MicroRNA-145 suppresses osteogenic differentiation of human jaw bone marrow mesenchymal stem cells partially via targeting semaphorin 3A

Abstract

<b>Purpose</b>: Human jaw bone marrow mesenchymal stem cells (h-JBMMSCs) are multipotent progenitor cells with osteogenic differentiation potential. MicroRNAs (miRNAs) have emerged as crucial modulators of osteoblast differentiation. In this study, we focus on the role of <i>miR-145</i> and its target protein in osteoblast differentiation of h-JBMMSCs. <b>Materials and Methods</b>: h-JBMMSCs were isolated and cultured in osteogenic medium. <i>miR-145</i> mimics and inhibitors were used to elevate and inhibit <i>miR-145</i> expression, respectively. Osteogenic differentiation was determined by Alkaline phosphatase (ALP) and Alizarin red S (ARS) staining, and osteogenic marker detection using quantitative real-time reverse transcription PCR (qRT-PCR) assay. Bioinformatic analysis and luciferase reporter assay were used to identify the target gene of <i>miR-145</i>. <b>Results</b>: <i>MiR-145</i> was down-regulated during osteogenesis of h-JBMMSCs. Inhibition of <i>miR-145</i> promoted osteogenic differentiation of h-JBMMSCs, revealed by enhanced activity of alkaline phosphatase (ALP), greater mineralisation, and increased expression levels of the osteogenic markers, such as Runt-related transcription factor 2 (RUNX2), Osterix (OSX), ALP and COL1A1. <i>MiR-145</i> could negatively regulate semaphorin3A (SEMA3A), which acts as a positive regulator of osteogenesis. <i>MiR-145</i> inhibitor induced osteogenesis could be partially attenuated by SEMA3A siRNA treatment in h-JBMMSCs. <b>Conclusions</b>: Our data show that <i>miR-145</i> directly targets SEMA3A, and also suggest <i>miR-145</i> as a suppressor, plays an important role in the osteogenic differentiation of h-JBMMSCs.