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Roy A, Ghosh A. Epigenetic Restriction Factors (eRFs) in Virus Infection. Viruses 2024; 16:183. [PMID: 38399958 PMCID: PMC10892949 DOI: 10.3390/v16020183] [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: 12/09/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
The ongoing arms race between viruses and their hosts is constantly evolving. One of the ways in which cells defend themselves against invading viruses is by using restriction factors (RFs), which are cell-intrinsic antiviral mechanisms that block viral replication and transcription. Recent research has identified a specific group of RFs that belong to the cellular epigenetic machinery and are able to restrict the gene expression of certain viruses. These RFs can be referred to as epigenetic restriction factors or eRFs. In this review, eRFs have been classified into two categories. The first category includes eRFs that target viral chromatin. So far, the identified eRFs in this category include the PML-NBs, the KRAB/KAP1 complex, IFI16, and the HUSH complex. The second category includes eRFs that target viral RNA or, more specifically, the viral epitranscriptome. These epitranscriptomic eRFs have been further classified into two types: those that edit RNA bases-adenosine deaminase acting on RNA (ADAR) and pseudouridine synthases (PUS), and those that covalently modify viral RNA-the N6-methyladenosine (m6A) writers, readers, and erasers. We delve into the molecular machinery of eRFs, their role in limiting various viruses, and the mechanisms by which viruses have evolved to counteract them. We also examine the crosstalk between different eRFs, including the common effectors that connect them. Finally, we explore the potential for new discoveries in the realm of epigenetic networks that restrict viral gene expression, as well as the future research directions in this area.
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Affiliation(s)
- Arunava Roy
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA;
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2
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Mueller F, Witteveldt J, Macias S. Antiviral Defence Mechanisms during Early Mammalian Development. Viruses 2024; 16:173. [PMID: 38399949 PMCID: PMC10891733 DOI: 10.3390/v16020173] [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: 12/14/2023] [Revised: 01/11/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024] Open
Abstract
The type-I interferon (IFN) response constitutes the major innate immune pathway against viruses in mammals. Despite its critical importance for antiviral defence, this pathway is inactive during early embryonic development. There seems to be an incompatibility between the IFN response and pluripotency, the ability of embryonic cells to develop into any cell type of an adult organism. Instead, pluripotent cells employ alternative ways to defend against viruses that are typically associated with safeguard mechanisms against transposable elements. The absence of an inducible IFN response in pluripotent cells and the constitutive activation of the alternative antiviral pathways have led to the hypothesis that embryonic cells are highly resistant to viruses. However, some findings challenge this interpretation. We have performed a meta-analysis that suggests that the susceptibility of pluripotent cells to viruses is directly correlated with the presence of receptors or co-receptors for viral adhesion and entry. These results challenge the current view of pluripotent cells as intrinsically resistant to infections and raise the fundamental question of why these cells have sacrificed the major antiviral defence pathway if this renders them susceptible to viruses.
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Affiliation(s)
- Felix Mueller
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King’s Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; (F.M.); (J.W.)
- Centre for Virus Research, MRC-University of Glasgow, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Jeroen Witteveldt
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King’s Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; (F.M.); (J.W.)
| | - Sara Macias
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King’s Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; (F.M.); (J.W.)
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3
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Shen S, Zhang LS. The regulation of antiviral innate immunity through non-m 6A RNA modifications. Front Immunol 2023; 14:1286820. [PMID: 37915585 PMCID: PMC10616867 DOI: 10.3389/fimmu.2023.1286820] [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: 08/31/2023] [Accepted: 10/04/2023] [Indexed: 11/03/2023] Open
Abstract
The post-transcriptional RNA modifications impact the dynamic regulation of gene expression in diverse biological and physiological processes. Host RNA modifications play an indispensable role in regulating innate immune responses against virus infection in mammals. Meanwhile, the viral RNAs can be deposited with RNA modifications to interfere with the host immune responses. The N6-methyladenosine (m6A) has boosted the recent emergence of RNA epigenetics, due to its high abundance and a transcriptome-wide widespread distribution in mammalian cells, proven to impact antiviral innate immunity. However, the other types of RNA modifications are also involved in regulating antiviral responses, and the functional roles of these non-m6A RNA modifications have not been comprehensively summarized. In this Review, we conclude the regulatory roles of 2'-O-methylation (Nm), 5-methylcytidine (m5C), adenosine-inosine editing (A-to-I editing), pseudouridine (Ψ), N1-methyladenosine (m1A), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), and N4-acetylcytidine (ac4C) in antiviral innate immunity. We provide a systematic introduction to the biogenesis and functions of these non-m6A RNA modifications in viral RNA, host RNA, and during virus-host interactions, emphasizing the biological functions of RNA modification regulators in antiviral responses. Furthermore, we discussed the recent research progress in the development of antiviral drugs through non-m6A RNA modifications. Collectively, this Review conveys knowledge and inspiration to researchers in multiple disciplines, highlighting the challenges and future directions in RNA epitranscriptome, immunology, and virology.
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Affiliation(s)
- Shenghai Shen
- Division of Life Science, The Hong Kong University of Science and Technology (HKUST), Kowloon, Hong Kong SAR, China
| | - Li-Sheng Zhang
- Division of Life Science, The Hong Kong University of Science and Technology (HKUST), Kowloon, Hong Kong SAR, China
- Department of Chemistry, The Hong Kong University of Science and Technology (HKUST), Kowloon, Hong Kong SAR, China
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Datta R, Adamska JZ, Bhate A, Li JB. A-to-I RNA editing by ADAR and its therapeutic applications: From viral infections to cancer immunotherapy. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 15:e1817. [PMID: 37718249 PMCID: PMC10947335 DOI: 10.1002/wrna.1817] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023]
Abstract
ADAR deaminases catalyze adenosine-to-inosine (A-to-I) editing on double-stranded RNA (dsRNA) substrates that regulate an umbrella of biological processes. One of the two catalytically active ADAR enzymes, ADAR1, plays a major role in innate immune responses by suppression of RNA sensing pathways which are orchestrated through the ADAR1-dsRNA-MDA5 axis. Unedited immunogenic dsRNA substrates are potent ligands for the cellular sensor MDA5. Upon activation, MDA5 leads to the induction of interferons and expression of hundreds of interferon-stimulated genes with potent antiviral activity. In this way, ADAR1 acts as a gatekeeper of the RNA sensing pathway by striking a fine balance between innate antiviral responses and prevention of autoimmunity. Reduced editing of immunogenic dsRNA by ADAR1 is strongly linked to the development of common autoimmune and inflammatory diseases. In viral infections, ADAR1 exhibits both antiviral and proviral effects. This is modulated by both editing-dependent and editing-independent functions, such as PKR antagonism. Several A-to-I RNA editing events have been identified in viruses, including in the insidious viral pathogen, SARS-CoV-2 which regulates viral fitness and infectivity, and could play a role in shaping viral evolution. Furthermore, ADAR1 is an attractive target for immuno-oncology therapy. Overexpression of ADAR1 and increased dsRNA editing have been observed in several human cancers. Silencing ADAR1, especially in cancers that are refractory to immune checkpoint inhibitors, is a promising therapeutic strategy for cancer immunotherapy in conjunction with epigenetic therapy. The mechanistic understanding of dsRNA editing by ADAR1 and dsRNA sensing by MDA5 and PKR holds great potential for therapeutic applications. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Rohini Datta
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Julia Z Adamska
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Amruta Bhate
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
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Mohanty S, Harhaj EW. Mechanisms of Innate Immune Sensing of HTLV-1 and Viral Immune Evasion. Pathogens 2023; 12:pathogens12050735. [PMID: 37242405 DOI: 10.3390/pathogens12050735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Human T lymphotropic virus-1 (HTLV-1) was the first identified oncoretrovirus, which infects and establishes a persistent infection in approximately 10-20 million people worldwide. Although only ~5% of infected individuals develop pathologies such as adult T-cell leukemia/lymphoma (ATLL) or a neuroinflammatory disorder termed HTLV-1-asssociated myelopathy/tropical spastic paraparesis (HAM/TSP), asymptomatic carriers are more susceptible to opportunistic infections. Furthermore, ATLL patients are severely immunosuppressed and prone to other malignancies and other infections. The HTLV-1 replication cycle provides ligands, mainly nucleic acids (RNA, RNA/DNA intermediates, ssDNA intermediates, and dsDNA), that are sensed by different pattern recognition receptors (PRRs) to trigger immune responses. However, the mechanisms of innate immune detection and immune responses to HTLV-1 infection are not well understood. In this review, we highlight the functional roles of different immune sensors in recognizing HTLV-1 infection in multiple cell types and the antiviral roles of host restriction factors in limiting persistent infection of HTLV-1. We also provide a comprehensive overview of intricate strategies employed by HTLV-1 to subvert the host innate immune response that may contribute to the development of HTLV-1-associated diseases. A more detailed understanding of HTLV-1-host pathogen interactions may inform novel strategies for HTLV-1 antivirals, vaccines, and treatments for ATLL or HAM/TSP.
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Affiliation(s)
- Suchitra Mohanty
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Edward W Harhaj
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA 17033, USA
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Zhu T, Niu G, Zhang Y, Chen M, Li CY, Hao L, Zhang Z. Host-mediated RNA editing in viruses. Biol Direct 2023; 18:12. [PMID: 36978112 PMCID: PMC10043548 DOI: 10.1186/s13062-023-00366-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Viruses rely on hosts for life and reproduction, cause a variety of symptoms from common cold to AIDS to COVID-19 and provoke public health threats claiming millions of lives around the globe. RNA editing, as a crucial co-/post-transcriptional modification inducing nucleotide alterations on both endogenous and exogenous RNA sequences, exerts significant influences on virus replication, protein synthesis, infectivity and toxicity. Hitherto, a number of host-mediated RNA editing sites have been identified in diverse viruses, yet lacking a full picture of RNA editing-associated mechanisms and effects in different classes of viruses. Here we synthesize the current knowledge of host-mediated RNA editing in a variety of viruses by considering two enzyme families, viz., ADARs and APOBECs, thereby presenting a landscape of diverse editing mechanisms and effects between viruses and hosts. In the ongoing pandemic, our study promises to provide potentially valuable insights for better understanding host-mediated RNA editing on ever-reported and newly-emerging viruses.
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Affiliation(s)
- Tongtong Zhu
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangyi Niu
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuansheng Zhang
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Chen
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuan-Yun Li
- Laboratory of Bioinformatics and Genomic Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Lili Hao
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
| | - Zhang Zhang
- National Genomics Data Center & CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Saini J, Kaur P, Malik N, Lakhawat SS, Sharma PK. Antimicrobial peptides: A promising tool to combat multidrug resistance in SARS CoV2 era. Microbiol Res 2022; 265:127206. [PMID: 36162150 PMCID: PMC9491010 DOI: 10.1016/j.micres.2022.127206] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/26/2022] [Accepted: 09/16/2022] [Indexed: 10/25/2022]
Abstract
COVID-19 (Coronavirus Disease 2019), a life-threatening viral infection, is caused by a highly pathogenic virus named SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). Currently, no treatment is available for COVID-19; hence there is an urgent need to find effective therapeutic drugs to combat COVID-19 pandemic. Considering the fact that the world is facing a major issue of antimicrobial drug resistance, naturally occurring compounds have the potential to achieve this goal. Antimicrobial peptides (AMPs) are naturally occurring antimicrobial agents which are effective against a wide variety of microbial infections. Therefore, the use of AMPs is an attractive therapeutic strategy for the treatment of SARS-CoV-2 infection. This review sheds light on the potential of antimicrobial peptides as antiviral agents followed by a comprehensive description of effective antiviral peptides derived from various natural sources found to be effective against SARS-CoV and other respiratory viruses. It also highlights the mechanisms of action of antiviral peptides with special emphasis on their effectiveness against SARS-CoV-2 infection.
