CCK independently activates intracellular trypsinogen and NF-kappa B in rat pancreatic acinar cells

In the cholecystokinin (CCK) hyperstimulation model of acute pancreatitis, two early intracellular events, activation of trypsinogen and activation of nuclear factor-kappaB (NF-kappaB), are thought to be important in the deve lopment of the disease. In this study, the relationship between these two e vents was investigated. NF-kappaB activity was monitored by using a DNA bin ding assay and mob-1 chemokine gene expression. Intracellular trypsin activ ity was measured by using a fluorogenic substrate. Protease inhibitors incl uding FUT-175, Pefabloc, and E-64d prevented CCK stimulation of intracellul ar trypsinogen and NF-kappaB activation. Likewise, the NF-kappaB inhibitors pyrrolidine dithiocarbamate and N-acetyl-L-cysteine inhibited CCK stimulat ion of NF-kappaB and intracellular trypsinogen activation. These results su ggested a possible codependency of these two events. However, CCK stimulate d NF-kappaB activation in Chinese hamster ovary-CCKA cells, which do not ex press trypsinogen, indicating that trypsin is not necessary for CCK activat ion of NF-kappaB. Furthermore, adenovirus-mediated expression in acinar cel ls of active p65 subunits to stimulate NF-kappaB, or of inhibitory kappaB-a lpha molecules to inhibit NF-kappaB, did not affect either basal or CCK-med iated trypsinogen activation. Thus trypsinogen and NF-kappaB activation are independent events stimulated by CCK.