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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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Normandin E, Triana S, Raju SS, Lan TCT, Lagerborg K, Rudy M, Adams GC, DeRuff KC, Logue J, Liu D, Strebinger D, Rao A, Messer KS, Sacks M, Adams RD, Janosko K, Kotliar D, Shah R, Crozier I, Rinn JL, Melé M, Honko AN, Zhang F, Babadi M, Luban J, Bennett RS, Shalek AK, Barkas N, Lin AE, Hensley LE, Sabeti PC, Siddle KJ. Natural history of Ebola virus disease in rhesus monkeys shows viral variant emergence dynamics and tissue-specific host responses. CELL GENOMICS 2023; 3:100440. [PMID: 38169842 PMCID: PMC10759212 DOI: 10.1016/j.xgen.2023.100440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 02/27/2023] [Accepted: 10/15/2023] [Indexed: 01/05/2024]
Abstract
Ebola virus (EBOV) causes Ebola virus disease (EVD), marked by severe hemorrhagic fever; however, the mechanisms underlying the disease remain unclear. To assess the molecular basis of EVD across time, we performed RNA sequencing on 17 tissues from a natural history study of 21 rhesus monkeys, developing new methods to characterize host-pathogen dynamics. We identified alterations in host gene expression with previously unknown tissue-specific changes, including downregulation of genes related to tissue connectivity. EBOV was widely disseminated throughout the body; using a new, broadly applicable deconvolution method, we found that viral load correlated with increased monocyte presence. Patterns of viral variation between tissues differentiated primary infections from compartmentalized infections, and several variants impacted viral fitness in a EBOV/Kikwit minigenome system, suggesting that functionally significant variants can emerge during early infection. This comprehensive portrait of host-pathogen dynamics in EVD illuminates new features of pathogenesis and establishes resources to study other emerging pathogens.
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Affiliation(s)
- Erica Normandin
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Sergio Triana
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Department of Chemistry, Institute for Medical Engineering and Sciences (IMES), and Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA 02142, USA; Ragon Institute of MGH, Harvard, and MIT, Cambridge, MA 02139, USA.
| | - Siddharth S Raju
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Tammy C T Lan
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Molecular and Cellular Biology, Harvard University, Boston, MA, USA
| | - Kim Lagerborg
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Harvard Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, USA
| | - Melissa Rudy
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Gordon C Adams
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - James Logue
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA
| | - David Liu
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA
| | - Daniel Strebinger
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815-6789, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Arya Rao
- Columbia University, New York, NY, USA; Harvard/MIT MD-PhD Program, Harvard Medical School, Boston, MA 02115, USA
| | | | - Molly Sacks
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Ricky D Adams
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA
| | - Krisztina Janosko
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA
| | - Dylan Kotliar
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Rickey Shah
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Ian Crozier
- Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - John L Rinn
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Marta Melé
- Life Sciences Department, Barcelona Supercomputing Center, 08034 Barcelona, Catalonia, Spain
| | - Anna N Honko
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA
| | - Feng Zhang
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815-6789, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mehrtash Babadi
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Jeremy Luban
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Ragon Institute of MGH, Harvard, and MIT, Cambridge, MA 02139, USA; Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Richard S Bennett
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA
| | - Alex K Shalek
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Department of Chemistry, Institute for Medical Engineering and Sciences (IMES), and Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA 02142, USA; Ragon Institute of MGH, Harvard, and MIT, Cambridge, MA 02139, USA
| | - Nikolaos Barkas
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Aaron E Lin
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Harvard Program in Virology, Harvard Medical School, Boston, MA 02115, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Lisa E Hensley
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA.
| | - Pardis C Sabeti
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815-6789, USA; Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
| | - Katherine J Siddle
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA.
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Zhang D, Irving AT. Antiviral effects of interferon-stimulated genes in bats. Front Cell Infect Microbiol 2023; 13:1224532. [PMID: 37661999 PMCID: PMC10472940 DOI: 10.3389/fcimb.2023.1224532] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/10/2023] [Indexed: 09/05/2023] Open
Abstract
The interferon pathway is the first line of defense in viral infection in all mammals, and its induction stimulates broad expression of interferon-stimulated genes (ISGs). In mice and also humans, the antiviral function of ISGs has been extensively studied. As an important viral reservoir in nature, bats can coexist with a variety of pathogenic viruses without overt signs of disease, yet only limited data are available for the role of ISGs in bats. There are multiple species of bats and work has begun deciphering the differences and similarities between ISG function of human/mouse and different bat species. This review summarizes the current knowledge of conserved and bat-specific-ISGs and their known antiviral effector functions.
