Figure 3

At nanomolar concentrations, curcumin slightly reduces aggregate size and at micromolar concentrations, curcumin increases aggregate size in PC12 cells inducibly expressing exon 1 of mutant htt [42]. Cells were induced with 0.1 μM tebufenozide and treated with curcumin (5 nM, 50 nM, 500 nM, 5 μM, 10 μM or 20 μM) or vehicle (DMSO) at the same time. Uninduced cells (treated with EtOH (vehicle) were used as a control for expression of the mutant protein) are not shown. At 48 h, cells treated with 5 nM curcumin show an 8% reduction in size of aggregates compared to vehicle-treated induced cells (no curcumin). At 48 h and at 72 h, 10 or 20 μM increase aggregate size markedly, possibly reflecting curcumin's effect on the UPS at micromolar concentrations [43]. Data shown are of the mean ± sem of n = 4 independent experiments.