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. Author manuscript; available in PMC: 2019 Apr 1.
Published in final edited form as: Mol Cell Neurosci. 2017 Dec 12;88:43–52. doi: 10.1016/j.mcn.2017.12.005

Figure 1. HD cells are more vulnerable to MG132-induced proteotoxicity.

Figure 1

A. Prolonged MG132 treatment causes more cell death in STHdhQ111 cells. STHdhQ7 and Q111 cells were incubated with 10 µM MG132 and/or 50 µM CQ for 16 hours as indicated. Cell viability was measured by ATP luminescence assay. ****p<0.0001; **p<0.01, *p<0.05, compared to their relative controls or as indicated. ####p<0.0001; ##p<0.01, STHdhQ111 compared to STHdhQ7 cells in the same treatment group. N=3 for each group. Two-way ANOVA with the Tukey’s post-hoc analysis. B. Representative Western blot from three independent experiments demonstrate that MG132 but not CQ treatment causes a significant accumulation of polyUb proteins in STHdhQ7 and Q111 cells. Both cells were treated with 10 µM MG132 or 50 µM CQ for 16 hours. Cell lysates were analyzed with antibodies against ubiquitin by Western blot. Actin was used as the loading control. C. Quantification of polyUb proteins in B by densitometry. *p<0.05, **p<0.01, compared to their relative controls. #p<0.05, STHdhQ111 vs. STHdhQ7, N=3 for each group. Student’s t-test. D. STHdhQ111 cells are more vulnerable to cell death after removal of proteotoxic stress. Cells were treated with 10 µM MG132 for 6 hours. After incubation, MG132 was removed and cells were further incubated in the complete medium for 18 hours. Cell viability was measured by ATP luminescence assay. ns, not significant; ****p<0.0001, compared to their respective MG132-treated groups. ####p<0.0001, STHdhQ111 compared to Q7 cells in the recovery group. N=7 for CTL and MG132 treated groups, N=10 for recovery groups. Two-way ANOVA with the Tukey’s post-hoc analysis. E. HD fibroblasts (GM04693 and GM05539) are more vulnerable to cell death after stress recovery or prolonged MG132 treatment. Cells were treated with 10 µM MG132 for the indicated time. At the end of the 6-hours incubation, MG132 was removed and cells were further incubated in the complete medium for 18 hours. Cell viability was measured by ATP luminescence assay. ns, not significant; **p<0.001, ***p<0.0001, compared to their respective control groups. ##p<0.001, HD fibroblasts compared to the healthy control in the same treatment group. N=4 for each group. Two-way ANOVA with the Tukey’s post-hoc analysis.