Upregulated Expression of microRNA-16 Correlates with Th17/Treg Cell Imbalance in Patients with Rheumatoid Arthritis

To explore the correlation between miR-16 expression in T cells of peripheral blood mononuclear cells (PBMCs) and Th17/Treg imbalance in rheumatoid arthritis (RA) patients. Forty RA patients were recruited as the case group and further grouped as active RA and inactive RA groups; 21 healthy individuals were selected as the control group. Th17 and Treg were measured by flow cytometry, and their related cytokines were measured by FlowCytomix. RORt, FoxP3 mRNA, and miR-16 expression in T cells was determined by real-time quantitative polymerase chain reaction. Western blotting was performed to measure RORt and FoxP3 protein expression. RA patients showed upregulated Th17 and RORt mRNA and protein expression compared with the controls (all p<0.05); active RA patients showed lower Treg and FoxP3 mRNA and protein expression compared with inactive RA patients and controls (all p<0.05). Secretion levels of Th17-related cytokines were higher in active RA patients than in inactive RA patients and controls (all p<0.05); whereas those of Treg-related cytokines were lower in active RA patients than in controls (all p<0.05). Active RA patients showed increased miR-16 expression in Th17 cells and decreased miR-16 expression in Treg cells of PBMCs (both p<0.05). Pearson's test showed that in the PBMCs of the RA patients, miR-16 expression in the Th17 cells was positively related with RORt mRNA expression, and miR-16 expression in the Treg cells was positively related with FoxP3 mRNA expression (both p<0.05). The expression of miR-16 in Th17 and Treg cells of PBMCs in RA patients was closely associated with the expression of RORt and FoxP3. MiR-16 may be involved in Th17/Treg imbalance of RA patients by affecting the expression of RORt and FoxP3.