Abstract
The dental follicle is an ectomesenchymal tissue that surrounds developing tooth germs, which contains osteoblastic/cementoblastic lineage committed stem/progenitor cells. The purpose ofthis study is to examine the gene expression and the protein production of leukemia inhibitory factor(LIF)in human dental follicle cells(hDFC)and to regulate these at the post-transcriptional level by miRNA targeting. We examined the kinetic gene expression ofLIF in hDFC cultured with mesenchymal stem cell osteogenic induction medium(MSCOIM)on days 0, 1, 2, 4, 7 and 11 using real-time PCR. Expression was decreased in MSCOIM culture in a time-dependent manner. LIF protein levels decreased until culture day 2, and then increased until day 4 in MSCOIM culture. These results suggest that LIF expression is regulated at the post-transcriptional level, and may be affected by microRNA(miRNA). To demonstrate the direct role of specific miRNAs in the modulation of LIF production, we transfected hDFC with miRNA mimics offour miRNAs predicted to target LIF; hsa-miR-29b, hsa-miR-125a, hsa-miR-199- 5p and hsa-miR-199-3p. After transfection, the production of LIF was significantly lower in the cells transfected with miRNA his-miR-29b, but hsa-miR-125a, hsa-miR-199-5p and hsamiR-199-3p showed no significant changes in LIF production. These results suggest that production ofLIF is partially regulated by miRNA, maintaining the undifferentiated status of hDFC and influencing differentiation toward the osteoblastic/ cementoblastic lineage.
