MiR-203 is essential for the shift from osteogenic differentiation to adipogenic differentiation of mesenchymal stem cells in postmenopausal osteoporosis

L. Qiao, D. Liu, C.-G. Li, Y.-J. Wang

Department of Arthropodidae, Shanghai Guanghua Hospitals of Traditional Chinese and Western Medicine, Shanghai, China. yjwang8888@126.com

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• Orthopedics

OBJECTIVE: The purpose of this study was to investigate how miR-203 promotes osteogenic differentiation of bone marrow mesenchymal cells (BMSCs) by regulating its target gene DKK1, thereby inhibiting the occurrence of osteoporosis.

PATIENTS AND METHODS: A total of 60 cases with postmenopausal osteoporosis and 40 cases of normal individuals were recruited. The expression of miR-203 in serum of all cases was detected by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). The capacity of osteogenesis and adipogenic differentiation of MSCs was determined by alizarin red staining and oil red staining, respectively. Transfection of miR-203 mimics and miR-203 inhibitor were mediated by Liposomes, and then the MSCs were induced osteogenic and adipogenic differentiation. MiR-203 mimic was co-transfected with wild-type or mutant DKK1 for luciferase reporter gene detection. In the osteoporosis model of rats, the tibia was taken for micro-CT examination of bone mineral density (BMD) and bone volume/structural parameters (BV/TV), while the femur was taken for the measurement of absorption parameters (Ob.S)./BS) and the number of osteoclasts per circumference of bone (N.Oc/B.Pm).

RESULTS: The expression level of miR-203 was significantly lower in patients with postmenopausal osteoporosis than that in normal individuals. The osteogenic capacity of BMSCs in these patients was reduced, while their adipogenic capacity was enhanced. MiR-203 promoted the expression of osteogenic genes and inhibited that of adipogenic genes. Knockdown of miR-203 decreased the level of osteogenic related genes but increased that of adipogenic related genes, while overexpression of miR-203 led to the opposite results. Furthermore, miR-203 inhibited the protein expression of DKK1. In addition, bone density and bone volume/structural parameters were lower in ovariectomized rats than those in normal rats. Meanwhile, bone resorption parameters and the number of osteoclasts per bone circumference in ovariectomized rats were higher than those in normal rats.

CONCLUSIONS: MiR-203 can promote osteogenic differentiation of mesenchymal stem cells by downregulating the gene expression of DKK1.

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