Microarray analysis of microRNA expression in LPS induced inflammation of human middle ear epithelial cells (HMEECs)

Objectives: The primary aim of this study was to reveal the relationship between inflammatory response of human middle ear epithelial cell (HMEEC) and microRNA (miRNA).

Methods: In experimental group, cells were treated with lipopolysaccharide (LPS) for 2 h. No LPS was treated in the control group. Total RNA was extractedand used for miRNA microarray analysis. The predicted targets of miRNA with significant change were obtained using miRBase. To assess the function of predicted target gene lists, we evaluated the frequency of specific gene ontology (GO) terms among the predicted target genes of the miRNA with significant change using DAVID (Database for Annotation, Visualization and Integrated Discovery).

Results: After normalization, the number of the differentially expressed genes was 15. Among them, 5 miRNAs were up-regulated and 10 miRNAs were down-regulated in LPS group compared with control group. The most enriched GO terms in the predicted target genes of miRNA with increased expression were developmental process, response to biotic stimulus, acute inflammatory response, and regulation of cell growth. The most enriched GO terms in the predicted target genes of miRNA with decreased expression were developmental process, cell differentiation, endocytosis, cell communication, IκB kinase/NFκB cascade, complement activation, innate immune response and cell adhesion.

Conclusions: In conclusion, we identified the differentially expressed miRNA in LPS induced acute inflammation of HMEECs whose expression profile may provide a useful clue for the understanding of pathophysiology of otitis media. Our work indicates that miRNA play important role in the pathogenesis of otitis media.