FIGURE 8.

Viability of H-END cells upon exposure to soluble (A, gray) or fibrillar (B, black) α-Syn in the absence or presence of Hsc70 and/or Hdj1 or Hdj2, as indicated. Before exposure to cells, soluble or fibrillar α-Syn (100 μm) was incubated for 1 h at 37 °C with Hsc70 (25 μm), Hdj1 (25 μm), Hdj2 (25 μm), Hsc70 and Hdj1 (25 μm each protein), or Hsc70 and Hdj2 (25 μm each protein). Fibrillar α-Syn was centrifuged for 20 min at 16,100 × g and the pellet was resuspended in the culture medium to remove unbound Hsc70, Hdj1, or Hdj2. The final protein concentration within the culture medium was 1 μm. The cells were incubated with the different proteins for 24 h. Cell viability is expressed as the percentage of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction using cells treated with the same volume of buffer as a reference (100% 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction). The values are averages ± S.D. obtained from three independent experiments.