scholarly journals ILDR1 Promotes Influenza a Virus Replication Through Binding to PLSCR1

2021 ◽  
Author(s):  
Yueyue Liu ◽  
Shuqian Lin ◽  
Yunhui Xie ◽  
Lu Zhao ◽  
Haibo Du ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Vital Role ◽  
Host Interactions ◽  
Phospholipid Scramblase ◽  
Antiviral Function ◽  
Siv Infection ◽  
Infected Cells

Abstract As a natural antiviral regulator, phospholipid scramblase 1 (PLSCR1) has been shown to inhibit influenza virus replication in infected cells through interacting with NP of influenza A virus (IAV). But its antiviral function as well as the underlying regulatory mechanism has not been examined in vivo. In the present work, we show that PLSCR1 expression is decreased in H1N1 SIV-infected mice, and Plscr1−/−mice are more susceptible to H1N1 SIV infection. By performing yeast two-hybrid screening, we identified immunoglobulin-like domain-containing receptor 1 (ILDR1) as a novel PLSCR1-binding partner. ILDR1 is highly expressed in the lungs, and its expression level is increased after virus infection. Interestingly, ILDR1 could not directly interact with virus NP protein, but could combine with PLSCR1 competitively. Our data indicates that there is a previously unidentified PLSCR1-ILDR1-NP regulatory pathway playing a vital role in limiting IAV infection, which provides novel insights into IAV-host interactions.

scholarly journals Novel Mode of ISG15-Mediated Protection against Influenza A Virus and Sendai Virus in Mice

2014 ◽  
Vol 89 (1) ◽  
pp. 337-349 ◽  
Author(s):  
David J. Morales ◽  
Kristen Monte ◽  
Lulu Sun ◽  
Jessica J. Struckhoff ◽  
Eugene Agapov ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Virus Infection ◽  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Type I ◽  
Induced Genes

ABSTRACTISG15 is a diubiquitin-like modifier and one of the most rapidly induced genes upon type I interferon stimulation. Hundreds of host proteins and a number of viral proteins have been shown to be ISGylated, and understanding how these modifications affect the interferon response and virus replication has been of considerable interest. ISG15−/−mice exhibit increased susceptibility to viral infection, and in the case of influenza B virus and vaccinia virus, ISG15 conjugation has been shown to restrict virus replicationin vivo. A number of studies have also found that ISG15 is capable of antagonizing replication of some viruses in tissue culture. However, recent findings have demonstrated that ISG15 can protect mice from Chikungunya virus infection without affecting the virus burden. In order to better understand the function of ISG15in vivo, we characterized the pathogenesis of influenza A virus and Sendai virus in ISG15−/−mice. We found that ISG15 protects mice from virus induced lethality by a conjugation-dependent mechanism in both of these models. However, surprisingly, we found that ISG15 had minimal effect on virus replication and did not have an obvious role in the modulation of the acute immune response to infection. Instead, we observed an increase in the number of diseased small airways in mice lacking ISG15. This ability of ISG15 to protect mice in a conjugation-dependent, but nonantiviral, manner from respiratory virus infection represents a previously undescribed role for ISG15 and demonstrates the importance of further characterization of ISG15in vivo.IMPORTANCEIt has previously been demonstrated that ISG15−/−mice are more susceptible to a number of viral infections. Since ISG15 is one of the most strongly induced genes after type I interferon stimulation, analysis of ISG15 function has largely focused on its role as an antiviral molecule during acute infection. Although a number of studies have shown that ISG15 does have a small effect on virus replication in tissue culture, few studies have confirmed this mechanism of protectionin vivo. In these studies we have found that while ISG15−/−mice are more susceptible to influenza A virus and Sendai virus infections, ISGylation does not appear to mediate this protection through the direct inhibition of virus replication or the modulation of the acute immune response. Thus, in addition to showing a novel mode of ISG15 mediated protection from virus infection, this study demonstrates the importance of studying the role of ISG15in vivo.

scholarly journals Engineered Small-Molecule Control of Influenza A Virus Replication

2018 ◽  
Vol 93 (1) ◽  
Author(s):  
Elizabeth J. Fay ◽  
Stephanie L. Aron ◽  
Ian A. Stone ◽  
Barbara M. Waring ◽  
Richard K. Plemper ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Small Molecule ◽  
Human Population ◽  
Influenza A ◽  
Health Concern ◽  
Highly Pathogenic ◽  
Significant Safety

