Figure 8

Effects of SMF on gangliosides GM3 and GD3 and IL-6. (A) mRNA levels increased for NEU3 and decreased for ST3GAL3 during the first 24 hours of SMF exposure consistent with a flow cytometry-measured reduction in GM3 (Panel B) and GD3/9-O-AcGD3 levels (the antibody used recognized both the 9-O-acetylated and hydroxyl forms of GD3, Panel C). (D) Data from three independent flow cytometry experiments are summarized; GM3 or GD3 levels are given as measured in the arbitrary units shown on the x-axis of Panels B and C. (E) IL-6, which led to a decrease in ganglioside levels in naïve cells (see Figure 6A) had no further effect on GM3 levels (or GD3 levels, not shown) in SMF-treated cells. (F) A time course of NEU3 and ST3GAL5 shows up- or down-regulation, respectively, over time points shorter than 24 h. Error bars for Panels A, D, and F represent SD for n ≥ 3 independent experiments and p < 0.05 for all data points that compare SMF-treated samples with the matched untreated controls.