miR-98-TXLNG1 (FIAT)/Sp7 function loop mediates osteoblast mineralization.

ABSTRACT

OBJECTIVE: To investigate the role of microRNAs (miRNAs) and its mechanism in osteoblast mineralization. MATERIALS AND METHODS: Real-time polymerase chain reaction (PCR), Northern Blot, and Western Blot were used to identify the expression mode of regulators. Overexpression and down-regulation experiments were carried out to study the role of miR-98 and interactions between regulators. Bioinformatics calculation and luciferase reporter assay were used to prove the target gene. Electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (CHIP), and promoter luciferase reporter assay confirmed the relationship between the regulator and the promoter of miR-98. RESULTS: MiR-98 was up-regulated during osteoblast mineralization. Overexpression of miR-98 promoted osteoblast mineralization. Factor inhibiting activating transcription factor 4 (ATF4)-mediated transcription (FIAT), a negative regulator of osteoblast differentiation, was confirmed to be a target of miR-98. As a motivator in osteoblast mineralization, Sp7 transcription factor 7 (Sp7) promoted miR-98 transcription by a combination on the promoter region. CONCLUSIONS: Our study showed that miR-98 was an important regulator in osteoblast mineralization and miR-98 carried out its function through a novel miR-98-FIAT/Sp7 regulatory loop. It provides new insights into the roles of miRNAs in osteoblast mineralization.