Figure 4

JNK mediates SNAP-induced apoptosis but is also strongly induced by early non-apoptotic mPT. In A eosinophils were incubated in the presence or absence of 1 mM SNAP, 1 mM penicillamine and/or 10 pM GM-CSF for indicated times and lysed for western blotting. pJNK and total JNK levels were normalized against 0 min GM-CSF (10 pM) sample. Total JNK was used as loading control and shown are 54 kDa pJNK and total JNK. * indicates p < 0.05 and ** p < 0.01 as compared with eosinophils stimulated with GM-CSF and penicillamine for the corresponding time, n = 7. Untreated cells were compared to 0 min GM-CSF sample, n = 5. In B, eosinophils were preincubated with bongkrekic acid for 2 h before adding SNAP, penicillamine and/or GM-CSF. Incubation was continued for 2 h before cell lysis and western blotting. Shown are mean ± SEM of 6 individual experiments. In C, time-points shown below the columns refer to the addition times of solvent, SP600125 (10 μM) or its negative control (10 μM). Time zero represents the time of adding GM-CSF (10 pM) and SNAP (1 mM) or penicillamine (1 mM). Total incubation time was 40 h and DNA fragmentation assay was used for determination of apoptosis. Values are mean ± SEM of 5 individual experiments. * indicates p < 0.05 and ** p < 0.01 versus respective control.