The Conserved Coronavirus Macrodomain Promotes Virulence and Suppresses the Innate Immune Response during Severe Acute Respiratory Syndrome Coronavirus Infection

Anthony R Fehr; Rudragouda Channappanavar; Gytis Jankevicius; Craig Fett; Jincun Zhao; Jeremiah Athmer; David K Meyerholz; Ivan Ahel; Stanley Perlman

doi:10.1128/mBio.01721-16

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The Conserved Coronavirus Macrodomain Promotes Virulence and Suppresses the Innate Immune Response during Severe Acute Respiratory Syndrome Coronavirus Infection

Journal article

Open access

The Conserved Coronavirus Macrodomain Promotes Virulence and Suppresses the Innate Immune Response during Severe Acute Respiratory Syndrome Coronavirus Infection

Anthony R Fehr, Rudragouda Channappanavar, Gytis Jankevicius, Craig Fett, Jincun Zhao, Jeremiah Athmer, David K Meyerholz, Ivan Ahel and Stanley Perlman

mBio, Vol.7(6), e01721-16

12/13/2016

DOI: 10.1128/mBio.01721-16

PMCID: PMC5156301

PMID: 27965448

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Abstract

ADP-ribosylation is a common posttranslational modification that may have antiviral properties and impact innate immunity. To regulate this activity, macrodomain proteins enzymatically remove covalently attached ADP-ribose from protein targets. All members of the Coronavirinae, a subfamily of positive-sense RNA viruses, contain a highly conserved macrodomain within nonstructural protein 3 (nsp3). However, its function or targets during infection remain unknown. We identified several macrodomain mutations that greatly reduced nsp3's de-ADP-ribosylation activity in vitro Next, we created recombinant severe acute respiratory syndrome coronavirus (SARS-CoV) strains with these mutations. These mutations led to virus attenuation and a modest reduction of viral loads in infected mice, despite normal replication in cell culture. Further, macrodomain mutant virus elicited an early, enhanced interferon (IFN), interferon-stimulated gene (ISG), and proinflammatory cytokine response in mice and in a human bronchial epithelial cell line. Using a coinfection assay, we found that inclusion of mutant virus in the inoculum protected mice from an otherwise lethal SARS-CoV infection without reducing virus loads, indicating that the changes in innate immune response were physiologically significant. In conclusion, we have established a novel function for the SARS-CoV macrodomain that implicates ADP-ribose in the regulation of the innate immune response and helps to demonstrate why this domain is conserved in CoVs. The macrodomain is a ubiquitous structural domain that removes ADP-ribose from proteins, reversing the activity of ADP-ribosyltransferases. All coronaviruses contain a macrodomain, suggesting that ADP-ribosylation impacts coronavirus infection. However, its function during infection remains unknown. Here, we found that the macrodomain is an important virulence factor for a highly pathogenic human CoV, SARS-CoV. Viruses with macrodomain mutations that abrogate its ability to remove ADP-ribose from protein were unable to cause lethal disease in mice. Importantly, the SARS-CoV macrodomain suppressed the innate immune response during infection. Our data suggest that an early innate immune response can protect mice from lethal disease. Understanding the mechanism used by this enzyme to promote disease will open up novel avenues for coronavirus therapies and give further insight into the role of macrodomains in viral pathogenesis.

Mutation

Bronchi - virology

Severe Acute Respiratory Syndrome - virology

Humans

Virulence

Severe Acute Respiratory Syndrome - immunology

Bronchi - immunology

Viral Load

Viral Nonstructural Proteins - chemistry

Protein Domains

Bronchi - cytology

Cytokines - immunology

Cell Line

Coronavirus - pathogenicity

Coinfection - immunology

Viral Nonstructural Proteins - genetics

Immunity, Innate

Coinfection - virology

SARS Virus - pathogenicity

Coronavirus - immunology

Host-Pathogen Interactions

Animals

Coronavirus - chemistry

Epithelial Cells - immunology

Epithelial Cells - virology

Coronavirus - genetics

Viral Nonstructural Proteins - metabolism

Mice

Adenosine Diphosphate - metabolism

Details

Title: Subtitle: The Conserved Coronavirus Macrodomain Promotes Virulence and Suppresses the Innate Immune Response during Severe Acute Respiratory Syndrome Coronavirus Infection
Creators: Anthony R Fehr - Department of Microbiology, University of Iowa, Iowa City, Iowa, USA
Rudragouda Channappanavar - Department of Microbiology, University of Iowa, Iowa City, Iowa, USA
Gytis Jankevicius - Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
Craig Fett - Department of Microbiology, University of Iowa, Iowa City, Iowa, USA
Jincun Zhao - University of Iowa
Jeremiah Athmer - Department of Microbiology, University of Iowa, Iowa City, Iowa, USA
David K Meyerholz - Department of Pathology, University of Iowa, Iowa City, Iowa, USA
Ivan Ahel - Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
Stanley Perlman - Department of Microbiology, University of Iowa, Iowa City, Iowa, USA Stanley-Perlman@uiowa.edu
Resource Type: Journal article
Publication Details: mBio, Vol.7(6), e01721-16
DOI: 10.1128/mBio.01721-16
PMID: 27965448
PMCID: PMC5156301
NLM abbreviation: mBio
ISSN: 2150-7511
eISSN: 2150-7511
Publisher: United States
Grant note: F32 AI113973 / NIAID NIH HHS 101794 / Wellcome Trust R01 AI091322 / NIAID NIH HHS P01 AI060699 / NIAID NIH HHS T32 AI007260 / NIAID NIH HHS T32 AI007533 / NIAID NIH HHS
Language: English
Date published: 12/13/2016
Academic Unit: Microbiology and Immunology; Stead Family Department of Pediatrics; Pathology; Iowa Neuroscience Institute; Infectious Disease (Pediatrics)
Record Identifier: 9983777469902771

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