MiR-129-5p shuttled by human synovial mesenchymal stem cell-derived exosomes relieves IL-1β induced osteoarthritis via targeting HMGB1

Aims: To explore the therapeutic effect of miR-129-5p carried by exosomes from Human Synovial Mesenchymal Stem Cell (HS-MSC) on osteoarthritis(OA).

Materials and methods: The levels of miR-129-5p and high mobility group protein -1 (HMGB1) and interleukin-1β (IL-1β) in the joint fluid of OA patients were respectively detected via real-time quantitative reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-1β was taken to act on chondrocytes for the establishment of OA model in vitro. Ultracentrifugation was conducted to isolate HS-MSC exosomes (HS-MSC-Exo) from the supernatant. Western blot and ELISA were carried out to measure the expression of iNOS, COX2, MMP13, Collagen 2, TLR4, NF-κB, Caspase3, Bcl-2, HMGB1 in chondrocytes. Flow cytometry was conducted to detect the Apoptosis of chondrocytes. Besides, bioinformatics was employed to predict the targeted relationship between miR-129-5p and HMGB1, which was further verified via dual luciferase activity experiments.

Key findings: The results illustrated that miR-129-5p was decreased in OA patients and IL-1β-induced chondrocytes, while HMGB1 was notably upregulated. HS-MSC-Exo rich in miR-129-5p remarkably declined the inflammatory response and Apoptosis of chondrocytes, while HS-MSC-Exo deficient in miR-129-5p increased the IL-1β-mediated inflammatory response and Apoptosis of chondrocytes. In terms of mechanism, miR-129-5p targets the 3'UTR end of HMGB1 and inhibits IL-1β-mediated upregulation of HMGB1.

Significance: In a word, this paper proved that miR-129-5p, existing in HS-MSC-Exo, can suppress the IL-1β-mediated OA by inhibiting HMGB1 release.