Cell-cell communication between chondrocytes and osteoblasts through miR-221-3p loaded extracellular vesicles

Osteoarthritis (OA) is a whole joint disease manifested by cartilage degeneration and subchondral bone remodeling, and bone-cartilage communication plays a vital role in the disease progression with the existence of microchannels across the bone-cartilage interface. However, the knowledge of how the signal transduction from chondrocytes to osteoblasts happens is limited. Recently, miR-221-3p was demonstrated to be mechanosensitive in cartilage chondrocytes and extracellular vesicles (EVs) have been deeply researched for a specific role in cell-cell communication. In the present study, we investigated the role of EVs in chondrocyte-osteoblast communication by transferring the signal of miR-221-3p. EVs were isolated from the supernatant of chondrocytes by the PEG precipitation method and identified with nanoparticle tracking analysis (NTA) and western blot. The results suggest that the chondrocytes secreted EVs not only mediate the communication of these two cells in a coculture model but also inhibit the bone formation capacity of osteoblasts via the cargo of miR-221-3p. Therefore, this study provides a novel perspective on the communication between chondrocytes and osteoblasts through EVs and this can be considered a reliable approach to modulate the bone-cartilage remodeling in the future.2022-09-2