Fig. 5

Staurosporine significantly increases ARNT2 protein levels. a Enriched neuronal cultures were treated with staurosporine at different doses for 24 h prior to analysis. Lines and whiskers indicate mean and standard deviation from results in three experiments with representative blots. *p ≤ 0.05 repeated measures ANOVA on ranks with Tukey’s multiple comparison test to vehicle (0.1% DMSO)-treated cells. b Phase microscopy images show dead/dying neurons following exposure to 500–1000 nM staurosporine. No change in % cytotoxicity as measured by LDH release was observed (data not shown). Enriched neuronal cortical cultures were treated with 1 μM staurosporine for 6 or 12 h and stained for NeuN to distinguish neurons for c ARNT2 and d cleaved caspase 3 intensity. Data points represent cells pooled from 11 random regions from wells treated in duplicate. *p ≤ 0.05 ANOVA followed by Bonferroni’s multiple comparisons test to vehicle-treated cells; bars represent the average mean intensity and whiskers the SEM. e Representative images from the wells analyzed in c and d reveal NeuN⁺ cells in vehicle-treated wells that stain brightly (asterisk) or faintly (circumflex accent) for ARNT2; cleaved caspase-3 staining (red) is negligible. With 6 or 12 h exposure to staurosporine (STS), ARNT2 intensity is significantly lowered in neurons (arrows) whereas Caspase3⁺ intensity increases in NeuN⁺ cells (circled)