Open AccessProtein kinase D1 mediates NF-κB activation induced by cholecystokinin and cholinergic signaling in pancreatic acinar cells
Author(s) -
Jingzhen Yuan,
Aurelia Lugea,
Ling Zheng,
Ilya Gukovsky,
Mouad Edderkaoui,
Enrique Rozengurt,
Stephen J. Pandol
Publication year - 2008
Publication title -
american journal of physiology. gastrointestinal and liver physiology/american journal of physiology: gastrointestinal and liver physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.644
H-Index - 169
eISSN - 1522-1547
pISSN - 0193-1857
DOI - 10.1152/ajpgi.90452.2008
Subject(s) - protein kinase c , cholecystokinin , acinar cell , cholinergic , endocrinology , medicine , chemistry , kinase , signal transduction , protein kinase a , microbiology and biotechnology , biology , pancreas , receptor
The transcription factor NF-kappaB plays a critical role in inflammatory and cell death responses during acute pancreatitis. Previous studies in our laboratory demonstrated that protein kinase C (PKC) isoforms PKCdelta and epsilon are key regulators of NF-kappaB activation induced by cholecystokinin-8 (CCK-8), tumor necrosis factor-alpha, and ethanol. However, the downstream participants in regulating NF-kappaB activation in exocrine pancreas remain poorly understood. Here, we demonstrate that protein kinase D1 (PKD1) is a key downstream target of PKCdelta and PKCepsilon in pancreatic acinar cells stimulated by two major secretagogues, CCK-8 and the cholinergic agonist carbachol (CCh), and that PKD1 is necessary for NF-kappaB activation induced by CCK-8 and CCh. Both CCK-8 and CCh dose dependently induced a rapid and striking activation of PKD1 in rat pancreatic acinar cells, as measured by in vitro kinase assay and by phosphorylation at PKD1 activation loop (Ser744/748) or autophosphorylation site (Ser916). The phosphorylation and activation of PKD1 correlated with NF-kappaB activity stimulated by CCK-8 or CCh, as measured by NF-kappaB DNA binding. Either inhibition of PKCdelta or epsilon by isoform-specific inhibitory peptides, genetic deletion of PKCdelta and epsilon in pancreatic acinar cells, or knockdown of PKD1 by using small interfering RNAs in AR42J cells resulted in a marked decrease in PKD1 and NF-kappaB activation stimulated by CCK-8 or CCh. Conversely, overexpression of PKD1 resulted in augmentation of CCK-8- and CCh-stimulated NF-kappaB activation. Finally, the kinetics of PKD1 and NF-kappaB activation during cerulein-induced rat pancreatitis showed that both PKD1 and NF-kappaB activation were early events during acute pancreatitis and that their time courses of response were similar. Our results identify PKD1 as a novel early convergent point for PKCdelta and epsilon in the signaling pathways mediating NF-kappaB activation in pancreatitis.