Background: Estrogen deficiency is closely related to the development of menopausal arthritis. Estrogen replacement therapy (ERT) shows a protective effect against the osteoarthritis. However, the underlying mechanism of this protective effect is unknown. This study aimed to determine the role of miR-140 in the estrogen-dependent regulation of MMP-13 in human chondrocytes.
Methods: Primary human articular chondrocytes were obtained from female OA patients undergoing knee replacement surgery. Normal articular chondrocytes were isolated from the knee joints of female donors after trauma and treated with interleukin-1 beta (IL-1β). Gene expression levels of miR-140, MMP-13, and ADAMTS-5 were detected by quantitative real-time PCR (qRT-PCR). miR-140 levels were upregulated or downregulated by transfecting cells with a miRNA mimic and inhibitor, respectively, prior to treatment with IL-1β. MMP-13 expression was then evaluated by Western blotting and immunofluorescence. Luciferase reporter assays were performed to verify the interaction between miR-140 and ER.
Results: 17-β-estradiol (E2) suppressed MMP-13 expression in human articular chondrocytes. miR-140 expression was upregulated after estrogen treatment. Knockdown of miR-140 expression abolished the inhibitory effect of estrogen on MMP-13. In addition, the estrogen/ER/miR-140 pathway showed an inhibitory effect on IL-1β-induced cartilage matrix degradation.
Conclusions: This study suggests that estrogen acts via ER and miR-140 to inhibit the catabolic activity of proteases within the chondrocyte extracellular matrix. These findings provide new insight into the mechanism of menopausal arthritis and indicate that the ER/miR-140 signaling pathway may be a potential target for therapeutic interventions for menopausal arthritis.
Keywords: Estrogen; MMP-13; Menopausal arthritis; miR-140.