MERS-CoV endoribonuclease and accessory proteins jointly evade host innate immunity during infection of lung and nasal epithelial cells

Courtney E Comar; Clayton J Otter; Jessica Pfannenstiel; Ethan Doerger; David M Renner; Li Hui Tan; Stanley Perlman; Noam A Cohen; Anthony R Fehr; Susan R Weiss

doi:10.1073/pnas.2123208119

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MERS-CoV endoribonuclease and accessory proteins jointly evade host innate immunity during infection of lung and nasal epithelial cells

Journal article

Open access

Peer reviewed

MERS-CoV endoribonuclease and accessory proteins jointly evade host innate immunity during infection of lung and nasal epithelial cells

Courtney E Comar, Clayton J Otter, Jessica Pfannenstiel, Ethan Doerger, David M Renner, Li Hui Tan, Stanley Perlman, Noam A Cohen, Anthony R Fehr and Susan R Weiss

Proceedings of the National Academy of Sciences - PNAS, Vol.119(21), pp.1-e2123208119

05/24/2022

DOI: 10.1073/pnas.2123208119

PMCID: PMC9173776

PMID: 35594398

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Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) emerged into humans in 2012, causing highly lethal respiratory disease. The severity of disease may be, in part, because MERS-CoV is adept at antagonizing early innate immune pathways-interferon (IFN) production and signaling, protein kinase R (PKR), and oligoadenylate synthetase/ribonuclease L (OAS/RNase L)-activated in response to viral double-stranded RNA (dsRNA) generated during genome replication. This is in contrast to severe acute respiratory syndrome CoV-2 (SARS-CoV-2), which we recently reported to activate PKR and RNase L and, to some extent, IFN signaling. We previously found that MERS-CoV accessory proteins NS4a (dsRNA binding protein) and NS4b (phosphodiesterase) could weakly suppress these pathways, but ablation of each had minimal effect on virus replication. Here we investigated the antagonist effects of the conserved coronavirus endoribonuclease (EndoU), in combination with NS4a or NS4b. Inactivation of EndoU catalytic activity alone in a recombinant MERS-CoV caused little if any effect on activation of the innate immune pathways during infection. However, infection with recombinant viruses containing combined mutations with inactivation of EndoU and deletion of NS4a or inactivation of the NS4b phosphodiesterase promoted robust activation of dsRNA-induced innate immune pathways. This resulted in at least tenfold attenuation of replication in human lung–derived A549 and primary nasal cells. Furthermore, replication of these recombinant viruses could be rescued to the level of wild-type MERS-CoV by knockout of host immune mediators MAVS, PKR, or RNase L. Thus, EndoU and accessory proteins NS4a and NS4b together suppress dsRNA-induced innate immunity during MERS-CoV infection in order to optimize viral replication.

Ablation

Catalytic activity

Coronaviruses

Deactivation

Double-stranded RNA

eIF-2 kinase

Epithelial cells

Epithelium

Gene deletion

Genomes

Immunity

Inactivation

Infections

Innate immunity

Interferon

Kinases

Lungs

Middle East respiratory syndrome

Mutation

Pathways

Phosphodiesterase

Protein kinase R

Proteins

Replication

Respiratory diseases

Ribonuclease L

Severe acute respiratory syndrome

Severe acute respiratory syndrome coronavirus 2

Signal transduction

Signaling

Viral diseases

Viruses

Details

Title: Subtitle: MERS-CoV endoribonuclease and accessory proteins jointly evade host innate immunity during infection of lung and nasal epithelial cells
Creators: Courtney E Comar - University of Pennsylvania
Clayton J Otter - University of Pennsylvania
Jessica Pfannenstiel - University of Kansas
Ethan Doerger - University of Kansas
David M Renner - University of Pennsylvania
Li Hui Tan - University of Pennsylvania
Stanley Perlman - University of Iowa
Noam A Cohen - University of Pennsylvania
Anthony R Fehr - University of Kansas
Susan R Weiss - University of Pennsylvania
Resource Type: Journal article
Publication Details: Proceedings of the National Academy of Sciences - PNAS, Vol.119(21), pp.1-e2123208119
DOI: 10.1073/pnas.2123208119
PMID: 35594398
PMCID: PMC9173776
NLM abbreviation: Proc Natl Acad Sci U S A
ISSN: 0027-8424
eISSN: 1091-6490
Publisher: National Academy of Sciences
Grant note: DOI: 10.13039/100000060, name: HHS | NIH | National Institute of Allergy and Infectious Diseases, award: R01AI140442; DOI: 10.13039/100000057, name: HHS | NIH | National Institute of General Medical Sciences, award: P20GM113117; DOI: 10.13039/100000060, name: HHS | NIH | National Institute of Allergy and Infectious Diseases, award: K22AI134993; DOI: 10.13039/100000060, name: HHS | NIH | National Institute of Allergy and Infectious Diseases, award: P01AI060699; DOI: 10.13039/100006492, name: Division of Intramural Research, National Institute of Allergy and Infectious Diseases, award: RO1AI129269; DOI: 10.13039/100000738, name: U.S. Department of Veterans Affairs, award: 1-I01-BX005432-01; DOI: 10.13039/100006492, name: Division of Intramural Research, National Institute of Allergy and Infectious Diseases, award: T32 AI055400; DOI: 10.13039/100000065, name: HHS | NIH | National Institute of Neurological Disorders and Stroke, award: T32 NS007180
Language: English
Date published: 05/24/2022
Academic Unit: Microbiology and Immunology; Stead Family Department of Pediatrics; Iowa Neuroscience Institute; Infectious Disease (Pediatrics)
Record Identifier: 9984259244602771

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