Fig. 4: ASC-Exos attenuates OA progression through miR-140-mediated MMP13 suppression.

A Dual-luciferase reporter assay showing direct targeting of MMP13 3′UTR by miR-140. Left: Schematic diagram of wild-type and mutant MMP13 3′UTR luciferase constructs with miR-140 binding sites. Right: Relative luciferase activity in 293T cells co-transfected with indicated constructs (n = 3). B Cell viability assay showing the protective effects of different exosomes treatments (150 μg/mL) against IL-1β and MMP13 overexpression-induced cytotoxicity in chondrocytes. Data are presented as mean ± SD. C Wound healing assay demonstrating the effects of different exosomes treatments on chondrocyte migration at 0 h and 48 h in IL-1β and MMP13 overexpression conditions. Red lines indicate wound edges. Scale bars: 500 μm. D Transwell migration assay and quantification confirming the migration-promoting effects of exosomes treatments under IL-1β and MMP13 overexpression conditions. Scale bars: 500 μm. E qPCR analysis showing relative expression levels of MMP13, COL2, and NLRP3 in chondrocytes treated with different exosomes under IL-1β and MMP13 overexpression conditions. F ELISA quantification of pro-inflammatory cytokines (IL-6 and TNF-α) in culture supernatants following different treatments. G, H Flow cytometry analysis of chondrocyte apoptosis under different treatment conditions. G qPCR analysis of NLRP3 expression in chondrocytes following MMP13 rescue experiments. H Quantification of relative Caspase-1 activity following different treatments. I Immunofluorescence analysis of ASC speck formation (red) in IL-1β-stimulated chondrocytes. Nuclei are stained with DAPI (blue).