Figure 1.

(A) Dose-dependent effect of fisetin on the survival of PC12/Htt^Q103 cells. Cells were un-induced or induced with 5 μm PA in N2 medium to express the entire Htt exon 1 fused to EGFP. Such cells typically form Htt protein aggregates (B) and die within 3–4 days. Fisetin was added to the un-induced cells or the induced cells at the time of induction. After 72h, cell survival was measured by the MTT assay. The results are plotted as the percentage cell survival in induced cells relative to un-induced cells and are the average ± SD of four independent experiments. (B) PC12/Htt^Q103 cells induced with 5 μm PA in the absence (control) or presence (+fisetin) of 10 μm fisetin were examined after 48 h by fluorescence microscopy to assess the presence and localization of Httex1-103QP-EGFP. Fluorescent aggregates were counted in five random fields from both control and fisetin-treated cells. (C) PC12/Htt^Q103 cells were induced with 5 μm PA in the absence (control) or presence (fisetin) of 10 μm fisetin. After 48 h, cell extracts were prepared and equal amounts of protein were analyzed by SDS–PAGE and immunoblotting with antibodies to GFP and actin as a loading control. A representative blot is shown. Similar results were obtained in three independent experiments. The average GFP signal from the fisetin-treated cells, quantified by densitometry, normalized to actin and then normalized to the levels of GFP in the absence of fisetin, was plotted as ±SD.