The role of extracellular vesicle miRNA released in response to influenza A virus

Influenza is a major cause of human disease and mortality and a key cause of exacerbation in chronic disease like COPD. Recent studies have shown that airway epithelial cells, the primary target of influenza, release lipid bilayer particles known as Extracelluar vesicles (EVs) which contain biological molecules such as micro-RNA (miRNA). Emerging evidence suggests that these small non-coding RNA molecules are selectively packaged into EVs and can regulate recipient cell gene expression including major pathways involved in inflammation and fibrosis. Further understanding the role of EVs and their miRNA cargo in cellular communication in response to infection may identify biomarkers of disease or lead to novel theraputics. This study utilised a 3D model of IAV infection to explore the impact of IAV on the miRNA profile of EVs released from bronchial epithelial cells in vitro. Infection with IAV at 3.6 x 106 IU/ml for 24 hours was determined to be a suitable condition for EV analyses due to the detection of significant upregulation of anti-viral genes without high levels of cell death or loss of barrier integrity. miRNA-seq profiling of EVs isolated from the apical wash of ALI differentiated BCi-NS1.1 cells. Samples were either uninfected (n=5) or IAV infected at 3,600,000 IU/ml for 24 hours (n=5).