Figure 6.

WST-1 assay of mouse spinal cord x neuroblastoma hybrid (NSC-34) cells differentiated (NSC-DIFF) for either 7, 14, 21, or 28 days revealed an increased sensitivity of NSC-DIFF to arginine-rich dipeptide repeat proteins (DRPs) with increased differentiation state. Cells treated with poly-glycine-arginine (GR₁₅) or poly-proline-arginine (PR₁₅) exhibited similar patterns of decreasing WST-1 absorbance with DRP treatment at each time point (a,b). Decreasing WST-1 absorbance with differentiation state was not observed in non-arginine containing DRPs poly-glycine-proline (GP₁₅) and poly-proline-alanine (PA₁₅) (c,d). Data are presented as average % values ± standard deviations (error bars). % values indicate the % change in toxicity DRP-treated or Dimethyl Sulfoxide (DMSO)-treated cells exhibited in comparison to untreated cells. DMSO values (gray) are calculated as an average of the four time points at each dose tested. Average value for untreated control is indicated with a dotted line. Statistical significance calculations are included in Table 1 and Table 2 below.