Regulated neutrophil microRNAs target multiple pathways, potentially downregulating neutrophil proinflammatory functions.

Total RNA from either freshly isolated neutrophils or those in culture for 1 or 4 hours was prepared (purity 97.8%±0.26; apoptosis rates at 20 hours 73.55%±3.39; n = 3) and were analysed for microRNA expression by microarray. Genes potentially regulated by the upregulated microRNAs were downloaded from www.miRecords.com, and compared with those genes shown to be regulated over time. Genes within both datasets that were potentially regulated by at least 2 of the 6 regulated microRNAs were selected and pathway analysis performed. Pathway analysis of the downregulated genes with at least 2 predicted microRNA binding sites at http://david.abcc.ncifcrf.gov/tools.jsp[35], revealed a significant enrichment (EASE Score p<0.05) of genes involved regulation of inflammation mediated by chemokine and cytokine signalling, the Ras pathway, and the regulation of the actin cytoskeleton.