Rsk protects against mhtt-induced cell death in striatal cells. (A) STHdhQ7/Q7 cells were transfected with full-length wild-type (FL-17Q htt) or mutant (FL-75Q htt) htt and then treated with the Rsk inhibitor BI-D1870 (0.1 μM; BI). Cell death was determined 72 hours after transfection using Hoechst 33258 staining and analyzing the condensation of the nucleus in transfected cells (cells expressing higher levels of htt). Representative photomicrographs show apoptotic nuclei in each condition. (B) STHdhQ7/Q7 cells were transfected with siCT, siRsk1, siRsk2 or siRsk1+siRsk2. Cells were lysed 72 hours after transfection and the levels of Rsk1, Rsk2 and tubulin were analyzed by western blot. (C) STHdhQ7/Q7 cells were co-transfected with FL-75Q htt and siCT, siRsk1, siRsk2 or siRsk1+siRsk2. Cell death was determined 72 hours after transfection using Hoechst 33258 staining. (D) STHdhQ7/Q7 cells were co-transfected with FL-75Q htt and HA or HA-Rsk to study cell death 72 hours later using Hoechst 33258 staining. Inset, A representative western blot showing the overexpression of Rsk 72 hours after transfection of STHdhQ7/Q7 cells with HA-Rsk. In all cases, results are shown as percentage of apoptotic nuclei versus total nuclei and are the mean ± SEM of three independent experiments performed in duplicate. Data were analyzed using two-way ANOVA followed by Bonferroni's post hoc test (A and C) and using a non-parametric t-test. In (A) *p < 0.05 as compared with FL-17Q htt-transfected cells and+p < 0.05 as compared with FL-75Q htt-transfected cells without BI-D1870 treatment; in (C) *p < 0.05 as compared with cells transfected with FL-75Q htt and siCT and in (D) *p < 0.05 as compared with cells transfected with FL-75Q htt and HA.