Fluid flow modulates the expression of genes involved in the Wnt signaling pathway in osteoblasts in 3D culture conditions.

The balance between osteoclastic bone resorption and osteoblastic bone formation maintains bone mass, while mechanical loads stimulate bone formation and suppress resorption. The molecular mechanisms responsible for this process have not yet been fully elucidated. In the present study, we assessed whether mechanical stimulation by pulsating fluid flow (PFF) leads to functional Wnt production and affects the function of osteoblasts. ROS17/2.8 osteoblasts were submitted to 1-4 h PFF (0.8 Pa) by three-dimensional (3D) cell culture system with fluid flow. PFF upregulated the gene expression levels of adenomatous polyposis coli, alkaline phosphatase, low density lipoprotein receptor-related protein 5 (LRP5), Wnt3a and ß-catenin [catenin beta 1 (CTNNB1)] in all the groups of osteoblasts. Our results suggest that mechanical stimulation by PFF induces the differentiation of osteoblasts and the activation of the Wnt/ß-catenin signaling pathway in a 3D cell culture system. Furthermore, mechanical stress plays an important role in the Wnt/ß-catenin signaling pathway and is involved in bone formation.