Fig. 3

Synaptic transmission is increased in VKI and altered by acute LRRK2 kinase inhibition. A Cortical neurons immunostained for PSD95 (cyan) and VGluT1 (magenta) (i). There was no genotype effect on VGluT1-PSD95 co-clusters (ii, 1-way ANOVA p = 0.57). B Whole-cell patch voltage clamp recording of mEPSCs in cortical neurons (i). There were significant shifts in frequency cumulative probabilities due to significantly smaller inter-event intervals in cells from both genotypes (ii, 2-way RM ANOVA WT-Het interaction p < 0.0001; genotype p < 0.03; 2-way RM ANOVA WT-Ho interaction p < 0.0001; genotype p < 0.11; Uncorrected Fisher’s LSD ***p < 0.001; **p < 0.007; *p < 0.05). Significant shifts were seen in amplitude cumulative probabilities due to increases in heterozygous and homozygous cells (iii, 2-way RM ANOVA WT-Het interaction p < 0.0001; genotype p < 0.03; 2-way RM ANOVA WT-Ho interaction p < 0.002; genotype p < 0.09; Uncorrected Fisher’s LSD ****p < 0.0001; ***p < 0.004; **p < 0.01; *p < 0.05). C Western blot of MLi-2 or vehicle treated cortical culture lysates probed for Rab10, Rab10 pT73, and GAPDH (i). There were significant genotype and treatment effects on Rab10 pT73 due to significant increases in vehicle-treated homozygous neurons over WT, which are significantly reduced by treatment (ii, 2-way ANOVA genotype x treatment p < 0.08; genotype p < 0.03; treatment p < 0.0004; Uncorrected Fisher’s LSD WT-Ho *p < 0.01; WT-WTMLi2 p = 0.99; Het-HetMLi2 p = 0.26; Ho-HoMLi2 **p < 0.005). D Cortical neurons immunostained as in A) plus MAP2 (blue) following MLi-2 or vehicle treatment (i). There were no significant effects on PSD95-VGluT1 co-cluster density (ii, 2-way ANOVA genotype x treatment p = 0.08; genotype p = 0.52; treatment p = 0.68; All groups n = 40[4]). E Whole-cell patch voltage clamp recording of mEPSCs in cortical neurons following MLi-2 treatment (i). Change in mEPSC frequency following treatment revealed a significant genotype effect due to a ~ two-fold increase in mEPSC frequency in only WT cells following treatment (ii, Kruskal–Wallis p < 0.04; Uncorrected Dunn’s WT-Ho **p < 0.01). Change in mEPSC amplitude following treatment revealed a significant genotype effect due to mildly opposing effects in heterozygous and homozygous cultures (iii, Kruskal–Wallis p < 0.03; Uncorrected Dunn’s Het-Ho **p < 0.01)