Hybrid Joint Fluid Extracellular Vesicles Drive Metabolic Damage Impairing Chondrogenesis

Elucidate the role of joint fluid extracellular vesicles (EVs) in regulating the metabolic homeostasis of degenerative cartilage and uncover the mechanisms behind the limited chondrocyte regenerative capacity in temporomandibular joint osteoarthritis (TMJOA). 1.EVs were isolated from the joint fluid of TMJOA patients and controls. They were characterized by the proteomic, immuno-electron microscope, nano-flow cytometry to identify hybrid EVs (hEVs) co-expressing macrophage and collagen markers correlated with OA progress. 2.The MIA-induced rat model was used to test the effect of hEVs on TMJOA. 3.An in vitro model of hEVs was developed to explore underlying mechanism on mitochondrial damage, metabolic reprogramming, TCA cycle metabolite alteration, and cell fate direction of chondrocytes. 1.Endogenous hEVs accumulate in joint fluid of OA patients, correlating with disease progression. 2.Intra-articular hEVs injection halts chondrogenic and increases mitochondrial defects and senescent chondrocytes in TMJOA rats. 3.hEVs enhance inflammation-induced glycolysis in cartilage stem/progenitor cells (CSPCs) and trigger irreversible mitochondrial fragmentation. Concurrently, they decrease mitochondrial membrane potential in an ANT1-dependent way, perturb TCA cycle metabolites, leading to cellular senescence and chondrogenic dysfunction. 4.A combination therapy using an ANT1 inhibitor supplying metabolites corrected hEVs-induced metabolic and cell fate reprogramming, ultimately restoring impaired CSPCs and rat TMJOA models. For the first time, this study identified a subtype of humoral hEVs in TMJOA patients, which contribute to irreversible mitochondria damage and cellular senescence of CSPCs, paving the way for developing new strategies to treat OA.