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Affiliation(s)
- Jasleen Saini
- Department of Biotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, India
| | - Pritpal Kaur
- Department of Biotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, India
| | - Naveen Malik
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
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Martignano F, Di Giorgio S, Mattiuz G, Conticello SG. Commentary on “Poor evidence for host-dependent regular RNA editing in the transcriptome of SARS-CoV-2”. J Appl Genet 2022; 63:423-428. [PMID: 35279801 PMCID: PMC8917825 DOI: 10.1007/s13353-022-00688-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 01/10/2023]
Abstract
Analysis of the SARS-CoV-2 transcriptome has revealed a background of low-frequency intra-host genetic changes with a strong bias towards transitions. A similar pattern is also observed when inter-host variability is considered. We and others have shown that the cellular RNA editing machinery based on ADAR and APOBEC host-deaminases could be involved in the onset of SARS-CoV-2 genetic variability. Our hypothesis is based both on similarities with other known forms of viral genome editing and on the excess of transition changes, which is difficult to explain with errors during viral replication. Zong et al. criticize our analysis on both conceptual and technical grounds. While ultimate proof of an involvement of host deaminases in viral RNA editing will depend on experimental validation, here, we address the criticism to suggest that viral RNA editing is the most reasonable explanation for the observed intra- and inter-host variability.
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Affiliation(s)
- F Martignano
- Core Research Laboratory, ISPRO, 50139, Firenze, Italy
| | - S Di Giorgio
- German Cancer Research Center (DKFZ), Division of Immune Diversity, Foundation Under Public Law, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - G Mattiuz
- Department of Experimental and Clinical Medicine, University of Florence, 50139, Firenze, Italy
| | - S G Conticello
- Core Research Laboratory, ISPRO, 50139, Firenze, Italy.
- Institute of Clinical Physiology, National Research Council, 56124, Pisa, Italy.
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Dutta N, Deb I, Sarzynska J, Lahiri A. Inosine and its methyl derivatives: Occurrence, biogenesis, and function in RNA. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 169-170:21-52. [PMID: 35065168 DOI: 10.1016/j.pbiomolbio.2022.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/11/2021] [Accepted: 01/11/2022] [Indexed: 05/21/2023]
Abstract
Inosine is one of the most common post-transcriptional modifications. Since its discovery, it has been noted for its ability to contribute to non-Watson-Crick interactions within RNA. Rapidly accumulating evidence points to the widespread generation of inosine through hydrolytic deamination of adenosine to inosine by different classes of adenosine deaminases. Three naturally occurring methyl derivatives of inosine, i.e., 1-methylinosine, 2'-O-methylinosine and 1,2'-O-dimethylinosine are currently reported in RNA modification databases. These modifications are expected to lead to changes in the structure, folding, dynamics, stability and functions of RNA. The importance of the modifications is indicated by the strong conservation of the modifying enzymes across organisms. The structure, binding and catalytic mechanism of the adenosine deaminases have been well-studied, but the underlying mechanism of the catalytic reaction is not very clear yet. Here we extensively review the existing data on the occurrence, biogenesis and functions of inosine and its methyl derivatives in RNA. We also included the structural and thermodynamic aspects of these modifications in our review to provide a detailed and integrated discussion on the consequences of A-to-I editing in RNA and the contribution of different structural and thermodynamic studies in understanding its role in RNA. We also highlight the importance of further studies for a better understanding of the mechanisms of the different classes of deamination reactions. Further investigation of the structural and thermodynamic consequences and functions of these modifications in RNA should provide more useful information about their role in different diseases.
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Affiliation(s)
- Nivedita Dutta
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata, 700009, West Bengal, India
| | - Indrajit Deb
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata, 700009, West Bengal, India
| | - Joanna Sarzynska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Ansuman Lahiri
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata, 700009, West Bengal, India.
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Impact of ADAR-induced editing of minor viral RNA populations on replication and transmission of SARS-CoV-2. Proc Natl Acad Sci U S A 2022; 119:2112663119. [PMID: 35064076 PMCID: PMC8833170 DOI: 10.1073/pnas.2112663119] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2021] [Indexed: 12/19/2022] Open
Abstract
Viral RNA may be edited by enzymes of the ADAR family that deaminate adenosine residues with ensuing A→G mutations. We found multiple A→G mutations in minor viral populations of the SARS-CoV-2 genome. A→G mutations accumulated in the receptor binding domain of the spike gene, which may cause structural changes by altering binding to the ACE2 receptor. Presence of A→G mutations in minor viral populations was associated with reduced viral load, implying that ADAR may limit viral replication. Analyses of >250,000 European samples from 2020 revealed that A→G mutations in SARS-CoV-2 RNA were inversely correlated with mortality as a reflection of incidence. ADAR may thus be important in providing new variants of SARS-CoV-2 with altered infectivity and transmissibility. Adenosine deaminases acting on RNA (ADAR) are RNA-editing enzymes that may restrict viral infection. We have utilized deep sequencing to determine adenosine to guanine (A→G) mutations, signifying ADAR activity, in clinical samples retrieved from 93 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–infected patients in the early phase of the COVID-19 pandemic. A→G mutations were detected in 0.035% (median) of RNA residues and were predominantly nonsynonymous. These mutations were rarely detected in the major viral population but were abundant in minor viral populations in which A→G was more prevalent than any other mutation (P < 0.001). The A→G substitutions accumulated in the spike protein gene at positions corresponding to amino acids 505 to 510 in the receptor binding motif and at amino acids 650 to 655. The frequency of A→G mutations in minor viral populations was significantly associated with low viral load (P < 0.001). We additionally analyzed A→G mutations in 288,247 SARS-CoV-2 major (consensus) sequences representing the dominant viral population. The A→G mutations observed in minor viral populations in the initial patient cohort were increasingly detected in European consensus sequences between March and June 2020 (P < 0.001) followed by a decline of these mutations in autumn and early winter (P < 0.001). We propose that ADAR-induced deamination of RNA is a significant source of mutated SARS-CoV-2 and hypothesize that the degree of RNA deamination may determine or reflect viral fitness and infectivity.
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Wu L, Wang D. The "Janus-like" RNA-editing machinery in innate antiviral immunity. CURRENT TRENDS IN IMMUNOLOGY 2022; 23:23-32. [PMID: 36398055 PMCID: PMC9668064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Our innate immune systems are evolved to provide the first line of immune defense against microbial infections. A key effector component is the adenosine deaminase acting on the RNA-1 (ADAR-1)/interferon (IFN) pathway of the innate cytoplasmic immunity that mounts rapid responses to many viral pathogens. As an RNA-editing enzyme, ADAR-1 targets viral RNA intermediates in the cytoplasmic compartment to interfere with the infection. However, ADAR-1 may also edit characteristic RNA structures of certain host genes, notably, the 5-hydroxytryptamine (serotonin) receptor 2C (5-HT2CR). Dysfunction of 5-HT2CR has been linked to the pathology of several human mental conditions, such as Schizophrenia, anxiety, bipolar disorder, major depression, and the mental illnesses of substance use disorders (SUD). Thus, the ADAR-1-mediated RNA editing may be either beneficial or harmful; these effects need to be tightly modulated to sustain innate antiviral immunity while restricting undesired off-target self-reactivity. In this communication, we discuss ideas and tools to identify the orphan drug candidates, including small molecules and biologics that may serve as effective modulators of the ADAR-1/IFN innate immunity and are thereby promising for use in treating or preventing SUD- and/or viral infection-associated mental illnesses.
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Piontkivska H, Wales-McGrath B, Miyamoto M, Wayne ML. ADAR Editing in Viruses: An Evolutionary Force to Reckon with. Genome Biol Evol 2021; 13:evab240. [PMID: 34694399 PMCID: PMC8586724 DOI: 10.1093/gbe/evab240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2021] [Indexed: 02/06/2023] Open
Abstract
Adenosine Deaminases that Act on RNA (ADARs) are RNA editing enzymes that play a dynamic and nuanced role in regulating transcriptome and proteome diversity. This editing can be highly selective, affecting a specific site within a transcript, or nonselective, resulting in hyperediting. ADAR editing is important for regulating neural functions and autoimmunity, and has a key role in the innate immune response to viral infections, where editing can have a range of pro- or antiviral effects and can contribute to viral evolution. Here we examine the role of ADAR editing across a broad range of viral groups. We propose that the effect of ADAR editing on viral replication, whether pro- or antiviral, is better viewed as an axis rather than a binary, and that the specific position of a given virus on this axis is highly dependent on virus- and host-specific factors, and can change over the course of infection. However, more research needs to be devoted to understanding these dynamic factors and how they affect virus-ADAR interactions and viral evolution. Another area that warrants significant attention is the effect of virus-ADAR interactions on host-ADAR interactions, particularly in light of the crucial role of ADAR in regulating neural functions. Answering these questions will be essential to developing our understanding of the relationship between ADAR editing and viral infection. In turn, this will further our understanding of the effects of viruses such as SARS-CoV-2, as well as many others, and thereby influence our approach to treating these deadly diseases.
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Affiliation(s)
- Helen Piontkivska
- Department of Biological Sciences, Kent State University, Ohio, USA
- School of Biomedical Sciences, Kent State University, Ohio, USA
- Brain Health Research Institute, Kent State University, Ohio, USA
| | | | - Michael Miyamoto
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Marta L Wayne
- Department of Biology, University of Florida, Gainesville, Florida, USA
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Markiewicz L, Drazkowska K, Sikorski PJ. Tricks and threats of RNA viruses - towards understanding the fate of viral RNA. RNA Biol 2021; 18:669-687. [PMID: 33618611 PMCID: PMC8078519 DOI: 10.1080/15476286.2021.1875680] [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: 08/25/2020] [Revised: 12/22/2020] [Accepted: 01/09/2021] [Indexed: 12/24/2022] Open
Abstract
Human innate cellular defence pathways have evolved to sense and eliminate pathogens, of which, viruses are considered one of the most dangerous. Their relatively simple structure makes the identification of viral invasion a difficult task for cells. In the course of evolution, viral nucleic acids have become one of the strongest and most reliable early identifiers of infection. When considering RNA virus recognition, RNA sensing is the central mechanism in human innate immunity, and effectiveness of this sensing is crucial for triggering an appropriate antiviral response. Although human cells are armed with a variety of highly specialized receptors designed to respond only to pathogenic viral RNA, RNA viruses have developed an array of mechanisms to avoid being recognized by human interferon-mediated cellular defence systems. The repertoire of viral evasion strategies is extremely wide, ranging from masking pathogenic RNA through end modification, to utilizing sophisticated techniques to deceive host cellular RNA degrading enzymes, and hijacking the most basic metabolic pathways in host cells. In this review, we aim to dissect human RNA sensing mechanisms crucial for antiviral immune defences, as well as the strategies adopted by RNA viruses to avoid detection and degradation by host cells. We believe that understanding the fate of viral RNA upon infection, and detailing the molecular mechanisms behind virus-host interactions, may be helpful for developing more effective antiviral strategies; which are urgently needed to prevent the far-reaching consequences of widespread, highly pathogenic viral infections.
