NFATc3 Regulates Trypsinogen Activation, Neutrophil Recruitment, and Tissue Damage in Acute Pancreatitis in Mice.

Summary, in English

BACKGROUND & AIMS:

The signaling mechanisms that regulate trypsinogen activation and inflammation in acute pancreatitis (AP) are unclear. We explored the involvement of the calcium- and calcineurin-dependent transcription factor nuclear factor of activated T-cells (NFAT) in development of AP in mice.



METHODS:

We measured levels of myeloperoxidase and macrophage inflammatory protein-2 (CXCL2), trypsinogen activation, and tissue damage in the pancreas 24 h after induction of AP by retrograde infusion of taurocholate into the pancreatic ducts of wild-type, NFAT luciferase reporter (NFAT-luc), and NFATc3-deficient mice. We isolated acinar cells and measured NFAT nuclear accumulation, trypsin activity, and expression of NFAT-regulated genes.



RESULTS:

Infusion of taurocholate increased the transcriptional activity of NFAT in the pancreas, aorta, lung, and spleen of NFAT-luc mice. Inhibition of NFAT with A-285222 blocked taurocholate-induced activation of NFAT in all organs. A-285222 also reduced taurocholate-induced increases in levels of amylase, myeloperoxidase and CXCL2; activation of trypsinogen; necrosis of acinar cells; edema; leukocyte infiltration; and hemorrhage in the pancreas. NFATc3-deficient mice were protected from these effects of taurocholate. Similar results were obtained using an L-arginine-induced model of AP. Reverse transcriptase PCR and confocal immunofluorescence analyses showed that NFATc3 is expressed by acinar cells. NFATc3 expression was activated by stimuli that increase intracellular calcium; activation was prevented by the calcineurin blocker cyclosporine A or A-285222. Activation of trypsinogen by secretagogues in acinar cells was prevented by pharmacologic inhibition of NFAT signaling or lack of NFATc3. A-285222 also reduced expression of inflammatory cytokines such as CXCL2 in acinar cells.



CONCLUSIONS:

NFATc3 regulates trypsinogen activation, inflammation, and pancreatic tissue damage during development of AP in mice, and might be a therapeutic target.