MiR-9-3 promotes osteoblast differentiation of bone marrow mesenchymal stem cells by targeting Smoc2

In this study, we reported that miR-9-3 regulate osteoblast differentiation and bone formation by targeting SPARC-related modular calcium binding 2 (Smoc2). MiR-9-3 deletion led to reduced size and postweaning lethality in 10% of the mice.

Using microcomputed tomography, we found that mice lacking miR-9-3 exhibited decreased trabecular bone mass and bone volume. Importantly, the serum level of PINP and OCN, both markers of bone formation, was also significantly decreased in miR-9-3-deficient mice. Deletion of miR-9-3 in mice did not affect osteoclast differentiation but impaired mesenchymal stem cells (MSCs)-mediated osteoblast differentiation and mineralization, as evidenced by reduced ALP and Alizarin Red S staining.