Fibroblast Growth Factor Receptor-2 Contributes to the Basic Fibroblast Growth Factor-Induced Neuronal Differentiation in Canine Bone Marrow Stromal Cells via Phosphoinositide 3-Kinase/Akt Signaling Pathway

Bone marrow stromal cells (BMSCs) are considered as candidates for regenerative therapy and a useful model for studying neuronal differentiation. The role of basic fibroblast growth factor (bFGF) in neuronal differentiation has been previously studied; however, the signaling pathway involved in this process remains poorly understood. In this study, we investigated the signaling pathway in the bFGF-induced neuronal differentiation of canine BMSCs. bFGF induced the mRNA expression of the neuron marker, microtubule associated protein-2 (MAP2) and the neuron-like morphological change in canine BMSCs. In the presence of inhibitors of fibroblast growth factor receptors (FGFR), phosphatidylinositol 3-kinase (PI3K) and Akt, i.e., SU5402, LY294002, and MK2206, respectively, bFGF failed to induce the MAP2 mRNA expression and the neuron-like morphological change. bFGF induced Akt phosphorylation, but it was attenuated by the FGFR inhibitor SU5402 and the PI3K inhibitor LY294002. In canine BMSCs, expression of FGFR-1 and FGFR-2 was confirmed, but only FGFR-2 activation was detected by cross-linking and immunoprecipitation analysis. Small interfering RNA-mediated knockdown of FGFR-2 in canine BMSCs resulted in the attenuation of bFGF-induced Akt phosphorylation. These results suggest that the FGFR-2/PI3K/Akt signaling pathway is involved in the bFGF-induced neuronal differentiation of canine BMSCs.