virus.
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Affiliation(s)
- Simone Bach
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Jana-Christin Demper
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Paul Klemm
- Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Julia Schlereth
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Marcus Lechner
- Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Andreas Schoen
- Institut für Virologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Lennart Kämper
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Friedemann Weber
- Institut für Virologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Nadine Biedenkopf
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (NB); (RKH)
| | - Roland K. Hartmann
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (NB); (RKH)
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Gern OL, Mulenge F, Pavlou A, Ghita L, Steffen I, Stangel M, Kalinke U. Toll-like Receptors in Viral Encephalitis. Viruses 2021; 13:v13102065. [PMID: 34696494 PMCID: PMC8540543 DOI: 10.3390/v13102065] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 12/23/2022] Open
Abstract
Viral encephalitis is a rare but serious syndrome. In addition to DNA-encoded herpes viruses, such as herpes simplex virus and varicella zoster virus, RNA-encoded viruses from the families of Flaviviridae, Rhabdoviridae and Paramyxoviridae are important neurotropic viruses. Whereas in the periphery, the role of Toll-like receptors (TLR) during immune stimulation is well understood, TLR functions within the CNS are less clear. On one hand, TLRs can affect the physiology of neurons during neuronal progenitor cell differentiation and neurite outgrowth, whereas under conditions of infection, the complex interplay between TLR stimulated neurons, astrocytes and microglia is just on the verge of being understood. In this review, we summarize the current knowledge about which TLRs are expressed by cell subsets of the CNS. Furthermore, we specifically highlight functional implications of TLR stimulation in neurons, astrocytes and microglia. After briefly illuminating some examples of viral evasion strategies from TLR signaling, we report on the current knowledge of primary immunodeficiencies in TLR signaling and their consequences for viral encephalitis. Finally, we provide an outlook with examples of TLR agonist mediated intervention strategies and potentiation of vaccine responses against neurotropic virus infections.
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Affiliation(s)
- Olivia Luise Gern
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany; (F.M.); (A.P.); (L.G.); (U.K.)
- Department of Pathology, University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany
- Correspondence:
| | - Felix Mulenge
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany; (F.M.); (A.P.); (L.G.); (U.K.)
| | - Andreas Pavlou
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany; (F.M.); (A.P.); (L.G.); (U.K.)
- Clinical Neuroimmunology and Neurochemistry, Department of Neurology, Hannover Medical School, 30625 Hannover, Germany
- Center for Systems Neuroscience, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Luca Ghita
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany; (F.M.); (A.P.); (L.G.); (U.K.)
- Division of Infectious Diseases and Geographic Medicine, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Imke Steffen
- Department of Biochemistry and Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany;
| | - Martin Stangel
- Translational Medicine, Novartis Institute for Biomedical Research (NIBR), 4056 Basel, Switzerland;
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany; (F.M.); (A.P.); (L.G.); (U.K.)
- Cluster of Excellence—Resolving Infection Susceptibility (RESIST, EXC 2155), Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
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Gao Y, Li C, Shi L, Wang F, Ye J, Lu YA, Liu XQ. Viperin_sv1 promotes RIG-I expression and suppresses SVCV replication through its radical SAM domain. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 123:104166. [PMID: 34116117 DOI: 10.1016/j.dci.2021.104166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/28/2021] [Accepted: 06/05/2021] [Indexed: 06/12/2023]
Abstract
SVCV infection is known to activate the host's innate immune responses, including the production of interferon (IFN) and interferon-stimulated genes (ISGs). Viperin_sv1 is a novel splice variant of viperin, which is induced during SVCV infection and proves to positively regulate the IFN activation and production. However, the underlying mechanism remains unsolved. In this study, the P protein of SVCV was identified to be the key to induce the mRNA modification and production of viperin_sv1 during the virus infection. Besides, Viperin_sv1 was able to trigger the RLR signaling cascades to activate type-1 interferon response. Additional analysis revealed that viperin_sv1 promoted the stability and function of RIG-I, which result in the production of IFN and ISGs. Moreover, the central SAM domain of viperin_sv1 was demonstrated to be essential for regulating RIG-I protein expression and inducing IFN production. Furthermore, this study also showed that SVCV replication could be inhibited by the viperin_sv1 SAM domain. In conclusion, our study demonstrates that viperin_sv1 reduces the replication of SVCV by promoting the RIG-I protein expression. Our findings identified the antiviral function played by the SAM domain of viperin_sv1 and suggested an antiviral mechanism that is conserved among different species.
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Affiliation(s)
- Yan Gao
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, 430070, Hubei, China
| | - Chen Li
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, 430070, Hubei, China
| | - Lin Shi
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, 430070, Hubei, China
| | - Fang Wang
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, 430070, Hubei, China
| | - Jing Ye
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Yuan-An Lu
- Department of Public Health Sciences, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Xue-Qin Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, 430070, Hubei, China.