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Vlachogiannis NI, Verrou KM, Stellos K, Sfikakis PP, Paraskevis D. The role of A-to-I RNA editing in infections by RNA viruses: Possible implications for SARS-CoV-2 infection. Clin Immunol 2021; 226:108699. [PMID: 33639276 PMCID: PMC7904470 DOI: 10.1016/j.clim.2021.108699] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
RNA editing is a fundamental biological process with 2 major forms, namely adenosine-to-inosine (A-to-I, recognized as A-to-G) and cytosine-to-uracil (C-to-U) deamination, mediated by ADAR and APOBEC enzyme families, respectively. A-to-I RNA editing has been shown to directly affect the genome/transcriptome of RNA viruses with significant repercussions for viral protein synthesis, proliferation and infectivity, while it also affects recognition of double-stranded RNAs by cytosolic receptors controlling the host innate immune response. Recent evidence suggests that RNA editing may be present in SARS-CoV-2 genome/transcriptome. The majority of mapped mutations in SARS-CoV-2 genome are A-to-G/U-to-C(opposite strand) and C-to-U/G-to-A(opposite strand) substitutions comprising potential ADAR-/APOBEC-mediated deamination events. A single nucleotide substitution can have dramatic effects on SARS-CoV-2 infectivity as shown by the D614G(A-to-G) substitution in the spike protein. Future studies utilizing serial sampling from patients with COVID-19 are warranted to delineate whether RNA editing affects viral replication and/or the host immune response to SARS-CoV-2.
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Affiliation(s)
- Nikolaos I. Vlachogiannis
- First Department of Propaedeutic Internal Medicine and Joint Rheumatology Program, National and Kapodistrian University of Athens Medical School, Athens, Greece,Biosciences Institute, Vascular Biology and Medicine Theme, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Kleio-Maria Verrou
- Center of New Biotechnologies & Precision Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Konstantinos Stellos
- Biosciences Institute, Vascular Biology and Medicine Theme, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Petros P. Sfikakis
- First Department of Propaedeutic Internal Medicine and Joint Rheumatology Program, National and Kapodistrian University of Athens Medical School, Athens, Greece,Center of New Biotechnologies & Precision Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Dimitrios Paraskevis
- Department of Hygiene, Epidemiology and Medical Statistics, National and Kapodistrian University of Athens Medical School, Athens, Greece,Corresponding author
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15
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Abstract
C6 deamination of adenosine (A) to inosine (I) in double-stranded RNA (dsRNA) is catalyzed by a family of enzymes known as ADARs (adenosine deaminases acting on RNA) encoded by three genes in mammals. Alternative promoters and splicing produce two ADAR1 proteins, an interferon-inducible cytoplasmic p150 and a constitutively expressed p110 that like ADAR2 is a nuclear enzyme. ADAR3 lacks deaminase activity. A-to-I editing occurs with both viral and cellular RNAs. Deamination activity is dependent on dsRNA substrate structure and regulatory RNA-binding proteins and ranges from highly site selective with hepatitis D RNA and glutamate receptor precursor messenger RNA (pre-mRNA) to hyperediting of measles virus and polyomavirus transcripts and cellular inverted Alu elements. Because I base-pairs as guanosine instead of A, editing can alter mRNA decoding, pre-mRNA splicing, and microRNA silencing. Editing also alters dsRNA structure, thereby suppressing innate immune responses including interferon production and action. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Christian K Pfaller
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, Langen 63225, Germany
| | - Cyril X George
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
| | - Charles E Samuel
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
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16
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Netzband R, Pager CT. Viral Epitranscriptomics. Virology 2021. [DOI: 10.1002/9781119818526.ch4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Roca Suarez AA, Testoni B, Baumert TF, Lupberger J. Nucleic Acid-Induced Signaling in Chronic Viral Liver Disease. Front Immunol 2021; 11:624034. [PMID: 33613561 PMCID: PMC7892431 DOI: 10.3389/fimmu.2020.624034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
A hallmark for the development and progression of chronic liver diseases is the persistent dysregulation of signaling pathways related to inflammatory responses, which eventually promotes the development of hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The two major etiological agents associated with these complications in immunocompetent patients are hepatitis B virus (HBV) and hepatitis C virus (HCV), accounting for almost 1.4 million liver disease-associated deaths worldwide. Although both differ significantly from the point of their genomes and viral life cycles, they exert not only individual but also common strategies to divert innate antiviral defenses. Multiple virus-modulated pathways implicated in stress and inflammation illustrate how chronic viral hepatitis persistently tweaks host signaling processes with important consequences for liver pathogenesis. The following review aims to summarize the molecular events implicated in the sensing of viral nucleic acids, the mechanisms employed by HBV and HCV to counter these measures and how the dysregulation of these cellular pathways drives the development of chronic liver disease and the progression toward HCC.
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Affiliation(s)
- Armando Andres Roca Suarez
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France.,INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, France.,University of Lyon, Université Claude-Bernard (UCBL), Lyon, France
| | - Barbara Testoni
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, France.,University of Lyon, Université Claude-Bernard (UCBL), Lyon, France
| | - Thomas F Baumert
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France.,Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Nouvel Hôpital Civil, Strasbourg, France.,Institut Universitaire de France (IUF), Paris, France
| | - Joachim Lupberger
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
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18
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Turjya RR, Khan MAAK, Mir Md. Khademul Islam AB. Perversely expressed long noncoding RNAs can alter host response and viral proliferation in SARS-CoV-2 infection. Future Virol 2020; 15:577-593. [PMID: 33224264 PMCID: PMC7664154 DOI: 10.2217/fvl-2020-0188] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/25/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Regulatory roles of long noncoding RNAs (lncRNAs) during viral infection has become more evident in last decade, but are yet to be explored for SARS-CoV-2. MATERIALS & METHODS We analyzed RNA-seq dataset of SARS-CoV-2 infected lung epithelial cells to identify differentially expressed genes. RESULTS Our analyses uncover 21 differentially expressed lncRNAs broadly involved in cell survival and regulation of gene expression. These lncRNAs can directly interact with six differentially expressed protein-coding genes, and ten host genes that interact with SARS-CoV-2 proteins. Also, they can block the suppressive effect of nine microRNAs induced in viral infections. CONCLUSION Our investigation determines that deregulated lncRNAs in SARS-CoV-2 infection are involved in viral proliferation, cellular survival, and immune response, ultimately determining disease outcome.
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Affiliation(s)
- Rafeed Rahman Turjya
- Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka, Bangladesh
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19
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Vogel OA, Han J, Liang CY, Manicassamy S, Perez JT, Manicassamy B. The p150 Isoform of ADAR1 Blocks Sustained RLR signaling and Apoptosis during Influenza Virus Infection. PLoS Pathog 2020; 16:e1008842. [PMID: 32898178 PMCID: PMC7500621 DOI: 10.1371/journal.ppat.1008842] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/18/2020] [Accepted: 07/28/2020] [Indexed: 12/24/2022] Open
Abstract
Signaling through retinoic acid inducible gene I (RIG-I) like receptors (RLRs) is tightly regulated, with activation occurring upon sensing of viral nucleic acids, and suppression mediated by negative regulators. Under homeostatic conditions aberrant activation of melanoma differentiation-associated protein-5 (MDA5) is prevented through editing of endogenous dsRNA by RNA editing enzyme Adenosine Deaminase Acting on RNA (ADAR1). In addition, ADAR1 is postulated to play pro-viral and antiviral roles during viral infections that are dependent or independent of RNA editing activity. Here, we investigated the importance of ADAR1 isoforms in modulating influenza A virus (IAV) replication and revealed the opposing roles for ADAR1 isoforms, with the nuclear p110 isoform restricting versus the cytoplasmic p150 isoform promoting IAV replication. Importantly, we demonstrate that p150 is critical for preventing sustained RIG-I signaling, as p150 deficient cells showed increased IFN-β expression and apoptosis during IAV infection, independent of RNA editing activity. Taken together, the p150 isoform of ADAR1 is important for preventing sustained RIG-I induced IFN-β expression and apoptosis during viral infection.
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Affiliation(s)
- Olivia A. Vogel
- Department of Microbiology, University of Chicago, Chicago, Illinois, United States of America
| | - Julianna Han
- Department of Microbiology, University of Chicago, Chicago, Illinois, United States of America
| | - Chieh-Yu Liang
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, United States of America
| | - Santhakumar Manicassamy
- Cancer Immunology, Inflammation, and Tolerance Program, GRU Cancer Center, Augusta University, Augusta, Georgia
| | - Jasmine T. Perez
- Department of Microbiology, University of Chicago, Chicago, Illinois, United States of America
| | - Balaji Manicassamy
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, United States of America
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20
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Li Y, Yang X, Wang N, Wang H, Yin B, Yang X, Jiang W. The divergence between SARS-CoV-2 and RaTG13 might be overestimated due to the extensive RNA modification. Future Virol 2020. [PMCID: PMC7346715 DOI: 10.2217/fvl-2020-0066] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Aim: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the world. There is urgent need to understand the phylogeny, divergence and origin of SARS-CoV-2. Materials & methods: A recent study claimed that there was 17% divergence between SARS-CoV-2 and RaTG13 (a SARS-related coronaviruses) on synonymous sites by using sequence alignment. We re-analyzed the sequences of the two coronaviruses with the same methodology. Results: We found that 87% of the synonymous substitutions between the two coronaviruses could be potentially explained by the RNA modification system in hosts, with 65% contributed by deamination on cytidines (C-T mismatches) and 22% contributed by deamination on adenosines (A-G mismatches). Conclusion: Our results demonstrate that the divergence between SARS-CoV-2 and RaTG13 has been overestimated.
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Affiliation(s)
- Yue Li
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
| | - Xinai Yang
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
| | - Na Wang
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
| | - Haiyan Wang
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
| | - Bin Yin
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
| | - Xiaoping Yang
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
| | - Wenqing Jiang
- Department of Respiratory Diseases, Qingdao Haici Hospital, PR China
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21
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Di Giorgio S, Martignano F, Torcia MG, Mattiuz G, Conticello SG. Evidence for host-dependent RNA editing in the transcriptome of SARS-CoV-2. SCIENCE ADVANCES 2020; 6:eabb5813. [PMID: 32596474 PMCID: PMC7299625 DOI: 10.1126/sciadv.abb5813] [Citation(s) in RCA: 242] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/05/2020] [Indexed: 05/13/2023]
Abstract
The COVID-19 outbreak has become a global health risk, and understanding the response of the host to the SARS-CoV-2 virus will help to combat the disease. RNA editing by host deaminases is an innate restriction process to counter virus infection, but it is not yet known whether this process operates against coronaviruses. Here, we analyze RNA sequences from bronchoalveolar lavage fluids obtained from coronavirus-infected patients. We identify nucleotide changes that may be signatures of RNA editing: adenosine-to-inosine changes from ADAR deaminases and cytosine-to-uracil changes from APOBEC deaminases. Mutational analysis of genomes from different strains of Coronaviridae from human hosts reveals mutational patterns consistent with those observed in the transcriptomic data. However, the reduced ADAR signature in these data raises the possibility that ADARs might be more effective than APOBECs in restricting viral propagation. Our results thus suggest that both APOBECs and ADARs are involved in coronavirus genome editing, a process that may shape the fate of both virus and patient.
