MicroRNAs expression and their regulatory networks during mesenchymal stem cells differentiation toward osteoblasts.

MicroRNAs (miRNAs) are small endogenous noncoding RNAs which regulate mRNAs post-transcriptionally. In this study, a selective number of miRNAs was investigated for their expression and intracellular regulatory networks involved in differentiation of human mesenchymal stem cells (hMSCs) toward osteoblasts. The expression of miR-424, miR-106a, miR-148a, let-7i and miR-99a miRNAs was found to be specific in hMSCs; whereas expression of miR-15b, miR-24, miR-130b, miR-30c, and miR-130a miRNAs was found to be specific in differentiated osteoblasts. A bioinformatics approach identified that the MAPK pathway was mostly targeted by hMSCs specific miRNAs; whereas JAK-STAT, p53, Focal adhesion, gap junction, ubiquitin mediated proteolysis pathways were targeted by osteblastic specific miRNAs. Altering expression of osteoblast specific miRNA (miR-15b) promoted adipogenesis and myogenesis lineages. Thus, we suggest that miRNAs' regulatory networks and their target genes might provide an insight of their role during differentiation of hMSCs toward osteoblasts, and alteration in the expression of miRNAs would be a valuable approach for controlling osteoblast differentiation.