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32
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Thoresen D, Wang W, Galls D, Guo R, Xu L, Pyle AM. The molecular mechanism of RIG-I activation and signaling. Immunol Rev 2021; 304:154-168. [PMID: 34514601 PMCID: PMC9293153 DOI: 10.1111/imr.13022] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/10/2021] [Accepted: 08/17/2021] [Indexed: 12/25/2022]
Abstract
RIG‐I is our first line of defense against RNA viruses, serving as a pattern recognition receptor that identifies molecular features common among dsRNA and ssRNA viral pathogens. RIG‐I is maintained in an inactive conformation as it samples the cellular space for pathogenic RNAs. Upon encounter with the triphosphorylated terminus of blunt‐ended viral RNA duplexes, the receptor changes conformation and releases a pair of signaling domains (CARDs) that are selectively modified and interact with an adapter protein (MAVS), thereby triggering a signaling cascade that stimulates transcription of interferons. Here, we describe the structural determinants for specific RIG‐I activation by viral RNA, and we describe the strategies by which RIG‐I remains inactivated in the presence of host RNAs. From the initial RNA triggering event to the final stages of interferon expression, we describe the experimental evidence underpinning our working knowledge of RIG‐I signaling. We draw parallels with behavior of related proteins MDA5 and LGP2, describing evolutionary implications of their collective surveillance of the cell. We conclude by describing the cell biology and immunological investigations that will be needed to accurately describe the role of RIG‐I in innate immunity and to provide the necessary foundation for pharmacological manipulation of this important receptor.
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Affiliation(s)
- Daniel Thoresen
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Wenshuai Wang
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Drew Galls
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Rong Guo
- Chemistry, Yale University, New Haven, CT, USA
| | - Ling Xu
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Anna Marie Pyle
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Chemistry, Yale University, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
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33
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Mammals Preferred: Reassortment of Batai and Bunyamwera orthobunyavirus Occurs in Mammalian but Not Insect Cells. Viruses 2021; 13:v13091702. [PMID: 34578285 PMCID: PMC8473249 DOI: 10.3390/v13091702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/17/2021] [Accepted: 08/21/2021] [Indexed: 12/20/2022] Open
Abstract
Reassortment is a viral genome-segment recomposition known for many viruses, including the orthobunyaviruses. The co-infection of a host cell with two viruses of the same serogroup, such as the Bunyamwera orthobunyavirus and the Batai orthobunyavirus, can give rise to novel viruses. One example is the Ngari virus, which has caused major outbreaks of human infections in Central Africa. This study aimed to investigate the potential for reassortment of Bunyamwera orthobunyavirus and the Batai orthobunyavirus during co-infection studies and the replication properties of the reassortants in different mammalian and insect cell lines. In the co-infection studies, a Ngari-like virus reassortant and a novel reassortant virus, the Batunya virus, arose in BHK-21 cells (Mesocricetus auratus). In contrast, no reassortment was observed in the examined insect cells from Aedes aegypti (Aag2) and Aedes albopictus (U4.4 and C6/36). The growth kinetic experiments show that both reassortants are replicated to higher titers in some mammalian cell lines than the parental viruses but show impaired growth in insect cell lines.
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Dual Effect of Organogermanium Compound THGP on RIG-I-Mediated Viral Sensing and Viral Replication during Influenza a Virus Infection. Viruses 2021; 13:v13091674. [PMID: 34578256 PMCID: PMC8473027 DOI: 10.3390/v13091674] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 12/28/2022] Open
Abstract
The interaction of viral nucleic acid with protein factors is a crucial process for initiating viral polymerase-mediated viral genome replication while activating pattern recognition receptor (PRR)-mediated innate immune responses. It has previously been reported that a hydrolysate of Ge-132, 3-(trihydroxygermyl) propanoic acid (THGP), shows a modulatory effect on microbial infections, inflammation, and immune responses. However, the detailed mechanism by which THGP can modify these processes during viral infections remained unknown. Here, we show that THGP can specifically downregulate type I interferon (IFN) production in response to stimulation with a cytosolic RNA sensor RIG-I ligand 5′-triphosphate RNA (3pRNA) but not double-stranded RNA, DNA, or lipopolysaccharide. Consistently, treatment with THGP resulted in the dose-dependent suppression of type I IFN induction upon infections with influenza virus (IAV) and vesicular stomatitis virus, which are known to be mainly sensed by RIG-I. Mechanistically, THGP directly binds to the 5′-triphosphate moiety of viral RNA and competes with RIG-I-mediated recognition. Furthermore, we found that THGP can directly counteract the replication of IAV but not EMCV (encephalitismyocarditis virus), by inhibiting the interaction of viral polymerase with RNA genome. Finally, IAV RNA levels were significantly reduced in the lung tissues of THGP-treated mice when compared with untreated mice. These results suggest a possible therapeutic implication of THGP and show direct antiviral action, together with the suppressive activity of innate inflammation.
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Steinberg J, Wadenpohl T, Jung S. The Endogenous RIG-I Ligand Is Generated in Influenza A-Virus Infected Cells. Viruses 2021; 13:1564. [PMID: 34452429 PMCID: PMC8402674 DOI: 10.3390/v13081564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 12/16/2022] Open
Abstract
As a result of a viral infection, viral genomes are not only recognized by RIG-I, but also lead to the activation of RNase L, which cleaves cellular RNA to generate the endogenous RIG-I ligand (eRL). The eRL was previously identified as a specific sequence derived from the internal transcribed spacer region 2, which bears a 2'3' cyclic phosphate instead of the common 5' triphosphate. By now, the generation of the eRL and its immunostimulatory effect were shown both in vitro and in reporter systems. In this work, we aimed to elucidate whether the eRL is also generated in Influenza A (IAV) and vesicular stomatitis virus (VSV) infected cells. RNA was extracted from virus-infected cells and used for immunostimulations as well as specific PCR-strategies to detect eRL cleavage. We show that the eRL is generated in IAV infected HEK293 cells, but we could not detect specific eRL fragments in VSV infected cells. Further, RIG-I mediated IFN-response depends not only on viral genomes but also on the eRL, as immunostimulatory properties remain present under 5'triphosphate degrading conditions. In summary, we prove the IAV infection induced eRL generation in HEK293 cells, amplifying the innate immune response.