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Affiliation(s)
- Salvatore Di Giorgio
- Core Research Laboratory, ISPRO, Firenze 50139, Italy
- Department of Medical Biotechnologies, University of Siena, Siena 53100, Italy
| | - Filippo Martignano
- Core Research Laboratory, ISPRO, Firenze 50139, Italy
- Department of Medical Biotechnologies, University of Siena, Siena 53100, Italy
| | - Maria Gabriella Torcia
- Department of Experimental and Clinical Medicine, University of Florence, Firenze 50139, Italy
| | - Giorgio Mattiuz
- Core Research Laboratory, ISPRO, Firenze 50139, Italy
- Department of Experimental and Clinical Medicine, University of Florence, Firenze 50139, Italy
| | - Silvestro G. Conticello
- Core Research Laboratory, ISPRO, Firenze 50139, Italy
- Institute of Clinical Physiology, National Research Council, 56124 Pisa, Italy
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22
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ADAR2 Is Involved in Self and Nonself Recognition of Borna Disease Virus Genomic RNA in the Nucleus. J Virol 2020; 94:JVI.01513-19. [PMID: 31852792 DOI: 10.1128/jvi.01513-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/13/2019] [Indexed: 12/28/2022] Open
Abstract
Cells sense pathogen-derived double-stranded RNA (dsRNA) as nonself. To avoid autoimmune activation by self dsRNA, cells utilize A-to-I editing by adenosine deaminase acting on RNA 1 (ADAR1) to disrupt dsRNA structures. Considering that viruses have evolved to exploit host machinery, A-to-I editing could benefit innate immune evasion by viruses. Borna disease virus (BoDV), a nuclear-replicating RNA virus, may require escape from nonself RNA-sensing and immune responses to establish persistent infection in the nucleus; however, the strategy by which BoDV evades nonself recognition is unclear. Here, we evaluated the involvement of ADARs in BoDV infection. The infection efficiency of BoDV was markedly decreased in both ADAR1 and ADAR2 knockdown cells at the early phase of infection. Microarray analysis using ADAR2 knockdown cells revealed that ADAR2 reduces immune responses even in the absence of infection. Knockdown of ADAR2 but not ADAR1 significantly reduced the spread and titer of BoDV in infected cells. Furthermore, ADAR2 knockout decreased the infection efficiency of BoDV, and overexpression of ADAR2 rescued the reduced infectivity in ADAR2 knockdown cells. However, the growth of influenza A virus, which causes acute infection in the nucleus, was not affected by ADAR2 knockdown. Moreover, ADAR2 bound to BoDV genomic RNA and induced A-to-G mutations in the genomes of persistently infected cells. We finally demonstrated that BoDV produced in ADAR2 knockdown cells induces stronger innate immune responses than those produced in wild-type cells. Taken together, our results suggest that BoDV utilizes ADAR2 to edit its genome to appear as "self" RNA in order to maintain persistent infection in the nucleus.IMPORTANCE Cells use the editing activity of adenosine deaminase acting on RNA proteins (ADARs) to prevent autoimmune responses induced by self dsRNA, but viruses can exploit this process to their advantage. Borna disease virus (BoDV), a nuclear-replicating RNA virus, must escape nonself RNA sensing by the host to establish persistent infection in the nucleus. We evaluated whether BoDV utilizes ADARs to prevent innate immune induction. ADAR2 plays a key role throughout the BoDV life cycle. ADAR2 knockdown reduced A-to-I editing of BoDV genomic RNA, leading to the induction of a strong innate immune response. These data suggest that BoDV exploits ADAR2 to edit nonself genomic RNA to appear as self RNA for innate immune evasion and establishment of persistent infection.
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23
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Pujantell M, Badia R, Galván-Femenía I, Garcia-Vidal E, de Cid R, Alcalde C, Tarrats A, Piñol M, Garcia F, Chamorro AM, Revollo B, Videla S, Parés D, Corral J, Tural C, Sirera G, Esté JA, Ballana E, Riveira-Muñoz E. ADAR1 function affects HPV replication and is associated to recurrent human papillomavirus-induced dysplasia in HIV coinfected individuals. Sci Rep 2019; 9:19848. [PMID: 31882741 PMCID: PMC6934649 DOI: 10.1038/s41598-019-56422-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 12/11/2019] [Indexed: 12/18/2022] Open
Abstract
Infection by human papillomavirus (HPV) alters the microenvironment of keratinocytes as a mechanism to evade the immune system. A-to-I editing by ADAR1 has been reported to regulate innate immunity in response to viral infections. Here, we evaluated the role of ADAR1 in HPV infection in vitro and in vivo. Innate immune activation was characterized in human keratinocyte cell lines constitutively infected or not with HPV. ADAR1 knockdown induced an innate immune response through enhanced expression of RIG-I-like receptors (RLR) signaling cascade, over-production of type-I IFNs and pro-inflammatory cytokines. ADAR1 knockdown enhanced expression of HPV proteins, a process dependent on innate immune function as no A-to-I editing could be identified in HPV transcripts. A genetic association study was performed in a cohort of HPV/HIV infected individuals followed for a median of 6 years (range 0.1-24). We identified the low frequency haplotype AACCAT significantly associated with recurrent HPV dysplasia, suggesting a role of ADAR1 in the outcome of HPV infection in HIV+ individuals. In summary, our results suggest that ADAR1-mediated innate immune activation may influence HPV disease outcome, therefore indicating that modification of innate immune effectors regulated by ADAR1 could be a therapeutic strategy against HPV infection.
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Affiliation(s)
- Maria Pujantell
- AIDS Research Institute-IrsiCaixa, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain
| | - Roger Badia
- AIDS Research Institute-IrsiCaixa, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain
| | - Iván Galván-Femenía
- Genomes for Life-GCAT Lab Group - Program of Predictive and Personalized Medicine of Cancer (PMPPC), Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain
| | - Edurne Garcia-Vidal
- AIDS Research Institute-IrsiCaixa, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain
| | - Rafael de Cid
- Genomes for Life-GCAT Lab Group - Program of Predictive and Personalized Medicine of Cancer (PMPPC), Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain
| | - Carmen Alcalde
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Antonio Tarrats
- Department of Gynecology, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Marta Piñol
- Department of Surgery, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Francesc Garcia
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Ana M Chamorro
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Boris Revollo
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Sebastian Videla
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - David Parés
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Javier Corral
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Cristina Tural
- Department of Internal Medicine, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Guillem Sirera
- Fundació Lluita contra la Sida, Hospital Germans Trias i Pujol, Badalona, Spain
| | - José A Esté
- AIDS Research Institute-IrsiCaixa, Badalona, Spain.
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain.
| | - Ester Ballana
- AIDS Research Institute-IrsiCaixa, Badalona, Spain.
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain.
| | - Eva Riveira-Muñoz
- AIDS Research Institute-IrsiCaixa, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Badalona, Spain
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24
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Goncharov AO, Kliuchnikova AA, Nasaev SS, Moshkovskii SA. RNA Editing by ADAR Adenosine Deaminases: From Molecular Plasticity of Neural Proteins to the Mechanisms of Human Cancer. BIOCHEMISTRY (MOSCOW) 2019; 84:896-904. [PMID: 31522671 DOI: 10.1134/s0006297919080054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
RNA editing by adenosine deaminases of the ADAR family attracts a growing interest of researchers, both zoologists studying ecological and evolutionary plasticity of invertebrates and medical biochemists focusing on the mechanisms of cancer and other human diseases. These enzymes deaminate adenosine residues in the double-stranded (ds) regions of RNA with the formation of inosine. As a result, some RNAs change their three-dimensional structure and functions. Adenosine-to-inosine editing in the mRNA coding sequences may cause amino acid substitutions in the encoded proteins. Here, we reviewed current concepts on the functions of two active ADAR isoforms identified in mammals (including humans). The ADAR1 protein, which acts non-specifically on extended dsRNA regions, is capable of immunosuppression via inactivation of the dsRNA interactions with specific sensors inducing the cell immunity. Expression of a specific ADAR1 splicing variant is regulated by the type I interferons by the negative feedback mechanism. It was shown that immunosuppressing effects of ADAR1 facilitate progression of some types of cancer. On the other hand, changes in the amino acid sequences resulting from the mRNA editing by the ADAR enzymes can result in the formation of neoantigens that can activate the antitumor immunity. The ADAR2 isoform acts on RNA more selectively; its function is associated with the editing of mRNA coding regions and can lead to the amino acid substitutions, in particular, those essential for the proper functioning of some neurotransmitter receptors in the central nervous system.
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Affiliation(s)
- A O Goncharov
- Institute of Biomedical Chemistry, Moscow, 119121, Russia.
| | - A A Kliuchnikova
- Institute of Biomedical Chemistry, Moscow, 119121, Russia.,Pirogov Russian National Research Medical University, Moscow, 117997, Russia
| | - S S Nasaev
- Pirogov Russian National Research Medical University, Moscow, 117997, Russia
| | - S A Moshkovskii
- Institute of Biomedical Chemistry, Moscow, 119121, Russia. .,Pirogov Russian National Research Medical University, Moscow, 117997, Russia
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25
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Jiang D, Zhang J. The preponderance of nonsynonymous A-to-I RNA editing in coleoids is nonadaptive. Nat Commun 2019; 10:5411. [PMID: 31776345 PMCID: PMC6881472 DOI: 10.1038/s41467-019-13275-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/31/2019] [Indexed: 01/24/2023] Open
Abstract
A-to-I editing enzymatically converts the base adenosine (A) in RNA molecules to inosine (I), which is recognized as guanine (G) in translation. Exceptionally abundant A-to-I editing was recently discovered in the neural tissues of coleoids (octopuses, squids, and cuttlefishes), with a greater fraction of nonsynonymous sites than synonymous sites subject to high levels of editing. Although this phenomenon is thought to indicate widespread adaptive editing, its potential advantage is unknown. Here we propose an alternative, nonadaptive explanation. Specifically, increasing the cellular editing activity permits some otherwise harmful G-to-A nonsynonymous substitutions, because the As are edited to Is at sufficiently high levels. These high editing levels are constrained upon substitutions, resulting in the predominance of nonsynonymous editing at highly edited sites. Our evidence for this explanation suggests that the prevalent nonsynonymous editing in coleoids is generally nonadaptive, as in species with much lower editing activities. The neural tissues of coleoids have a greater fraction of nonsynonymous sites than synonymous sites subject to high levels of A-to-I RNA editing, a pattern thought to indicate widespread adaptive editing. Here the authors propose and provide evidence for an alternative, nonadaptive explanation.
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Affiliation(s)
- Daohan Jiang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA.
