Fig. 5

METTL3 knockdown in the hippocampus caused neurodegeneration and dendritic spine loss. (A-B) Representative immunohistochemistry images (A) of NeuN or cresyl violet staining (Nissl staining) in the hippocampus of shRNA-injected mice and quantifications (B) of relative cell numbers in GFP-positive area. (C-D) Representative immunohistochemistry images (C) and quantifications (D) of caspase 9 and cleaved caspase 3 in the GFP-positive hippocampal regions of shRNA-injected mice. (E-F) TUNEL staining (Excitation laser wavelength 488 nm) was performed in GFP (Alexa Fluor 568) stained hippocampal sections from shRNA-injected mice (E) and quantifications of relative TUNEL-positive cell numbers in GFP-positive regions were shown (F). (G-J) Golgi staining was performed to reveal the spine structures in hippocampal CA1 neurons 4 weeks after AAV-GFP-shRNA injection (G). Quantification shows that dendritic spine number (H) and mushroom spine number (I, J) in CA1 neurons are decreased by METTL3 depletion. (A-F, n = 4–6 mice in each group; H-J, 22–31 random dendrites from 4 mice were analyzed) (Data are means±SEM, *p < 0.05, ***p < 0.001, B, D, F, H-J unpaired student’s t-test)