MicroRNA-124-3p inhibits the differentiation of precartilaginous stem cells into nucleus pulposus-like cells via targeting FSTL1

MicroRNA (miRNA/miR)-124-3p has been extensively studied in tumor biology and stem cells. However, little is known regarding its functional roles in the differentiation of precartilaginous stem cells (PSCs) into nucleus pulposus-like cells (NPLCs). In the present study, using miRNA microarray screening, it was demonstrated that the miRNA expression profiles differed between rat primary PSCs and TGF-β1-induced differentiated NPLCs, and that miR-124-3p was significantly differentially expressed during the differentiation of PSCs to NPLCs. Furthermore, RT-qPCR analysis verified that miR-124-3p expression was decreased during PSC differentiation, with the lowest levels being detected at the later stages. Subsequent experiments revealed that miR-124-3p overexpression significantly decreased the expression of the extracellular matrix proteins, aggrecan and collagen type II, which was accompanied by a significant decrease in follistatin-related protein 1 (FSTL1) expression levels. Moreover, bioinformatics analysis indicated that FSTL1 was a potential target of miR-124-3p, which was additionally verified using luciferase reporter assays. Taken together, these data revealed a specific regulatory pathway of miR-124-3p, which negatively regulated its target gene, FSTL1, during the differentiation of PSCs to NPLCs, and suggested a functional role for miR-124-3p in the differentiation of PSCs.