Mesenchymal stem cell extracellular vesicles-derived microRNA-194-5p delays the development of intervertebral disc degeneration by targeting TRAF6

OBJECTIVE: Mesenchymal stem cells-derived extracellular vesicles (MSCs-EVs) can improve intervertebral disc degeneration (IDD). Considering that, their concrete mechanisms from microRNA-194-5p/tumor receptor-associated factor 6 (miR-194-5p/TRAF6) axis in IDD ask for disclosure in a scientific way. METHODS: Nucleus pulposus (NP) cells and MSCs were obtained. EVs were isolated from the obtained MSCs and identified. miR-194-5p expression in MSC-EVs was altered by sequence transfection. Subsequently, MSCs-EVs were co-cultured with NP cells intervened by tumor necrosis factor α (TNF-α). NP cell proliferation and apoptosis, along with their osteogenic differentiation ability were evaluated. miR-194-5p and TRAF6 expression and their interaction were determined. RESULTS: In TNF-α-intervened NP cells, miR-194-5p was down-regulated and TRAF6 was up-regulated. Restoring miR-194-5p effectively enhanced proliferation and osteogenic differentiation, and reduced apoptosis of TNF-α-intervened NP cells. miR-194-5p-enriched MSCs-EVs protected TNF-α-intervened NP cells. miR-194-5p targeted TRAF6, TRAF6 overexpression exerted negatively for the growth of TNF-α-intervened NP cells, and could reduce the protective effects of miR-194-5p on TNF-α-intervened NP cells. CONCLUSION: It is elucidated that miR-194-5p derived from MSCs-EVs protects TNF-α-intervened NP cells through restricting TRAF6, replenishing a potential target for IDD treatment.