Differentially enriched miRNAs in EVs derived from young and aged osteocytes of mice

Young and Aged osteocytes in bone matrix secreted plenty of extracellular vesicles (EVs) with different functions. We found that EVs released from aged bone matrix (AB-EVs) during bone resorption favor adipogenesis rather than osteogenesis of BMSCs and augment calcification of vascular smooth muscle cells (VSMCs). In this work, we aim to detect the differential regulation microRNAs. Vascular calcification often occurs with osteoporosis, a contradictory association called “calcification paradox”. We find that extracellular vesicles (EVs) released from aged bone matrix (AB-EVs) during bone resorption favor adipogenesis rather than osteogenesis of BMSCs and augment calcification of vascular smooth muscle cells (VSMCs). Intravenous or intramedullary injection of AB-EVs promotes bone-fat imbalance and exacerbates Vitamin D3 (VD3)-induced vascular calcification in young or old mice. To explore the involvement of miRNAs in the AB-EVs-induced promotion of adipocyte formation and vascular calcification, the Agilent miRNA array was conducted to compare the miRNA expression profiles in AB-EVs and YB-EVs from mouse bone specimens. Our study uncovers the role of AB-EVs as a messenger for calcification paradox by transferring functional miRNAs. 3 of YB-EVs isolated from 1-month-old male mice, 3 of AB-EVs isolated from 16-month-old male mice