ABSTRACT Influenza A virus (IAV) remains a global health concern despite the availability of a seasonal vaccine. It is difficult to predict which strains will circulate during influenza season, and therefore, it is extremely challenging to test novel vaccines in the human population. To overcome this obstacle, new vaccines must be tested in challenge studies. This approach poses significant safety problems, since current pharmacological interventions for IAV are poorly efficacious. New methods are needed to enhance the safety of these challenge studies. In this study, we have generated a virus expressing a small-molecule-assisted shutoff (SMASh) tag as a safety switch for IAV replication. The addition of the SMASh tag to an essential IAV protein allows for small-molecule-mediated inhibition of replication. Treatment with this drug controls the replication of a SMASh-tagged virus in vitro and in vivo. This model for restriction of viral replication has potential for broad applications in vaccine studies, virotherapy, and basic virus research. IMPORTANCE Influenza A virus (IAV) causes significant morbidity and mortality annually worldwide, despite the availability of new formulations of the vaccine each season. There is a critical need to develop more-efficacious vaccines. However, testing novel vaccines in the human population in controlled studies is difficult due to the limited availability and efficacy of intervention strategies should the vaccine fail. There are also significant safety concerns for work with highly pathogenic IAV strains in the laboratory. Therefore, novel strategies are needed to improve the safety of vaccine studies and of research on highly pathogenic IAV. In this study, we developed an IAV strain engineered to contain a small-molecule-mediated safety switch. This tag, when attached to an essential viral protein, allows for the regulation of IAV replication in vitro and in vivo. This strategy provides a platform for the regulation of virus replication without targeting viral proteins directly.

scholarly journals Prevailing PA Mutation K356R in Avian Influenza H9N2 Virus Increases Mammalian Replication and Pathogenicity

2016 ◽  
Vol 90 (18) ◽  
pp. 8105-8114 ◽  
Author(s):  
Guanlong Xu ◽  
Xuxiao Zhang ◽  
Weihua Gao ◽  
Chenxi Wang ◽  
Jinliang Wang ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
H9n2 Virus ◽  
Nuclear Accumulation ◽  
Adaptive Mutation ◽  
Viral Polymerase ◽  
Polymerase Complex

ABSTRACTAdaptation of the viral polymerase complex comprising PB1, PB2, and PA is necessary for efficient influenza A virus replication in new host species. We found that PA mutation K356R (PA-K356R) has become predominant since 2014 in avian H9N2 viruses in China as with seasonal human H1N1 viruses. The same mutation is also found in most human isolates of emergent avian H7N9 and H10N8 viruses whose six internal gene segments are derived from the H9N2 virus. We further demonstrated the mammalian adaptive functionality of the PA-K356R mutation. Avian H9N2 virus with the PA-K356R mutation in human A549 cells showed increased nuclear accumulation of PA and increased viral polymerase activity that resulted in elevated levels of viral transcription and virus output. The same mutant virus in mice also enhanced virus replication and caused lethal infection. In addition, combined mutation of PA-K356R and PB2-E627K, a well-known mammalian adaptive marker, in the H9N2 virus showed further cooperative increases in virus production and severity of infectionin vitroandin vivo. In summary, PA-K356R behaves as a novel mammalian tropism mutation, which, along with other mutations such as PB2-E627K, might render avian H9N2 viruses adapted for human infection.IMPORTANCEMutations of the polymerase complex (PB1, PB2, and PA) of influenza A virus are necessary for viral adaptation to new hosts. This study reports a novel and predominant mammalian adaptive mutation, PA-K356R, in avian H9N2 viruses and human isolates of emergent H7N9 and H10N8 viruses. We found that PA-356R in H9N2 viruses causes significant increases in virus replication and severity of infection in human cells and mice and that PA-K356R cooperates with the PB2-E627K mutation, a well-characterized human adaptive marker, to exacerbate mammalian infectionin vitroandin vivo. Therefore, the PA-K356R mutation is a significant adaptation in H9N2 viruses and related H7N9 and H10N8 reassortants toward human infectivity.

scholarly journals Identification of a Novel Viral Protein Expressed from the PB2 Segment of Influenza A Virus

2015 ◽  
Vol 90 (1) ◽  
pp. 444-456 ◽  
Author(s):  
Seiya Yamayoshi ◽  
Mariko Watanabe ◽  
Hideo Goto ◽  
Yoshihiro Kawaoka
Keyword(s):  
Influenza Virus ◽  
Influenza A Virus ◽  
Viral Protein ◽  
Influenza A ◽  
Viral Infections ◽  
Viral Proteins ◽  
Wild Type Virus ◽  
Infected Cells