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Affiliation(s)
- Dan Zhang
- Zhejiang University-University of Edinburgh Institute, Haining, China
| | - Aaron T. Irving
- Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Infection, Immunity & Cancer, Zhejiang University-University of Edinburgh Institute, Haining, China
- BIMET - Biomedical and Health Translational Research Centre of Zhejiang Province, China
- College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
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Escudero-Pérez B, Lalande A, Mathieu C, Lawrence P. Host–Pathogen Interactions Influencing Zoonotic Spillover Potential and Transmission in Humans. Viruses 2023; 15:v15030599. [PMID: 36992308 PMCID: PMC10060007 DOI: 10.3390/v15030599] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/13/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Emerging infectious diseases of zoonotic origin are an ever-increasing public health risk and economic burden. The factors that determine if and when an animal virus is able to spill over into the human population with sufficient success to achieve ongoing transmission in humans are complex and dynamic. We are currently unable to fully predict which pathogens may appear in humans, where and with what impact. In this review, we highlight current knowledge of the key host–pathogen interactions known to influence zoonotic spillover potential and transmission in humans, with a particular focus on two important human viruses of zoonotic origin, the Nipah virus and the Ebola virus. Namely, key factors determining spillover potential include cellular and tissue tropism, as well as the virulence and pathogenic characteristics of the pathogen and the capacity of the pathogen to adapt and evolve within a novel host environment. We also detail our emerging understanding of the importance of steric hindrance of host cell factors by viral proteins using a “flytrap”-type mechanism of protein amyloidogenesis that could be crucial in developing future antiviral therapies against emerging pathogens. Finally, we discuss strategies to prepare for and to reduce the frequency of zoonotic spillover occurrences in order to minimize the risk of new outbreaks.
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Affiliation(s)
- Beatriz Escudero-Pérez
- WHO Collaborating Centre for Arbovirus and Haemorrhagic Fever Reference and Research, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel-Reims, 38124 Braunschweig, Germany
| | - Alexandre Lalande
- CIRI (Centre International de Recherche en Infectiologie), Team Neuro-Invasion, TROpism and VIRal Encephalitis, INSERM U1111, CNRS UMR5308, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Cyrille Mathieu
- CIRI (Centre International de Recherche en Infectiologie), Team Neuro-Invasion, TROpism and VIRal Encephalitis, INSERM U1111, CNRS UMR5308, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Philip Lawrence
- CONFLUENCE: Sciences et Humanités (EA 1598), Université Catholique de Lyon (UCLy), 69002 Lyon, France
- Correspondence:
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Jayaprakash AD, Ronk AJ, Prasad AN, Covington MF, Stein KR, Schwarz TM, Hekmaty S, Fenton KA, Geisbert TW, Basler CF, Bukreyev A, Sachidanandam R. Marburg and Ebola Virus Infections Elicit a Complex, Muted Inflammatory State in Bats. Viruses 2023; 15:350. [PMID: 36851566 PMCID: PMC9958679 DOI: 10.3390/v15020350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
The Marburg and Ebola filoviruses cause a severe, often fatal, disease in humans and nonhuman primates but have only subclinical effects in bats, including Egyptian rousettes, which are a natural reservoir of Marburg virus. A fundamental question is why these viruses are highly pathogenic in humans but fail to cause disease in bats. To address this question, we infected one cohort of Egyptian rousette bats with Marburg virus and another cohort with Ebola virus and harvested multiple tissues for mRNA expression analysis. While virus transcripts were found primarily in the liver, principal component analysis (PCA) revealed coordinated changes across multiple tissues. Gene signatures in kidney and liver pointed at induction of vasodilation, reduction in coagulation, and changes in the regulation of iron metabolism. Signatures of immune response detected in spleen and liver indicated a robust anti-inflammatory state signified by macrophages in the M2 state and an active T cell response. The evolutionary divergence between bats and humans of many responsive genes might provide a framework for understanding the differing outcomes upon infection by filoviruses. In this study, we outline multiple interconnected pathways that respond to infection by MARV and EBOV, providing insights into the complexity of the mechanisms that enable bats to resist the disease caused by filoviral infections. The results have the potential to aid in the development of new strategies to effectively mitigate and treat the disease caused by these viruses in humans.
