Korean J Gastroenterol.
2002 Nov;40(5):326-333.
The Role of Heat Shock Protein 70 in the Pancreatic Trypsinogen Activation: Studies in Hsp70.1 Knock-out Mice
- Affiliations
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- 1Department of Internal Medicine and Biochemistry, Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea. yongtkim@plaza.snu.ac.kr
- 2Ilchun Molecular Medicine Institute Medical Research Center, Seoul National University College of Medicine, Seoul, Korea.
Abstract
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BACKGROUND/AIMS: Heat shock proteins (Hsps) are expressed in the cell as a response to the external stimulation such as heat. There are some reports that the Hsp (i.e. Hsp70) is involved in pancreatitis. However, the role of Hsp70 in experimental pancreatitis is not clear yet. To elucidate the role of Hsp70 in experimental pancreatitis, we carried out animal studies using a knock-out model.
METHODS
We used FVB/NJ wild type mice and homozygous Hsp70.1 knock-out (Hsp70.1-/-) mice, in which Hsp70.3, another Hsp70 gene, was intact. They were divided into 4 groups each according to treatments (with or without hyperthermia and with or without cerulein). After the pancreas was homogenized, trypsin activities, protein expression levels, and protein kinase activities were measured.
RESULTS
Basal pancreatic trypsin activities were more elevated in Hsp70.1-/- mice than wild type mice. However, there was no pathologic evidence of acute pancreatitis in Hsp70.1-/- mice. When cerulein was administered, basally elevated trypsin activity did not increase further in Hsp70.1-/- mice, and the pancreas showed the same degree of pancreatitis as wild type mice. The expression level of Hsp70 is higher in wild type mice than in Hsp70.1-/- mice after either hyperthermia or cerulein stimulation. Hyperthermia prevented cerulein-induced trypsinogen activation in both groups. Phosphorylation of extracellular signal-regulated protein kinase (ERK) increased by either heat or cerulein stimulation alone. However, heat pretreatment suppressed cerulein-induced ERK phosphorylation in both groups.
CONCLUSIONS
Hsp70 suppresses spontaneous trypsinogen activation in mice.