The silencing of JAK-1 gene did not fully affect the effects induced by TGF-β and IL-6. (A) JAK-1-siRNA efficiently knocked down JAK-1 molecule in RA-FLSs, and, after silencing, TGF-β + IL6 were unable to modulate the JAK-1 expression; qRT-PCR of JAK- 1 (JAK-1 mRNA expression in scr-siRNA untreated (UT)-RA-FLSs 0.027 (0.023–0.042) vs. JAK-1 mRNA expression in JAK-1-siRNA UT-RA-FLSs 0.00037 (0.00035–0.00050, p = 0.002), (JAK-1 mRNA expression in scr-siRNA UT-RA-FLSs 0.027 (0.023–0.042) vs. JAK-1 mRNA expression in scr-siRNA RA-FLSs treated with TGF-β + IL-6 0.0078 (0.0029–0.0093), p = 0.002). (B) In the RA-FLSs silenced with JAK-1-siRNA, TGF-β + IL-6 stimulation induced a more significant increase in collagen I than UT cells; collagen I (collagen I mRNA expression in JAK-1-siRNA UT-RA-FLSs 0.00031 (0.00030–0.00040) vs. collagen I mRNA expression in JAK-1-siRNA RA-FLSs treated with TGF-β + IL-6 0.00051 (0.00043–0.0025), p = 0.002; Collagen I mRNA expression in scr-siRNA UT-RA-FLSs 0.00021 (0.00013–0.00026) vs. collagen I mRNA expression in scr-siRNA RA-FLSs treated with TGF-β + IL-6 0.00048 (0.00042–0.00062), p = 0.002). (C) In the cells silenced with JAK-1-siRNA, the treatment with TGF-β + IL-6 promoted a significant decrease in E-Cad mRNA expression when compared to UT cells; E-Cad, (ECad mRNA expression in JAK-1-siRNA UT-RA-FLSs 8.98 × 10−5 (7.50 × 10−5–0.0001512) vs. E-Cad mRNA expression in JAK-1-siRNA RA-FLSs treated with TGF-β + IL-6 9.45 × 10−7 (2.02 × 10−8–6.52 × 10−6), p = 0.004; E-Cad mRNA expression in scr-siRNA UT-RA-FLSs 0.00045 (0.00040–0.00094) vs. E-Cad mRNA expression in scr-siRNA RA-FLSs treated with TGF-β + IL-6 7.03 × 10−7 (3.07 × 10−9–2.12 × 10−6), p = 0.004). (D) In scr-siRNA, TGF-β and IL-6 induced a significant increase in α-SMA mRNA levels. α-SMA; (α-SMA mRNA expression in scr-siRNA UT-RA-FLSs 0.020 (0.020–0.03) vs. α-SMA mRNA expression in scr-siRNA RA-FLSs treated with TGF-β + IL-6 0.036 (0.027–0.041), p = 0.04). The histogram showed median of triplicate experiments (* = p < 0.05 > 0.001; ** = p < 0.001).