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Affiliation(s)
| | - Adam J. Ronk
- Department of Pathology, the University Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Abhishek N. Prasad
- Department of Pathology, the University Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | | | - Kathryn R. Stein
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Toni M. Schwarz
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Saboor Hekmaty
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Karla A. Fenton
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
- Department Microbiology & Immunology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Thomas W. Geisbert
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
- Department Microbiology & Immunology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Christopher F. Basler
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alexander Bukreyev
- Department of Pathology, the University Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
- Department Microbiology & Immunology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Ravi Sachidanandam
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Sun J, Uwishema O, Kassem H, Abbass M, Uweis L, Rai A, El Saleh R, Adanur I, Onyeaka H. Ebola virus outbreak returns to the Democratic Republic of Congo: An urgent rising concern. Ann Med Surg (Lond) 2022; 79:103958. [PMID: 35757313 PMCID: PMC9218350 DOI: 10.1016/j.amsu.2022.103958] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/05/2022] [Indexed: 11/21/2022] Open
Abstract
On April 23, 2022, the Ministry of Health of the Democratic Republic of the Congo announced an EVD outbreak after discovering 2 confirmed cases and identifying 267 contacts. With collaboration from the WHO, the MoH are taking many interventions to prevent further expansion of this outbreak. Forty-six years ago, the Ebola virus was first discovered in 1976 near the Ebola River in the DRC. Since then, 13 outbreaks of EVD have occurred in the DRC and, in 2020, it witnessed the second largest EVD outbreak in the world, resulting in 3481 cases and 2299 mortalities. This article discusses the epidemiology of the current DRC outbreak by examining the etiology of EVD, the number of affected cases, and the subsequent case index. Considering these data, this paper discusses measures taken by the MoH, WHO, CDC, and UNICEF to mitigate the Ebola outbreak, such as supporting local teams to provide essential care, training medical staff, and raising awareness for vaccination. Finally, by comparing the gravity of the situation to current measures, this article provides recommendations for individuals and governments to protect themselves and mitigate future outbreaks.
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Kavulikirwa OK, Sikakulya FK. Recurrent Ebola outbreaks in the eastern Democratic Republic of the Congo: A wake-up call to scale up the integrated disease surveillance and response strategy. One Health 2022; 14:100379. [PMID: 35313715 PMCID: PMC8933533 DOI: 10.1016/j.onehlt.2022.100379] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 11/03/2022] Open
Abstract
Ebola virus disease (EVD) is a dangerous viral zoonotic hemorrhagic fever caused by a deadly pathogenic filovirus. Frugivorous bats are recognized as being the natural reservoir, playing a pivotal role in the epidemiological dynamics. Since its discovery in 1976, the disease has been shown to be endemic in the Democratic Republic of the Congo (DRC). So far, thirteen outbreaks have occurred, and EVD has been prioritized in the national surveillance system. Additionally, EVD is targeted by the Integrated Disease Surveillance and Response (IDSR) strategy in DRC. The IDSR strategy is a collaborative, comprehensive and innovative surveillance approach developed and adopted by WHO's African region member states (WHO/Afro) to strengthen their surveillance capacity at all levels for early detection, response and recovery from priority diseases and public health events. We provide an overview of the IDSR strategy and the issues that can prevent its expected outcome (early detection for timely response) in eastern DRC where there are still delays in EVD outbreaks detection and weaknesses in response capacity and health crisis recovery. Therefore, this paper highlights the advantages linked to the implementation of the IDSR and calls for an urgent need to scale up its materialization against the recurrent Ebola outbreaks in eastern DRC. Consequently, the paper advocates for rapidly addressing the obstacles hindering its operationalization and adapting the approach to the local context using implementation science.
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Affiliation(s)
- Olivier Kambere Kavulikirwa
- Faculty of Veterinary Medicine, Université Catholique du Graben de Butembo, Democratic Republic of the Congo
| | - Franck Katembo Sikakulya
- Faculty of Clinical Medicine and Dentistry, Department of Surgery, Kampala International University Western Campus, Ishaka-Bushenyi, Uganda
- Faculty of Medicine, Université Catholique du Graben de Butembo, Democratic Republic of the Congo
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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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Shan KJ, Wei C, Wang Y, Huan Q, Qian W. Host-specific asymmetric accumulation of mutation types reveals that the origin of SARS-CoV-2 is consistent with a natural process. Innovation (N Y) 2021; 2:100159. [PMID: 34485968 PMCID: PMC8405235 DOI: 10.1016/j.xinn.2021.100159] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 08/26/2021] [Indexed: 12/28/2022] Open
Abstract
The capacity of RNA viruses to adapt to new hosts and rapidly escape the host immune system is largely attributable to de novo genetic diversity that emerges through mutations in RNA. Although the molecular spectrum of de novo mutations-the relative rates at which various base substitutions occur-are widely recognized as informative toward understanding the evolution of a viral genome, little attention has been paid to the possibility of using molecular spectra to infer the host origins of a virus. Here, we characterize the molecular spectrum of de novo mutations for SARS-CoV-2 from transcriptomic data obtained from virus-infected cell lines, enabled by the use of sporadic junctions formed during discontinuous transcription as molecular barcodes. We find that de novo mutations are generated in a replication-independent manner, typically on the genomic strand, and highly dependent on mutagenic mechanisms specific to the host cellular environment. De novo mutations will then strongly influence the types of base substitutions accumulated during SARS-CoV-2 evolution, in an asymmetric manner favoring specific mutation types. Consequently, similarities between the mutation spectra of SARS-CoV-2 and the bat coronavirus RaTG13, which have accumulated since their divergence strongly suggest that SARS-CoV-2 evolved in a host cellular environment highly similar to that of bats before its zoonotic transfer into humans. Collectively, our findings provide data-driven support for the natural origin of SARS-CoV-2.
