Fig. 6: CUL4B deficiency impairs neurogenesis through activating PP2A.

A qRT-PCR analysis of PPP2R2B and PPP2R2C expression in the isogenic control (Correct) and the patient-derived (Patient) NPCs. N = 3. B Western blots of p-AKT, AKT, p-ERK, ERK, PPP2R2B and PPP2R2C proteins in the indicated NPC cultures. C Western blots of PPP2R2B and PPP2R2C in day-28 organoids. D The PP2A activity in the indicated groups. N = 6. The values were normalized to the average in the Correct group. E Ki67 staining (green) of the indicated NPC cultures at 48 h after EdU labeling (red). Scale bar, 50 μm. N = 12. F Western blots showing the effect of LB-100 and SMAP treatment on phosphorylation of AKT and ERK in organoids. In (B, C and F), the number below each band is the normalized ratio between the intensity of the band and the intensity of GAPDH band from the same sample. G The effect of LB-100 and SMAP treatment on the size of day-50 cerebral organoids. Each data point represents the area of a single organoid. N = 20. H Quantification of the thickness and area of the PAX6⁺ layer in day-35 organoids. N = 14-20. I Ki67 staining (green) of the indicated organoids at 48 h after EdU labeling (red). Scale bar, 50 μm. N = 14. J Quantification of the percentage of CTIP2⁺ cells and TBR2⁺ cells in day-55 organoids. 14 to 20 neural tube-like regions in at least 7 organoids per group were counted. Data are presented as the mean ± SEM. The statistical significance was determined using one-way ANOVA with Tukey test. *P < 0.05; **P < 0.01; ***P < 0.001. ns: no significance.