Fig. 2

Elongated primary cilia and upregulated 5-HT6 in the hippocampus of APP/PS1 mice. (a) Primary cilia marker AC3 (green) indicated the primary cilia in brain sections from APP/PS1 and WT C57 mice by immunofluorescence staining in vivo. DAPI (blue) was used to indicate cell nuclei. Scale bars, 500 μm. (b) Primary cilia were elongated in the hippocampus of APP/PS1 mice. Scale bars, 10 μm. (c) Primary cilia of the hippocampus were obviously elongated in the hippocampus of APP/PS1 mice. Cilia length, **p < 0.01 (t test). The number of primary cilia (normalized to the number of cell nuclei) was similar in the hippocampus of APP/PS1 and WT mice. Number of cilia, p = 0.76 (Mann–Whitney U test). (d) Primary cultures of hippocampal neurons showed that the length of primary cilia was increased by immunostaining in vitro. ARL13B (red) and 5-HT6 (purple) indicated primary cilia. MAP2 (green) was used as a neuronal marker. DAPI (blue) indicated cell nuclei. (e) Primary cilia were elongated in primary cultures of hippocampal neurons from APP/PS1 and WT mice. Cilia length, **p < 0.01 (t test). (f) Protein levels of 5-HT6 and GAPDH in the hippocampus, PFC, olfactory blub, striatum, diencephalon, cerebellum, and whole brain of APP/PS1 and WT mice. GAPDH was used as an internal control. (g) In APP/PS1 mice, the protein level of 5-HT6 (normalized to GAPDH) was significantly increased in the hippocampus. Hippocampus, *p < 0.05; PFC, *p < 0.05; olfactory blub, p = 0.62; striatum, p = 0.22; diencephalon, p = 0.57; cerebellum, p = 0.71; whole brain, p = 0.13 (Mann–Whitney U test). All data presented as mean ± SEM (≥3 independent experiments). 5-HT6, serotonin 6 receptor, DAPI 4',6-diamidino-2-phenylindole