Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity

ABSTRACT Influenza viruses are deadly respiratory pathogens of special importance due to their long history of global pandemics. During influenza virus infections, the host responds by producing interferons, which activate interferon-stimulated genes (ISGs) inside target cells. One of these ISGs is...

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Main Authors: Harrison Dulin, Nathan Hendricks, Duo Xu, Linfeng Gao, Keidy Wuang, Huiwang Ai, Rong Hai
Format: Article
Language:English
Published: American Society for Microbiology 2022-12-01
Series:Microbiology Spectrum
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/spectrum.01902-22
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author Harrison Dulin
Nathan Hendricks
Duo Xu
Linfeng Gao
Keidy Wuang
Huiwang Ai
Rong Hai
author_facet Harrison Dulin
Nathan Hendricks
Duo Xu
Linfeng Gao
Keidy Wuang
Huiwang Ai
Rong Hai
author_sort Harrison Dulin
collection DOAJ
description ABSTRACT Influenza viruses are deadly respiratory pathogens of special importance due to their long history of global pandemics. During influenza virus infections, the host responds by producing interferons, which activate interferon-stimulated genes (ISGs) inside target cells. One of these ISGs is inducible nitric oxide synthase (iNOS). iNOS produces nitric oxide (NO) from arginine and molecular oxygen inside the cell. NO can react with superoxide radicals to form reactive nitrogen species, principally peroxynitrite. While much work has been done studying the many roles of nitric oxide in influenza virus infections, the direct effect of peroxynitrite on influenza virus proteins has not been determined. Manipulations of NO, either by knocking out iNOS or chemically inhibiting NO, produced no change in virus titers in mouse models of influenza infection. However, peroxynitrite has a known antimicrobial effect on various bacteria and parasites, and the reason for its lack of antimicrobial effect on influenza virus titers in vivo remains unclear. Therefore, we wished to test the direct effect of nitration of influenza virus proteins. We examined the impact of nitration on virus infectivity, replication, and immunogenicity. We observed that the nitration of influenza A virus proteins decreased virus infectivity and replication ex vivo. We also determined that the nitration of influenza virus hemagglutinin protein can reduce antibody responses to native virus protein. However, our study also suggests that nitration of influenza virus proteins in vivo is likely not extensive enough to inhibit virus functions substantially. These findings will help clarify the role of peroxynitrite during influenza virus infections. IMPORTANCE Nitric oxide and peroxynitrite produced during microbial infections have diverse and seemingly paradoxical functions. While nitration of lung tissue during influenza virus infection has been observed in both mice and humans, the direct effect of protein nitration on influenza viruses has remained elusive. We addressed the impact of nitration of influenza virus proteins on virus infectivity, replication, and immunogenicity. We observed that ex vivo nitration of influenza virus proteins reduced virus infectivity and immunogenicity. However, we did not detect nitration of influenza virus hemagglutinin protein in vivo. These results contribute to our understanding of the roles of nitric oxide and peroxynitrite in influenza virus infections.
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spelling doaj.art-c3f3c7367fb74f48a68aa842aec594032022-12-22T04:24:26ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972022-12-0110610.1128/spectrum.01902-22Impact of Protein Nitration on Influenza Virus Infectivity and ImmunogenicityHarrison Dulin0Nathan Hendricks1Duo Xu2Linfeng Gao3Keidy Wuang4Huiwang Ai5Rong Hai6Cell, Molecular, and Developmental Biology Graduate Program, University of California, Riverside, Riverside, California, USAProteomics Core, University of California, Riverside, Riverside, California, USAMicrobiology and Plant Pathology, University of California, Riverside, Riverside, California, USAMicrobiology and Plant Pathology, University of California, Riverside, Riverside, California, USAMicrobiology and Plant Pathology, University of California, Riverside, Riverside, California, USADepartment of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USACell, Molecular, and Developmental Biology Graduate Program, University of California, Riverside, Riverside, California, USAABSTRACT Influenza viruses are deadly respiratory pathogens of special importance due to their long history of global pandemics. During influenza virus infections, the host responds by producing interferons, which activate interferon-stimulated genes (ISGs) inside target cells. One of these ISGs is inducible nitric oxide synthase (iNOS). iNOS produces nitric oxide (NO) from arginine and molecular oxygen inside the cell. NO can react with superoxide radicals to form reactive nitrogen species, principally peroxynitrite. While much work has been done studying the many roles of nitric oxide in influenza virus infections, the direct effect of peroxynitrite on influenza virus proteins has not been determined. Manipulations of NO, either by knocking out iNOS or chemically inhibiting NO, produced no change in virus titers in mouse models of influenza infection. However, peroxynitrite has a known antimicrobial effect on various bacteria and parasites, and the reason for its lack of antimicrobial effect on influenza virus titers in vivo remains unclear. Therefore, we wished to test the direct effect of nitration of influenza virus proteins. We examined the impact of nitration on virus infectivity, replication, and immunogenicity. We observed that the nitration of influenza A virus proteins decreased virus infectivity and replication ex vivo. We also determined that the nitration of influenza virus hemagglutinin protein can reduce antibody responses to native virus protein. However, our study also suggests that nitration of influenza virus proteins in vivo is likely not extensive enough to inhibit virus functions substantially. These findings will help clarify the role of peroxynitrite during influenza virus infections. IMPORTANCE Nitric oxide and peroxynitrite produced during microbial infections have diverse and seemingly paradoxical functions. While nitration of lung tissue during influenza virus infection has been observed in both mice and humans, the direct effect of protein nitration on influenza viruses has remained elusive. We addressed the impact of nitration of influenza virus proteins on virus infectivity, replication, and immunogenicity. We observed that ex vivo nitration of influenza virus proteins reduced virus infectivity and immunogenicity. However, we did not detect nitration of influenza virus hemagglutinin protein in vivo. These results contribute to our understanding of the roles of nitric oxide and peroxynitrite in influenza virus infections.https://journals.asm.org/doi/10.1128/spectrum.01902-22hemagglutinininfectioninfluenzalung infectionnitric oxide synthasenitrotyrosine
spellingShingle Harrison Dulin
Nathan Hendricks
Duo Xu
Linfeng Gao
Keidy Wuang
Huiwang Ai
Rong Hai
Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity
Microbiology Spectrum
hemagglutinin
infection
influenza
lung infection
nitric oxide synthase
nitrotyrosine
title Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity
title_full Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity
title_fullStr Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity
title_full_unstemmed Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity
title_short Impact of Protein Nitration on Influenza Virus Infectivity and Immunogenicity
title_sort impact of protein nitration on influenza virus infectivity and immunogenicity
topic hemagglutinin
infection
influenza
lung infection
nitric oxide synthase
nitrotyrosine
url https://journals.asm.org/doi/10.1128/spectrum.01902-22
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AT huiwangai impactofproteinnitrationoninfluenzavirusinfectivityandimmunogenicity
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