Fig. 4

E2 acts via the ER/miR-140 pathway to suppress IL-1β-mediated catabolic responses in chondrocytes. a Transfection efficiency of miR-140 inhibitor and miR-140 mimic in chondrocytes. Chondrocytes (2.5 × 10⁴ cells per well in a 24-well plate) were planted and transfected with miR-140 inhibitor, miR-140 mimic, and their negative controls (miR-Scr) up to 24 hr. b Relative MMP-13 mRNA in normal chondrocytes transfected with miR-140 inhibitor then stimulated with IL-1β (5 ng/ml) for 4 hr, then treated with 10 nM E2 for 24 hr. Inhibitor NC was set to one, as control. c Relative expression of MMP-13 in normal chondrocytes transfected with miR-140 mimic and pretreated with IL-1β (5 ng/ml) for 4 hr, then treated with 10 nM E2 for 24 hr. miR-scramble was set to one, as control. d Western blot of MMP-13 expression in normal chondrocytes transfected with miR-140 inhibitor or miR-140 mimic pretreated and untreated with IL-1β (5 ng/ml) for 4 hr, then treated with10 nM E2 for 24 hr. GAPDH was used as internal control. Data are represented as mean ± SEM. ^* P < 0.05, ^** P < 0.001. E2 17-β-estradiol, GAPDH glyceraldehyde 3-phosphate dehydrogenase, IL-1β interleukin-1 beta, MMP-13 metalloproteinase 13