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Affiliation(s)
| | | | - Stephanie Jung
- Institute of Cardiovascular Immunology, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany; (J.S.); (T.W.)
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36
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de Oliveira Mann CC, Hornung V. Molecular mechanisms of nonself nucleic acid recognition by the innate immune system. Eur J Immunol 2021; 51:1897-1910. [PMID: 34138462 DOI: 10.1002/eji.202049116] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/13/2021] [Accepted: 06/15/2021] [Indexed: 12/24/2022]
Abstract
Nucleic acids (NAs) represent one of the most important classes of molecules recognized by the innate immune system. However, NAs are not limited to pathogens, but are also present within the host. As such, the immune system has evolved an elaborate set of pathogen recognition receptors (PRRs) that employ various strategies to recognize distinct types of NAs, while reliably distinguishing between self and nonself. The here-employed strategies encompass the positioning of NA-sensing PRRs in certain subcellular compartments that potentially come in contact with pathogens but not host NAs, the existence of counterregulatory measures that keep endogenous NAs below a certain threshold, and also the specific identification of certain nonself patterns. Here, we review recent advances in the molecular mechanisms of NA recognition by TLRs, RLRs, and the cGAS-STING axis. We highlight the differences in NA-PRR interfaces that confer specificity and selectivity toward an NA ligand, as well as the NA-dependent induced conformational changes required for signal transduction.
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Affiliation(s)
| | - Veit Hornung
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
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Characterization of the Molecular Interactions That Govern the Packaging of Viral RNA Segments into Rift Valley Fever Phlebovirus Particles. J Virol 2021; 95:e0042921. [PMID: 33952635 DOI: 10.1128/jvi.00429-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Rift Valley fever phlebovirus (RVFV) has a single-stranded, negative-sense RNA genome, consisting of L, M, and S segments. The virion carries two envelope glycoproteins, Gn and Gc, along with ribonucleoprotein complexes (RNPs), composed of encapsidated genomes carrying N protein and the viral polymerase, L protein. A quantitative analysis of the profile of viral RNA segments packaged into RVFV particles showed that all three genomic RNA segments had similar packaging abilities, whereas among antigenomic RNA segments, the antigenomic S RNA, which serves as the template for the transcription of mRNA expressing the RVFV virulence factor, NSs, displayed a significantly higher packaging ability. To delineate the factor(s) governing the packaging of RVFV RNA segments, we characterized the interactions between Gn and viral RNPs in RVFV-infected cells. Coimmunoprecipitation analysis demonstrated the interaction of Gn with N protein, L protein, and viral RNAs in RVFV-infected cells. Furthermore, UV-cross-linking and immunoprecipitation analysis revealed, for the first time in bunyaviruses, the presence of a direct interaction between Gn and all the viral RNA segments in RVFV-infected cells. Notably, analysis of the ability of Gn to bind to RVFV RNA segments indicated a positive correlation with their respective packaging abilities and highlighted a binding preference of Gn for antigenomic S RNA, among the antigenomic RNA segments, suggesting the presence of a selection mechanism for antigenomic S RNA incorporation into infectious RVFV particles. Collectively, the results of our study illuminate the importance of a direct interaction between Gn and viral RNA segments in determining their efficiency of incorporation into RVFV particles. IMPORTANCE Rift Valley fever phlebovirus, a bunyavirus, is a mosquito-borne, segmented RNA virus that can cause severe disease in humans and ruminants. An essential step in RVFV life cycle is the packaging of viral RNA segments to produce infectious virus particles for dissemination to new hosts. However, there are key gaps in knowledge regarding the mechanisms that regulate viral RNA packaging efficiency in bunyaviruses. Our studies investigating the mechanism of RNA packaging in RVFV revealed the presence of a direct interaction between the viral envelope glycoprotein, Gn, and the viral RNA segments in infected cells, for the first time in bunyaviruses. Furthermore, our data strongly indicate a critical role for the direct interaction between Gn and viral RNAs in determining the efficiency of incorporation of viral RNA segments into RVFV particles. Clarifying the fundamental mechanisms of RNA packaging in RVFV would be valuable for the development of antivirals and live-attenuated vaccines.
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Lee AC, Castaneda G, Li WT, Chen C, Shende N, Chakladar J, Taub PR, Chang EY, Ongkeko WM. COVID-19 Severity Potentially Modulated by Cardiovascular-Disease-Associated Immune Dysregulation. Viruses 2021; 13:1018. [PMID: 34071557 PMCID: PMC8228164 DOI: 10.3390/v13061018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 12/15/2022] Open
Abstract
Patients with underlying cardiovascular conditions are particularly vulnerable to severe COVID-19. In this project, we aimed to characterize similarities in dysregulated immune pathways between COVID-19 patients and patients with cardiomyopathy, venous thromboembolism (VTE), or coronary artery disease (CAD). We hypothesized that these similarly dysregulated pathways may be critical to how cardiovascular diseases (CVDs) exacerbate COVID-19. To evaluate immune dysregulation in different diseases, we used four separate datasets, including RNA-sequencing data from human left ventricular cardiac muscle samples of patients with dilated or ischemic cardiomyopathy and healthy controls; RNA-sequencing data of whole blood samples from patients with single or recurrent event VTE and healthy controls; RNA-sequencing data of human peripheral blood mononuclear cells (PBMCs) from patients with and without obstructive CAD; and RNA-sequencing data of platelets from COVID-19 subjects and healthy controls. We found similar immune dysregulation profiles between patients with CVDs and COVID-19 patients. Interestingly, cardiomyopathy patients display the most similar immune landscape to COVID-19 patients. Additionally, COVID-19 patients experience greater upregulation of cytokine- and inflammasome-related genes than patients with CVDs. In all, patients with CVDs have a significant overlap of cytokine- and inflammasome-related gene expression profiles with that of COVID-19 patients, possibly explaining their greater vulnerability to severe COVID-19.
