miR‑98‑5p promotes osteoblast differentiation in MC3T3‑E1 cells by targeting CKIP‑1.

Casein kinase 2-interacting protein 1 (CKIP-1) is a negative regulator for bone formation. Previously, using bioinformatics analysis, CKIP‑1 has been predicted to serve the role of target gene of miR‑98‑5p. In the present study, the potential role of miR‑98‑5p in regulating osteoblast differentiation through CKIP‑1 was investigated. Following pre‑treatment with microRNA (miR)‑98‑5p agomir or miR‑98‑5p antagomir, MC3T3‑E1 cells were cultured in an osteoinductive medium. Subsequently, the expression of miR‑98‑5p, CKIP‑1 and levels of osteoblast differentiation markers, including alkaline phosphatase, matrix mineralization, osteocaicin, collagen type I, runt‑related transcription factor 2 and osteopontin were assayed. Using a dual‑luciferase reporter assay, it was demonstrated that CKIP‑1 was the target gene of miR‑98‑5p. miR‑98‑5p was upregulated as a result of treatment with miR‑98‑5p agomir and promoted osteoblast differentiation. Conversely, miR‑98‑5p antagomir inhibited miR‑98‑5p expression and osteoblast differentiation. miR‑98‑5p targeted CKIP‑1 by binding to its 3'‑untranslated region. Furthermore, miR‑98‑5p overexpression decreased the protein levels of CKIP‑1 and inhibition of miR‑98‑5p increased the protein levels of CKIP‑1. The results of the present study indicated that CKIP‑1 was a target gene of miR‑98‑5p and that miR‑98‑5p regulated osteoblast differentiation in MC3T3‑E1 cells by targeting CKIP‑1.