Bone marrow mesenchymal stem cells-derived exosomes mediate nuclear receptor coactivator-3 expression in osteoblasts by delivering miR-532-5p to influence osteonecrosis of the femoral head development.

Exosomes (Exo) originated from bone marrow mesenchymal stem cells (BMSCs) have therapeutic impacts on osteonecrosis of the femoral head (ONFH), and microRNA (miR)-532-5p has been confirmed to participate in ONFH progression. In the research, it was figured out whether BMSCs-Exo could relieve ONFH by delivering miR-532-5p. MG-63 cells were treated with DEX to construct an ONFH cell model in vitro. The effects of Exo and miR-532-5p on the cell viability, lactate dehydrogenase (LDH) content, and apoptosis of BMSCs were detected. The ONFH rat model was established, and the effect of BMSCs-Exo delivering miR-532-5p on the pathological damage of ONFH rats was evaluated. Changes in nuclear receptor coactivator-3 (NCOA3) and apoptotic proteins were assessed by western blot. The relationship between miR-532-5p and NCOA3 was verified by dual luciferase reporter experiments. miR-532-5p was elevated in vivo and in vitro ONFH-models, while NCOA3 expression was reduced. Overexpression of miR-532-5p aggravated DEX toxicity in osteoblasts, decreased cell viability, and promoted apoptosis. Knockdown of miR-532-5p made Exo further attenuate the toxic effect of DEX on osteoblasts and inhibited apoptosis. The protective effect of miR-532-5p-delivering Exo on osteoblasts was reversed by NCOA3 silencing. In addition, in vivo experiments also confirmed that knockdown of miR-532-5p enhanced the therapeutic effect of Exo on ONFH rats. This study demonstrates that miR-532-5p-delivering BMSCs-Exo inhibits osteoblast viability and promote apoptosis by targeting NCOA3, thereby aggravating ONFH development.