Figure 1.
Conditioned media from Aβ-stimulated microglia induce neuron death in a TNFα-dependent manner. Conditioned Neurobasal media (CM) from primary mouse microglia (400 cells/mm2) stimulated for 48 h with or without (control) immobilized Aβ1-42 fibrils (48 pmol/mm2) was generated. A, Control and Aβ-stimulated conditioned media were applied to mouse cortical neuron cultures (E16; 7 d in vitro) for 72 h. Neurons were fixed in 4% paraformaldehyde, stained using anti-MAP2 antibody, and counted. Neurons from four fields/conditions were counted in quadruplicate wells and averaged ± SEM. The graph is representative of three independent experiments. B, Conditioned media were collected, and TNFα concentrations were determined via commercial ELISA. The graph is representative of three independent experiments. C, Cortical neurons were cultured for 72 h with unstimulated and Aβ-stimulated conditioned medium in the absence or presence of soluble TNFRI (0.1 μg/ml). Neurons were fixed, stained using anti-MAP2 antibody, counted as above, and averaged ± SEM. The graph is representative of three independent experiments. D, Media from plates containing increasing concentrations of immobilized Aβ (0, 48, 96, and 192 pmol Aβ1-42/mm2) alone were transferred to cortical neurons for 72 h. Neurons were fixed and counted, and statistical significance was determined as above. *p < 0.001 from control; **p < 0.001 from CM.