Background/Purpose:

The altered expression of cellular miRNAs in the immune and resident cells involved in the pathogenesis of rheumatoid arthritis (RA) has been shown to contribute to the maintenance of pathognomic features typical of RA. Differential levels of circulating miRNAs in plasma were reported between patients with RA and osteoarthritis. Our aim was to analyze the effect of therapy on levels of circulating miRNAs in sera of patients with early RA (ERA).

Methods:

Sera were obtained from patients with ERA (n=34, disease duration <8 months, fulfilling 2010 EULAR/ACR criteria) at baseline and correspondingly after 3 (M3) and 12 (M12) months therapy with disease modifying antirheumatic drugs (DMARDs, methotrexate n=28, sulphasalazine n=4, leflunomide n=1) and glucocorticoids (n=30). In addition, sera were obtained also from patients with established RA (estRA, n=28, disease duration 9.28±6.52 years, fulfilling 1987 revised ACR criteria) treated with DMARDs (methotrexate n=14, sulphasalazine n=2, leflunomide n=8), glucocorticoids (n=6) or biologics (n=19). Total RNA was isolated using phenol-chloroform extraction and the levels of RA-associated miR-155, 223, 16, 146a, 132, 203 and 124a were analyzed using specific primers by TaqMan Real-Time PCR. dCt method was used for relative quantification using let-7a as a normalization control (with a detection limit at Ct= 40).

Results:

MiR-155 in sera of treatment naïve ERA patients showed significantly lower levels than in patients with estRA (dCt -6.31±1.05 v.s. -4.68±1.86, p<0.001). Treatment in ERA did not change the levels of miR-155 at M3 (dCt -6.13±1.62) or M12 (dCt -6.99±1.54). Interestingly, levels of miR-155 dropped below the detection limit in 14 ERA patients at M12. Levels of miR-223 were comparable between treatment naïve ERA and estRA (dCt 5.67±1.04 vs. 6.23±1.45) and did not change after M3 following treatment initiation in ERA (dCt 5.12±0.91). Most impressively, miR-223 in ERA showed significantly lower levels at M12 (dCt 4.34±0.78) in comparison with baseline (p<0.001) as well as M3 (p<0.01).  MiR-16 was found at significantly lower levels in treatment naïve ERA patients compared with estRA (dCt 4.93±0.91 v.s. 6.10±1.22, p<0.001). During treatment levels of miR-16 in ERA did not change after 3 months (M3: dCt 5.71±1.27) but they significantly decreased after 12 months (M12: dCt 3.85±1.37 in comparison with baseline (p<0.05) and M3 (p<0.001). The levels of miR-146a were significantly lower in ERA sera in comparison with estRA (dCt 0.44±0.93 v.s. 1.20±1.00, p<0.01) but were not changed upon treatment in ERA (dCt 0.50±0.64 at M3, 0.02±1.97 at M12 respectively). The levels of miR-132 in ERA before treatment were comparable with estRA (dCt -4.31±0.90 v.s. -3.76±1.07) and were not affected by therapy over time (dCt -4.47±0.0.91 at M3, -4.94±1.83 at M12, 4 were undetectable).  MiR-124a and miR-203 in sera were present in negligible amounts close to the detection limit and were therefore excluded from further analysis.

Conclusion:

We show here that the levels of circulating miRNA-16 and -223 are changed upon therapy such as MTX combined with glucocorticoids in patients with ERA after 12 months suggesting miRNAs as potential biomarkers in ERA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/levels-of-circulating-mirnas-before-and-after-12-months-therapy-with-dmards-in-patients-with-early-rheumatoid-arthritis/