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Affiliation(s)
- Abby C. Lee
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
| | - Grant Castaneda
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
| | - Wei Tse Li
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
| | - Chengyu Chen
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
| | - Neil Shende
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
| | - Jaideep Chakladar
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
| | - Pam R. Taub
- Department of Medicine, Division of Cardiovascular Medicine, University of California, San Diego, CA 92093, USA;
| | - Eric Y. Chang
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
- Department of Radiology, University of California, San Diego, CA 92093, USA
| | - Weg M. Ongkeko
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, UC San Diego School of Medicine, San Diego, CA 92093, USA; (A.C.L.); (G.C.); (W.T.L.); (C.C.); (N.S.); (J.C.)
- Research Service, VA San Diego Healthcare System, San Diego, CA 92161, USA;
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Linder A, Bothe V, Linder N, Schwarzlmueller P, Dahlström F, Bartenhagen C, Dugas M, Pandey D, Thorn-Seshold J, Boehmer DFR, Koenig LM, Kobold S, Schnurr M, Raedler J, Spielmann G, Karimzadeh H, Schmidt A, Endres S, Rothenfusser S. Defective Interfering Genomes and the Full-Length Viral Genome Trigger RIG-I After Infection With Vesicular Stomatitis Virus in a Replication Dependent Manner. Front Immunol 2021; 12:595390. [PMID: 33995343 PMCID: PMC8119886 DOI: 10.3389/fimmu.2021.595390] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 03/30/2021] [Indexed: 12/25/2022] Open
Abstract
Replication competent vesicular stomatitis virus (VSV) is the basis of a vaccine against Ebola and VSV strains are developed as oncolytic viruses. Both functions depend on the ability of VSV to induce adequate amounts of interferon-α/β. It is therefore important to understand how VSV triggers interferon responses. VSV activates innate immunity via retinoic acid-inducible gene I (RIG-I), a sensor for viral RNA. Our results show that VSV needs to replicate for a robust interferon response. Analysis of RIG-I-associated RNA identified a copy-back defective-interfering (DI) genome and full-length viral genomes as main trigger of RIG-I. VSV stocks depleted of DI genomes lost most of their interferon-stimulating activity. The remaining full-length genome and leader-N-read-through sequences, however, still triggered RIG-I. Awareness for DI genomes as trigger of innate immune responses will help to standardize DI genome content and to purposefully deplete or use DI genomes as natural adjuvants in VSV-based therapeutics.
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Affiliation(s)
- Andreas Linder
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
- Department of Medicine II, University Hospital, LMU Munich, Munich, Germany
| | - Viktoria Bothe
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Nicolas Linder
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Paul Schwarzlmueller
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Frank Dahlström
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | | | - Martin Dugas
- Institute of Medical Informatics, University of Münster, Münster, Germany
| | - Dharmendra Pandey
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Julia Thorn-Seshold
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
- Einheit für Klinische Pharmakologie (EKLiP), Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Neuherberg, Germany
| | - Daniel F. R. Boehmer
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Lars M. Koenig
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Sebastian Kobold
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
- German Center for Translational Cancer Research (DKTK), Partner Site Munich, Munich, Germany
| | - Max Schnurr
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Johannes Raedler
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Giulia Spielmann
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Hadi Karimzadeh
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
- Einheit für Klinische Pharmakologie (EKLiP), Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Neuherberg, Germany
| | - Andreas Schmidt
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
| | - Stefan Endres
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
- Einheit für Klinische Pharmakologie (EKLiP), Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Neuherberg, Germany
| | - Simon Rothenfusser
- Division of Clinical Pharmacology, University Hospital, LMU Munich, Munich, Germany
- Einheit für Klinische Pharmakologie (EKLiP), Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Neuherberg, Germany
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Host Cell Restriction Factors of Bunyaviruses and Viral Countermeasures. Viruses 2021; 13:v13050784. [PMID: 33925004 PMCID: PMC8146327 DOI: 10.3390/v13050784] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/14/2021] [Accepted: 04/20/2021] [Indexed: 01/01/2023] Open
Abstract
The Bunyavirales order comprises more than 500 viruses (generally defined as bunyaviruses) classified into 12 families. Some of these are highly pathogenic viruses infecting different hosts, including humans, mammals, reptiles, arthropods, birds, and/or plants. Host cell sensing of infection activates the innate immune system that aims at inhibiting viral replication and propagation. Upon recognition of pathogen-associated molecular patterns (PAMPs) by cellular pattern recognition receptors (PRRs), numerous signaling cascades are activated, leading to the production of interferons (IFNs). IFNs act in an autocrine and paracrine manner to establish an antiviral state by inducing the expression of hundreds of IFN-stimulated genes (ISGs). Some of these ISGs are known to restrict bunyavirus infection. Along with other constitutively expressed host cellular factors with antiviral activity, these proteins (hereafter referred to as “restriction factors”) target different steps of the viral cycle, including viral entry, genome transcription and replication, and virion egress. In reaction to this, bunyaviruses have developed strategies to circumvent this antiviral response, by avoiding cellular recognition of PAMPs, inhibiting IFN production or interfering with the IFN-mediated response. Herein, we review the current knowledge on host cellular factors that were shown to restrict infections by bunyaviruses. Moreover, we focus on the strategies developed by bunyaviruses in order to escape the antiviral state developed by the infected cells.
