The specific objectives of the present grant proposal are to determine the role of chymotrypsin C (CTRC) in the regulation of digestive enzyme activation and degradation and to investigate the mechanism(s) by which CTRC mutants act as risk factors for chronic pancreatitis in humans. This project forms a part of a broad, long-term research program on the molecular pathomechanism of genetic risk factors associated with human chronic pancreatitis. The studies combine biochemical and cell biological approaches with data obtained from human genetic association studies to formulate a molecular disease model that underlies chronic pancreatitis. According to our working hypothesis chymotrypsin C is an essential regulator of digestive enzyme activation and degradation and mutation-induced defects in this regulatory function predisposes to chronic pancreatitis. An alternative hypothesis will be also explored, which suggests that intracellular misfolding of CTRC mutants would elicit endoplasmic reticulum stress;induce the unfolded protein response and trigger the inflammatory process through activation of nuclear factor ?B. Thus, a direct link might be established between mutations in the CTRC gene and pancreatic inflammation.

Public Health Relevance

The present grant proposal intends to characterize a novel genetic risk factor for chronic pancreatitis, an often debilitating and potentially fatal human disease. We wish to find out why mutations in the digestive enzyme chymotrypsin C can increase the risk of chronic pancreatitis in humans. The results can advance the development of novel diagnostic and therapeutic interventions for human pancreatitis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK082412-04
Application #
8250401
Study Section
Clinical and Integrative Gastrointestinal Pathobiology Study Section (CIGP)
Program Officer
Serrano, Jose
Project Start
2009-04-01
Project End
2014-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
4
Fiscal Year
2012
Total Cost
$346,405
Indirect Cost
$133,233
Name
Boston University
Department
Biochemistry
Type
Schools of Dentistry
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Szabó, András; Radisky, Evette S; Sahin-Tóth, Miklós (2014) Zymogen activation confers thermodynamic stability on a key peptide bond and protects human cationic trypsin from degradation. J Biol Chem 289:4753-61
Szabó, András; Salameh, Moh'd A; Ludwig, Maren et al. (2014) Tyrosine sulfation of human trypsin steers S2' subsite selectivity towards basic amino acids. PLoS One 9:e102063
Németh, Balázs Csaba; Sahin-Tóth, Miklós (2014) Human cationic trypsinogen (PRSS1) variants and chronic pancreatitis. Am J Physiol Gastrointest Liver Physiol 306:G466-73
Beer, Sebastian; Sahin-Toth, Miklos (2014) Exonic variants affecting pre-mRNA splicing add to genetic burden in chronic pancreatitis. Gut 63:860-1
Schnur, Andrea; Beer, Sebastian; Witt, Heiko et al. (2014) Functional effects of 13 rare PRSS1 variants presumed to cause chronic pancreatitis. Gut 63:337-43
Batra, Jyotica; Szabo, Andras; Caulfield, Thomas R et al. (2013) Long-range electrostatic complementarity governs substrate recognition by human chymotrypsin C, a key regulator of digestive enzyme activation. J Biol Chem 288:9848-59
Geisz, Andrea; Hegyi, Peter; Sahin-Toth, Miklos (2013) Robust autoactivation, chymotrypsin C independence and diminished secretion define a subset of hereditary pancreatitis-associated cationic trypsinogen mutants. FEBS J 280:2888-99
Witt, Heiko; Beer, Sebastian; Rosendahl, Jonas et al. (2013) Variants in CPA1 are strongly associated with early onset chronic pancreatitis. Nat Genet 45:1216-20
Beer, Sebastian; Zhou, Jiayi; Szabo, Andras et al. (2013) Comprehensive functional analysis of chymotrypsin C (CTRC) variants reveals distinct loss-of-function mechanisms associated with pancreatitis risk. Gut 62:1616-24
Nemeth, Balazs Csaba; Wartmann, Thomas; Halangk, Walter et al. (2013) Autoactivation of mouse trypsinogens is regulated by chymotrypsin C via cleavage of the autolysis loop. J Biol Chem 288:24049-62

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