Identification of the microRNA which regulates chondrogenic differentiation of bone marrow-derived mesenchymal stem cell

Abstract

Human bone marrow mesenchymal stem cells (hMSCs) differentiate into multiple connective tissue cell types including adipocyte, chondrocyte, myoblast, osteoblast, depending on specific condition. Chondrogenic differentiation of human MSC passes through multiple stages and it carried out by various factors and their interactions. As a possible regulator of MSC chondrogenic differentiation, microRNA has identified recently. microRNA is consisted of 20-24 nucleotide and inhibits its target gene expression through target mRNA cleavage or translational repression. Current reports indicate that microRNAs play critical roles in diverse biological process including cell proliferation, apoptosis and differentiation. In this study, we showed that miR-495 regulates chondrogenic differentiation. High throughput screening though microRNA microarray analysis was performed to find microRNA expression change during chondrogenic differentiation. By statistical analysis We have found that miR-495 was especially down-regulated in hMSCs induced chondrogenic differentiation. Using microRNA target prediction database, we have selected its target, Sox9, SRY-related high mobility group-Box gene 9. Sox9 has been extensively reported its critical role in overall progression of chondrogenic differentiation. We have confirmed opposite expression of miR-495 and Sox9 using realime PCR. Furthermore, over-expression of miR-495 has inhibited Sox9 expression in cell line and hMSCs. Additionally, Luciferase analysis data revealed that miR-495 directly binding to Sox9 3’UTR. Subsequently, over-expression of miR-495 has repressed expression of chondrogenic marker genes, such as type II collagen (Col2A1), aggrecan and proteoglycan products. Thus, our finding suggests that miR-495 regulates chondrogenic differentiation of hMSCs by directly binding Sox9.