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Nonsegmented Negative-Sense RNA Viruses Utilize N 6-Methyladenosine (m 6A) as a Common Strategy To Evade Host Innate Immunity. J Virol 2021; 95:JVI.01939-20. [PMID: 33536170 DOI: 10.1128/jvi.01939-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/22/2021] [Indexed: 12/22/2022] Open
Abstract
N 6-Methyladenosine (m6A) is the most abundant internal RNA modification catalyzed by host RNA methyltransferases. As obligate intracellular parasites, many viruses acquire m6A methylation in their RNAs. However, the biological functions of viral m6A methylation are poorly understood. Here, we found that viral m6A methylation serves as a molecular marker for host innate immunity to discriminate self from nonself RNA and that this novel biological function of viral m6A methylation is universally conserved in several families in nonsegmented negative-sense (NNS) RNA viruses. Using m6A methyltransferase (METTL3) knockout cells, we produced m6A-deficient virion RNAs from the representative members of the families Pneumoviridae, Paramyxoviridae, and Rhabdoviridae and found that these m6A-deficient viral RNAs triggered significantly higher levels of type I interferon compared to the m6A-sufficient viral RNAs, in a RIG-I-dependent manner. Reconstitution of the RIG-I pathway revealed that m6A-deficient virion RNA induced higher expression of RIG-I, bound to RIG-I more efficiently, enhanced RIG-I ubiquitination, and facilitated RIG-I conformational rearrangement and oligomerization. Furthermore, the m6A binding protein YTHDF2 is essential for suppression of the type I interferon signaling pathway, including by virion RNA. Collectively, our results suggest that several families in NNS RNA viruses acquire m6A in viral RNA as a common strategy to evade host innate immunity.IMPORTANCE The nonsegmented negative-sense (NNS) RNA viruses share many common replication and gene expression strategies. There are no vaccines or antiviral drugs for many of these viruses. We found that representative members of the families Pneumoviridae, Paramyxoviridae, and Rhabdoviridae among the NNS RNA viruses acquire m6A methylation in their genome and antigenome as a means to escape recognition by host innate immunity via a RIG-I-dependent signaling pathway. Viral RNA lacking m6A methylation induces a significantly higher type I interferon response than m6A-sufficient viral RNA. In addition to uncovering m6A methylation as a common mechanism for many NNS RNA viruses to evade host innate immunity, this study discovered a novel strategy to enhance type I interferon responses, which may have important applications in vaccine development, as robust innate immunity will likely promote the subsequent adaptive immunity.
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Zhang Z, Urban S. New insights into HDV persistence: The role of interferon response and implications for upcoming novel therapies. J Hepatol 2021; 74:686-699. [PMID: 33276031 DOI: 10.1016/j.jhep.2020.11.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/12/2020] [Accepted: 11/22/2020] [Indexed: 02/06/2023]
Abstract
Chronic hepatitis D (CHD), a global health problem, manifests as the most severe form of viral hepatitis. The causative agent, HDV, is the smallest known human virus; it replicates its circular single-stranded RNA genome in the nucleus of hepatocytes. HDV requires HBV-encoded envelope proteins for dissemination and de novo cell entry. However, HDV can also spread through cell division. Following entry into hepatocytes, replicative intermediates of HDV RNA are sensed by the pattern recognition receptor MDA5 (melanoma differentiation antigen 5) resulting in interferon (IFN)-β/λ induction. This IFN response strongly suppresses cell division-mediated spread of HDV genomes, however, it only marginally affects HDV RNA replication in already infected, resting hepatocytes. Monotherapy with IFN-α/λ shows efficacy but rarely results in HDV clearance. Recent molecular insights into key determinants of HDV persistence and the accelerated development of specifically acting antivirals that interfere with the replication cycle have revealed promising new therapeutic perspectives. In this review, we briefly summarise our knowledge on replication/persistence of HDV, the newly discovered HDV-like agents, and the interplay of HDV with the IFN response and its consequences for persistence. Finally, we discuss the possible role of IFNs in combination with upcoming therapies aimed at HDV cure.
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Affiliation(s)
- Zhenfeng Zhang
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Stephan Urban
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany; German Center for Infection Research (DZIF) - Heidelberg Partner Site, Heidelberg, Germany.
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Onomoto K, Onoguchi K, Yoneyama M. Regulation of RIG-I-like receptor-mediated signaling: interaction between host and viral factors. Cell Mol Immunol 2021; 18:539-555. [PMID: 33462384 PMCID: PMC7812568 DOI: 10.1038/s41423-020-00602-7] [Citation(s) in RCA: 175] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/17/2020] [Indexed: 01/31/2023] Open
Abstract
Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) are RNA sensor molecules that play essential roles in innate antiviral immunity. Among the three RLRs encoded by the human genome, RIG-I and melanoma differentiation-associated gene 5, which contain N-terminal caspase recruitment domains, are activated upon the detection of viral RNAs in the cytoplasm of virus-infected cells. Activated RLRs induce downstream signaling via their interactions with mitochondrial antiviral signaling proteins and activate the production of type I and III interferons and inflammatory cytokines. Recent studies have shown that RLR-mediated signaling is regulated by interactions with endogenous RNAs and host proteins, such as those involved in stress responses and posttranslational modifications. Since RLR-mediated cytokine production is also involved in the regulation of acquired immunity, the deregulation of RLR-mediated signaling is associated with autoimmune and autoinflammatory disorders. Moreover, RLR-mediated signaling might be involved in the aberrant cytokine production observed in coronavirus disease 2019. Since the discovery of RLRs in 2004, significant progress has been made in understanding the mechanisms underlying the activation and regulation of RLR-mediated signaling pathways. Here, we review the recent advances in the understanding of regulated RNA recognition and signal activation by RLRs, focusing on the interactions between various host and viral factors.
