Basic fibroblast growth factor induces miR-134 upregulation in astrocyte for cell maturation

Evidence suggests that neuronal microRNAs (miRs) contribute to synaptic plasticity, although a role of glial miRs have been unknown. Growth factors including brain-derived neurotrophic factor (BDNF) regulate neuronal functions via upregulation of miRs, while possible influences on expression/function of glial miRs have not been fully understood. Here, we report that basic fibroblast growth factor (bFGF) increased miR-134 expression in astrocyte. The miR-134 was upregulated through stimulating extracellular signal-regulated kinase and phosphatidylinositol 3-kinase signaling, because inhibitors for each signaling blocked the miR-134 induction by bFGF. We also found upregulation of glial fibrillary acidic protein (astrocyte marker) and decreased extracellular concentration of glutamate after miR-134 overexpression and bFGF application, suggesting that astroglial cell maturation is enhanced by bFGF through induction of miR-134.