ABSTRACTOver the past 2 decades, several novel influenza virus proteins have been identified that modulate viral infectionsin vitroand/orin vivo. The PB2 segment, which is one of the longest influenza A virus segments, is known to encode only one viral protein, PB2. In the present study, we used reverse transcription-PCR (RT-PCR) targeting viral mRNAs transcribed from the PB2 segment to look for novel viral proteins encoded by spliced mRNAs. We identified a new viral protein, PB2-S1, encoded by a novel spliced mRNA in which the region corresponding to nucleotides 1513 to 1894 of the PB2 mRNA is deleted. PB2-S1 was detected in virus-infected cells and in cells transfected with a protein expression plasmid encoding PB2. PB2-S1 localized to mitochondria, inhibited the RIG-I-dependent interferon signaling pathway, and interfered with viral polymerase activity (dependent on its PB1-binding capability). The nucleotide sequences around the splicing donor and acceptor sites for PB2-S1 were highly conserved among pre-2009 human H1N1 viruses but not among human H1N1pdm and H3N2 viruses. PB2-S1-deficient viruses, however, showed growth kinetics in MDCK cells and virulence in mice similar to those of wild-type virus. The biological significance of PB2-S1 to the replication and pathogenicity of seasonal H1N1 influenza A viruses warrants further investigation.IMPORTANCETranscriptome analysis of cells infected with influenza A virus has improved our understanding of the host response to viral infection, because such analysis yields considerable information about bothin vitroandin vivoviral infections. However, little attention has been paid to transcriptomes derived from the viral genome. Here we focused on the splicing of mRNA expressed from the PB2 segment and identified a spliced viral mRNA encoding a novel viral protein. This result suggests that other, as yet unidentified viral proteins encoded by spliced mRNAs could be expressed in virus-infected cells. A viral transcriptome including the viral spliceosome should be evaluated to gain new insights into influenza virus infection.

scholarly journals Live Visualization of Hemagglutinin Dynamics during Infection by Using a Novel Reporter Influenza A Virus

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 687
Author(s):  
Luiz Gustavo dos Anjos Borges ◽  
Giuseppe Pisanelli ◽  
Oyahida Khatun ◽  
Adolfo García-Sastre ◽  
Shashank Tripathi
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Immunofluorescence Assay ◽  
Confocal Imaging ◽  
Host Interactions ◽  
Chemical Inhibitors ◽  
Versatile Tool ◽  
Infected Cells ◽  
Ha Protein ◽  
In Cells

Live visualization of influenza A virus (IAV) structural proteins during viral infection in cells is highly sought objective to study different aspects of the viral replication cycle. To achieve this, we engineered an IAV to express a Tetra Cysteine tag (TC tag) from hemagglutinin (HA), which allows intracellular labeling of the engineered HA protein with biarsenic dyes and subsequent fluorescence detection. Using such constructs, we rescued a recombinant IAV with TC tag inserted in HA, in A/Puerto Rico/8/1934(H1N1) background (HA-TC). This recombinant HA-TC tag reporter IAV was replication-competent; however, as compared to wild type PR8 IAV, it was attenuated in multicycle replication. We confirmed expression of TC tag and biarsenical labeling of HA by immunofluorescence assay in cells infected with an HA-TC tag reporter IAV. Further, we used this reporter virus to visualize HA expression and translocation in IAV infected cells by live confocal imaging. We also tested the utility of the HA-TC IAV in testing chemical inhibitors of the HA translocation. Overall, HA-TC IAV is a versatile tool that will be useful for studying viral life cycle events, virus-host interactions, and anti-viral testing.

scholarly journals Palmitoylation of the Influenza A Virus M2 Protein Is Not Required for Virus Replication In Vitro but Contributes to Virus Virulence

2009 ◽  
Vol 83 (17) ◽  
pp. 8655-8661 ◽  
Author(s):  
Michael L. Grantham ◽  
Wai-Hong Wu ◽  
Erin N. Lalime ◽  
Maria E. Lorenzo ◽  
Sabra L. Klein ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Mdck Cells ◽  
Cysteine Residue ◽  
M2 Protein ◽  
Recombinant Viruses ◽  
Virus Particles

ABSTRACT The influenza A virus M2 protein has important roles during virus entry and in the assembly of infectious virus particles. The cytoplasmic tail of the protein can be palmitoylated at a cysteine residue, but this residue is not conserved in a number of human influenza A virus isolates. Recombinant viruses encoding M2 proteins with a serine substituted for the cysteine at position 50 were generated in the A/WSN/33 (H1N1) and A/Udorn/72 (H3N2) genetic backgrounds. The recombinant viruses were not attenuated for replication in MDCK cells, Calu-3 cells, or in primary differentiated murine trachea epithelial cell cultures, indicating there was no significant contribution of M2 palmitoylation to virus replication in vitro. The A/WSN/33 M2C50S virus displayed a slightly reduced virulence after infection of mice, suggesting that there may be novel functions for M2 palmitoylation during in vivo infection.

scholarly journals In vivo inhibition of influenza A virus replication by RNA interference targeting the PB2 subunit via intratracheal delivery

PLoS ONE ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. e0174523 ◽  
Author(s):  
Daniel Tsung-Ning Huang ◽  
Chun-Yi Lu ◽  
Pei-Lan Shao ◽  
Luan-Yin Chang ◽  
Jin-Yuan Wang ◽  
...  
Keyword(s):  
Rna Interference ◽  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Intratracheal Delivery
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