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Affiliation(s)
- Koji Onomoto
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | - Kazuhide Onoguchi
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8673, Japan
| | - Mitsutoshi Yoneyama
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8673, Japan.
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Khan MI, Nur SM, Adhami V, Mukhtar H. Epigenetic regulation of RNA sensors: Sentinels of immune response. Semin Cancer Biol 2021; 83:413-421. [PMID: 33484869 DOI: 10.1016/j.semcancer.2020.12.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/11/2022]
Abstract
Living host system possess mechanisms like innate immune system to combat against inflammation, stress singling, and cancer. These mechanisms are initiated by PAMP and DAMP mediated recognition by PRR. PRR is consist of variety of nucleic acid sensors like-RNA sensors. They play crucial role in identifying exogenous and endogenous RNA molecules, which subsequently mediate pro/inflammatory cytokine, IFN and ISGs response in traumatized or tumorigenic conditions. The sensors can sensitize wide range of nucleic acid particle in term of size and structure, while each category sensors belongs subclasses with differentially expressed in cell and distinguished functioning mechanisms. They are also able to make comparison between self and non-self-nucleic acid molecules through specific mechanisms. Besides exhibiting anti-inflammatory and anti-tumorigenic responses, RNA sensors cover the broad spectrum of response mechanisms. Transcriptionally RNA sensors undergo with tight epigenetic regulations. In this review study, we will be going to discuss about the details of RNA sensors, their functional mechanisms and epi-transactional regulations.
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Affiliation(s)
- Mohammad Imran Khan
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Suza Mohammad Nur
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Vaqar Adhami
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, USA
| | - Hasan Mukhtar
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, USA.
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Donelick HM, Talide L, Bellet M, Aruscavage PJ, Lauret E, Aguiar ERGR, Marques JT, Meignin C, Bass BL. In vitro studies provide insight into effects of Dicer-2 helicase mutations in Drosophila melanogaster. RNA (NEW YORK, N.Y.) 2020; 26:1847-1861. [PMID: 32843367 PMCID: PMC7668257 DOI: 10.1261/rna.077289.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 08/20/2020] [Indexed: 05/03/2023]
Abstract
In vitro, Drosophila melanogaster Dicer-2 (Dcr-2) uses its helicase domain to initiate processing of dsRNA with blunt (BLT) termini, and its Platform•PAZ domain to initiate processing of dsRNA with 3' overhangs (ovrs). To understand the relationship of these in vitro observations to roles of Dcr-2 in vivo, we compared in vitro effects of two helicase mutations to their impact on production of endogenous and viral siRNAs in flies. Consistent with the importance of the helicase domain in processing BLT dsRNA, both point mutations eliminated processing of BLT, but not 3'ovr, dsRNA in vitro. However, the mutations had different effects in vivo. A point mutation in the Walker A motif of the Hel1 subdomain, G31R, largely eliminated production of siRNAs in vivo, while F225G, located in the Hel2 subdomain, showed reduced levels of endogenous siRNAs, but did not significantly affect virus-derived siRNAs. In vitro assays monitoring dsRNA cleavage, dsRNA binding, ATP hydrolysis, and binding of the accessory factor Loquacious-PD provided insight into the different effects of the mutations on processing of different sources of dsRNA in flies. Our in vitro studies suggest effects of the mutations in vivo relate to their effects on ATPase activity, dsRNA binding, and interactions with Loquacious-PD. Our studies emphasize the importance of future studies to characterize dsRNA termini as they exist in Drosophila and other animals.
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Affiliation(s)
- Helen M Donelick
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Loïc Talide
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
| | - Matthieu Bellet
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
| | - P Joseph Aruscavage
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Emilie Lauret
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
| | - Eric R G R Aguiar
- Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil
| | - Joao T Marques
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Belo Horizonte, CEP 31270-901, Brazil
| | - Carine Meignin
- Université de Strasbourg, CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
| | - Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112, USA
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Hare DN, Baid K, Dvorkin-Gheva A, Mossman KL. Virus-Intrinsic Differences and Heterogeneous IRF3 Activation Influence IFN-Independent Antiviral Protection. iScience 2020; 23:101864. [PMID: 33319181 PMCID: PMC7726339 DOI: 10.1016/j.isci.2020.101864] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/04/2020] [Accepted: 11/20/2020] [Indexed: 02/09/2023] Open
Abstract
Type 1 interferon (IFN) plays a critical role in early antiviral defense and priming of adaptive immunity by signaling upregulation of host antiviral IFN-stimulated genes (ISGs). Certain stimuli trigger strong activation of IFN regulatory factor 3 (IRF3) and direct upregulation of ISGs in addition to IFN. It remains unclear why some stimuli are stronger activators of IRF3 and how this leads to IFN-independent antiviral protection. We found that UV-inactivated human cytomegalovirus (HCMV) particles triggered an IFN-independent ISG signature that was absent in cells infected with UV-inactivated Sendai virus particles. HCMV particles triggered mostly uniform activation of IRF3 and low-level IFN-β production within the population while SeV particles triggered a small fraction of cells producing abundant IFN-β. These findings suggest that population-level activation of IRF3 and antiviral protection emerges from a diversity of responses occurring simultaneously in single cells. Moreover, this occurs in the absence of virus replication. The antiviral response to virus particles requires low levels of interferon Cells respond differently to HCMV or SeV particles Heterogeneous IRF3 activation influences the response to virus
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Affiliation(s)
- David N Hare
- Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S4L8, Canada
| | - Kaushal Baid
- Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S4L8, Canada
