BMS-204352 at 10 μM rescues dendrite spines maturation in Fmr1 KO neurons cultures. (a) Representative pictures of neuron dendrites in different culture conditions with BMS-204352 (5 or 10 μM) or with only its vehicle (DMSO 0.1%). Red arrows indicate filopodia. Scale bar = 10 μM (b) Filopodia length ( M) and (c) density (nbr/10 μM) were investigated in each condition. A two-way ANOVA revealed that vehicle-treated Fmr1 KO neurons showed a significantly higher filopodia length and density compared to vehicle-treated WT neurons. Acute treatment (4 hrs) with BMS-204352 10 μM corrected the Fmr1 KO dendritic spine phenotype, whereas, BMS-204352 5 μM had no significant effect on Fmr1 KO neurons. NS, not significant; ***p < 0.001 for genotype comparison; #p < 0.05 for treatment comparison; n = 60 neurons (from 10 mice) in all groups. Data represent mean ± s.e.m.