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Affiliation(s)
- Ke-Jia Shan
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changshuo Wei
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qing Huan
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenfeng Qian
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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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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3' untranslated regions of Marburg and Ebola virus mRNAs possess negative regulators of translation that are modulated by ADAR1 editing. J Virol 2021; 95:e0065221. [PMID: 34346762 PMCID: PMC8428382 DOI: 10.1128/jvi.00652-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The filovirus family includes deadly pathogens such as Ebola virus (EBOV) and Marburg virus (MARV). A substantial portion of filovirus genomes encode 5′ and 3′ untranslated regions (UTRs) of viral mRNAs. Select viral genomic RNA sequences corresponding to 3′ UTRs are prone to editing by adenosine deaminase acting on RNA 1 (ADAR1). A reporter mRNA approach, in which different 5′ or 3′ UTRs were inserted into luciferase-encoding mRNAs, demonstrates that MARV 3′ UTRs yield different levels of reporter gene expression, suggesting modulation of translation. The modulation occurs in cells unable to produce microRNAs (miRNAs) and can be recapitulated in a MARV minigenome assay. Deletion mutants identified negative regulatory regions at the ends of the MARV nucleoprotein (NP) and large protein (L) 3′ UTRs. Apparent ADAR1 editing mutants were previously identified within the MARV NP 3′ UTR. Introduction of these changes into the MARV nucleoprotein (NP) 3′ UTR or deletion of the region targeted for editing enhances translation, as indicated by reporter assays and polysome analysis. In addition, the parental NP 3′ UTR, but not the edited or deletion mutant NP 3′ UTRs, induces a type I interferon (IFN) response upon transfection into cells. Because some EBOV isolates from the West Africa outbreak exhibited ADAR1 editing of the viral protein of 40 kDa (VP40) 3′ UTR, VP40 3′ UTRs with parental and edited sequences were similarly assayed. The EBOV VP40 3′ UTR edits also enhanced translation, but neither the wild-type nor the edited 3′ UTRs induced IFN. These findings implicate filoviral mRNA 3′ UTRs as negative regulators of translation that can be inactivated by innate immune responses that induce ADAR1. IMPORTANCE UTRs comprise a large percentage of filovirus genomes and are apparent targets of editing by ADAR1, an enzyme with pro- and antiviral activities. However, the functional significance of the UTRs and ADAR1 editing has been uncertain. This study demonstrates that MARV and EBOV 3′ UTRs can modulate translation, in some cases negatively. ADAR1 editing or deletion of select regions within the translation suppressing 3′ UTRs relieves the negative effects of the UTRs. These data indicate that filovirus 3′ UTRs contain translation regulatory elements that are modulated by activation of ADAR1, suggesting a complex interplay between filovirus gene expression and innate immunity.
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Wardeh M, Blagrove MSC, Sharkey KJ, Baylis M. Divide-and-conquer: machine-learning integrates mammalian and viral traits with network features to predict virus-mammal associations. Nat Commun 2021; 12:3954. [PMID: 34172731 PMCID: PMC8233343 DOI: 10.1038/s41467-021-24085-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 05/21/2021] [Indexed: 11/09/2022] Open
Abstract
Our knowledge of viral host ranges remains limited. Completing this picture by identifying unknown hosts of known viruses is an important research aim that can help identify and mitigate zoonotic and animal-disease risks, such as spill-over from animal reservoirs into human populations. To address this knowledge-gap we apply a divide-and-conquer approach which separates viral, mammalian and network features into three unique perspectives, each predicting associations independently to enhance predictive power. Our approach predicts over 20,000 unknown associations between known viruses and susceptible mammalian species, suggesting that current knowledge underestimates the number of associations in wild and semi-domesticated mammals by a factor of 4.3, and the average potential mammalian host-range of viruses by a factor of 3.2. In particular, our results highlight a significant knowledge gap in the wild reservoirs of important zoonotic and domesticated mammals' viruses: specifically, lyssaviruses, bornaviruses and rotaviruses.
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Affiliation(s)
- Maya Wardeh
- Department of Livestock and One Health, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK.
- Department of Mathematical Sciences, University of Liverpool, Liverpool, UK.
| | - Marcus S C Blagrove
- Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Kieran J Sharkey
- Department of Mathematical Sciences, University of Liverpool, Liverpool, UK
| | - Matthew Baylis
- Department of Livestock and One Health, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
- Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
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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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