Effect of Sirtuin1 (Sirt1) on Bone Marrow Mesenchymal Stem Cells (BMSCs) Osteogenesis/Adipogenesis via β-Catenin/The Transcription Factor T Cell Factor 1 (TCF1)/Runt-Related Transcription Factor 2 (RUNX2)

Abstract

Bone marrow mesenchymal stem cells (BMSCs) have self-renewal potential. Sirt1 regulates cell differentiation and apoptosis. However, Sirt1’s effect on BMSCs osteogenic/adipogenic differentiation has not been fully elucidated. SD rats were randomly divided into Osteoporosis (OP) group and sham operation group. OP rat BMSCs were isolated and assigned into control group, NC group and Sirt1 siRNA group followed by analysis of Sirt1 level by Real-time PCR, cell proliferation by MTT assay, expression of OC, OPN and FABP4 level by real time PCR, and β-Catenin/TCF1/Runx2 protein expression by Western blot. In OP group, Sirt1 expression was significantly increased and BMSCs proliferation was decreased along with reduced OC and OPN mRNA expression, increased FABP4 expression and reduced β-Catenin/TCF1/Runx2 expression compared with sham operation group (P < 0.05). In Sirt1 siRNA group, Sirt1 expression was significantly reduced, BMSCs proliferation was increased, OC and OPN mRNA expression was increased, FABP4 expression was decreased, and β-Catenin/TCF1/Runx2 expression was increased compared to OP group (P < 0.05). Sirt1 is increased in osteoporosis. Down-regulating Sirt1 in osteoporotic BMSCs can regulate β-Catenin/TCF1/Runx2 signaling and promote BMSCs osteogenic differentiation and inhibit adipogenic differentiation.