Human Dental Follicle Cell-Derived Small Extracellular Vesicles Attenuate Temporomandibular Joint Cartilage Damage through Inhibiting HIF-2α

Mesenchymal stem cell (MSC)-based therapies for articular cartilage regeneration are effective mostly due to paracrine signals mediated by extracellular vesicles, especially small extracellular vesicles (sEV). However, it is unknown whether dental follicle cell-derived sEV (DFC-sEV) affect cartilage regeneration in temporomandibular joint osteoarthritis (TMJ-OA). In this study, the effects of DFC-sEV on IL-1β-induced mandibular condylar chondrocytes (MCCs) were determined using CCK8 assays, scratch assays, flow cytometry, and Western blot analysis of matrix synthesis and catabolic proteins. Furthermore, we used an abnormal occlusion-induced rat model and intra-articular injection of DFC-sEV, the pathological changes of which were observed by HE staining, safranin O staining, immunohistochemistry, and micro-CT analysis of subchondral bone loss. Gene set enrichment analysis (GSEA) was used to determine the related mechanism involved in the effect of DFC-sEV. Immunofluorescence analysis and Western blotting were used to evaluate the expression of HIF-1α, HIF-2α, MMP13, and VEGF in MCCs. Then, lentivirus-induced Epas1 overexpression and Western blot analysis of the downstream regulators of HIF-2α were performed. We found that DFC-sEV promoted MCCs proliferation and migration and protected against cartilage matrix destruction induced by IL-1β. In addition, DFC-sEV prevented cartilage destruction in an abnormal occlusion rat model. Furthermore, we found that DFC-sEV reduced the expression of HIF-1α and HIF-2α in vitro and in vivo and decreased the downstream regulators of HIF-2α, including MMP13 and VEGF. Our study indicated that DFC-sEV attenuated TMJ cartilage damage in vitro and in vivo, which might be involved in the regulation of HIF-2α.