In this study, we first tried to determine whether the expression level of 9 miRNAs in the peripheral blood CD8+ T cells of asthmatic patients varies from that of controls, and secondly, we investigated the effects of fluticasone furoate and vilanterol on the expression level of these miRNAs. Fifteen subjects including 8 healthy individuals and 7 asthmatic patients were included in this study. CD8+T cells were isolated from participants' peripheral blood by a negative selection method using magnetic-activated cell sorting (MACS). The expression of 9 miRNAs was examined between the healthy individuals and asthmatic patients. Then the expression level of 9 miRNAs before and after treatment with the drugs was examined by quantitative real-time PCR. No significant changes in the expression level of 9 miRNAs were observed in asthmatic patients compared to the healthy controls. Fluticasone and vilanterol, in combination, had the greatest effect on miRNA expression. MiR-150 and miR-106a were the most and the least miRNAs, respectively, present in CD8+ T cells of patients and controls. MiR-106a and miR-126 had a positive correlation in CD8+ cells of asthmatic patients. Although no significant difference in the expression level of studies miRNAs was observed, the correlations among miRNAs were significant. Therefore, we suggest that the correlation between miRNAs would be a very important factor in physiological and pathological conditions in healthy individuals and asthmatic patients. Such a miRNA-miRNA correlation network can be even more critical than any changes in the variation of their expression in the CD8+ T cells.
Keywords: CD8 T cells; Fluticasone furoate; MicroRNAs; Vilanterol.