Extracellular vesicles from adipose-derived stromal/stem cells reprogram dendritic cells to alleviate rat TMJOA by transferring mitochondria.

Temporomandibular joint osteoarthritis (TMJOA) urgently needs regenerative therapies due to the limited effects of traditional treatments. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are considered a potent alternative for MSC therapy for the treatment of TMJOA. However, the specific mechanisms remain inadequately investigated. In this study, we explored how EVs from adipose-derived stromal/stem cells (ASCs) influence the TMJOA model triggered by Complete Freund's Adjuvant in rats and their impact on the state of dendritic cells (DCs) under pathological conditions. Subsequently, we conducted transcriptomic and metabolomic analyses to elucidate the specific mechanisms by which EVs affect DCs. Mechanistically, we demonstrate that EVs transferred functional mitochondria to DCs, which reverses their metabolic states. The internalized functional mitochondria from EVs activate the MAPK/ERK1/2/FoxO1/autophagy pathway, which causes the metabolic reprogramming of DCs and facilitates the achievement of therapeutic effects. These findings provide a mechanistic rationale for utilizing ASCs-EVs as cell-free alternatives to MSC transplantation in TMJOA therapy.