Fig. 3

MSC-Exos: generation, structural composition, and protective effects on joint cartilage. MSC-Exos are nanoscale extracellular vesicles that originate from the inward budding of late endosomal membranes called MVBs and are released after fusion with the plasma membrane. The major components of MSC-released exosomes are lipid membranes rich in cholesterol, sphingomyelin, ceramide, and lipid raft proteins, which protect the contents from degradation or fusion with the membranes of target cells. In addition, exosomes of MSCs carry small nucleic acid molecules that play an important role in cartilage tissue regeneration, cartilage immunomodulation, and other processes