Fig. 7.

Schematic diagram illustrating the mechanism by which YO-EVs transfer TPM1 to facilitate BMSC osteogenesis. During bone resorption in young mice, YO-EVs are released from the bone matrix into the bone marrow, where they transfer TPM1 to promote osteogenic differentiation of BMSCs, rather than adipogenesis, by regulating F-actin polymerization. However, in elderly mice, a decrease in the delivery of TPM1 via SO-EVs leads to a bone-fat imbalance and, ultimately, osteoporosis. This schematic diagram provides a crucial visual representation of how osteocyte-derived EVs can affect bone homeostasis and underscores the importance of understanding the regulatory mechanisms involved in bone metabolism, particularly in regard to aging