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26
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Netzband R, Pager CT. Epitranscriptomic marks: Emerging modulators of RNA virus gene expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1576. [PMID: 31694072 PMCID: PMC7169815 DOI: 10.1002/wrna.1576] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/27/2022]
Abstract
Epitranscriptomics, the study of posttranscriptional chemical moieties placed on RNA, has blossomed in recent years. This is due in part to the emergence of high‐throughput detection methods as well as the burst of discoveries showing biological function of select chemical marks. RNA modifications have been shown to affect RNA structure, localization, and functions such as alternative splicing, stabilizing transcripts, nuclear export, cap‐dependent and cap‐independent translation, microRNA biogenesis and binding, RNA degradation, and immune regulation. As such, the deposition of chemical marks on RNA has the unique capability to spatially and temporally regulate gene expression. The goal of this article is to present the exciting convergence of the epitranscriptomic and virology fields, specifically the deposition and biological impact of N7‐methylguanosine, ribose 2′‐O‐methylation, pseudouridine, inosine, N6‐methyladenosine, and 5‐methylcytosine epitranscriptomic marks on gene expression of RNA viruses. This article is categorized under:RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications
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Affiliation(s)
- Rachel Netzband
- Department of Biological Sciences, The RNA Institute, University at Albany-SUNY, Albany, New York
| | - Cara T Pager
- Department of Biological Sciences, The RNA Institute, University at Albany-SUNY, Albany, New York
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Christofi T, Zaravinos A. RNA editing in the forefront of epitranscriptomics and human health. J Transl Med 2019; 17:319. [PMID: 31547885 PMCID: PMC6757416 DOI: 10.1186/s12967-019-2071-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/17/2019] [Indexed: 12/21/2022] Open
Abstract
Post-transcriptional modifications have been recently expanded with the addition of RNA editing, which is predominantly mediated by adenosine and cytidine deaminases acting on DNA and RNA. Here, we review the full spectrum of physiological processes in which these modifiers are implicated, among different organisms. Adenosine to inosine (A-to-I) editors, members of the ADAR and ADAT protein families are important regulators of alternative splicing and transcriptional control. On the other hand, cytidine to uridine (C-to-U) editors, members of the AID/APOBEC family, are heavily implicated in innate and adaptive immunity with important roles in antibody diversification and antiviral response. Physiologically, these enzymes are present in the nucleus and/or the cytoplasm, where they modify various RNA molecules, including miRNAs, tRNAs apart from mRNAs, whereas DNA editing is also possible by some of them. The expansion of next generation sequencing technologies provided a wealth of data regarding such modifications. RNA editing has been implicated in various disorders including cancer, and neurological diseases of the brain or the central nervous system. It is also related to cancer heterogeneity and the onset of carcinogenesis. Response to treatment can also be affected by the RNA editing status where drug efficacy is significantly compromised. Studying RNA editing events can pave the way to the identification of new disease biomarkers, and provide a more personalised therapy to various diseases.
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Affiliation(s)
- Theodoulakis Christofi
- Department of Life Sciences, School of Sciences, European University Cyprus, 2404, Nicosia, Cyprus
| | - Apostolos Zaravinos
- Department of Life Sciences, School of Sciences, European University Cyprus, 2404, Nicosia, Cyprus. .,Centre for Risk and Decision Sciences (CERIDES), 2404, Nicosia, Cyprus.
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Liu G, Ma X, Wang Z, Wakae K, Yuan Y, He Z, Yoshiyama H, Iizasa H, Zhang H, Matsuda M, Sugiyama R, Yuan Z, Muramatsu M, Li L. Adenosine deaminase acting on RNA-1 (ADAR1) inhibits hepatitis B virus (HBV) replication by enhancing microRNA-122 processing. J Biol Chem 2019; 294:14043-14054. [PMID: 31366735 DOI: 10.1074/jbc.ra119.007970] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/04/2019] [Indexed: 12/18/2022] Open
Abstract
Adenosine deaminases acting on RNA-1 (ADAR1) involves adenosine to inosine RNA editing and microRNA processing. ADAR1 is known to be involved in the replication of various viruses, including hepatitis C and D. However, the role of ADAR1 in hepatitis B virus (HBV) infection has not yet been elucidated. Here, for the first time, we demonstrated ADAR1 antiviral activity against HBV. ADAR1 has two splicing isoforms in human hepatocytes: constitutive p110 protein and interferon-α (IFN-α)-responsive p150 protein. We found that overexpression of ADAR1 decreased HBV RNA in an HBV culture model. A catalytic-site mutant ADAR1 also decreased HBV RNA levels, whereas another adenosine deaminases that act on the RNA (ADAR) family protein, ADAR2, did not. Moreover, the induction of ADAR1 by stimulation with IFN-α also reduced HBV RNA levels. Decreases in endogenous ADAR1 expression by knock-down or knock-out increased HBV RNA levels. A major hepatocyte-specific microRNA, miRNA-122, was found to be positively correlated with ADAR1 expression, and exogenous miRNA-122 decreased both HBV RNA and DNA, whereas, conversely, transfection with a miRNA-122 inhibitor increased them. The reduction of HBV RNA by ADAR1 expression was abrogated by p53 knock-down, suggesting the involvement of p53 in the ADAR1-mediated reduction of HBV RNA. This study demonstrated, for the first time, that ADAR1 plays an antiviral role against HBV infection by increasing the level of miRNA-122 in hepatocytes.
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Affiliation(s)
- Guangyan Liu
- College of Basic Medical Sciences, Shenyang Medical College, Shenyang 110034, China.,Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China.,Department of Molecular Genetics, Kanazawa University, Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa 920-8640, Japan
| | - Xiancai Ma
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
| | - Zhe Wang
- Department of Molecular Genetics, Kanazawa University, Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa 920-8640, Japan.,Department of Medical Oncology, Affiliated Zhongshan Hospital of Dalian University, Dalian 116001, China.,The Key Laboratory of Biomarker High Throughput Screening and Target Translation of Breast and Gastrointestinal Tumor, Dalian University, Dalian 116001, China
| | - Kousho Wakae
- Department of Molecular Genetics, Kanazawa University, Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa 920-8640, Japan
| | - Yaochang Yuan
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
| | - Zhangping He
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
| | - Hironori Yoshiyama
- Department of Microbiology, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo, Shimane 693-8501, Japan
| | - Hisashi Iizasa
- Department of Microbiology, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo, Shimane 693-8501, Japan
| | - Hui Zhang
- Institute of Human Virology, Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, Guangdong, China
| | - Mami Matsuda
- Department of Virology II, National Institute of Infectious Disease, Tokyo 164-8640, Japan
| | - Ryuichi Sugiyama
- Department of Virology II, National Institute of Infectious Disease, Tokyo 164-8640, Japan
| | - Zhiyu Yuan
- College of Basic Medical Sciences, Shenyang Medical College, Shenyang 110034, China
| | - Masamichi Muramatsu
- Department of Molecular Genetics, Kanazawa University, Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa 920-8640, Japan .,Department of Virology II, National Institute of Infectious Disease, Tokyo 164-8640, Japan
| | - Linghua Li
- Department of Infectious Diseases, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou 510060, China
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Kliuchnikova AA, Moshkovskii SA. Adenosine-to-inosine RNA editing may be implicated in human pathogenesis. BULLETIN OF RUSSIAN STATE MEDICAL UNIVERSITY 2019. [DOI: 10.24075/brsmu.2019.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenosine-to-inosine (A-to-I) RNA editing is a common mechanism of post-transcriptional modification in many metazoans including vertebrates; the process is catalyzed by adenosine deaminases acting on RNA (ADARs). Using high-throughput sequencing technologies resulted in finding thousands of RNA editing sites throughout the human transcriptome however, their functions are still poorly understood. The aim of this brief review is to draw attention of clinicians and biomedical researchers to ADAR-mediated RNA editing phenomenon and its possible implication in development of neuropathologies, antiviral immune responses and cancer.
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Affiliation(s)
| | - SA Moshkovskii
- Pirogov Russian National Research Medical University, Moscow, Russia
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30
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Adenosine Deaminase Acting on RNA 1 Associates with Orf Virus OV20.0 and Enhances Viral Replication. J Virol 2019; 93:JVI.01912-18. [PMID: 30651363 DOI: 10.1128/jvi.01912-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/21/2018] [Indexed: 01/08/2023] Open
Abstract
Orf virus (ORFV) infects sheep and goats and is also an important zoonotic pathogen. The viral protein OV20.0 has been shown to suppress innate immunity by targeting the double-stranded RNA (dsRNA)-activated protein kinase (PKR) by multiple mechanisms. These mechanisms include a direct interaction with PKR and binding with two PKR activators, dsRNA and the cellular PKR activator (PACT), which ultimately leads to the inhibition of PKR activation. In the present study, we identified a novel association between OV20.0 and adenosine deaminase acting on RNA 1 (ADAR1). OV20.0 bound directly to the dsRNA binding domains (RBDs) of ADAR1 in the absence of dsRNA. Additionally, OV20.0 preferentially interacted with RBD1 of ADAR1, which was essential for its dsRNA binding ability and for the homodimerization that is critical for intact adenosine-to-inosine (A-to-I)-editing activity. Finally, the association with OV20.0 suppressed the A-to-I-editing ability of ADAR1, while ADAR1 played a proviral role during ORFV infection by inhibiting PKR phosphorylation. These observations revealed a new strategy used by OV20.0 to evade antiviral responses via PKR.IMPORTANCE Viruses evolve specific strategies to counteract host innate immunity. ORFV, an important zoonotic pathogen, encodes OV20.0 to suppress PKR activation via multiple mechanisms, including interactions with PKR and two PKR activators. In this study, we demonstrated that OV20.0 interacts with ADAR1, a cellular enzyme responsible for converting adenosine (A) to inosine (I) in RNA. The RNA binding domains, but not the catalytic domain, of ADAR1 are required for this interaction. The OV20.0-ADAR1 association affects the functions of both proteins; OV20.0 suppressed the A-to-I editing of ADAR1, while ADAR1 elevated OV20.0 expression. The proviral role of ADAR1 is likely due to the inhibition of PKR phosphorylation. As RNA editing by ADAR1 contributes to the stability of the genetic code and the structure of RNA, these observations suggest that in addition to serving as a PKR inhibitor, OV20.0 might modulate ADAR1-dependent gene expression to combat antiviral responses or achieve efficient viral infection.
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Lv BM, Tong XY, Quan Y, Liu MY, Zhang QY, Song YF, Zhang HY. Drug Repurposing for Japanese Encephalitis Virus Infection by Systems Biology Methods. Molecules 2018; 23:molecules23123346. [PMID: 30567313 PMCID: PMC6320907 DOI: 10.3390/molecules23123346] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 12/22/2022] Open
Abstract
Japanese encephalitis is a zoonotic disease caused by the Japanese encephalitis virus (JEV). It is mainly epidemic in Asia with an estimated 69,000 cases occurring per year. However, no approved agents are available for the treatment of JEV infection, and existing vaccines cannot control various types of JEV strains. Drug repurposing is a new concept for finding new indication of existing drugs, and, recently, the concept has been used to discover new antiviral agents. Identifying host proteins involved in the progress of JEV infection and using these proteins as targets are the center of drug repurposing for JEV infection. In this study, based on the gene expression data of JEV infection and the phenome-wide association study (PheWAS) data, we identified 286 genes that participate in the progress of JEV infection using systems biology methods. The enrichment analysis of these genes suggested that the genes identified by our methods were predominantly related to viral infection pathways and immune response-related pathways. We found that bortezomib, which can target these genes, may have an effect on the treatment of JEV infection. Subsequently, we evaluated the antiviral activity of bortezomib using a JEV-infected mouse model. The results showed that bortezomib can lower JEV-induced lethality in mice, alleviate suffering in JEV-infected mice and reduce the damage in brains caused by JEV infection. This work provides an agent with new indication to treat JEV infection.
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Affiliation(s)
- Bo-Min Lv
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
| | - Xin-Yu Tong
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yuan Quan
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
| | - Meng-Yuan Liu
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
| | - Qing-Ye Zhang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yun-Feng Song
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Hong-Yu Zhang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.
