miR-124-3p promotes BMSC osteogenesis via suppressing the GSK-3β/β-catenin signaling pathway in diabetic osteoporosis rats.

The purpose of this study is to investigate miRNAs' effects, targeting the Wnt signaling pathway, on osteogenic differentiation to provide new targets for diabetic osteoporosis treatments. Twelve male rats were divided into a normal rat group (NOR group) and a model rat group (MOD group). Cluster analysis of differentially expressed miRNAs and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed. Primary rat bone marrow mesenchymal stem cells (BMSCs) were divided into a high-glucose group and a low-glucose group, and osteogenic differentiation was induced. Alkaline phosphatase (ALP) staining and Alizarin Red staining were used for pathological analysis of the cells. Western blot analysis was used to measure GSK-3β, β-catenin, p-β-catenin, c-Myc, and CyclinD1 expression. Immunofluorescence (IF) was used to analyze the effect of GSK-3β inhibitor (CHIR99021) on β-catenin and CyclinD1 expressions levels in BMSCs. A total of 428 differentially expressed miRNAs were found between the NOR and MOD groups. KEGG analysis showed that the target genes were mostly enriched in signaling pathways, including PI3K-Akt, focal adhesion, AGE-RAGE, HIF-1, and Wnt. qPCR verification demonstrated that miR-124-3p exhibited the greatest difference in expression level. In BMSCs, miR-124-3p overexpression could reverse the inhibited expression of BMSC osteogenic markers, including Alpl, Bglap, and Runx2, induced by high glucose. Western blot analysis revealed that the transfection of miR-124-3p mimics could further reverse the upregulated p-β-catenin and GSK-3β levels and the downregulated c-Myc and CyclinD1 levels induced by high glucose. IF results revealed that BMSCs treated CHIR99021 under high glucose showed the reduced GSK-3β and increased β-catenin and CyclinD1 expression levels. Our research highlighted miRNAs' important roles in regulating the Wnt pathway and provided new information for the diagnosis and treatment of diabetic osteoporosis.