Secreted Frizzled-Related Protein 2 Promotes Osteogenic Differentiation and Bone Regeneration in Perthes Disease When Targeted by miR-106a-5p

Abstract

Although the pathogenesis of Perthes disease remains unclear, the mechanism of bone regeneration in the defective femoral head is an area of particular interest. Improving understanding of the underlying mechanisms is essential for the development of an effective treatment for this condition. This study explored the roles of secreted frizzled-related protein 2 (SFRP2) and micro ribonucleic acid (miR)-106a-5p in the regulation of osteogenic differentiation (in vitro) and bone regeneration (in vivo). Cells were transfected with plasmids carrying the genes encoding SFRP2 and miR-106a-5p. Cell proliferation and apoptosis were evaluated using 5-ethynyl-2′-deoxyuridine staining, flow cytometry and the terminal deoxynucleotidyl transferase dUTP nick end-labelling assay. Osteogenic differentiation was identified using alkaline phosphatase and alizarin red S staining. Reverse transcription quantitative polymerase chain reaction and western blot were used to assess messenger ribonucleic acid and protein levels. The dual-luciferase reporter gene assay was used to confirm the targeting relationship between miR-106a-5p and SFRP2. Changes in bone structure were evaluated by morphological observation, micro-computed tomography and alkaline phosphatase staining. The findings showed that SFRP2 significantly increased cell proliferation and osteogenic differentiation and inhibited apoptosis of bone marrow mesenchymal stem and MC3T3-E1 cells. It upregulated the expression of PCNA, Bcl-2, ALP, Col1a1, Runx2, Osterix, Wnt3a, β-catenin, LRP5 and LRP6, and downregulated that of Bax. Negative regulation of SFRP2 by miR-106a-5p (via the Wnt/β-catenin pathway) could rescue the influence of the latter; this showed that SFRP2 is a target gene of miR-106a-5p.In conclusion, miR-106a-5p/SFRP2 may play a crucial role in bone regeneration in the defective femoral head and may be a potential therapeutic target in Perthes disease.