Safflomin A inhibits neuraminidase activity and influenza virus replication

Neuraminidase (NA) is a glycoprotein on the surface of the influenza virus that plays an important role in the early processes of virus infection and viral release from the infected cells.

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Inhibitory effect of microalgae and cyanobacteria extracts on influenza virus replication and neuraminidase activity

Anais do VI Seminário Anual Científico e Tecnológico de Bio-Manguinhos ◽

10.35259/isi.sact.2018_27270 ◽

2018 ◽

Author(s):

Milene Miranda ◽

Thauane Silva ◽

Paulo Salomon ◽

Lidilhone Hamerski ◽

Fabiano Thompson ◽

...

Keyword(s):

Influenza Virus ◽

Virus Replication ◽

Inhibitory Effect ◽

Neuraminidase Activity ◽

Influenza Virus Replication

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The Microbiota Contributes to the Control of Highly Pathogenic H5N9 Influenza Virus Replication in Ducks

Journal of Virology ◽

10.1128/jvi.00289-20 ◽

2020 ◽

Vol 94 (10) ◽

Cited By ~ 1

Author(s):

Thomas Figueroa ◽

Pierre Bessière ◽

Amelia Coggon ◽

Kim M. Bouwman ◽

Roosmarijn van der Woude ◽

...

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Virus Replication ◽

Clinical Signs ◽

Influenza Viruses ◽

Highly Pathogenic ◽

Antiviral Immune Response ◽

Influenza Virus Replication

ABSTRACT Ducks usually show little or no clinical signs following highly pathogenic avian influenza virus infection. In order to analyze whether the microbiota could contribute to the control of influenza virus replication in ducks, we used a broad-spectrum oral antibiotic treatment to deplete the microbiota before infection with a highly pathogenic H5N9 avian influenza virus. Antibiotic-treated ducks and nontreated control ducks did not show any clinical signs following H5N9 virus infection. We did not detect any significant difference in virus titers neither in the respiratory tract nor in the brain nor spleen. However, we found that antibiotic-treated H5N9 virus-infected ducks had significantly increased intestinal virus excretion at days 3 and 5 postinfection. This was associated with a significantly decreased antiviral immune response in the intestine of antibiotic-treated ducks. Our findings highlight the importance of an intact microbiota for an efficient control of avian influenza virus replication in ducks. IMPORTANCE Ducks are frequently infected with avian influenza viruses belonging to multiple subtypes. They represent an important reservoir species of avian influenza viruses, which can occasionally be transmitted to other bird species or mammals, including humans. Ducks thus have a central role in the epidemiology of influenza virus infection. Importantly, ducks usually show little or no clinical signs even following infection with a highly pathogenic avian influenza virus. We provide evidence that the microbiota contributes to the control of influenza virus replication in ducks by modulating the antiviral immune response. Ducks are able to control influenza virus replication more efficiently when they have an intact intestinal microbiota. Therefore, maintaining a healthy microbiota by limiting perturbations to its composition should contribute to the prevention of avian influenza virus spread from the duck reservoir.

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Nuclear Factor 90 Negatively Regulates Influenza Virus Replication by Interacting with Viral Nucleoprotein

Journal of Virology ◽

10.1128/jvi.00735-09 ◽

2009 ◽

Vol 83 (16) ◽

pp. 7850-7861 ◽

Cited By ~ 52

Author(s):

Pui Wang ◽

Wenjun Song ◽

Bobo Wing-Yee Mok ◽

Pengxi Zhao ◽

Kun Qin ◽

...

Keyword(s):

Influenza Virus ◽

Viral Replication ◽

Virus Replication ◽

Early Phase ◽

Rna Binding ◽

Direct Interaction ◽

Mass Spectrometry Analysis ◽

Nuclear Factor ◽

Infected Cells ◽

Influenza Virus Replication

ABSTRACT Interactions between host factors and the viral replication complex play important roles in host adaptation and regulation of influenza virus replication. A cellular protein, nuclear factor 90 (NF90), was copurified with H5N1 viral nucleoprotein (NP) from human cells in which NP was transiently expressed and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis. In vitro coimmunoprecipitation of NF90 and NP coexpressed in HEK 293T cells or individually expressed in bacterial and HEK 293T cells, respectively, confirmed a direct interaction between NF90 and NP, independent of other subunits of the ribonucleoprotein complex. This interaction was prevented by a mutation, F412A, in the C-terminal region of the NP, indicating that the C-terminal of NP is required for NF90 binding. RNase V treatment did not prevent coprecipitation of NP and NF90, which demonstrates that the interaction is RNA binding independent. After small interfering RNA knockdown of NF90 expression in A549 and HeLa cells, viral polymerase complex activity and virus replication were significantly increased, suggesting that NF90 negatively affects viral replication. Both NP and NF90 colocalized in the nucleus of virus-infected cells during the early phase of infection, suggesting that the interaction between NF90 and NP is an early event in virus replication. Quantitative reverse transcription-PCR showed that NF90 downregulates both viral genome replication and mRNA transcription in infected cells. These results suggest that NF90 inhibits influenza virus replication during the early phase of infection through direct interaction with viral NP.