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32
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Riemondy KA, Gillen AE, White EA, Bogren LK, Hesselberth JR, Martin SL. Dynamic temperature-sensitive A-to-I RNA editing in the brain of a heterothermic mammal during hibernation. RNA (NEW YORK, N.Y.) 2018; 24:1481-1495. [PMID: 30065024 PMCID: PMC6191720 DOI: 10.1261/rna.066522.118] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
RNA editing diversifies genomically encoded information to expand the complexity of the transcriptome. In ectothermic organisms, including Drosophila and Cephalopoda, where body temperature mirrors ambient temperature, decreases in environmental temperature lead to increases in A-to-I RNA editing and cause amino acid recoding events that are thought to be adaptive responses to temperature fluctuations. In contrast, endothermic mammals, including humans and mice, typically maintain a constant body temperature despite environmental changes. Here, A-to-I editing primarily targets repeat elements, rarely results in the recoding of amino acids, and plays a critical role in innate immune tolerance. Hibernating ground squirrels provide a unique opportunity to examine RNA editing in a heterothermic mammal whose body temperature varies over 30°C and can be maintained at 5°C for many days during torpor. We profiled the transcriptome in three brain regions at six physiological states to quantify RNA editing and determine whether cold-induced RNA editing modifies the transcriptome as a potential mechanism for neuroprotection at low temperature during hibernation. We identified 5165 A-to-I editing sites in 1205 genes with dynamically increased editing after prolonged cold exposure. The majority (99.6%) of the cold-increased editing sites are outside of previously annotated coding regions, 82.7% lie in SINE-derived repeats, and 12 sites are predicted to recode amino acids. Additionally, A-to-I editing frequencies increase with increasing cold-exposure, demonstrating that ADAR remains active during torpor. Our findings suggest that dynamic A-to-I editing at low body temperature may provide a neuroprotective mechanism to limit aberrant dsRNA accumulation during torpor in the mammalian hibernator.
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Affiliation(s)
- Kent A Riemondy
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Austin E Gillen
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Emily A White
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | | | - Jay R Hesselberth
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Sandra L Martin
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- Department of Cell and Developmental Biology
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33
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Neuralized E3 Ubiquitin Protein Ligase 3 Is an Inducible Antiviral Effector That Inhibits Hepatitis C Virus Assembly by Targeting Viral E1 Glycoprotein. J Virol 2018; 92:JVI.01123-18. [PMID: 30111563 DOI: 10.1128/jvi.01123-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/08/2018] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV) infection is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV can be sensed by host innate immunity to induce expression of interferons (IFNs) and a number of antiviral effectors. In this study, we found HCV infection induced the expression of neuralized E3 ubiquitin protein ligase 3 (NEURL3), a putative E3 ligase, in a manner that requires the involvement of innate immune sensing but is independent of the IFN action. Furthermore, we showed that NEURL3 inhibited HCV infection while it had little effect on other RNA viruses, including Zika virus (ZIKV), dengue virus (DENV), and vesicular stomatitis virus (VSV). Mechanistic studies demonstrated that NEURL3 inhibited HCV assembly by directly binding HCV envelope glycoprotein E1 to interfere with the E1/E2 heterodimerization, an important prerequisite for virion morphogenesis. Finally, we showed that knockout of NEURL3 significantly enhanced HCV infection. In summary, we identified NEURL3 as a novel inducible antiviral host factor that suppresses HCV assembly. Our results not only shed new insight into how host innate immunity acts against HCV but also revealed a new important biological function for NEURL3.IMPORTANCE The exact biological function of NEURL3, a putative E3 ligase, remains largely unknown. In this study, we found that NEURL3 could be upregulated upon HCV infection in a manner dependent on pattern recognition receptor-mediated innate immune response. NEURL3 inhibits HCV assembly by directly binding viral E1 envelope glycoprotein to disrupt its interaction with E2, an action that requires its Neuralized homology repeat (NHR) domain but not the RING domain. Furthermore, we found that NEURL3 has a pangenotypic anti-HCV activity and interacts with E1 of genotypes 2a, 1b, 3a, and 6a but does not inhibit other closely related RNA viruses, such as ZIKV, DENV, and VSV. To our knowledge, our study is the first report to demonstrate that NEURL3 functions as an antiviral host factor. Our results not only shed new insight into how host innate immunity acts against HCV, but also revealed a new important biological function for NEURL3.
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34
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ADAR1 affects HCV infection by modulating innate immune response. Antiviral Res 2018; 156:116-127. [PMID: 29906476 DOI: 10.1016/j.antiviral.2018.05.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/24/2018] [Accepted: 05/30/2018] [Indexed: 02/06/2023]
Abstract
The hepatitis C virus (HCV) is a globally prevalent infectious pathogen. As many as 80% of people infected with HCV do not control the virus and develop a chronic infection. Response to interferon (IFN) therapy is widely variable in chronic HCV infected patients, suggesting that HCV has evolved mechanisms to suppress and evade innate immunity responsible for its control and elimination. Adenosine deaminase acting on RNA 1 (ADAR1) is a relevant factor in the regulation of the innate immune response. The loss of ADAR1 RNA-editing activity and the resulting loss of inosine bases in RNA are critical in producing aberrant RLR-mediated innate immune response, mediated by RNA sensors MDA5 and RIG-I. Here, we describe ADAR1 role as a regulator of innate and antiviral immune function in HCV infection, both in vitro and in patients. Polymorphisms within ADAR1 gene were found significantly associated to poor clinical outcome to HCV therapy and advanced liver fibrosis in a cohort of HCV and HIV-1 coinfected patients. Moreover, ADAR1 knockdown in primary macrophages and Huh7 hepatoma cells enhanced IFN and IFN stimulated gene expression and increased HCV replication in vitro. Overall, our results demonstrate that ADAR1 regulates innate immune signaling and is an important contributor to the outcome of the HCV virus-host interaction. ADAR1 is a potential target to boost antiviral immune response in HCV infection.
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Dou N, Yu S, Ye X, Yang D, Li Y, Gao Y. Aberrant overexpression of ADAR1 promotes gastric cancer progression by activating mTOR/p70S6K signaling. Oncotarget 2018; 7:86161-86173. [PMID: 27863387 PMCID: PMC5349904 DOI: 10.18632/oncotarget.13354] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/08/2016] [Indexed: 12/24/2022] Open
Abstract
ADAR1, one of adenosine deaminases acting on RNA, modulates RNA transcripts through converting adenosine (A) to inosine (I) by deamination. Emerging evidence has implicated that ADAR1 plays an important role in a few of human cancers, however, its expression and physiological significance in gastric cancer remain undefined. In the present study, we demonstrated that ADAR1 was frequently overexpressed in gastric cancer samples by quantitative real-time PCR analysis. In a gastric cancer tissue microarray, ADAR1 staining was closely correlated with tumor stage (P < 0.001) and N classification (P < 0.001). Functional analysis indicated that ADAR1 overexpression promoted cell proliferation and migration in vitro, whereas ADAR1 knockdown resulted in an opposite phenotypes. Furthermore, ADAR1 knockdown also inhibited tumorigenicity and lung metastasis potential of gastric cancer cells in nude mice models. Mechanistically, ADAR1 expression had a significant effect on phosphorylation level of mTOR, p70S kinase, and S6 ribosomal protein, implying its involvement in the regulation of mTOR signaling pathway. We conclude that ADAR1 contributes to gastric cancer development and progression via activating mTOR/p70S6K/S6 ribosomal protein signaling axis. Our findings suggest that ADAR1 may be a valuable biomarker for GC diagnosis and prognosis and may represent a new novel therapeutic opportunities.
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Affiliation(s)
- Ning Dou
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Shijun Yu
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Xiaojuan Ye
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Dong Yang
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Yandong Li
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Yong Gao
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
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36
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Medrano LM, Berenguer J, Jiménez-Sousa MA, Aldámiz-Echevarria T, Tejerina F, Diez C, Vigón L, Fernández-Rodríguez A, Resino S. ADAR1 polymorphisms are related to severity of liver fibrosis in HIV/HCV-coinfected patients. Sci Rep 2017; 7:12918. [PMID: 29018269 PMCID: PMC5635123 DOI: 10.1038/s41598-017-12885-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/15/2017] [Indexed: 01/07/2023] Open
Abstract
The adenosine deaminase acting on RNA (ADAR1) gene is an interferon-stimulated gene involved in liver injury protection. Our aim was to analyze the association of polymorphisms within this gene with the severity of liver disease in European HIV/HCV-coinfected patients. We performed a cross-sectional study in 220 patients that underwent a liver biopsy. Five SNPs in the ADAR1 gene (rs1127326, rs1127317, rs1127314, rs1127313, rs2229857) were genotyped by GoldenGate assay. The outcome variables were fibrosis stage and necroinflammatory activity grade by METAVIR-score, aspartate aminotransferase to platelet ratio index (APRI), FIB-4 index, and fibrosis progression rate (FPR). In multivariate analysis, fibrosis progression rate (FPR) (aAMRs = 0.97) decreased in a dose-dependent manner with the presence of rs2229857_T, rs1127313_G, rs1127314_G and rs1127317_G; while rs1127326_T allele had only significant associations with FIB-4 (aAMRs ≤ 0.63) and FPR (aAMRs ≤ 0.97). Moreover, carriers of rs2229857_T, rs1127314_G, rs1127317_G, and rs1127326_T alleles were protected against advanced fibrosis (F ≥ 3) (adjusted ORs (aORs) ≤ 0.44), APRI ≥ 1.5 (aORs ≤ 0.33), and FPR ≥ 0.075 (aORs ≤ 0.45). rs1127313_G carriers showed lower odds of having F ≥ 3 (aORs = 0.39), FIB4 ≥ 3.25 (aOR = 0.22) and FPR ≥ 0.075 (aORs = 0.44). In conclusion, ADAR1 polymorphisms protected against severe liver disease in HIV/HCV-coinfected patients. These results could be used to improve therapeutic decision-making in clinical practice.
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Affiliation(s)
- Luz M Medrano
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Juan Berenguer
- Unidad de Enfermedades Infecciosas/VIH, Hospital General Universitario "Gregorio Marañón", Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - María A Jiménez-Sousa
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Teresa Aldámiz-Echevarria
- Unidad de Enfermedades Infecciosas/VIH, Hospital General Universitario "Gregorio Marañón", Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Francisco Tejerina
- Unidad de Enfermedades Infecciosas/VIH, Hospital General Universitario "Gregorio Marañón", Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Cristina Diez
- Unidad de Enfermedades Infecciosas/VIH, Hospital General Universitario "Gregorio Marañón", Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Lorena Vigón
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Amanda Fernández-Rodríguez
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
| | - Salvador Resino
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
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37
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Theotokis PI, Usher L, Kortschak CK, Schwalbe E, Moschos SA. Profiling the Mismatch Tolerance of Argonaute 2 through Deep Sequencing of Sliced Polymorphic Viral RNAs. MOLECULAR THERAPY. NUCLEIC ACIDS 2017; 9:22-33. [PMID: 29246301 PMCID: PMC5602524 DOI: 10.1016/j.omtn.2017.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 08/17/2017] [Accepted: 08/17/2017] [Indexed: 01/08/2023]
Abstract
Low allelic and clonal variability among endogenous RNAi targets has focused mismatch tolerance studies to RNAi-active guide strands. However, the inherent genomic instability of RNA viruses such as hepatitis C virus (HCV) gives rise to quasi-species mutants within discrete clones: this facilitates mismatch tolerance studies from a target perspective. We recently quantified the slicing imprecision of Argonaute 2 using small interfering RNA (siRNA) analogs of the DNA-directed RNAi drug TT-034 and next-generation sequencing of 5' RNA ligase-mediated rapid amplification of cDNA ends (RACE-SEQ). Here, we present an open-source, customizable, and computationally light RACE-SEQ bioinformatic pipeline, describing adaptations that semiquantitatively report the impact of RNAi hybridization site mismatches from the target perspective. The analysis shows that Argonaute 2 has a substitution-specific, 3- to 5-log activity window between fully complementary targets and targets with mismatches across positions 10-11. It further focuses the endonucleotic Slicer imprecision around positions 13-17, demonstrating its dependence on guide strand central region complementarity, and potentiation by even a single mismatch. We further propose pharmacogenomics value in testing endogenous targets using recombinant replicon systems and RACE-SEQ to report the pharmacodynamics of sequence-specific oligonucleotide therapeutics against all possible polymorphisms in a population, in a minimally biased, patient-free manner.
