Cloning and Expression of Mouse IP15 Interferon-inducible Protein 15), a New Gene Activated in Pancreas during Acute Pancreatitis that Inhibits Cell Proliferation.

ROPOLO A; GRASSO D; PARDO R; CERQUETTI MC; IOVANNA JL; VACCARO MI

New Orleans, LA, USA.

Congreso; Digestive Disease Week and the 105th Annual Meeting of the American Gastroenterological Association; 2004

American Gastroenterological Association

Acute pancreatitis is the most frequent disease of the pancreas. During the acute phase of pancreatitis, harmful pancreatic enzyme expression is reduced. However, other genes are strongly activated. These phenotypic changes might enable the pancreas to protect itself against the acute attack of pancreatitis or, conversely, participate in the pathophysiological mechanism of the disease. The aim of our research is to characterize at the molecular level the pancreatic emergency program set up in response to pancreatitis. We have used a quantitative fluorescent cDNA microarray hybridization approach to identify pancreatic genes induced in pancreatic cells by acute pancreatitis in the mouse. Here, we describe the cloning, sequencing, and expression analysis of a gene, named IP15, whose activation is related to the acute phase of experimental pancreatitis. Analysis of its structure indicated that this gene is interferon-inducible and encodes a putative trans-membrane protein of 137 amino acids long, with a theoretical pI of 7.50 and a predicted molecular weight of 14.954 Da. In vivo studies on swiss mice showed that IP15 is strongly activated in pancreas early during caerulein treatment. Northern blot analysis of pancreas tissue with the IP15 cDNA probe showed maximal expression 3 hours after cerulein administration. In situ hybridization of the IP15 mRNA with a digoxigenin labeled cRNA probe on pancreatic tissue from mouse with acute pancreatitis showed that the expression is restricted to the acinar cell. Interestingly, IP15 mRNA was also expressed in intestine during the early stages of Salmonella typhimurium infection. In vitro studies using NIH 3T3 cells showed that IP15 expression is induced by INF-alpha and it is not activated by stress treatments like H2O2 or heat shock. Cells expressing IP15/V5 have less capacity to develop colonies after appropriate antibiotic selection. Hela cells transfected with pCDNA4-IP15 yielded 46.8% surviving colonies as compared to the pCDNA4 empty transfected cells (100%). In the same cell lines, we followed the growth and death rate during a 5 day period. IP15-expressing cells showed significantly lower (p<0.01) proliferation rate than control cells. In conclusion, we identified a new interferon-inducible gene that is activated in pancreas during the acute phase of pancreatitis and whose expression inhibits cell proliferation.