Figure 5.

Effects of NF-κB inhibitor on neuron-dependent promoter activation or GLT-1 expression. A, Cortical astrocytes were transfected (FuGENE) with a 958 bp wild-type GLT-1 promoter fragment and treated with NF-κB-SN50 inhibitor peptide or SM inactive control peptide (20 μm). Five days post-transfection, cultures were overlaid with a cell suspension containing neurons and astrocytes from wild-type E17 brain. Cells were harvested, and luciferase activity was measured after 10 d. Luciferase activity was normalized to β-galactosidase activity and expressed relative to that measured in astrocytes transfected with empty vector. B, GLT-1 protein levels were analyzed in the same samples. Ten micrograms of cell lysate was loaded in each lane. GLT-1 protein levels were normalized to actin and expressed relative to the levels observed in astrocytes (with neurons) treated with control peptide. Data are the mean ± SEM of three independent experiments. **p < 0.01, ***p < 0.001 compared with corresponding astrocyte control; ^#p < 0.05, ^###p < 0.001 compared with astrocytes with neurons and treated with control peptide.