MiRNA-27a-3p promotes osteogenic differentiation of human mesenchymal stem cells through targeting ATF3.

OBJECTIVE: To elucidate whether miRNA-27a-3p can promote osteogenic differentiation of hMSCs by targeting ATF3, thus alleviating osteoporosis symptoms. PATIENTS AND METHODS: The serum levels of miRNA-27a-3p in osteoporosis patients (n=20) and normal controls (n=20) were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Human bone marrow mesenchymal stem cells (hMSCs) were subjected to osteogenic differentiation for 1, 3 and 7 days. Subsequently, mRNA levels of miRNA-27a-3p, ALP, and Bglap in hMSCs were determined by qRT-PCR. The regulatory effects of miRNA-27a-3p levels and the mRNA levels of ALP, Bglap, and Runx2 were detected. After the overexpression or knockdown of miRNA-27a-3p, we evaluated the changes in the osteogenic differentiation by alizarin red staining and ALP staining. Through Dual-Luciferase Reporter Gene Assay, we verified the binding relationship between miRNA-27a-3p and ATF3. Rescue experiments were finally conducted to prove whether miRNA-27a-3p regulated the osteogenic differentiation by targeting ATF3. RESULTS: The serum level of miRNA-27a-3p remained lower in osteoporosis patients relative to controls. With the prolongation of osteogenic differentiation, the mRNA levels of miRNA-27a-3p, ALP, and Bglap gradually increased. The overexpression of miRNA-27a-3p upregulated mRNA and the protein levels of osteogenesis-related genes, increased ALP activity, and enhanced mineralization capacity. The knockdown of miRNA-27a-3p obtained the opposite trends. MiRNA-27a-3p could target ATF3, and the overexpression of ATF3 reversed the promotive effects of miRNA-27a-3p on osteogenic differentiation. CONCLUSIONS: MiRNA-27a-3p promotes the differentiation of hMSCs into osteoblasts by targeting ATF3, thus alleviating osteoporosis symptoms.