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Affiliation(s)
- Pantazis I Theotokis
- Department of Biomedical Sciences, Faculty of Science and Technology, University of Westminster, London W1W 6UW, UK
| | - Louise Usher
- Department of Biomedical Sciences, Faculty of Science and Technology, University of Westminster, London W1W 6UW, UK; Westminster Genomic Services, Faculty of Science and Technology, University of Westminster, London W1W 6UW, UK
| | - Christopher K Kortschak
- Department of Biomedical Sciences, Faculty of Science and Technology, University of Westminster, London W1W 6UW, UK
| | - Ed Schwalbe
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle, Tyne and Wear NE1 8ST, UK
| | - Sterghios A Moschos
- Department of Biomedical Sciences, Faculty of Science and Technology, University of Westminster, London W1W 6UW, UK; Westminster Genomic Services, Faculty of Science and Technology, University of Westminster, London W1W 6UW, UK; Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle, Tyne and Wear NE1 8ST, UK.
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Secreted Interferon-Inducible Factors Restrict Hepatitis B and C Virus Entry In Vitro. J Immunol Res 2017; 2017:4828936. [PMID: 28367455 PMCID: PMC5358466 DOI: 10.1155/2017/4828936] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/24/2017] [Accepted: 02/06/2017] [Indexed: 02/06/2023] Open
Abstract
Interferon-α (IFN-α) has been used for more than 20 years as the first-line therapy for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, because it has a number of antiviral effects. In this study, we describe a novel mode of its antiviral action. We demonstrate that the supernatant from IFN-α-treated cultured cells restricted HBV and HCV infection by inhibiting viral entry into hepatoma cells. The factors contained in the supernatant competed with the virus for binding to heparan glycosaminoglycans—the nonspecific attachment step shared by HBV and HCV. Secreted factors of high molecular mass that bind to heparin columns elicited the antiviral effect. In conclusion, IFN-α is able to induce soluble factors that can bind to heparan glycosaminoglycans thus leading to the inhibition of viral binding.
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39
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Epitranscriptomic regulation of viral replication. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:460-471. [PMID: 28219769 DOI: 10.1016/j.bbagrm.2017.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/10/2017] [Accepted: 02/10/2017] [Indexed: 12/11/2022]
Abstract
RNA plays central roles in biology and novel functions and regulation mechanisms are constantly emerging. To accomplish some of their functions within the cell, RNA molecules undergo hundreds of chemical modifications from which N6-methyladenosine (m6A), inosine (I), pseudouridine (ψ) and 5-methylcytosine (5mC) have been described in eukaryotic mRNA. Interestingly, the m6A modification was shown to be reversible, adding novel layers of regulation of gene expression through what is now recognized as epitranscriptomics. The development of molecular mapping strategies coupled to next generation sequencing allowed the identification of thousand of modified transcripts in different tissues and under different physiological conditions such as viral infections. As intracellular parasites, viruses are confronted to cellular RNA modifying enzymes and, as a consequence, viral RNA can be chemically modified at some stages of the replication cycle. This review focuses on the chemical modifications of viral RNA and the impact that these modifications have on viral gene expression and the output of infection. A special emphasis is given to m6A, which was recently shown to play important yet controversial roles in different steps of the HIV-1, HCV and ZIKV replication cycles.
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40
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Functions of the RNA Editing Enzyme ADAR1 and Their Relevance to Human Diseases. Genes (Basel) 2016; 7:genes7120129. [PMID: 27999332 PMCID: PMC5192505 DOI: 10.3390/genes7120129] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/07/2016] [Accepted: 12/12/2016] [Indexed: 12/17/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) convert adenosine to inosine in double-stranded RNA (dsRNA). Among the three types of mammalian ADARs, ADAR1 has long been recognized as an essential enzyme for normal development. The interferon-inducible ADAR1p150 is involved in immune responses to both exogenous and endogenous triggers, whereas the functions of the constitutively expressed ADAR1p110 are variable. Recent findings that ADAR1 is involved in the recognition of self versus non-self dsRNA provide potential explanations for its links to hematopoiesis, type I interferonopathies, and viral infections. Editing in both coding and noncoding sequences results in diseases ranging from cancers to neurological abnormalities. Furthermore, editing of noncoding sequences, like microRNAs, can regulate protein expression, while editing of Alu sequences can affect translational efficiency and editing of proximal sequences. Novel identifications of long noncoding RNA and retrotransposons as editing targets further expand the effects of A-to-I editing. Besides editing, ADAR1 also interacts with other dsRNA-binding proteins in editing-independent manners. Elucidating the disease-specific patterns of editing and/or ADAR1 expression may be useful in making diagnoses and prognoses. In this review, we relate the mechanisms of ADAR1′s actions to its pathological implications, and suggest possible mechanisms for the unexplained associations between ADAR1 and human diseases.
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41
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Janus effects of ADAR1 on CVB3-induced viral myocarditis at different infection stages. Int J Cardiol 2016; 223:898-905. [DOI: 10.1016/j.ijcard.2016.08.315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/18/2016] [Accepted: 08/19/2016] [Indexed: 01/05/2023]
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42
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Orecchini E, Doria M, Antonioni A, Galardi S, Ciafrè SA, Frassinelli L, Mancone C, Montaldo C, Tripodi M, Michienzi A. ADAR1 restricts LINE-1 retrotransposition. Nucleic Acids Res 2016; 45:155-168. [PMID: 27658966 PMCID: PMC5224506 DOI: 10.1093/nar/gkw834] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 12/16/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) are involved in RNA editing that converts adenosines to inosines in double-stranded RNAs. ADAR1 was demonstrated to be functional on different viruses exerting either antiviral or proviral effects. Concerning HIV-1, several studies showed that ADAR1 favors viral replication. The aim of this study was to investigate the composition of the ADAR1 ribonucleoprotein complex during HIV-1 expression. By using a dual-tag affinity purification procedure in cells expressing HIV-1 followed by mass spectrometry analysis, we identified 14 non-ribosomal ADAR1-interacting proteins, most of which are novel. A significant fraction of these proteins were previously demonstrated to be associated to the Long INterspersed Element 1 (LINE1 or L1) ribonucleoparticles and to regulate the life cycle of L1 retrotransposons that continuously re-enter host-genome. Hence, we investigated the function of ADAR1 in the regulation of L1 activity. By using different cell-culture based retrotransposition assays in HeLa cells, we demonstrated a novel function of ADAR1 as suppressor of L1 retrotransposition. Apparently, this inhibitory mechanism does not occur through ADAR1 editing activity. Furthermore, we showed that ADAR1 binds the basal L1 RNP complex. Overall, these data support the role of ADAR1 as regulator of L1 life cycle.
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Affiliation(s)
- Elisa Orecchini
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Margherita Doria
- Laboratory of Immunoinfectivology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, Rome 00165, Italy
| | - Ambra Antonioni
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Silvia Galardi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Silvia Anna Ciafrè
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Loredana Frassinelli
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Carmine Mancone
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Italy.,L. Spallanzani National Institute for Infectious Diseases, IRCCS, via Portuense 292, Rome 00149, Italy
| | - Claudia Montaldo
- L. Spallanzani National Institute for Infectious Diseases, IRCCS, via Portuense 292, Rome 00149, Italy
| | - Marco Tripodi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Italy.,L. Spallanzani National Institute for Infectious Diseases, IRCCS, via Portuense 292, Rome 00149, Italy
| | - Alessandro Michienzi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
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43
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Innate immunity against hepatitis C virus. Curr Opin Immunol 2016; 42:98-104. [PMID: 27366996 DOI: 10.1016/j.coi.2016.06.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/09/2016] [Accepted: 06/15/2016] [Indexed: 12/24/2022]
Abstract
Hepatitis C virus (HCV) infection tends persistent and causes chronic liver diseases, including inflammation, cirrhosis and hepatocellular carcinoma. Innate immune responses triggered by HCV infection, particularly the production of interferons and pro-inflammatory cytokines, shape the early host antiviral defense, and orchestrate subsequent HCV-specific adaptive immunity. Host has evolved multifaceted means to sense HCV infection to induce innate immune responses, whereas HCV has also developed elaborate strategies to evade immune attack. Recent studies in the field have provided many new insights into the interplay of HCV and innate immunity. In this review, we summarized these recent advances, focusing on pathogen recognition by innate sensors, newly discovered anti-HCV innate effectors and new viral strategies to evade innate immunity.
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44
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Yin W, Tong S, Zhang Q, Shao J, Liu Q, Peng H, Hu H, Peng M, Hu P, Ren H, Tian Z, Zhang D. Functional dichotomy of Vδ2 γδ T cells in chronic hepatitis C virus infections: role in cytotoxicity but not for IFN-γ production. Sci Rep 2016; 6:26296. [PMID: 27192960 PMCID: PMC4872040 DOI: 10.1038/srep26296] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 04/29/2016] [Indexed: 02/08/2023] Open
Abstract
Vδ2 γδ (Vδ2) T cells, a major human γδ T cell subset, exhibit broad anti-tumor and anti-infective activity; however, their precise role in chronic hepatitis C virus (HCV) infections remains unclear. In this study, we analyzed the phenotype and function of Vδ2 T cells in 43 HCV-infected patients compared to 39 healthy controls (HCs). Vδ2 T cells from HCV-infected patients were activated and differentiated into effector cells. Vδ2 T cells in patients expressed significantly higher levels of natural killer (NK) cell markers CD56 and CD16 than in HCs, acquiring cytotoxic NK-like phenotype. The Vδ2 T cell phenotype was associated with increased cytolytic effector molecules expression in HCV-infected patients with elevated serum ALT levels. Surprisingly, Vδ2 T cells in patients had a markedly impaired capacity to produce IFN-γ. Further in vitro and in vivo analysis showed that interferon-α, which was induced during HCV infection, caused Vδ2 T cell function bias toward cytotoxicity. These results suggest a functional dichotomy for Vδ2 T cells in chronic HCV infections: a role in cytotoxicity but not for IFN-γ production, which may contribute to both the liver inflammation and HCV persistence.
