Figure 5.

Ethanol upregulates ATG4B through inhibiting its degradation by caspases. Mouse pancreatic acinar cells were incubated with and without 100 mM EtOH for 4 h in the presence or absence of the pan-caspase inhibitor zVAD-fmk (50 µM), proteasomal inhibitor MG-132 (20 µM), apoptosis activator Ridaifen B (RidB; 5 µM), or calpain inhibitor ALLN (50 µM). CCK (100 pM) was added to the cells for the last 30 min of incubation. A–C, E, and F: ATG4B mRNA and protein levels were analyzed by qPCR and IB. Densitometric quantification of ATG4B band (C) was done as described in Fig. 1. D and G: Caspase-3-like (DEVDase) activity was measured with a fluorogenic assay. Values are means ± SE; each symbol represents an individual acinar cell preparation (n = 3–9/condition). *P < 0.05, **P < 0.01, ***P < 0.001; one-way ANOVA with Tukey’s multiple comparison test. CCK, cholecystokinin; EtOH, ethanol; IB, immunoblot.