Cholecystokinin activates pancreatic calcineurin-NFAT signaling in vitro and in vivo.
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.
Gurda
Grzegorz T
GT
Department of Molecular and Integrative Physiology, The University of Michigan Medical School, Ann Arbor, MI 48109-0622, USA. ggurda@umich.edu
Guo
LiLi
L
Lee
Sae-Hong
SH
Molkentin
Jeffery D
JD
Williams
John A
JA
D000818:Animals; D019703:Calcineurin / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002469:Cell Separation; D002766:Cholecystokinin / Q000494:pharmacology*; D004952:Esters; D016670:Gabexate / Q000031:analogs & derivatives / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006146:Guanidines; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D046790:Pancreas, Exocrine / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D015533:Transcriptional Activation / Q000187:drug effects
D004952:Esters; D006146:Guanidines; D050778:NFATC Transcription Factors; D011993:Recombinant Fusion Proteins; C034532:camostat; D049452:Green Fluorescent Proteins; D016670:Gabexate; D002766:Cholecystokinin; D019703:Calcineurin