Acute pancreatitis is a common life-threatening disorder of the pancreas. Although there are several known etiologies, the mechanisms leading to the disease are unclear. However, we do know that irrespective of etiology an early step is the premature activation of digestive proenzymes (zymogens) within the pancreatic acinar cell. Our previous studies demonstrate that this activation requires a distinct pathologic rise in cytosolic Ca2+. However, the downstream effectors of the Ca2+ rise are not known. An important target of Ca2+ is the Ca2+/calmodulin-dependent serine/threonine phosphatase PP2B, or calcineurin. It has been associated with pancreatitis and also plays a role in pancreatic physiology. The hypothesis of this proposal is that calcineurin activation due to a rise in acinar cell Ca2+ mediates pathologic pancreatic zymogen activation. In this proposal, using a combination of pharmacologic and genetic strategies, we will (1) characterize the calcineurin isoforms expressed in the pancreatic acinar cell, (2) study the role of calcineurin in premature pancreatic zymogen activation in isolated pancreatic acinar cells, and (3) study the role of calcineurin in vivo on long term effects of pancreatitis. Our primary methods will be to use calcineurin inhibitors, CN isoform-specific knockout mice, and siRNA knockdown. In preliminary results, we have shown that (1) calcineurin A-alpha is distributed in the cytoplasm of pancreatic acinar cells and (2) calcineurin inhibition reduces premature zymogen activation without affecting acinar cell enzyme secretion. It is anticipated that these studies will provide new insight into the factors causing pancreatitis and may also suggest prophylactic treatment strategies that target calcineurin in the pancreas.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Small Research Grants (R03)
Project #
5R03DK078707-02
Application #
7591102
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Podskalny, Judith M,
Project Start
2008-06-01
Project End
2010-05-31
Budget Start
2009-06-01
Budget End
2010-05-31
Support Year
2
Fiscal Year
2009
Total Cost
$82,750
Indirect Cost
Name
Yale University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Reed, Anamika M; Husain, Sohail Z; Thrower, Edwin et al. (2011) Low extracellular pH induces damage in the pancreatic acinar cell by enhancing calcium signaling. J Biol Chem 286:1919-26
Hoque, Rafaz; Sohail, Muhammad; Malik, Ahsan et al. (2011) TLR9 and the NLRP3 inflammasome link acinar cell death with inflammation in acute pancreatitis. Gastroenterology 141:358-69
Orabi, Abrahim I; Shah, Ahsan U; Muili, Kamaldeen et al. (2011) Ethanol enhances carbachol-induced protease activation and accelerates Ca2+ waves in isolated rat pancreatic acini. J Biol Chem 286:14090-7
Orabi, Abrahim I; Shah, Ahsan U; Ahmad, Mahwish U et al. (2010) Dantrolene mitigates caerulein-induced pancreatitis in vivo in mice. Am J Physiol Gastrointest Liver Physiol 299:G196-204
Thrower, Edwin C; Gorelick, Fred S; Husain, Sohail Z (2010) Molecular and cellular mechanisms of pancreatic injury. Curr Opin Gastroenterol 26:484-9
Shah, Ahsan U; Sarwar, Amna; Orabi, Abrahim I et al. (2009) Protease activation during in vivo pancreatitis is dependent on calcineurin activation. Am J Physiol Gastrointest Liver Physiol 297:G967-73
Husain, Sohail; Thrower, Edwin (2009) Molecular and cellular regulation of pancreatic acinar cell function. Curr Opin Gastroenterol 25:466-71
Shah, Ahsan U; Grant, Wayne M; Latif, Sahibzada U et al. (2008) Cyclic AMP accelerates calcium waves in pancreatic acinar cells. Am J Physiol Gastrointest Liver Physiol 294:G1328-34
Thrower, Edwin; Husain, Sohail; Gorelick, Fred (2008) Molecular basis for pancreatitis. Curr Opin Gastroenterol 24:580-5