Figure 2

Tau deletion protects neurons from E-NMDAR-triggered neuronal death and degeneration in cortical neurons. (a) Primary cultured mouse cortical neurons at DIV 12–14 were subjected to extrasynaptic NMDAR activation for 12 or 24 h. The level of LDH released into the culture medium was determined by measuring the decrease in absorbance at 490 nm resulting from the oxidation of NADH. LDH levels in wildtype (Wt, left) or tau knockout (tau Ko, right) neurons treated with DMSO (Ctrl) or extrasynaptic NMDAR activation protocols (E-NMDAR) during the indicated times (12 or 24 h). *P<0.05, **P<0.01 and ***P<0.001 versus control group, n=20, N=3 independent cultures. (b) Quantification of apoptotic cells in Wt (left) or tau Ko (right) neuron cultures exposed to extrasynaptic treatment for 24 h. Quantification of the cell populations was achieved on four independent cultures. About 6000 cells were evaluated in each group. *P<0.05 versus control group. (c) Wt mouse primary cortical neurons at 5 DIV were transfected with EGFP by lentivirus. At 12 DIV, neurons were subjected to extrasynaptic NMDAR activation for 24 h. Morphological changes of EGFP-labeled neurons treated with DMSO (Ctrl) or the extrasynaptic NMDA receptor activating protocol for 24 h (E-NMDAR). Images were acquired by confocal microscopy. White arrows showed abnormal neurodegeneration. (d) Representative neuron images from tau Ko mouse cortical neurons treated with DMSO (Ctrl) or E-NMDARs activation protocol (E-NMDAR) for 24 h, neurons were directly fixed and visualized under the fluorescence microscope. Scale bar=50 μm