Cysteine Dioxygenase Type 1 Inhibits Osteogenesis by Regulating Wnt Signaling in Primary Mouse Bone Marrow Stromal Cells

Mesenchymal stem cells (MSCs) are multipotent cells, which can give rise to variety of cell types, including adipocytes and osteoblasts. Previously, we have shown that cysteine dioxygenase type 1 (Cdo1) promoted adipogenesis of primary mouse bone marrow stromal cells (BMSCs) and 3T3-L1 pre-adipocytes via interaction with Pparγ. However, the role of Cdo1 in osteogenesis remains unclear. Here, we demonstrated that expression of Cdo1 was elevated during osteoblastic differentiation of BMSCs in vitro. Interestingly, knockdown of Cdo1 by siRNA led to an increased expression of osteogenic related genes, elevated alkaline phosphatase (ALP) activity, and enhanced mineralization. Overexpression of Cdo1 in BMSCs inversely suppressed the osteogenesis. Furthermore, we found that overexpression of Cdo1 impaired Wnt signaling and restricted the Wnt3a induced expression of osteogenic transcriptional factors, such as Runx2 and Dlx5. Collectively, our findings indicate Cdo1 suppresses osteogenic differentiation of BMSCs, through a potential mechanism which involves in Wnt signaling reduction concomitantly.