MicroRNA-320a Regulates the Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells by Targeting HOXA10.

BACKGROUND/AIMS Human bone marrow-derived mesenchymal stem cells (hMSCs) are a promising cell source for bone engineering owing to their high potential to differentiate into osteoblasts. The bone morphogenetic protein-inducible gene homeobox a10 (HOXA10) is a critical regulator of osteogenesis. The objective of the present study was to identify microR-NAs (miRNAs) targeting HOXA10 and examine the effects on the osteogenic differentiation of hMSCs. METHODS Based on in silico analysis, HOXA10-targeting miRNAs were selected and their regulatory roles in osteoblast differentiation were investigated. RESULTS Six HOXA10-targeting miRNAs were identifIed by computational analysis, of which miR-320a was selected for further analysis because it was downregulated during osteogenic induction. Overexpression of miR-320a downregulated HOXA10 and significantly inhibited osteogenesis in hMSCs, as determined by the downregulation of the osteogenic markers Runx2, ALP, and OC and the inhibition of ALP activity and matrix mineralization, whereas miR-320a inhibition had the opposite effects. Furthermore, ectopic expression of HOXA10 (not including 3'-UTR) rescued the effects of miR-320a on osteogenic differentiation. CONCLUSION These results suggest that miR-320a acts as a critical regulator of osteogenic differentiation of hMSCs by repressing its target HOXA10.