MiR-204 enhances the progression of osteoarthritis by suppressing the production of IL-1β.

Recent studies suggest that cytokines and microRNAs play a key role in the destruction of cartilage matrix in osteoarthritis (OA) tissues. In the current study, we focused on miR-204, which has never been explored in OA. We found that the level of miR-204 was markedly reduced in the OA cartilage tissues compared with that of normal control. Real time PCR analysis demonstrated that the level of miR-204 was markedly decreased after IL-1β treatment for 3, 6, 12 h in the normal chondrocytes and OA chondrocytes, respectively. Furthermore, overexpression of miR-204 markedly suppressed the protein levels of IL-1β, COX-2 and IL6 in human OA chondrocytes and chondrogenic SW1353 cells. Dual luciferase reporter assay demonstrated that miR-204 significantly suppressed the relative luciferase activity of pmirGLO-IL-1β-3'UTR, indicating that IL-1β was a target gene of miR-204. More importantly, treatment with IL-1β significantly enhanced the protein levels of IL-1β, COX-2 and IL6. However, overexpression of miR-204 could partially abolish such effects. In conclusion, our data demonstrate that reduced miR-204 expression enhances the destruction of the cartilage tissues among OA patients mainly through targeting IL-1β.