miR­98­5p promotes osteoblast differentiation in MC3T3­E1 cells by targeting CKIP­1.

ABSTRACT

Casein kinase 2-interacting protein 1 (CKIP-1) is a negative regulator for bone formation. Previously, using bioinformatics analysis, CKIP­1 has been predicted to serve the role of target gene of miR­98­5p. In the present study, the potential role of miR­98­5p in regulating osteoblast differentiation through CKIP­1 was investigated. Following pre­treatment with microRNA (miR)­98­5p agomir or miR­98­5p antagomir, MC3T3­E1 cells were cultured in an osteoinductive medium. Subsequently, the expression of miR­98­5p, CKIP­1 and levels of osteoblast differentiation markers, including alkaline phosphatase, matrix mineralization, osteocaicin, collagen type I, runt­related transcription factor 2 and osteopontin were assayed. Using a dual­luciferase reporter assay, it was demonstrated that CKIP­1 was the target gene of miR­98­5p. miR­98­5p was upregulated as a result of treatment with miR­98­5p agomir and promoted osteoblast differentiation. Conversely, miR­98­5p antagomir inhibited miR­98­5p expression and osteoblast differentiation. miR­98­5p targeted CKIP­1 by binding to its 3'­untranslated region. Furthermore, miR­98­5p overexpression decreased the protein levels of CKIP­1 and inhibition of miR­98­5p increased the protein levels of CKIP­1. The results of the present study indicated that CKIP­1 was a target gene of miR­98­5p and that miR­98­5p regulated osteoblast differentiation in MC3T3­E1 cells by targeting CKIP­1.