Heat shock protein 70 prevents secretagogue-induced cell injury in the pancreas by preventing intracellular trypsinogen activation
Lakshmi Bhagat, … , Michael L. Steer, Ashok K. Saluja
Lakshmi Bhagat, … , Michael L. Steer, Ashok K. Saluja
Published January 1, 2000
Citation Information: J Clin Invest. 2000;106(1):81-89. https://doi.org/10.1172/JCI8706.
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Article

Heat shock protein 70 prevents secretagogue-induced cell injury in the pancreas by preventing intracellular trypsinogen activation

Abstract

Rodents given a supramaximally stimulating dose of cholecystokinin or its analogue cerulein develop acute pancreatitis with acinar cell injury, pancreatic inflammation, and intrapancreatic digestive enzyme (i.e., trypsinogen) activation. Prior thermal stress is associated with heat shock protein 70 (HSP70) expression and protection against cerulein-induced pancreatitis. However, thermal stress can also induce expression of other HSPs. The current studies were performed using an in vitro system to determine whether HSP70 can actually mediate protection against pancreatitis and, if so, to define the mechanism underlying that protection. We show that in vitro exposure of freshly prepared rat pancreas fragments to a supramaximally stimulating dose of cerulein results in changes similar to those noted in cerulein-induced pancreatitis, i.e., intra-acinar cell trypsinogen activation and acinar cell injury. Short-term culture of the fragments results in HSP70 expression and loss of the pancreatitis-like changes noted after addition of cerulein. The culture-induced enhanced HSP70 expression can be prevented by addition of either the flavonoid antioxidant quercetin or an antisense oligonucleotide to HSP70. Under these latter conditions, addition of a supramaximally stimulating concentration of cerulein results in trypsinogen activation and acinar cell injury. These findings indicate that the protection against cerulein-induced pancreatitis that follows culture-induced (and possibly thermal) stress is mediated by HSP70. They suggest that the HSP acts by preventing trypsinogen activation within acinar cells.

Authors

Lakshmi Bhagat, Vijay P. Singh, Antti J. Hietaranta, Sudhir Agrawal, Michael L. Steer, Ashok K. Saluja

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Effect of incubation of pancreas fragments with quercetin or antisense/s...
Effect of incubation of pancreas fragments with quercetin or antisense/sense HSP70 oligonucleotides on HSP expression. (a) C0, freshly prepared pancreas fragments; C12, pancreas fragments after 12 hours of culture; Q, pancreas fragments after 12 hours of culture with quercetin (50 μM). HSP70 protein expression was evaluated by Western blotting, and relative optical densities are expressed as mean ± SEM for at least three separate experiments in each group. AP < 0.01 when quercetin-incubated fragments are compared with untreated 12-hour control fragments. (b) C0, freshly prepared pancreas fragments; C12, pancreas fragments after 12 hours of culture; S I, pancreas fragments incubated with sense oligonucleotide S I (1 μM) for 12 hours; AS I, pancreas fragments incubated with 14-mer antisense oligonucleotide AS I (1 μM) for 12 hours; S II, pancreas fragments incubated with sense oligonucleotide S II (1 μM) for 12 hours; AS II, pancreas fragments incubated with 18-mer antisense oligonucleotide AS II (1 μM) for 12 hours. Expression of indicated HSPs was assessed by Western blotting. Relative optical densities of HSP70 bands are expressed as mean ± SEM for at least three separate experiments in each group. AP < 0.01 when antisense oligonucleotide-incubated fragments are compared with untreated 12-hour control fragments.