Tanshinone IIA promotes osteogenic differentiation potential and suppresses adipogenic differentiation potential of bone marrow mesenchymal stem cells.

Tanshinone IIA (Tan IIA) may have therapeutic effects on avascular necrosis of the femoral head (ANFH) by targeting bone marrow mesenchymal stem cells (BMSCs). The effect and underlying mechanism of Tan IIA on adipogenesis and osteogenesis ability of BMSCs remain to be elucidated. In the present study BMSCs were treated with osteogenic or adipogenic differentiation medium with or without Tan IIA under hypoxic environment. Osteogenic differentiation potential was evaluated by alkaline phosphatase (ALP) measurement, alizarin red staining and reverse transcription‑quantitative (RT‑q) PCR of osteogenic marker genes. Adipogenic differentiation potential was evaluated with oil red staining and RT‑qPCR of adipogenic marker genes. Detailed mechanism was explored by RNA‑seq and small molecular treatment during osteogenesis and adipogenesis of BMSCs. ALP level, mineralized nodules and expression level of osteogenic marker genes significantly increased following Tan IIA treatment during osteogenic differentiation of BMSCs. Lipid droplet and expression levels of adipogenic marker genes significantly decreased following Tan IIA treatment during adipogenic differentiation of BMSCs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses of RNA‑seq data indicated increased Akt and TGFβ signaling following Tan IIA treatment. Further western blot assay confirmed that Tan IIA significantly activated Akt/cAMP response element‑binding protein signaling and TGFβ/Smad3 signaling. Application of Akti1/2 (an Akt inhibitor) significantly decreased the promotion effect of osteogenesis induced by Tan IIA, while the addition of SB431542 significantly reduced inhibition effect of adipogenesis caused by Tan IIA. Tan IIA could promote osteogenic differentiation potential of BMSCs by activating AKT signaling and suppress adipogenic differentiation potential of BMSCs by activating TGFβ signaling.