| | - Anna Dvorkin-Gheva
- Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S4L8, Canada
| | - Karen L Mossman
- Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S4L8, Canada.,Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S4L8, Canada
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47
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Zhang Z, Urban S. Interplay between Hepatitis D Virus and the Interferon Response. Viruses 2020; 12:v12111334. [PMID: 33233762 PMCID: PMC7699955 DOI: 10.3390/v12111334] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis D (CHD) is the most severe form of viral hepatitis, with rapid progression of liver-related diseases and high rates of development of hepatocellular carcinoma. The causative agent, hepatitis D virus (HDV), contains a small (approximately 1.7 kb) highly self-pairing single-strand circular RNA genome that assembles with the HDV antigen to form a ribonucleoprotein (RNP) complex. HDV depends on hepatitis B virus (HBV) envelope proteins for envelopment and de novo hepatocyte entry; however, its intracellular RNA replication is autonomous. In addition, HDV can amplify HBV independently through cell division. Cellular innate immune responses, mainly interferon (IFN) response, are crucial for controlling invading viruses, while viruses counteract these responses to favor their propagation. In contrast to HBV, HDV activates profound IFN response through the melanoma differentiation antigen 5 (MDA5) pathway. This cellular response efficiently suppresses cell-division-mediated HDV spread and, to some extent, early stages of HDV de novo infection, but only marginally impairs RNA replication in resting hepatocytes. In this review, we summarize the current knowledge on HDV structure, replication, and persistence and subsequently focus on the interplay between HDV and IFN response, including IFN activation, sensing, antiviral effects, and viral countermeasures. Finally, we discuss crosstalk with HBV.
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Affiliation(s)
- Zhenfeng Zhang
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Stephan Urban
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, 69120 Heidelberg, Germany
- Correspondence: ; Tel.: +49-6221-564-902
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48
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Sarohan AR. COVID-19: Endogenous Retinoic Acid Theory and Retinoic Acid Depletion Syndrome. Med Hypotheses 2020; 144:110250. [PMID: 33254555 PMCID: PMC7481114 DOI: 10.1016/j.mehy.2020.110250] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 08/01/2020] [Accepted: 09/04/2020] [Indexed: 01/08/2023]
Abstract
This study presents two new concepts and definitions to the medical literature. One of those is "endogenous retinoic acid theory" and the other "retinoic acid depletion syndrome". A new classification will be provided for the immune system: "retinoic acid-dependent component" and "retinoic acid non-dependent component". If this theory is verified, all the diseases where the retinoic acid metabolism is defective and retinoic acid levels are low will be identified and new approaches will be developed fortreating such diseases. When the need for retinoic acids increases, such as acute infection, high fever, severe catabolic process, or chronic antigenic stimulation, cytochrome oxidase enzymes are inhibited by drugs or internal mechanisms. Metabolism and excretion of retinoic acids stored in the liver are prevented. In this way, retinoic acid levels in the blood are raised to therapeutic levels. This is called "Endogenous Retinoic Acid Theory". Retinoic acids also manage their metabolism through feedback mechanisms. Despite compensatory mechanisms, causes such as high fever, serious catabolic process and excessively large viral genome (SARS-CoV-2), excessive use of RIG-I and Type I interferon synthesis pathway using retinoic acid causes emptying of retinoic acid stores. As a result, the RIG-I pathway becomes ineffective, Type I IFN synthesis stops, and the congenital immune system collapses. Then the immune mechanism passes to TLR3, TLR7, TLR8, TLR9, MDA5 and UPS pathways in the monocyte, macrophage, neutrophil and dendritic cells of the adaptive immune defense system that do not require retinoic acid. This leads to excessive TNFα and cytokine discharge from the pathway. With the depletion of retinoic acid stores as a result of this overuse, the immune defense mechanism switches from the congenital immune system to the adaptive immune system, where retinoic acids cannot be used. As a result of this depletion of retinoic acids, the shift of the immune system to the NFκB arm, which causes excessive cytokine release, is called "retinoic acid depletion syndrome". COVID-19 and previously defined sepsis, SIRS and ARDS are each retinoic acid depletion syndrome. We claim that retinoic acid metabolism is defective in most inflammatory diseases, particularly COVID-19 (cytokine storm) sepsis, SIRS and ARDS. Finding a solution to this mechanism will bring a new perspective and treatment approach to such diseases.
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Jung S, von Thülen T, Yang I, Laukemper V, Rupf B, Janga H, Panagiotidis GD, Schoen A, Nicolai M, Schulte LN, Obermann HL, Weber F, Kaufmann A, Bauer S. A ribosomal RNA fragment with 2',3'-cyclic phosphate and GTP-binding activity acts as RIG-I ligand. Nucleic Acids Res 2020; 48:10397-10412. [PMID: 32946572 PMCID: PMC7544222 DOI: 10.1093/nar/gkaa739] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022] Open
Abstract
The RNA helicase RIG-I plays a key role in sensing pathogen-derived RNA. Double-stranded RNA structures bearing 5'-tri- or diphosphates are commonly referred to as activating RIG-I ligands. However, endogenous RNA fragments generated during viral infection via RNase L also activate RIG-I. Of note, RNase-digested RNA fragments bear a 5'-hydroxyl group and a 2',3'-cyclic phosphate. How endogenous RNA fragments activate RIG-I despite the lack of 5'-phosphorylation has not been elucidated. Here we describe an endogenous RIG-I ligand (eRL) that is derived from the internal transcribed spacer 2 region (ITS2) of the 45S ribosomal RNA after partial RNase A digestion in vitro, RNase A protein transfection or RNase L activation. The immunostimulatory property of the eRL is dependent on 2',3'-cyclic phosphate and its sequence is characterized by a G-quadruplex containing sequence motif mediating guanosine-5'-triphosphate (GTP) binding. In summary, RNase generated self-RNA fragments with 2',3'-cyclic phosphate function as nucleotide-5'-triphosphate binding aptamers activating RIG-I.
