SATB2 Potentiates BMP9-induced Osteogenic Differentiation Of Mesenchymal Stem Cells

Objective: To study the effect special AT-rich sequence-binding protein(SATB2) on BMP9-induced osteogenic differentiation of mesenchymal stem cell(MSCs), and explore the related mechanism.Methods: Firstly, C2C12, C3H10T1/2, and MEFs cells were infected with Ad-BMP9/Ad-GFP, and the expression of SATB2 were detected by RT-PCR and Western Blot at 2 and 3 days post-treatment; a recombinant adenovirus-expressing human SATB2 was constructed by Ad Easy system. Secondly, C2C12, C3H10T1/2, and MEFs cells were handled with Ad-SATB2/Ad-RFP, and then treated with BMP9 condition medium, alkaline phosphatase(ALP) activity were measured by quantitative chimiluminescence assay and cytochemical staining at 5, 7 days post-treatment respectively; calcium deposition were detected by alizarin red S at 14 days post-treatment; the expression of Id1, Id2, Id3 and transcription factor Runx2, Osterix, Dlx5 were measured by Q-PCR and Western Blot. Finally, transcriptional activity of Smad1/5/8 were assessed by Luciferase Reporter Assay.Conclusion: Firstly, BMP9 can induce the expression of SATB2; next, SATB2 can induce the expression of osteogenesis related transcription factors, early and late osteogenic differentiation of MSCs, and strengthen the expression of the BMP9-induced osteogenesis related transcription factors, early and late osteogenic differentiation of MSCs; SATB2 can promote osteogenic differentiation of MSCs through regulating the transcriptional activity of Smad1/5/8.