Expression of microRNAs during chondrogenesis of human adipose-derived stem cells

MicroRNAs (miRNAs) play an important role in the regulation of chondrogenesis of mesenchymal stem cells, but their expression still remains unknown in human adipose-derived stem cells (hADSCs). In this study the miRNA expression profile during chondrogenic differentiation of hADSC and the potential mechanism whereby miRNAs may affect the process of chondrogenesis are considered.

hADSCs were isolated and cultured. The expression of chondrogenic proteins was detected using enzyme-linked immunosorbent assay (ELISA). miRNA expression profiles before and after chondrogenic induction were obtained using miRNA microarray essay and differently expressed miRNAs were primarily verified using quantitative real-time polymerase chain reaction (qRT-PCR). Putative targets of the miRNAs were predicted using online software programs MiRanda, TargetScan and miRBase.

Twelve miRNAs were found to be differentially expressed pre- and post-chondrogenic induction by over a two-fold change, including eight up-regulated miRNAs (miR-193b, miR-199a-3p/hsa-miR-199b-3p, miR-455-3p, miR-210, miR-381, miR-92a, miR-320c, and miR-136), and four down-regulated miRNAs (miR-490-5p, miR-4287, miR-BART8*, and miR-US25-1*). qRT-PCR analysis further confirmed these results. Predicted target genes of the differentially expressed miRNAs were based on the overlap of at least two online prediction algorithms, with the known functions of regulating chondrogenic differentiation, self-renewal, signal transduction and cell cycle control.

In this study we have identified a group of miRNAs and their target genes, which may play important roles in regulating chondrogenic differentiation of hADSCs. Our results provide the basis for further investigation into the molecular mechanism of chondrogenesis in hADSCs and their differentiation for cartilage engineering.