_version_ 1868266069668397056
author Kuryshko, Maryna
Luttermann, Christine
Bayoumi, Mahmoud
Mostafa, Ahmed
Weißmann, Jula
Schäfer, Alexander
Wendt, Lisa
Hoenen, Thomas
Müller, Jendrik
Martinez-Sobrido, Luis
Mettenleiter, Thomas C
Abdelwhab, Elsayed M
author_facet Kuryshko, Maryna
Luttermann, Christine
Bayoumi, Mahmoud
Mostafa, Ahmed
Weißmann, Jula
Schäfer, Alexander
Wendt, Lisa
Hoenen, Thomas
Müller, Jendrik
Martinez-Sobrido, Luis
Mettenleiter, Thomas C
Abdelwhab, Elsayed M
Kuryshko, Maryna
Luttermann, Christine
Bayoumi, Mahmoud
Mostafa, Ahmed
Weißmann, Jula
Schäfer, Alexander
Wendt, Lisa
Hoenen, Thomas
Müller, Jendrik
Martinez-Sobrido, Luis
Mettenleiter, Thomas C
Abdelwhab, Elsayed M
collection PubMed - marine biology
contents Host-specific functional evolution of seal influenza A virus NS1 protein following avian-to-seal transmission. Kuryshko, Maryna Luttermann, Christine Bayoumi, Mahmoud Mostafa, Ahmed Weißmann, Jula Schäfer, Alexander Wendt, Lisa Hoenen, Thomas Müller, Jendrik Martinez-Sobrido, Luis Mettenleiter, Thomas C Abdelwhab, Elsayed M Viral Nonstructural Proteins Animals Influenza A virus Humans Birds Host Specificity Influenza in Birds Phylogeny Orthomyxoviridae Infections Evolution, Molecular Virus Replication Influenza, Human Amino Acid Substitution Interferons Marine mammals, particularly seals, are susceptible to both avian and human influenza A viruses (IAVs), making them potential intermediates for zoonotic virus emergence. In recent decades, repeated transmissions of avian influenza viruses (AIVs) from wild aquatic birds, their natural reservoir, have caused significant mortality in seals. Defining the molecular determinants of viral adaptation in marine mammals, and their implications for replication in human cells, is therefore essential. The non-structural protein 1 (NS1) of AIV, a key antagonist of the interferon (IFN) response, plays a central role in host adaptation. Here, we analyzed NS1 proteins from seal influenza viruses (H3, H4, H5, H7, and H10 subtypes) and their closest avian relatives isolated between 1980 and 2023, and evaluated their function in seal, avian, and human cells. Phylogenetic analysis confirmed multiple bird-to-seal transmission events. Seal-derived NS1 proteins generally contained few strain-specific amino acid substitutions and showed comparable expression and IFN antagonism to their avian precursors. A notable exception was the seal H10N7 virus isolated in 2014 in Northeastern Europe, which harbored three previously uncharacterized substitutions at NS1 amino acid residues 94, 104, and 171. These amino acid substitutions markedly altered NS1 properties to enhance protein stability, suppress IFN induction, mediate host transcription shut-off, and increase polymerase activity in human cells, without affecting NS1 expression or reducing virus replication in avian cells. Overall, these results reveal how NS1 undergoes host-specific functional evolution following avian-to-seal transmission and provide mechanistic insight into the adaptation of influenza A viruses to mammalian hosts.IMPORTANCEAvian influenza viruses (AIVs) circulate naturally in wild aquatic birds but occasionally infect mammals, including seals, where they can cause severe outbreaks. Seals are of particular concern because they can harbor both avian and human influenza viruses, creating opportunities for reassortment and the emergence of novel zoonotic strains. Understanding how AIVs adapt to mammalian hosts is therefore critical for anticipating and mitigating future influenza threats. Here, we investigated the role of the NS1 protein, a key viral factor that suppresses host immune responses, in seal-derived AIVs. Overall, NS1 expression and function were conserved across different subtypes and host cells. However, we identified unique amino acid substitutions in the NS1 of a seal H10N7 virus that enhanced protein stability, interferon antagonism, and viral adaptation in human cells. These findings illustrate how minor changes in NS1 protein can drive host adaptation and underscore the need for continued surveillance of AIVs in seals.
format Artículo científico
id pubmed_41874045
institution PubMed
language en
publishDate 2026
publisher Journal of virology
record_format pubmed
spellingShingle Host-specific functional evolution of seal influenza A virus NS1 protein following avian-to-seal transmission.
