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Influenza A virus (IAV) infections result in a large number of deaths and substantial economic losses each year. MicroRNAs repress gene expression and are involved in virus-host interactions. miR-29a is known to have anti-tumor and anti-fibrotic effects. However, the role of miR-29a in IAV infection is unclear. In the present study, we investigated the effect of miR-29a on IAV infection and the mechanisms by which it functions. IAV infection was found to cause decreased miR-29a expression in lung epithelial A549 cells and mouse lungs. Overexpression of miR-29a reduced IAV mRNA and protein levels and progeny virus production in HEK293 and A549 cells. Inhibition of IAV infection by miR-29a was observed with different strains of IAV, including A/PR/8/34, A/WSN/1933, and clinical isolates A/OK/3052/09 and A/OK/309/06 H3N2. Knockout of miR-29a using CRISPR/Cas9 resulted in an increase in viral mRNA and protein levels, confirming that miR-29a suppresses IAV infection. A 3' untranslated region (3'-UTR) reporter assay showed that miR-29a had binding sites in the 3'-UTR of the Wnt-Ca signaling receptor frizzled 5 gene, and overexpression of miR-29a reduced the level of the endogenous frizzled 5 protein. Wnt5a treatment of HEK293 and A549 cells enhanced IAV infection. Our results suggest that miR-29a inhibits IAV infection, probably via the frizzled 5 receptor.
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http://dx.doi.org/10.1007/s00705-020-04877-z | DOI Listing |
PLoS Pathog
September 2025
Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, State Key Laboratory of Pathogen and Biosecurity, Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun, China.
In this study, we identified a new chicken-specific protein, named chicken interferon-related antiviral protein (chIRAP) after sequence analysis and comparison, which inhibited the proliferation of various viruses including influenza A virus (IAV) and Newcastle Disease Virus (NDV) in vitro, and chicken embryos with high expression of chIRAP reduced IAV infection. Mass spectrometry analysis of chIRAP interacting proteins and screening of interacting proteins affecting the function of chIRAP revealed that the deletion of endogenous chicken peroxiredoxin 1 (chPRDX1) significantly reduced the antiviral effect of chIRAP. In order to clarify the functional site of chPRDX1 affecting the antiviral effect of chIRAP, we constructed the point mutants of chPRDX1 based on the results of molecular docking (D79A, T90A, K93A, Q94A, R110A, R123A), and screened the sites affecting the antiviral effects of chIRAP by knockdown of endogenous chPRDX1 combined with the overexpression mutant strategy, the results showed that the mutations in the sites affected the antiviral effects of chIRAP to different degrees, with D79A being the most significant, and the D79A mutation of chPRDX1 reduces the ability of chPRDX1 to regulate reactive oxygen species (ROS).
View Article and Find Full Text PDFPLoS Pathog
September 2025
Institute of Medical Virology, University of Zurich, Zurich, Switzerland.
SUMO-modified Tripartite Motif Protein 28 (TRIM28; KAP1) plays a crucial role in repressing endogenous retroelement (ERE) transcription. We previously provided evidence that loss of SUMO-modified TRIM28 triggered by influenza A virus (IAV) infection promotes activation of host antiviral immunity via a mechanism involving derepression of EREs and production of immunostimulatory RNAs. While the IAV NS1 protein might limit consequences of such activation via its dsRNA-binding activity, we hypothesized that other human pathogenic viruses could have evolved more direct strategies to counteract this potential ERE-based defense system.
View Article and Find Full Text PDFmSphere
September 2025
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
The ferret model is widely used to study influenza A viruses (IAVs) isolated from multiple avian and mammalian species, as IAVs typically replicate in the respiratory tract of ferrets without the need for prior host adaptation. During standard IAV risk assessments, tissues are routinely collected from ferrets at a fixed time point post-inoculation to assess the capacity for systemic spread. Here, we describe a data set of virus titers in tissues collected from both respiratory tract and extrapulmonary sites 3 days post-inoculation from over 300 ferrets inoculated with more than 100 unique IAVs (inclusive of H1, H2, H3, H5, H7, and H9 IAV subtypes, both mammalian and zoonotic origin).
View Article and Find Full Text PDFJ Virol
September 2025
Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan.
Double-stranded RNA (dsRNA), which induces an innate immune response against viral infections, is rarely detected in influenza A virus (IAV)-infected cells. Nevertheless, we previously reported that the influenza A viral ribonucleoprotein (vRNP) complex generates looped dsRNAs during RNA synthesis . This finding suggests that IAV possesses a specific mechanism for sequestering dsRNA within infected cells, thereby enabling viral evasion of the innate immune response.
View Article and Find Full Text PDFFront Cell Infect Microbiol
September 2025
Institute of Systems Biomedicine, Department of Immunology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, National Health Commission (NHC) Key Laboratory of Medical Immunology, Peking University Health Science Center, Beijing, China.
The innate immune system serves as the first line of defense against viral infections. Type I interferon (IFN-I) signaling, in particular, plays a crucial role in mediating antiviral immunity. Here, we identify Betrixaban (BT), a novel small-molecule compound that activates innate immune responses, leading to broad-spectrum antiviral effects.
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