Microarray Analysis Of Microrna Expression In Peripheral Blood Mononulear Cells Of Critically ILL Patients With Influenza A (H1N1)

Influenza A virus, being responsible for epidemics and reoccurring pandemics, represents a worldwide threat to public health and global economy. Comprehensively understanding the molecular mechanisms of complex host and virus interactions can facilitate the development of a novel generation of drugs that target host cell factors. MicroRNAs (miRNAs) are small (~22 nucleotides long), single-stranded non-coding RNAs that mediate posttranscriptional silencing of target genes. The role of microRNA has been highlighted in pathogen-host interactions recently. On the one hand, cellular miRNAs could be involved in regulating the molecular pathways of innate and adaptive immune responses and may act as an antiviral defense mechanism or even inhibit virus replication directly. On the other hand, cellular miRNAs may be used by viruses for their own advantage. For influenza virus, differential expression of cellular miRNAs have been found both in avian influenza virus infected chickens and reconstructed 1918 influenza virus infected mice. However, to the best of our knowledge, investigations relevant to miRNAs from patients infected with influenza virus are still lacking.In this study, eleven H1N1 critically ill patients with no underlying diseases like cancers were included. To identify cellular miRNAs involved in the host response to influenza virus infection, Agilent's human miRNA microarrays were used to compare the expression profiles of peripheral blood mononuclear cells (PBMCs) from critically ill patients (n=5) and healthy controls (n=3). Fifty significantly differentially expressed miRNAs were found which may be highly associated with influenza infection. Four miRNAs (hsa-miR-146b-5p, hsa-miR-148a, hsa-miR-150, hsa-miR-31) were comparatively performed for quantitative Taqman Real Time PCR assays from H1N1 critically ill patient (n=11) and healthy control (n=13) samples. Expression level of the small nuclear RNU44 was used as the normalization control. Pearson correlation test with a calculated R~2 value of 0.865 indicated high correlation between the results obtained from microRNA microarrays and those obtained from qRT-PCR. After we expanded the samples, miR-148a, miR-31 and miR-150 were proved to be significantly differentially expressed, while miR-146b-5p has no statistically difference.We subsequently used different algorithms for miRNA target prediction and got experimentally validated targets genes data of these 50 differentially expressed miRNAs. We also generated a comprehensive human-influenza protein-protein interaction database by combining information from published literatures and public databases. We then integrated these data together and constructed an integrative network of miRNA mediated host-influenza virus protein interactions, from which we found miRNAs were involved in regulating important pathways, such as MAPK signaling pathway, EGFR signaling pathway, Toll-like receptor signaling pathway and chemokine signal pathway during influenza virus infection. Further understanding of the roles of these miRNAs in influenza virus infection will provide new insight into the host pathogen interactions.