Comprehensive miRNA expression profiles in the ilea of Lawsonia intracellularis-infected pigs

To analyze the miRNA expression profiles in Lawsonia intracellularis-infected porcine intestines, infected pigs were first identified using PCR (Polymerase Chain Reaction). Then, RNA from infected intestines and control tissues were isolated and subjected to microarray analysis and RT-PCR. Results showed that a total of 83 miRNAs were differentially expressed between the infected samples and controls, out of which 53 were upregulated and 30 were downregulated. Validation using RT-PCR showed a high degree of confidence for the obtained data. Using the current miRBase release 21.0, nine groups of miRNAs were located in the same cluster, and three groups of miRNAs were found to belong to the same family. Interestingly, except for ssc-miR-10a-5p, all clustered miRNAs and the family members exhibited the same expression patterns. Pathway analysis of the putative gene targets of the differentially expressed miRNAs showed that they were involved in the immune response, amino acid metabolism and cell communication/growth/motility. Thus, the results indicate that altered miRNA expression profiles can affect immunity, metabolism and cellular processes.