MiRNA-7b-5p attenuates the progression of osteoporosis by inhibiting adipose differentiation of hMSCs via regulating IRS2

Q.-Q. Li, Q. Wei, X.-C. Zhai, L. Qin, H.-B. Li, R. Meng, S.-C. Chen

Department of Orthopedics, Shanxian Central Hospital, Heze, China. shancheng_2008@163.com

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• Orthopedics

OBJECTIVE: To elucidate whether microRNA-7b-5p (miRNA-7b-5p) could inhibit adipose differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) through regulating IRS2, thereby alleviating the progression of osteoporosis.

MATERIALS AND METHODS: Expression levels of miRNA-7b-5p and IRS2 in hMSCs at different stages of adipogenic differentiation and osteogenic differentiation were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot. After transfection of miRNA-7b-5p mimic or pcDNA-IRS2 in hMSCs, lipid droplet formation in cells was observed by oil red O staining. Expressions of C/EBPα and PPARγ were detected by qRT-PCR and Western blot. The potential target gene of miRNA-7b-5p was predicted by bioinformatics and verified by dual-luciferase reporter gene assay. Finally, expressions of IRS2 in hMSCs transfected with miRNA-7b-5p-NC, miRNA-7b-5p mimic or co-transfected with miRNA-7b-5p mimic and pcDNA-IRS2 were examined.

RESULTS: Expressions of miRNA-7b-5p and IRS2 gradually decreased with the prolongation of adipogenic differentiation, but increased during osteogenic differentiation of hMSCs. Transfection of miRNA-7b-5p mimic reduced oil red O staining after adipogenic differentiation and downregulated mRNA and protein levels of C/EBPα and PPARγ. Transfection of pcDNA-IRS2 increased oil red O staining after osteogenic differentiation and upregulated mRNA and protein levels of C/EBPα and PPARγ. Dual-luciferase reporter gene results showed that miRNA-7b-5p could bind to IRS2. Overexpression of IRS2 reversed the downregulated mRNA and protein levels of adipogenic-related genes C/EBPα and PPARγ due to the overexpression of miRNA-7b-5p.

CONCLUSIONS: MiRNA-7b-5p inhibits the adipogenic differentiation of hMSCs through IRS2, thus alleviating the development of osteoporosis.

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