Cholecystokinin Activates Pancreatic Calcineurin-NFAT Signaling In Vitro and In Vivo

Abstract

Elevated endogenous cholecystokinin (CCK) release induced by protease inhibitors leads to pancreatic growth. This response has been shown to be mediated by the phosphatase calcineurin, but its downstream effectors are unknown. Here we examined activation of calcineurin-regulated nuclear factor of activated T-cells (NFATs) in isolated acinar cells, as well as in an in vivo model of pancreatic growth. Western blotting of endogenous NFATs and confocal imaging of NFATc1-GFP in pancreatic acini showed that CCK dose-dependently stimulated NFAT translocation from the cytoplasm to the nucleus within 0.5-1 h. This shift in localization correlated with CCK-induced activation of NFAT-driven luciferase reporter and was similar to that induced by a calcium ionophore and constitutively active calcineurin. The effect of CCK was dependent on calcineurin, as these changes were blocked by immunosuppressants FK506 and CsA and by overexpression of the endogenous protein inhibitor CAIN. Parallel NFAT activation took place in vivo. Pancreatic growth was accompanied by an increase in nuclear NFATs and subsequent elevation in expression of NFAT-luciferase in the pancreas, but not in organs unresponsive to CCK. The changes also required calcineurin, as they were blocked by FK506. We conclude that CCK activates NFATs in a calcineurin-dependent manner, both in vitro and in vivo.

Bile Acids Induce Pancreatic Acinar Cell Injury and Pancreatitis by Activating Calcineurin

“…NFAT-Luciferase Activity Assay-Acinar cells were infected with Ad-NFAT-luciferase following a previously described procedure (26). The construct includes a luciferase gene placed downstream of an IL-4 promoter that contains nine tandem NFAT binding sites.…”

Profiling CCK-mediated pancreatic growth: the dynamic genetic program and the role of STATs as potential regulators

“…We investigated genes upregulated at any point in the course of our 1-8 h profile of pancreatic growth (Ն3-fold induction vs. fasting and q Յ 0.04 -0.06), yielding a set of 314 genes. In addition, we also used a previously defined set of 51 probes, representing 38 unique CN-dependent genes (10). Analyzing the two groups in conjunction via MCM, we showed associations with growth factor activity, cytoskeletal organization and apoptosis, NF-B and Jak-STAT signaling, as well as two literature-derived concepts related to differentiation (Fig.…”

“…This concept is not without precedent in the exocrine pancreas. We have shown that NFATs, known to be involved in T-cell differentiation and cytokine production (25), are activated in the course of CCK-mediated pancreatic growth (10). Furthermore, a key transcriptional effector of microbial and cytokine-induced signaling, NF-B, has now been shown to be activated in pancreatitis and may be an important determinant of disease severity (34).…”

“…In addition, rapamycin, a well-known inhibitor of mTOR, blocks CCKinduced pancreatic growth and acinar cell division (3). Finally, CCK activates CN and its downstream transcriptional effector nuclear NFATs, both in vivo and in isolated acini (10). CN is necessary for pancreatic growth, as administration of its inhibitors FK506 and cyclosporin A leads to near complete ablation of this response (41).…”

The Compatibility of Christianity and Socialism in the Context of the Kress Controversy of 1905 in Milwaukee

“…68 important social institution in the lives of its members," the Catholics must have felt that all other alternatives were exhausted or that the priests exaggerated the evils of Socialism. 73 For Milwaukee Catholics to break with tradition and the focal point of their lives was unprecedented and makes their political shift all the more dramatic. The 1910 election, and the Catholics' support of the SocialDemocratic Party, demonstrates the extent to which "the gap between cleric and lay had only widened."…”