The Regulatory Effect of Mir-181c-5p On the Differentiation Function of Bone Marrow Mesenchymal Stem Cells in Postmenopausal Osteoporotic Mice

Background: Osteoporosis (OP) is a metabolic bone disease syndrome for which there is no good treatment. In this study, we investigated the expression changes of miR-181c-5p in osteoporosis-derived BMMSCs, and the role and molecular mechanism in the osteogenic-lipogenic differentiation of BMMSCs. Methods: In this study, an OP mouse model was successfully established using the ovariectomy method, and osteoporotic-derived BMMSCs (O-BMMSCs) and sham-operated-derived BMMSCs (S-BMMSCs) were isolated and cultured using the whole bone marrow method. A genetic screen revealed that miR-181c-5p was differentially expressed in O-BMMSCs and S-BMMSCs. The expression levels of miR-181c-5p in BMMSCs were overexpressed or inhibited by cell transfection, and the regulatory effects of miR-181c-5p on the proliferation and osteogenic-adipogenic differentiation of BMMSCs were examined using MTT, multi-directional differentiation induction, alizarin red staining, oil red O staining, qRT-PCR and Western blot. Candidate target genes for miR181c-5p were screened by target gene prediction software and bioinformatics websites, and target gene validation was performed. Results: The study found that overexpression of miR-181c-5p or inhibition of miR-181c-5p had no significant effect on the proliferation ability of BMMSCs. Upregulation of miR-181c-5p could reduce the osteogenic ability and enhance the adipogenic ability of BMMSCs, while downregulation of miR-181c-5p could increase the osteogenic ability and inhibit the adipogenic ability of BMMSCs. Besides, Foxo1 was confirmed as a direct target gene of miR-181c-5p, and miR-181c-5p negatively regulated Foxo1 expression. Downregulation of miR-181c-5p in O-BMMSCs promoted Foxo1 expression, improved the osteogenic differentiation of O-BMMSCs, and reduced abnormal lipogenic differentiation of O-BMMSCs and eventually partially restored the normal differentiation ability of O-BMMSCs. Conclusion: miR-181c-5p regulated the osteogenic and adipogenic differentiation of BMMSCs by negatively regulating the expression of target gene Foxo1. The overexpression of miR-181c-5p in the process of osteoporosis leads to the disruption of the balance of osteogenic and adipogenic differentiation of BMMSCs, and reduces the bone formation ability of stem cells.