Fig. 8

METTL3 knockdown caused postsynaptic damage and neurite degeneration in primary neuronal culture. (A, B) Primary cortical neurons were transfected with GFP-shRNA at DIV12. Dendritic spine morphology (A) was examined by GFP fluorescence 4 days after transfection. Quantification shows dendritic spine number (B) was decreased by METTL3 knockdown in primary cortical neurons. For each neuron, dendritic segments with 100-200 μm in length beginning 100 μm from the cell body were selected for analysis (n = 39 neurons in each group). (C-H) Primary cortical neurons were infected by AAV-GFP-shRNA at DIV7. About 8–9 days after infection, primary neurons were extracted for immunoblot analysis (C) and immunofluorescence analysis (E, G). Quantifications shows decreased PSD95, but not Synaptophysin, after METTL3 depletion by immunoblot analysis (D) and immunofluorescence analysis (F), respectively. Quantification reveals reduced immunoreactivity of dendritic marker MAP 2 in shMettl3-infected neurons (H). (Data are means±SEM from at least 3 independent experiments, *p < 0.05, ***p < 0.001; B, D, F, H unpaired student’s t-test)