The broad, long-term objectives of this grant proposal are to understand the molecular mechanisms of genetic risk factors associated with chronic hereditary pancreatitis in humans. The studied genetic alterations include mutations of the cationic trypsinogen (PRSS1) and pro-carboxypeptidase A1 (CPA1). The research design combines biochemical and cell biological approaches with data obtained from human genetic association studies to formulate a disease model that can explain the higher susceptibility of mutation carriers to chronic pancreatitis. We hypothesize that genetic risk in chronic pancreatitis is mediated via two independent pathological pathways, both of which can result in acinar cell damage and death. In the trypsin-dependent pathological pathway intracellular autoactivation of trypsinogen to active trypsin causes acinar cell apoptosis;whereas in the misfolding-dependent pathological pathway retention of misfolded mutant proenzymes induces endoplasmic reticulum stress, which can trigger apoptotic cell death. In the next funding period, the following specific aims will be studied. (1) Acinar cell damage caused by intracellular autoactivation of cationic trypsinogen (PRSS1) mutants;(2) Misfolding of cationic trypsinogen (PRSS1) mutants and endoplasmic reticulum stress (3) Analysis of the enzymatic and cellular effects of novel CPA1 mutations associated with chronic pancreatitis.

Public Health Relevance

The present grant proposal investigates how gene mutations in digestive enzymes cause hereditary pancreatitis, an inherited, progressive inflammatory disease of the pancreas. Results from this study can advance the development of novel diagnostic and therapeutic interventions for all forms of human pancreatitis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK058088-12
Application #
8286409
Study Section
Clinical, Integrative and Molecular Gastroenterology Study Section (CIMG)
Program Officer
Serrano, Jose
Project Start
2000-07-01
Project End
2014-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
12
Fiscal Year
2012
Total Cost
$336,281
Indirect Cost
$130,856
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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