Visfatin induces neurite outgrowth in PC12 cells via ERK1/2 signaling pathway

The angiogenic and inflammatory functions of visfatin and its effect on vascular cells, are fairly well known. However, its role within the nervous system remains largely unclear. To gain insight into this area, we studied the neuritogenic effect of visfatin on PC12 rat pheochromocytoma cells. We investigated whether visfatin gene expression, which is upregulated by hypoxia in cancer cells, is associated with neuritogenesis in PC12 cells. Using RT-PCR, Western blot analysis, ELISA, morphological observations, and immunostaining, we initially showed that CoCl(2), a hypoxic mimetic agent, upregulated visfatin gene expression along with neurite outgrowth in PC12 cells. We also showed that visfatin stimulated neurite outgrowth in PC12 cells. Moreover, in PC12 cells, visfatin evoked the activation of the extracellular signal-regulated kinase 1/2 (ERK1/2), which is closely linked to neuritogenesis. Visfatin-induced outgrowth of neurites was prevented by inhibition of the ERK1/2 pathway. Taken together, our results demonstrate for the first time that visfatin induces neurite outgrowth in PC12 cells via the activation of an ERK-dependent pathway, and suggest that visfatin may exert various biological, physiological, and pathological functions in not only the vascular system but also the nervous system.