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Affiliation(s)
- Wenwei Yin
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Shiwen Tong
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Qiongfang Zhang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Jianying Shao
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Qian Liu
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Hong Peng
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Huaidong Hu
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Mingli Peng
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Peng Hu
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Hong Ren
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
| | - Zhigang Tian
- Institute of Immunology, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Dazhi Zhang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, P. R. China
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45
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Bang BR, Elmasry S, Saito T. Organ system view of the hepatic innate immunity in HCV infection. J Med Virol 2016; 88:2025-2037. [PMID: 27153233 DOI: 10.1002/jmv.24569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2016] [Indexed: 12/12/2022]
Abstract
An orchestration of innate and adaptive immunity determines the infection outcome and whether the host achieves clearance or allows the pathogen to establish persistent infection. The robust activation of the innate immune response plays the most critical role in both limiting viral replication and halting the spread of the pathogen immediately after infection. The magnitude of innate immune activation is coupled with the efficient mounting of the adaptive immunity. Although immunity against HCV infection is known to be inadequate as most cases transitions to chronicity, approximately 25% of acute infection cases result in spontaneous clearance. The exact immune mechanisms that govern the infection outcome remain largely unknown; recent discoveries suggest that the innate immune system facilitates this event. Both infected hepatocytes and local innate immune cells trigger the front line defense program of the liver as well as the recruitment of diverse adaptive immune cells to the site of infection. Although hepatocyte is the target of HCV infection, nearly all cell types that exist in the liver are involved in the innate defense and contribute to the pathophysiology of hepatic inflammation. The main focus of this comprehensive review is to discuss the current knowledge on how each hepatic cell type contributes to the organ system level innate immunity against HCV infection as well as interplays with the viral evasion program. Furthermore, this review article also aims to synchronize the observations from both molecular biological studies and clinical studies with the ultimate goal of improving our understanding of HCV mediated hepatitis. J. Med. Virol. 88:2025-2037, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bo-Ram Bang
- Division of Gastrointestinal and Liver Diseases, Department of Medicine, USC Research Center for Liver Diseases, University of Southern California, Keck School of Medicine, Los Angeles, California
| | - Sandra Elmasry
- Division of Gastrointestinal and Liver Diseases, Department of Medicine, USC Research Center for Liver Diseases, University of Southern California, Keck School of Medicine, Los Angeles, California
| | - Takeshi Saito
- Division of Gastrointestinal and Liver Diseases, Department of Medicine, USC Research Center for Liver Diseases, University of Southern California, Keck School of Medicine, Los Angeles, California. .,Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, Los Angeles, California. .,Department of Pathology, University of Southern California, Keck School of Medicine, Los Angeles, California.
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46
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Geller R, Estada Ú, Peris JB, Andreu I, Bou JV, Garijo R, Cuevas JM, Sabariegos R, Mas A, Sanjuán R. Highly heterogeneous mutation rates in the hepatitis C virus genome. Nat Microbiol 2016; 1:16045. [PMID: 27572964 DOI: 10.1038/nmicrobiol.2016.45] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/09/2016] [Indexed: 01/10/2023]
Abstract
Spontaneous mutations are the ultimate source of genetic variation and have a prominent role in evolution. RNA viruses such as hepatitis C virus (HCV) have extremely high mutation rates, but these rates have been inferred from a minute fraction of genome sites, limiting our view of how RNA viruses create diversity. Here, by applying high-fidelity ultradeep sequencing to a modified replicon system, we scored >15,000 spontaneous mutations, encompassing more than 90% of the HCV genome. This revealed >1,000-fold differences in mutability across genome sites, with extreme variations even between adjacent nucleotides. We identify base composition, the presence of high- and low-mutation clusters and transition/transversion biases as the main factors driving this heterogeneity. Furthermore, we find that mutability correlates with the ability of HCV to diversify in patients. These data provide a site-wise baseline for interrogating natural selection, genetic load and evolvability in HCV, as well as for evaluating drug resistance and immune evasion risks.
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Affiliation(s)
- Ron Geller
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain
| | - Úrsula Estada
- Unitat de Genómica, Servei Central de Suport a la Investigació Experimental, Universitat de València, 46100 Burjassot, València, Spain
| | - Joan B Peris
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain
| | - Iván Andreu
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain
| | - Juan-Vicente Bou
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain
| | - Raquel Garijo
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain
| | - José M Cuevas
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain
| | - Rosario Sabariegos
- Regional Center for Biomedical Research, Universidad de Castilla-La Mancha, 02006 Albacete, Spain
| | - Antonio Mas
- Regional Center for Biomedical Research, Universidad de Castilla-La Mancha, 02006 Albacete, Spain
| | - Rafael Sanjuán
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, 46980 Paterna, València, Spain.,Departament de Genètica, Universitat de València, 46100 Burjassot, València, Spain
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47
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Guanylate-Binding Protein 1, an Interferon-Induced GTPase, Exerts an Antiviral Activity against Classical Swine Fever Virus Depending on Its GTPase Activity. J Virol 2016; 90:4412-4426. [PMID: 26889038 PMCID: PMC4836331 DOI: 10.1128/jvi.02718-15] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/11/2016] [Indexed: 12/11/2022] Open
Abstract
Many viruses trigger the type I interferon (IFN) pathway upon infection, resulting in the transcription of hundreds of interferon-stimulated genes (ISGs), which define the antiviral state of the host. Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), a highly contagious viral disease endangering the pig industry in many countries. However, anti-CSFV ISGs are poorly documented. Here we screened 20 ISGs that are commonly induced by type I IFNs against CSFV in lentivirus-delivered cell lines, resulting in the identification of guanylate-binding protein 1 (GBP1) as a potent anti-CSFV ISG. We observed that overexpression of GBP1, an IFN-induced GTPase, remarkably suppressed CSFV replication, whereas knockdown of endogenous GBP1 expression by small interfering RNAs significantly promoted CSFV growth. Furthermore, we demonstrated that GBP1 acted mainly on the early phase of CSFV replication and inhibited the translation efficiency of the internal ribosome entry site of CSFV. In addition, we found that GBP1 was upregulated at the transcriptional level in CSFV-infected PK-15 cells and in various organs of CSFV-infected pigs. Coimmunoprecipitation and glutathione S-transferase (GST) pulldown assays revealed that GBP1 interacted with the NS5A protein of CSFV, and this interaction was mapped in the N-terminal globular GTPase domain of GBP1. Interestingly, the K51 of GBP1, which is crucial for its GTPase activity, was essential for the inhibition of CSFV replication. We showed further that the NS5A-GBP1 interaction inhibited GTPase activity, which was critical for its antiviral effect. Taking our findings together, GBP1 is an anti-CSFV ISG whose action depends on its GTPase activity. IMPORTANCE Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), an economically important viral disease affecting the pig industry in many countries. To date, only a few host restriction factors against CSFV, including interferon-stimulated genes (ISGs), have been characterized. Using a minilibrary of porcine ISGs, we identify porcine guanylate-binding protein 1 (GBP1) as a potent antiviral ISG against CSFV. We further show that the anti-CSFV action of GBP1 depends on its GTPase activity. The K51 of GBP1, critical for its GTPase activity, is essential for the antiviral action of GBP1 against CSFV replication, and the binding of the NS5A protein to GBP1 antagonizes the GTPase activity and thus the antiviral effect. This study will facilitate the development of anti-CSFV therapeutic agents by targeting host factors and may provide a new strategy for the control of CSF.
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48
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Reiss CS. Innate Immunity in Viral Encephalitis. NEUROTROPIC VIRAL INFECTIONS 2016. [PMCID: PMC7153449 DOI: 10.1007/978-3-319-33189-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Carol Shoshkes Reiss
- Departments of Biology and Neural Science, New York University, New York, New York USA
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49
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Cuadrado E, Booiman T, van Hamme JL, Jansen MH, van Dort KA, Vanderver A, Rice GI, Crow YJ, Kootstra NA, Kuijpers TW. ADAR1 Facilitates HIV-1 Replication in Primary CD4+ T Cells. PLoS One 2015; 10:e0143613. [PMID: 26629815 PMCID: PMC4667845 DOI: 10.1371/journal.pone.0143613] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 11/06/2015] [Indexed: 01/09/2023] Open
Abstract
Unlike resting CD4+ T cells, activated CD4+T cells are highly susceptible to infection of human immunodeficiency virus 1 (HIV-1). HIV-1 infects T cells and macrophages without activating the nucleic acid sensors and the anti-viral type I interferon response. Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA editing enzyme that displays antiviral activity against several RNA viruses. Mutations in ADAR1 cause the autoimmune disorder Aicardi-Goutieères syndrome (AGS). This disease is characterized by an inappropriate activation of the interferon-stimulated gene response. Here we show that HIV-1 replication, in ADAR1-deficient CD4+T lymphocytes from AGS patients, is blocked at the level of protein translation. Furthermore, viral protein synthesis block is accompanied by an activation of interferon-stimulated genes. RNA silencing of ADAR1 in Jurkat cells also inhibited HIV-1 protein synthesis. Our data support that HIV-1 requires ADAR1 for efficient replication in human CD4+T cells.
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Affiliation(s)
- Eloy Cuadrado
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
- * E-mail:
| | - Thijs Booiman
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
- Sanquin Research, Landsteiner Laboratory and Center for Infection and Immunity (CINIMA) at the Academic Medical Center of the University of Amsterdam, Amsterdam, The Netherlands
| | - John L. van Hamme
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
- Sanquin Research, Landsteiner Laboratory and Center for Infection and Immunity (CINIMA) at the Academic Medical Center of the University of Amsterdam, Amsterdam, The Netherlands
| | - Machiel H. Jansen
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
| | - Karel A. van Dort
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
- Sanquin Research, Landsteiner Laboratory and Center for Infection and Immunity (CINIMA) at the Academic Medical Center of the University of Amsterdam, Amsterdam, The Netherlands
| | - Adeline Vanderver
- Center for Genetic Medicine Research, Children’s National Medical Center, Washington DC, United States of America
| | - Gillian I. Rice
- Manchester Centre for Genomic Medicine, University of Manchester, Manchester Academic Health Sciences Centre (MAHSC), Manchester, United Kingdom
| | - Yanick J. Crow
- Manchester Centre for Genomic Medicine, University of Manchester, Manchester Academic Health Sciences Centre (MAHSC), Manchester, United Kingdom
- INSERM UMR 1163, Laboratory of Neurogenetics and Neuroinflammation, Institut Imagine, Hôpital Necker, Paris, France
| | - Neeltje A. Kootstra
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
- Sanquin Research, Landsteiner Laboratory and Center for Infection and Immunity (CINIMA) at the Academic Medical Center of the University of Amsterdam, Amsterdam, The Netherlands
| | - Taco W. Kuijpers
- Department of Experimental Immunology, Academic Medical Center (AMC), University of Amsterdam (UvA), Amsterdam, The Netherlands
- Emma Children’s Hospital, Dept of Pediatric Hematology, Immunology and Infectious disease, AMC, UvA, Amsterdam, The Netherlands
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50
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Mannion N, Arieti F, Gallo A, Keegan LP, O'Connell MA. New Insights into the Biological Role of Mammalian ADARs; the RNA Editing Proteins. Biomolecules 2015; 5:2338-62. [PMID: 26437436 PMCID: PMC4693238 DOI: 10.3390/biom5042338] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/09/2015] [Accepted: 09/11/2015] [Indexed: 12/20/2022] Open
Abstract
The ADAR proteins deaminate adenosine to inosine in double-stranded RNA which is one of the most abundant modifications present in mammalian RNA. Inosine can have a profound effect on the RNAs that are edited, not only changing the base-pairing properties, but can also result in recoding, as inosine behaves as if it were guanosine. In mammals there are three ADAR proteins and two ADAR-related proteins (ADAD) expressed. All have a very similar modular structure; however, both their expression and biological function differ significantly. Only two of the ADAR proteins have enzymatic activity. However, both ADAR and ADAD proteins possess the ability to bind double-strand RNA. Mutations in ADARs have been associated with many diseases ranging from cancer, innate immunity to neurological disorders. Here, we will discuss in detail the domain structure of mammalian ADARs, the effects of RNA editing, and the role of ADARs in human diseases.
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Affiliation(s)
- Niamh Mannion
- Paul O'Gorman Leukaemia Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, 21 Shelley Road, Glasgow G12 0ZD, UK.
| | - Fabiana Arieti
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.
| | - Angela Gallo
- Oncohaematoogy Department, Ospedale Pediatrico Bambino Gesù (IRCCS) Viale di San Paolo, Roma 15-00146, Italy.
| | - Liam P Keegan
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.
| | - Mary A O'Connell
- CEITEC-Central European Institute of Technology, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic.
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