Fig. 1: Frizzled 1 and Frizzled 7 are downregulated in early AD.

A Scheme representing a synapse showing the localisation at pre- and/or post-synaptic sides for Fzd1, Fzd5, Fzd7 and Fzd9. B qPCR analyses showing reduced mRNA levels of FZD1 and FZD7 in human hippocampal samples from Braak stages I-III (BI–III) subjects compared to controls. No changes are observed for FZD5 and FZD9 in early AD. C qPCR analysis shows the reduced mRNA levels of Fzd1 and Fzd7 in 2-month-old hAPP^NLGF/NLGF hippocampus (NLGF). No differences in Fzd5 and Fzd9 levels are observed in NLGF hippocampal mRNA. D Representative smFISH images of WT and NLGF CA1 hippocampal region. First column shows merged images with DAPI (blue), Fzd1 (green), Fzd7 (yellow) and Rbfox3 (magenta) mRNAs. Fzd1 in black (second column) and its representative neuronal Rbfox3⁺ cells corresponding to 3 and >3 Fzd1 copies (third column). Fzd7 in black (fourth column) and its representative cells corresponding to one Fzd7 copy (fifth column). Scale bars represent 50 µm and 12.5 µm in the zoomed inserts. Single-cell analyses expressed as H-score for Fzd1 (E) and Fzd7 (F) in neuronal (Rbfox3⁺) and non-neuronal (Rbfoz3^-) cells. Single-cell distribution of neurons (Rbfox3⁺) containing 1, 2, 3 or >3 transcripts for Fzd1 (G) or Fzd7 (H). Data are represented as mean + SEM. Statistical analysis by t Test in B for FZD1, FZD7 and FZD9 and by Mann-Whitney for FZD5; in C t-Test for all genes analysed; in E and F t-Test for neuronal and non-neuronal; in G t-Test for 1, 2 and 3 copies and by Mann-Whitney for >3 copies; in H t-Test for 1 and 2 copies and by Mann-Whitney for 3 and >3 copies. N is indicated in each bar by the number of symbols. Asterisks indicate *p < 0.05; **p < 0.01, ***p < 0.005.