Figure 3

Down-regulation of cav-1 expression protects against cytokine mixture-induced beta cell apoptosis. (a) Cav-1 mRNA was measured after transfection with cav-1 siRNA at various concentrations (5, 10, 25, and 50 μM) for 24 h. (b) INS-1 cells were transfected CON siRNA (10 μM) or Cav-1 siRNA (10 μM) for 24 h. The amount of cav-1 protein was determined by western blot analysis after 24 h incubation with the cytokine mixture (CM; IL-1β 20 ng/ml, TNFα 20 ng/ml). (c) The densities of western blot signals were measured, and the relative expression levels were normalized to that of actin. (d) Cells were transfected with CON siRNA or Cav-1 siRNA for 24 h, followed by CM treatment. After 24 h, the cells were harvested and stained with Annexin V/propidium iodide, and apoptotic cells were evaluated by flow cytometry. (e) Quantitative data demonstrating the Annexin-V-FITC⁺ cells (%) (lower right quadrant). Values are means ± SEM from triplicate experiments, + p < 0.05 vs. 0 μM, *p < 0.05 vs. CON siRNA treated with CON, ^#p < 0.05 vs. CON siRNA treated with CM.