RESUMEN
Objective:To investigate the expression of miRNA-146a-5p and miRNA-155-5p in the plasma exosomes of patients with rheumatoid arthritis (RA) and their roles in the pathogenesis of RA.Methods:Plasma exosomes of 56 RA patients and 24 healthy controls were extracted with Qiagen exogenous extraction kit. Real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the expression of miRNA-146a-5p and miRNA-155-5p in exosomes using miRNA-451a as the internal control. The relative expression level was calculated by 2 -△△Ct method. Results:The relative expression of miRNA-146a-5p and miRNA-155-5p in exosomes of RA patients were significantly higher than those in healthy controls [13.662 (6.058, 30.801) vs 5.261 (2.453, 12.103), 33.354 (15.087, 275.309) vs 11.684 (1.551, 17.221), both P<0.05]. Moreover, their expression was also significantly higher in patients with active RA than in patients with inactive RA [27.542 (13.905, 87.017) vs 7.217 (5.218, 13.697), 155.110 (35.600, 437.745) vs 15.526 (10.628, 24.504), both P<0.05]. The levels of miRNA-146a-5p and miRNA-155-5p in plasma exosomes were positively correlated with 28-Joint Disease Activity Score (DAS28) using C-reactive protein (DAS28-CRP), DAS28 using erythrocyte sedimentation rate (DAS28-ESR), tender joint count (TJC) and swollen joint count (SJC). No significant difference in exosome concentration was found between the RA patients and healthy controls [660.381 (581.212, 807.308) μg/ml vs 675.897 (559.328, 752.316) μg/ml, P>0.05], or between patients with active or inactive RA [634.963 (561.095, 756.107) μg/ml vs 676.374 (589.167, 898.333) μg/ml, P>0.05]. Conclusions:Both miRNA-146a-5p and miRNA-155-5p were significantly highly expressed in plasma exosomes of RA patients, especially in patients with active RA, suggesting that miRNA-146a-5p and miRNA-155-5p in plasma exosomes might play important roles in the pathogenesis of RA and be related to disease activity.