IL-1β-Induced Accumulation of Amyloid: Macroautophagy in Skeletal Muscle Depends on ERK

Figure 4

ERK inhibition diminishes amyloid formation and reduces autophagy. Immunofluorescence analysis revealed an increase in thioflavin-S fluorescence in human myoblasts incubated with IL-1β and IFN-γ for 48 hours. This was reversed after inhibition of the ERK pathway via PD98059. IL-1β and IFN-γ induced accumulation of autophagosomes in GFP-LC3-transfected rhabdomyosarcoma cells. Inhibition of the ERK pathway led to reduced autophagy. Quantitative greyscale analysis was performed using Image J and results are shown as standard error of mean of three independent experiments. Exposure of human myoblasts to IL-1β and IFN-γ led to an increased cell death, demonstrated by propidium iodide (PI) staining. Treatment with the ERK inhibitor PD98059 partially prevented cell death. Quantitative greyscale analysis was performed using Image J and results are shown as standard error of mean of three independent experiments. and .