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

Han, Bing, Baoan Ji, and Craig D. Logsdon. CCK independently activates intracellular trypsinogen and NF-kB in rat pancreatic acinar cells. Am J Physiol Cell Physiol 49: C465–C472, 2001.—In the cholecystokinin (CCK) hyperstimulation model of acute pancreatitis, two early intracellular events, activation of trypsinogen and activation of nuclear factor-kB (NF-kB), are thought to be important in the development of the disease. In this study, the relationship between these two events was investigated. NF-kB activity was monitored by using a DNA binding assay and mob-1 chemokine gene expression. Intracellular trypsin activity was measured by using a fluorogenic substrate. Protease inhibitors including FUT-175, Pefabloc, and E-64d prevented CCK stimulation of intracellular trypsinogen and NF-kB activation. Likewise, the NF-kB inhibitors pyrrolidine dithiocarbamate and N-acetyl-L-cysteine inhibited CCK stimulation of NF-kB and intracellular trypsinogen activation. These results suggested a possible codependency of these two events. However, CCK stimulated NF-kB activation in Chinese hamster ovary-CCKA cells, which do not express trypsinogen, indicating that trypsin is not necessary for CCK activation of NF-kB. Furthermore, adenovirus-mediated expression in acinar cells of active p65 subunits to stimulate NF-kB, or of inhibitory kB-a molecules to inhibit NF-kB, did not affect either basal or CCK-mediated trypsinogen activation. Thus trypsinogen and NF-kB activation are independent events stimulated by CCK.