Host microRNA molecular signatures associated with human H1N1 and H3N2 influenza A viruses

In this study, we performed a miRNA global profiling in human lung epithelial cells (A549) infected by two different subtypes of human influenza A viruses (H1N1 and H3N2). A549 cells were either mock-infected or infected at a multiplicity of infection (MOI) of 1 with H1N1 or H3N2 viruses, and total RNAs were isolated at 24 hours post-infection (hpi). An MOI of 1 was performed to ensure that 100% of the cells were infected at 24 hpi, a strategy that we have previously validated and used for a transcriptional profiling study of infected cells (Josset et al. , 2010). The purified RNAs were subjected to reverse transcription using a pool of miRNA RT primers (Human pool A v2.1, Applied Biosystems) and subsequently amplified and quantified by RT-qPCR in a TaqMan array MicroRNA card (Applied biosystems).