Defective Influenza A Virus RNA Products Mediate MAVS-Dependent Upregulation of Human Leukocyte Antigen Class I Proteins.
Influenza A virus (IAV) increases the presentation of class I human leukocyte antigen (HLA) proteins that limit antiviral responses mediated by natural killer (NK) cells, but molecular mechanisms for these processes have not yet been fully elucidated. We observed that infection with A/Fort Monmouth/1/1947(H1N1) IAV significantly increased the presentation of HLA-B, -C, and -E on lung epithelial cells. Virus entry was not sufficient to induce HLA upregulation because UV-inactivated virus had no effect. Aberrant internally deleted viral RNAs (vRNAs) known as mini viral RNAs (mvRNAs) and defective interfering RNAs (DI RNAs) expressed from an IAV minireplicon were sufficient for inducing HLA upregulation. These defective RNAs bind to retinoic acid-inducible gene I (RIG-I) and initiate mitochondrial antiviral signaling (MAVS) protein-dependent antiviral interferon (IFN) responses. Indeed, MAVS was required for HLA upregulation in response to IAV infection or ectopic mvRNA/DI RNA expression. The effect was partially due to paracrine signaling, as we observed that IAV infection or mvRNA/DI RNA-expression stimulated production of IFN-β and IFN-λ1 and conditioned media from these cells elicited a modest increase in HLA surface levels in naive epithelial cells. HLA upregulation in response to aberrant viral RNAs could be prevented by the Janus kinase (JAK) inhibitor ruxolitinib. While HLA upregulation would seem to be advantageous to the virus, it is kept in check by the viral nonstructural 1 (NS1) protein; we determined that NS1 limits cell-intrinsic and paracrine mechanisms of HLA upregulation. Taken together, our findings indicate that aberrant IAV RNAs stimulate HLA presentation, which may aid viral evasion of innate immunity.IMPORTANCE Human leukocyte antigens (HLAs) are cell surface proteins that regulate innate and adaptive immune responses to viral infection by engaging with receptors on immune cells. Many viruses have evolved ways to evade host immune responses by modulating HLA expression and/or processing. Here, we provide evidence that aberrant RNA products of influenza virus genome replication can trigger retinoic acid-inducible gene I (RIG-I)/mitochondrial antiviral signaling (MAVS)-dependent remodeling of the cell surface, increasing surface presentation of HLA proteins known to inhibit the activation of an immune cell known as a natural killer (NK) cell. While this HLA upregulation would seem to be advantageous to the virus, it is kept in check by the viral nonstructural 1 (NS1) protein, which limits RIG-I activation and interferon production by the infected cell.
['Rahim|Mir Munir A|MMA|', 'Parsons|Brendon D|BD|0000-0002-9255-0290', 'Price|Emma L|EL|', 'Slaine|Patrick D|PD|', 'Chilvers|Becca L|BL|', 'Seaton|Gregory S|GS|', 'Wight|Andrew|A|', 'Medina-Luna|Daniel|D|', 'Dey|Sayanti|S|', 'Grandy|Shannen L|SL|', 'Anderson|Lauryn E|LE|', 'Zamorano Cuervo|Natalia|N|', 'Grandvaux|Nathalie|N|', 'Gaglia|Marta M|MM|0000-0002-1791-0663', 'Kelvin|Alyson A|AA|', 'Khaperskyy|Denys A|DA|', 'McCormick|Craig|C|0000-0003-2794-3722', 'Makrigiannis|Andrew P|AP|']
D000072283:A549 Cells D048868:Adaptor Proteins, Signal Transducing D000071457:DEAD Box Protein 58 D030541:Databases, Genetic D004847:Epithelial Cells D005805:Genes, MHC Class I D006680:HLA Antigens D054884:Host-Pathogen Interactions D006801:Humans D007113:Immunity, Innate D053118:Influenza A Virus, H1N1 Subtype D009980:Influenza A virus D007251:Influenza, Human D007694:Killer Cells, Natural D008168:Lung D012367:RNA, Viral D015398:Signal Transduction D015533:Transcriptional Activation D017361:Viral Nonstructural Proteins D014779:Virus Replication
influenza A virus mvRNAs DI RNAs RIG-I MAVS interferon KIR NK cells class I HLA class I MHC