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Affiliation(s)
- Stephanie Jung
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Tina von Thülen
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Ines Yang
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl Neuberg Straße 1, 30625 Hannover, Germany
| | - Viktoria Laukemper
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Benjamin Rupf
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Harshavardhan Janga
- Institut für Lungenforschung/iLung, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Georgios-Dimitrios Panagiotidis
- Institut für Virologie, Fachbereich Veterinärmedizin (FB10), Justus-Liebig-Universität Gießen, Schubertstr. 81, 35392 Gießen, Germany
| | - Andreas Schoen
- Institut für Virologie, Fachbereich Veterinärmedizin (FB10), Justus-Liebig-Universität Gießen, Schubertstr. 81, 35392 Gießen, Germany
| | - Marina Nicolai
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Leon N Schulte
- Institut für Lungenforschung/iLung, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
- Deutsches Zentrum für Lungenforschung (DZL), 35392 Gießen, Germany
| | - Hannah-Lena Obermann
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Friedemann Weber
- Institut für Virologie, Fachbereich Veterinärmedizin (FB10), Justus-Liebig-Universität Gießen, Schubertstr. 81, 35392 Gießen, Germany
| | - Andreas Kaufmann
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
| | - Stefan Bauer
- Institut für Immunologie, Philipps-Universität Marburg, BMFZ, Hans-Meerwein-Straße 2, 35043 Marburg, Germany
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Devignot S, Kromer T, Mirazimi A, Weber F. ISG15 overexpression compensates the defect of Crimean-Congo hemorrhagic fever virus polymerase bearing a protease-inactive ovarian tumor domain. PLoS Negl Trop Dis 2020; 14:e0008610. [PMID: 32931521 PMCID: PMC7518590 DOI: 10.1371/journal.pntd.0008610] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 09/25/2020] [Accepted: 07/16/2020] [Indexed: 12/25/2022] Open
Abstract
Crimean-Congo Hemorrhagic Fever virus (CCHFV; family Nairoviridae) is an extremely pathogenic member of the Bunyavirales order. Previous studies have shown that the N-terminal domain of the CCHFV polymerase (L) contains an ovarian tumor-type protease (OTU) domain with the capability to remove both ubiquitin and ISG15 molecules from proteins. The approximately 200 amino acids-long OTU domain, if ectopically expressed, can interfere with both the induction of antiviral type I interferons (IFN) as well as the IFN-stimulated signaling. A OTU protease mutant (C40A), by contrast, was inactive in that respect. However, the effect of the OTU protease activity in the context of the full-length L protein (approximately 4000 amino acids) is only poorly characterized, and recombinant CCHFV with the C40A mutation could not be rescued. Here, we employed transcriptionally active virus-like particles (tc-VLPs) to investigate the interaction between the L-embedded OTU protease and the IFN system. Our data show a cis requirement of the OTU protease for optimal CCHFV polymerase activity in human HuH-7 cells. The L-embedded OTU did not influence IFN signaling, the sensitivity to IFN, or IFN induction. Moreover, the attenuation of OTU C40A-mutated L could not be relieved by inactivating the IFN response, but after overexpression of conjugation-competent ISG15 the polymerase activity recovered to wild-type levels. Consequently, ISG15 was used to produce OTU-deficient tc-VLPs, a potential vaccine candidate. Our data thus indicate that in the context of full-length L the OTU domain is important for the regulation of CCHFV polymerase by ISG15. Tick-transmitted Crimean-Congo Hemorrhagic Fever virus (CCHFV) causes a serious and potentially fatal disease in humans. The CCHFV polymerase possesses an N-terminal ovarian tumor-type protease (OTU) domain that cleaves ubiquitin and ISG15 modifiers from target proteins. Previous studies demonstrated that the ectopically expressed OTU domain can inhibit antiviral type I interferon responses. Hence, cleavage-negative OTU mutants of virus or transcriptionally active virus-like particles (tc-VLPs) are expected to exhibit elevated immunogenicity and would be candidates for a live vaccine. For unknown reasons, however, recombinant virus with just the OTU minus mutation cannot be generated. Using tc-VLPs, we show that in human HuH-7 cells the activity of the OTU minus polymerase is reduced by more than 80%. Curiously, the attenuation could not be compensated by inactivating the interferon system or by adding the OTU domain in trans. However, a complete reversion of the OTU minus phenotype was achieved by transcomplementation with ISG15, whereas the other OTU substrate, ubiquitin, had no such positive influence. Our data thus indicate a role of cis OTU in CCHFV polymerase regulation that is independent of an anti-interferon activity but connected to ISG15. Transcomplementation with ISG15 may be a means to rescue the OTU minus CCHV vaccine candidate.
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Affiliation(s)
- Stephanie Devignot
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Thilo Kromer
- Faculty of Health, Safety, Society, Furtwangen University, Furtwangen, Germany
| | - Ali Mirazimi
- Public Health Agency of Sweden, Solna, Sweden
- National Veterinary Institute, Solna, Sweden
- Karolinska Institute, Stockholm, Sweden
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
- * E-mail:
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