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The Intestinal Microbiota Contributes to the Control of Highly Pathogenic H5N9 Influenza Virus Replication in Ducks

10.1101/778258 ◽

2019 ◽

Author(s):

Thomas Figueroa ◽

Pierre Bessière ◽

Amelia Coggon ◽

Roosmarijn van der Woude ◽

Maxence Delverdier ◽

...

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Virus Replication ◽

Intestinal Microbiota ◽

Clinical Signs ◽

Influenza Viruses ◽

Highly Pathogenic ◽

Influenza Virus Replication

ABSTRACTDucks usually show little or no clinical signs following highly pathogenic avian influenza virus infection. In order to analyze if the gut microbiota could contribute to the control of influenza virus replication in ducks, we used a broad-spectrum oral antibiotic treatment to deplete the gut microbiota before infection with a highly pathogenic H5N9 avian influenza virus. Antibiotic-treated ducks and non-treated control ducks did not show any clinical signs following H5N9 virus infection. We did not detect any difference in virus titers neither in the respiratory tract, nor in the brain and spleen. However, we found that antibiotic-treated H5N9 virus infected ducks had significantly increased intestinal virus excretion at day 3 and 5 post-infection. This was associated with a significantly decreased antiviral immune response in the intestine of antibiotic-treated ducks. Our findings highlight the importance of an intact microbiota for an efficient control of avian influenza virus replication in ducks.IMPORTANCEDucks are frequently infected with avian influenza viruses belonging to multiple subtypes. They represent an important reservoir species of avian influenza viruses, which can occasionally be transmitted to other bird species or mammals, including humans. Ducks thus have a central role in the epidemiology of influenza virus infection. Importantly, ducks usually show little or no clinical signs even following infection with a highly pathogenic avian influenza virus. We provide evidence that the intestinal microbiota contributes to the control of influenza virus replication in ducks by modulating the antiviral immune response. Ducks are able to control influenza virus replication more efficiently when they have an intact intestinal microbiota. Therefore, maintaining a healthy microbiota by limiting perturbations to its composition should contribute to prevention of avian influenza virus spread from the duck reservoir.

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An A14U Substitution in the 3′ Noncoding Region of the M Segment of Viral RNA Supports Replication of Influenza Virus with an NS1 Deletion by Modulating Alternative Splicing of M Segment mRNAs

Journal of Virology ◽

10.1128/jvi.00919-15 ◽

2015 ◽

Vol 89 (20) ◽

pp. 10273-10285 ◽

Cited By ~ 7

Author(s):

Min Zheng ◽

Pui Wang ◽

Wenjun Song ◽

Siu-Ying Lau ◽

Siwen Liu ◽

...

Keyword(s):

Influenza Virus ◽

Alternative Splicing ◽

Virus Replication ◽

Viral Proteins ◽

Influenza Viruses ◽

Noncoding Region ◽

Ns1 Protein ◽

Functional Studies ◽

Infected Cells ◽

Influenza Virus Replication

ABSTRACTThe NS1 protein of influenza virus has multiple functions and is a determinant of virulence. Influenza viruses with NS1 deletions (DelNS1 influenza viruses) are a useful tool for studying virus replication and can serve as effective live attenuated vaccines, but deletion of NS1 severely diminishes virus replication, hampering functional studies and vaccine production. We found that WSN-DelNS1 viruses passaged in cells consistently adapted to gain an A14U substitution in the 3′ noncoding region of the M segment of viral RNA (vRNA) which restored replicative ability. DelNS1-M-A14U viruses cannot inhibit interferon expression in virus infected-cells, providing an essential model for studying virus replication in the absence of the NS1 protein. Characterization of DelNS1-M-A14U virus showed that the lack of NS1 has no apparent effect on expression of other viral proteins, with the exception of M mRNAs. Expression of the M transcripts, M1, M2, mRNA3, and mRNA4, is regulated by alternative splicing. The A14U substitution changes the splicing donor site consensus sequence of mRNA3, altering expression of M transcripts, with M2 expression significantly increased and mRNA3 markedly suppressed in DelNS1-M-A14U, but not DelNS1-M-WT, virus-infected cells. Further analysis revealed that the A14U substitution also affects promoter function during replication of the viral genome. The M-A14U mutation increases M vRNA synthesis in DelNS1 virus infection and enhances alternative splicing of M2 mRNA in the absence of other viral proteins. The findings demonstrate that NS1 is directly involved in influenza virus replication through modulation of alternative splicing of M transcripts and provide strategic information important to construction of vaccine strains with NS1 deletions.IMPORTANCENonstructural protein (NS1) of influenza virus has multiple functions. Besides its role in antagonizing host antiviral activity, NS1 is also believed to be involved in regulating virus replication, but mechanistic details are not clear. The NS1 protein is a virulence determinant which inhibits both innate and adaptive immunity and live attenuated viruses with NS1 deletions show promise as effective vaccines. However, deletion of NS1 causes severe attenuation of virus replication during infection, impeding functional studies and vaccine development. We characterized a replication-competent DelNS1 virus which carries an A14U substitution in the 3′ noncoding region of the vRNA M segment. We found that M-A14U mutation supports virus replication through modulation of alternative splicing of mRNAs transcribed from the M segment. Our findings give insight into the role of NS1 in influenza virus replication and provide an approach for constructing replication-competent strains with NS1 deletions for use in functional and vaccine studies.

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