Glial cell line-derived neurotrophic factor promotes survival and induces differentiation through the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathway respectively in PC12 cells.

PC12-GFRalpha1 cells, a clonal cell line engineered to express glial cell line-derived neurotrophic factor receptor alpha1 were constructed. Given glial cell line-derived neurotrophic factor could induce the differentiation and promote the survival of PC12-GFRalpha1 cells at low concentrations, the cells provide an unlimited source of monoclonal cells for studies on the signal transduction pathway of glial cell line-derived neurotrophic factor. To characterize the involvement of the mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways in the biological effect of glial cell line-derived neurotrophic factor, we used the mitogen-activated protein kinase kinase inhibitor PD98059 and the phosphatidylinositol 3-kinase inhibitor LY294002. PD98059 blocked glial cell line-derived neurotrophic factor-induced PC12-GFRalpha1 cells neurite formation in a dose-dependent manner, without significantly altering cell viability. LY294002 reversed the survival-promoting effect of glial cell line-derived neurotrophic factor on the PC12-GFRalpha1 cells in serum-deprived medium. The present study demonstrates that phosphatidylinositol 3-kinase pathway seems to mediate the survival-promoting effect of glial cell line-derived neurotrophic factor on PC12-GFRalpha1 cells, while the activation of mitogen-activated protein kinase pathway could be an important step in mediating PC12-GFRalpha1 cells differentiation induced by glial cell line-derived neurotrophic factor. Therefore, it is inferred that similar intracellular signaling components are used by distinct growth factors toward a common biological effect.