ABSTRACT
Objective To identify the specific microRNA (miRNA) that can be taken as a molecular marker for human bone marrow-derived mesenchymal stem cells (MSCs). Methods MSCs were isolated and cultured from bone marrow through density centrifugation and then were induced to differentiate into osteoblasts and chondrocytes. Samples of MSCs, osteoblasts and chondrocytes were detected by miRNA microarrays single channel fluorescence chip to determine the expression levels of miRNAs. Significance Analysis of Microarrays ( SAM, version 2.1 ) software was used to analyze the raw data to determine the miRNAs overexpressed in MSCs, which was validated in the same sample using real time reserve transcriptase polymerase chain reaction (RT-PCR). Results MSCs were successfully isolated from bone marrow and induced to differentiate into osteoblasts and chondrocytes in vitro. Microarrays showed that eight miRNAs (has-miR-424, has-miR-34a, has-miR-593, has-miR-10a, has-miR-148a,has-miR-602, mmu-miR-709 and mmu-miR-665) were overexpressed in MSCs but underexpressed in osteoblasts. Three miRNAs including has-miR-424, PREDICTED_MIR189 and mmu-miR-665, were overexpressed in MSCs but underexpressed in chondrocytes. The has-miR-424 expression in MSCs was 6.6times higher than in osteoblasts and 4.4 times higher than in chondrocytes. The results of real time RTPCR showed that the miR-424 was overexpressed in MSCs, 3.6 times higher than that in osteoblasts and 3.1 times higher than that in chondrocytes, which was coincident with the results of microarray. Conclusions The screened MSCs express more miRNAs in comparison with osteoblasts and chondrocytes,play important roles in maintaining self renewal and undifferentiation of MSCs and is a promising specific molecule marker for MSCs.