Downregulation of miR-27a* and miR-532-5p and upregulation of miR-146a and miR-155 in LPS-induced RAW264.7 macrophage cells.

MicroRNAs (miRNAs) are short non-coding RNAs that are involved in the epigenetic regulation of cellular processes. To identify more miRNAs which are involved in the macrophage inflammatory response to lipopolysaccharide (LPS) stimulation and dissect the mechanisms more clearly, microRNA profiling of LPS-treated RAW264.7 macrophage cells was performed by initial high-throughput array-based screen and further real-time RT-PCR validation; bioinformatics approaches were used to analyze the target genes of the differentially expressed miRNAs. Compared to the untreated control, two microRNAs (miR-146a and miR-155) with more than twofold higher expression and two microRNAs (miR-27a* and miR-532-5p) with twofold lower expression were detected by array-based screen, which can be validated by qRT-PCR, and more than 1,000 candidate target genes were detected by at least of one of four different algorithms (TargetScan, PicTar, miRDB, and microRNA.org); with gene ontology classification, we were able to correlate the upregulation and downregulation of miRNA to the differential expression of inflammation-related candidate target gene during LPS-induced inflammation. Our findings may provide the basic information for the precise roles of miRNAs in the macrophage inflammatory response to LPS stimulation in the future.