Kuryshko, Maryna
Luttermann, Christine
Bayoumi, Mahmoud
Mostafa, Ahmed
Weißmann, Jula
Schäfer, Alexander
Wendt, Lisa
Hoenen, Thomas
Müller, Jendrik
Martinez-Sobrido, Luis
Mettenleiter, Thomas C
Abdelwhab, Elsayed M
Viral Nonstructural Proteins
Animals
Influenza A virus
Humans
Birds
Host Specificity
Influenza in Birds
Phylogeny
Orthomyxoviridae Infections
Evolution, Molecular
Virus Replication
Influenza, Human
Amino Acid Substitution
Interferons
Host-specific functional evolution of seal influenza A virus NS1 protein following avian-to-seal transmission. Kuryshko, Maryna Luttermann, Christine Bayoumi, Mahmoud Mostafa, Ahmed Weißmann, Jula Schäfer, Alexander Wendt, Lisa Hoenen, Thomas Müller, Jendrik Martinez-Sobrido, Luis Mettenleiter, Thomas C Abdelwhab, Elsayed M Viral Nonstructural Proteins Animals Influenza A virus Humans Birds Host Specificity Influenza in Birds Phylogeny Orthomyxoviridae Infections Evolution, Molecular Virus Replication Influenza, Human Amino Acid Substitution Interferons Marine mammals, particularly seals, are susceptible to both avian and human influenza A viruses (IAVs), making them potential intermediates for zoonotic virus emergence. In recent decades, repeated transmissions of avian influenza viruses (AIVs) from wild aquatic birds, their natural reservoir, have caused significant mortality in seals. Defining the molecular determinants of viral adaptation in marine mammals, and their implications for replication in human cells, is therefore essential. The non-structural protein 1 (NS1) of AIV, a key antagonist of the interferon (IFN) response, plays a central role in host adaptation. Here, we analyzed NS1 proteins from seal influenza viruses (H3, H4, H5, H7, and H10 subtypes) and their closest avian relatives isolated between 1980 and 2023, and evaluated their function in seal, avian, and human cells. Phylogenetic analysis confirmed multiple bird-to-seal transmission events. Seal-derived NS1 proteins generally contained few strain-specific amino acid substitutions and showed comparable expression and IFN antagonism to their avian precursors. A notable exception was the seal H10N7 virus isolated in 2014 in Northeastern Europe, which harbored three previously uncharacterized substitutions at NS1 amino acid residues 94, 104, and 171. These amino acid substitutions markedly altered NS1 properties to enhance protein stability, suppress IFN induction, mediate host transcription shut-off, and increase polymerase activity in human cells, without affecting NS1 expression or reducing virus replication in avian cells. Overall, these results reveal how NS1 undergoes host-specific functional evolution following avian-to-seal transmission and provide mechanistic insight into the adaptation of influenza A viruses to mammalian hosts.IMPORTANCEAvian influenza viruses (AIVs) circulate naturally in wild aquatic birds but occasionally infect mammals, including seals, where they can cause severe outbreaks. Seals are of particular concern because they can harbor both avian and human influenza viruses, creating opportunities for reassortment and the emergence of novel zoonotic strains. Understanding how AIVs adapt to mammalian hosts is therefore critical for anticipating and mitigating future influenza threats. Here, we investigated the role of the NS1 protein, a key viral factor that suppresses host immune responses, in seal-derived AIVs. Overall, NS1 expression and function were conserved across different subtypes and host cells. However, we identified unique amino acid substitutions in the NS1 of a seal H10N7 virus that enhanced protein stability, interferon antagonism, and viral adaptation in human cells. These findings illustrate how minor changes in NS1 protein can drive host adaptation and underscore the need for continued surveillance of AIVs in seals.
title Host-specific functional evolution of seal influenza A virus NS1 protein following avian-to-seal transmission.
topic Viral Nonstructural Proteins
Animals
Influenza A virus
Humans
Birds
Host Specificity
Influenza in Birds
Phylogeny
Orthomyxoviridae Infections
Evolution, Molecular
Virus Replication
Influenza, Human
Amino Acid Substitution
Interferons
url https://pubmed.ncbi.nlm.nih.gov/41874045/