MiR-125b Inhibits LPS-Induced Inflammatory Injury via Targeting MIP-1α in Chondrogenic Cell ATDC5.

BACKGROUND/AIMS: Chondrocyte apoptosis is largely responsible for cartilage degeneration in osteoarthritis (OA). MicroRNAs (miRNAs) play an important role in chondrogenesis and cartilage remodeling. This study explored the effect of miR-125b on inflammatory injury in chondrogenic cells.

METHODS: LPS was used to simulate inflammatory injury in murine chondrogenic ATDC5 cell lines. Targeting effect of miR-125b on MIP-1α 3'UTR was assessed by dual luciferase activity assay. Regulatory effect of miR-125b on MIP-1α expression and the potential regulatory mechanism on inflammatory injury were assessed by Western blot.

RESULTS: miR-125b expression was decreased in LPS-induced ATDC5 cells and overexpression of miR-125b inhibited LPS-induced cell viability decline, the rise of apoptosis and inflammatory factors' productions. MIP-1α expression was negatively related to miR-125b, and miR-125b directly targeted with 3'UTR of MIP-1α. Knockdown of miR-125b promoted LPS-induced inflammatory response via upregulation of MIP-1α. miR-125b expression in LPS-induced ATDC5 cells was negatively related with activations of NF-κB and JNK signaling pathways. Overexpression of miR-125b inhibited LPS-induced inflammation injury via suppressing MIP-1α expression and inhibiting activations of NF-κB and JNK signaling pathways.

CONCLUSION: miR-125b could play an important role in inflammatory injury of chondrogenic cells and miR-125b affected inflammatory injury of ATDC5 cells via regulating expression of MIP-1α and regulating NF-κB and JNK signaling pathways.