miRNA expression profile during osteogenic differentiation of human adipose-derived stem cells

Human adipose-derived stem cells (hADSC) are capable of differentiating into an osteogenic lineage. It is believed that microRNAs (miRNAs) play important roles in regulating this osteogenic differentiation of human adipose-derived cells, although its molecular mechanism remains unclear. We investigated the miRNA expression profile during osteogenic differentiation of hADSCs, and assessed the roles of involved miRNAs during the osteogenic differentiation. We obtained and cultured human adipose-derived stems cells from donors who underwent elective liposuction or other abdominal surgery at our institution. miRNA expression profiles pre- and post-osteogenic induction were obtained using microarray essay, and differently expressed miRNAs were verified using quantitative real-time polymerase chain reaction (qRT-PCR). The expression of osteogenic proteins was detected using an enzyme-linked immunosorbent assay. Putative targets of the miRNAs were predicted using online software MiRanda, TargetScan, and miRBase. Eight miRNAs were found differently expressed pre- and post-osteogenic induction, among which four miRNAs (miR-17, miR-20a, miR-20b, and miR-106a) were up-regulated and four miRNAs (miR-31, miR-125a-5p, miR-125b, and miR-193a) were down-regulated. qRT-PCR analysis further confirmed the results. Predicted target genes of the differentially expressed miRNAs based on the overlap from three public prediction algorithms: MiRanda, TargetScan, and miRBase Target have the known functions of regulating stem cell osteogenic differentiation, self-renewal, signal transduction, and cell cycle control. We identified a group of miRNAs that may play important roles in regulating hADSC cell differentiation toward an osteoblast lineage. Further study of these miRNAs may elucidate the mechanism of hADSC differentiation into adipose tissue, and thus provide basis for tissue engineering.